xref: /linux/drivers/tty/serial/sc16is7xx.c (revision d8b78066f4c9c8ec898bd4246fc4db31d476dd88)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * SC16IS7xx tty serial driver - common code
4  *
5  * Copyright (C) 2014 GridPoint
6  * Author: Jon Ringle <jringle@gridpoint.com>
7  * Based on max310x.c, by Alexander Shiyan <shc_work@mail.ru>
8  */
9 
10 #undef DEFAULT_SYMBOL_NAMESPACE
11 #define DEFAULT_SYMBOL_NAMESPACE SERIAL_NXP_SC16IS7XX
12 
13 #include <linux/bits.h>
14 #include <linux/clk.h>
15 #include <linux/delay.h>
16 #include <linux/device.h>
17 #include <linux/export.h>
18 #include <linux/gpio/consumer.h>
19 #include <linux/gpio/driver.h>
20 #include <linux/idr.h>
21 #include <linux/kthread.h>
22 #include <linux/mod_devicetable.h>
23 #include <linux/module.h>
24 #include <linux/property.h>
25 #include <linux/regmap.h>
26 #include <linux/sched.h>
27 #include <linux/serial_core.h>
28 #include <linux/serial.h>
29 #include <linux/string.h>
30 #include <linux/tty.h>
31 #include <linux/tty_flip.h>
32 #include <linux/uaccess.h>
33 #include <linux/units.h>
34 
35 #include "sc16is7xx.h"
36 
37 #define SC16IS7XX_MAX_DEVS		8
38 
39 /* SC16IS7XX register definitions */
40 #define SC16IS7XX_RHR_REG		(0x00) /* RX FIFO */
41 #define SC16IS7XX_THR_REG		(0x00) /* TX FIFO */
42 #define SC16IS7XX_IER_REG		(0x01) /* Interrupt enable */
43 #define SC16IS7XX_IIR_REG		(0x02) /* Interrupt Identification */
44 #define SC16IS7XX_FCR_REG		(0x02) /* FIFO control */
45 #define SC16IS7XX_LCR_REG		(0x03) /* Line Control */
46 #define SC16IS7XX_MCR_REG		(0x04) /* Modem Control */
47 #define SC16IS7XX_LSR_REG		(0x05) /* Line Status */
48 #define SC16IS7XX_MSR_REG		(0x06) /* Modem Status */
49 #define SC16IS7XX_SPR_REG		(0x07) /* Scratch Pad */
50 #define SC16IS7XX_TXLVL_REG		(0x08) /* TX FIFO level */
51 #define SC16IS7XX_RXLVL_REG		(0x09) /* RX FIFO level */
52 #define SC16IS7XX_IODIR_REG		(0x0a) /* I/O Direction
53 						* - only on 75x/76x
54 						*/
55 #define SC16IS7XX_IOSTATE_REG		(0x0b) /* I/O State
56 						* - only on 75x/76x
57 						*/
58 #define SC16IS7XX_IOINTENA_REG		(0x0c) /* I/O Interrupt Enable
59 						* - only on 75x/76x
60 						*/
61 #define SC16IS7XX_IOCONTROL_REG		(0x0e) /* I/O Control
62 						* - only on 75x/76x
63 						*/
64 #define SC16IS7XX_EFCR_REG		(0x0f) /* Extra Features Control */
65 
66 /* TCR/TLR Register set: Only if ((MCR[2] == 1) && (EFR[4] == 1)) */
67 #define SC16IS7XX_TCR_REG		(0x06) /* Transmit control */
68 #define SC16IS7XX_TLR_REG		(0x07) /* Trigger level */
69 
70 /* Special Register set: Only if ((LCR[7] == 1) && (LCR != 0xBF)) */
71 #define SC16IS7XX_DLL_REG		(0x00) /* Divisor Latch Low */
72 #define SC16IS7XX_DLH_REG		(0x01) /* Divisor Latch High */
73 
74 /* Enhanced Register set: Only if (LCR == 0xBF) */
75 #define SC16IS7XX_EFR_REG		(0x02) /* Enhanced Features */
76 #define SC16IS7XX_XON1_REG		(0x04) /* Xon1 word */
77 #define SC16IS7XX_XON2_REG		(0x05) /* Xon2 word */
78 #define SC16IS7XX_XOFF1_REG		(0x06) /* Xoff1 word */
79 #define SC16IS7XX_XOFF2_REG		(0x07) /* Xoff2 word */
80 
81 /* IER register bits */
82 #define SC16IS7XX_IER_RDI_BIT		BIT(0)   /* Enable RX data interrupt */
83 #define SC16IS7XX_IER_THRI_BIT		BIT(1)   /* Enable TX holding register
84 						  * interrupt */
85 #define SC16IS7XX_IER_RLSI_BIT		BIT(2)   /* Enable RX line status
86 						  * interrupt */
87 #define SC16IS7XX_IER_MSI_BIT		BIT(3)   /* Enable Modem status
88 						  * interrupt */
89 
90 /* IER register bits - write only if (EFR[4] == 1) */
91 #define SC16IS7XX_IER_SLEEP_BIT		BIT(4)   /* Enable Sleep mode */
92 #define SC16IS7XX_IER_XOFFI_BIT		BIT(5)   /* Enable Xoff interrupt */
93 #define SC16IS7XX_IER_RTSI_BIT		BIT(6)   /* Enable nRTS interrupt */
94 #define SC16IS7XX_IER_CTSI_BIT		BIT(7)   /* Enable nCTS interrupt */
95 
96 /* FCR register bits */
97 #define SC16IS7XX_FCR_FIFO_BIT		BIT(0)   /* Enable FIFO */
98 #define SC16IS7XX_FCR_RXRESET_BIT	BIT(1)   /* Reset RX FIFO */
99 #define SC16IS7XX_FCR_TXRESET_BIT	BIT(2)   /* Reset TX FIFO */
100 #define SC16IS7XX_FCR_RXLVLL_BIT	BIT(6)   /* RX Trigger level LSB */
101 #define SC16IS7XX_FCR_RXLVLH_BIT	BIT(7)   /* RX Trigger level MSB */
102 
103 /* FCR register bits - write only if (EFR[4] == 1) */
104 #define SC16IS7XX_FCR_TXLVLL_BIT	BIT(4)   /* TX Trigger level LSB */
105 #define SC16IS7XX_FCR_TXLVLH_BIT	BIT(5)   /* TX Trigger level MSB */
106 
107 /* IIR register bits */
108 #define SC16IS7XX_IIR_NO_INT_BIT	0x01		/* No interrupts pending */
109 #define SC16IS7XX_IIR_ID_MASK		GENMASK(5, 1)	/* Mask for the interrupt ID */
110 #define SC16IS7XX_IIR_THRI_SRC		0x02		/* TX holding register empty */
111 #define SC16IS7XX_IIR_RDI_SRC		0x04		/* RX data interrupt */
112 #define SC16IS7XX_IIR_RLSE_SRC		0x06		/* RX line status error */
113 #define SC16IS7XX_IIR_RTOI_SRC		0x0c		/* RX time-out interrupt */
114 #define SC16IS7XX_IIR_MSI_SRC		0x00		/* Modem status interrupt
115 							 * - only on 75x/76x
116 							 */
117 #define SC16IS7XX_IIR_INPIN_SRC		0x30		/* Input pin change of state
118 							 * - only on 75x/76x
119 							 */
120 #define SC16IS7XX_IIR_XOFFI_SRC		0x10		/* Received Xoff */
121 #define SC16IS7XX_IIR_CTSRTS_SRC	0x20		/* nCTS,nRTS change of state
122 							 * from active (LOW)
123 							 * to inactive (HIGH)
124 							 */
125 /* LCR register bits */
126 #define SC16IS7XX_LCR_LENGTH0_BIT	BIT(0)   /* Word length bit 0 */
127 #define SC16IS7XX_LCR_LENGTH1_BIT	BIT(1)   /* Word length bit 1
128 						  *
129 						  * Word length bits table:
130 						  * 00 -> 5 bit words
131 						  * 01 -> 6 bit words
132 						  * 10 -> 7 bit words
133 						  * 11 -> 8 bit words
134 						  */
135 #define SC16IS7XX_LCR_STOPLEN_BIT	BIT(2)   /* STOP length bit
136 						  *
137 						  * STOP length bit table:
138 						  * 0 -> 1 stop bit
139 						  * 1 -> 1-1.5 stop bits if
140 						  *      word length is 5,
141 						  *      2 stop bits otherwise
142 						  */
143 #define SC16IS7XX_LCR_PARITY_BIT	BIT(3)   /* Parity bit enable */
144 #define SC16IS7XX_LCR_EVENPARITY_BIT	BIT(4)   /* Even parity bit enable */
145 #define SC16IS7XX_LCR_FORCEPARITY_BIT	BIT(5)   /* 9-bit multidrop parity */
146 #define SC16IS7XX_LCR_TXBREAK_BIT	BIT(6)   /* TX break enable */
147 #define SC16IS7XX_LCR_DLAB_BIT		BIT(7)   /* Divisor Latch enable */
148 #define SC16IS7XX_LCR_WORD_LEN_5	(0x00)
149 #define SC16IS7XX_LCR_WORD_LEN_6	(0x01)
150 #define SC16IS7XX_LCR_WORD_LEN_7	(0x02)
151 #define SC16IS7XX_LCR_WORD_LEN_8	(0x03)
152 #define SC16IS7XX_LCR_CONF_MODE_A	SC16IS7XX_LCR_DLAB_BIT /* Special
153 								* reg set */
154 #define SC16IS7XX_LCR_CONF_MODE_B	0xBF                   /* Enhanced
155 								* reg set */
156 
157 /* MCR register bits */
158 #define SC16IS7XX_MCR_DTR_BIT		BIT(0)   /* DTR complement
159 						  * - only on 75x/76x
160 						  */
161 #define SC16IS7XX_MCR_RTS_BIT		BIT(1)   /* RTS complement */
162 #define SC16IS7XX_MCR_TCRTLR_BIT	BIT(2)   /* TCR/TLR register enable */
163 #define SC16IS7XX_MCR_LOOP_BIT		BIT(4)   /* Enable loopback test mode */
164 #define SC16IS7XX_MCR_XONANY_BIT	BIT(5)   /* Enable Xon Any
165 						  * - write enabled
166 						  * if (EFR[4] == 1)
167 						  */
168 #define SC16IS7XX_MCR_IRDA_BIT		BIT(6)   /* Enable IrDA mode
169 						  * - write enabled
170 						  * if (EFR[4] == 1)
171 						  */
172 #define SC16IS7XX_MCR_CLKSEL_BIT	BIT(7)   /* Divide clock by 4
173 						  * - write enabled
174 						  * if (EFR[4] == 1)
175 						  */
176 
177 /* LSR register bits */
178 #define SC16IS7XX_LSR_DR_BIT		BIT(0)   /* Receiver data ready */
179 #define SC16IS7XX_LSR_OE_BIT		BIT(1)   /* Overrun Error */
180 #define SC16IS7XX_LSR_PE_BIT		BIT(2)   /* Parity Error */
181 #define SC16IS7XX_LSR_FE_BIT		BIT(3)   /* Frame Error */
182 #define SC16IS7XX_LSR_BI_BIT		BIT(4)   /* Break Interrupt */
183 #define SC16IS7XX_LSR_BRK_ERROR_MASK \
184 	(SC16IS7XX_LSR_OE_BIT | \
185 	 SC16IS7XX_LSR_PE_BIT | \
186 	 SC16IS7XX_LSR_FE_BIT | \
187 	 SC16IS7XX_LSR_BI_BIT)
188 
189 #define SC16IS7XX_LSR_THRE_BIT		BIT(5)   /* TX holding register empty */
190 #define SC16IS7XX_LSR_TEMT_BIT		BIT(6)   /* Transmitter empty */
191 #define SC16IS7XX_LSR_FIFOE_BIT		BIT(7)   /* Fifo Error */
192 
193 /* MSR register bits */
194 #define SC16IS7XX_MSR_DCTS_BIT		BIT(0)   /* Delta CTS Clear To Send */
195 #define SC16IS7XX_MSR_DDSR_BIT		BIT(1)   /* Delta DSR Data Set Ready
196 						  * or (IO4)
197 						  * - only on 75x/76x
198 						  */
199 #define SC16IS7XX_MSR_DRI_BIT		BIT(2)   /* Delta RI Ring Indicator
200 						  * or (IO7)
201 						  * - only on 75x/76x
202 						  */
203 #define SC16IS7XX_MSR_DCD_BIT		BIT(3)   /* Delta CD Carrier Detect
204 						  * or (IO6)
205 						  * - only on 75x/76x
206 						  */
207 #define SC16IS7XX_MSR_CTS_BIT		BIT(4)   /* CTS */
208 #define SC16IS7XX_MSR_DSR_BIT		BIT(5)   /* DSR (IO4)
209 						  * - only on 75x/76x
210 						  */
211 #define SC16IS7XX_MSR_RI_BIT		BIT(6)   /* RI (IO7)
212 						  * - only on 75x/76x
213 						  */
214 #define SC16IS7XX_MSR_CD_BIT		BIT(7)   /* CD (IO6)
215 						  * - only on 75x/76x
216 						  */
217 
218 /*
219  * TCR register bits
220  * TCR trigger levels are available from 0 to 60 characters with a granularity
221  * of four.
222  * The programmer must program the TCR such that TCR[3:0] > TCR[7:4]. There is
223  * no built-in hardware check to make sure this condition is met. Also, the TCR
224  * must be programmed with this condition before auto RTS or software flow
225  * control is enabled to avoid spurious operation of the device.
226  */
227 #define SC16IS7XX_TCR_RX_HALT(words)	((((words) / 4) & 0x0f) << 0)
228 #define SC16IS7XX_TCR_RX_RESUME(words)	((((words) / 4) & 0x0f) << 4)
229 
230 /*
231  * TLR register bits
232  * If TLR[3:0] or TLR[7:4] are logical 0, the selectable trigger levels via the
233  * FIFO Control Register (FCR) are used for the transmit and receive FIFO
234  * trigger levels. Trigger levels from 4 characters to 60 characters are
235  * available with a granularity of four.
236  *
237  * When the trigger level setting in TLR is zero, the SC16IS74x/75x/76x uses the
238  * trigger level setting defined in FCR. If TLR has non-zero trigger level value
239  * the trigger level defined in FCR is discarded. This applies to both transmit
240  * FIFO and receive FIFO trigger level setting.
241  *
242  * When TLR is used for RX trigger level control, FCR[7:6] should be left at the
243  * default state, that is, '00'.
244  */
245 #define SC16IS7XX_TLR_TX_TRIGGER(words)	((((words) / 4) & 0x0f) << 0)
246 #define SC16IS7XX_TLR_RX_TRIGGER(words)	((((words) / 4) & 0x0f) << 4)
247 
248 /* IOControl register bits (Only 75x/76x) */
249 #define SC16IS7XX_IOCONTROL_LATCH_BIT	BIT(0)   /* Enable input latching */
250 #define SC16IS7XX_IOCONTROL_MODEM_A_BIT	BIT(1)   /* Enable GPIO[7:4] as modem A pins */
251 #define SC16IS7XX_IOCONTROL_MODEM_B_BIT	BIT(2)   /* Enable GPIO[3:0] as modem B pins */
252 #define SC16IS7XX_IOCONTROL_SRESET_BIT	BIT(3)   /* Software Reset */
253 
254 /* EFCR register bits */
255 #define SC16IS7XX_EFCR_9BIT_MODE_BIT	BIT(0)   /* Enable 9-bit or Multidrop
256 						  * mode (RS485) */
257 #define SC16IS7XX_EFCR_RXDISABLE_BIT	BIT(1)   /* Disable receiver */
258 #define SC16IS7XX_EFCR_TXDISABLE_BIT	BIT(2)   /* Disable transmitter */
259 #define SC16IS7XX_EFCR_AUTO_RS485_BIT	BIT(4)   /* Auto RS485 RTS direction */
260 #define SC16IS7XX_EFCR_RTS_INVERT_BIT	BIT(5)   /* RTS output inversion */
261 #define SC16IS7XX_EFCR_IRDA_MODE_BIT	BIT(7)   /* IrDA mode
262 						  * 0 = rate upto 115.2 kbit/s
263 						  *   - Only 75x/76x
264 						  * 1 = rate upto 1.152 Mbit/s
265 						  *   - Only 76x
266 						  */
267 
268 /* EFR register bits */
269 #define SC16IS7XX_EFR_AUTORTS_BIT	BIT(6)   /* Auto RTS flow ctrl enable */
270 #define SC16IS7XX_EFR_AUTOCTS_BIT	BIT(7)   /* Auto CTS flow ctrl enable */
271 #define SC16IS7XX_EFR_XOFF2_DETECT_BIT	BIT(5)   /* Enable Xoff2 detection */
272 #define SC16IS7XX_EFR_ENABLE_BIT	BIT(4)   /* Enable enhanced functions
273 						  * and writing to IER[7:4],
274 						  * FCR[5:4], MCR[7:5]
275 						  */
276 #define SC16IS7XX_EFR_SWFLOW3_BIT	BIT(3)
277 #define SC16IS7XX_EFR_SWFLOW2_BIT	BIT(2)
278 						 /*
279 						  * SWFLOW bits 3 & 2 table:
280 						  * 00 -> no transmitter flow
281 						  *       control
282 						  * 01 -> transmitter generates
283 						  *       XON2 and XOFF2
284 						  * 10 -> transmitter generates
285 						  *       XON1 and XOFF1
286 						  * 11 -> transmitter generates
287 						  *       XON1, XON2, XOFF1 and
288 						  *       XOFF2
289 						  */
290 #define SC16IS7XX_EFR_SWFLOW1_BIT	BIT(1)
291 #define SC16IS7XX_EFR_SWFLOW0_BIT	BIT(0)
292 						 /*
293 						  * SWFLOW bits 1 & 0 table:
294 						  * 00 -> no received flow
295 						  *       control
296 						  * 01 -> receiver compares
297 						  *       XON2 and XOFF2
298 						  * 10 -> receiver compares
299 						  *       XON1 and XOFF1
300 						  * 11 -> receiver compares
301 						  *       XON1, XON2, XOFF1 and
302 						  *       XOFF2
303 						  */
304 #define SC16IS7XX_EFR_FLOWCTRL_BITS	(SC16IS7XX_EFR_AUTORTS_BIT | \
305 					SC16IS7XX_EFR_AUTOCTS_BIT | \
306 					SC16IS7XX_EFR_XOFF2_DETECT_BIT | \
307 					SC16IS7XX_EFR_SWFLOW3_BIT | \
308 					SC16IS7XX_EFR_SWFLOW2_BIT | \
309 					SC16IS7XX_EFR_SWFLOW1_BIT | \
310 					SC16IS7XX_EFR_SWFLOW0_BIT)
311 
312 
313 /* Misc definitions */
314 #define SC16IS7XX_FIFO_SIZE		(64)
315 #define SC16IS7XX_GPIOS_PER_BANK	4
316 
317 #define SC16IS7XX_RECONF_MD		BIT(0)
318 #define SC16IS7XX_RECONF_IER		BIT(1)
319 #define SC16IS7XX_RECONF_RS485		BIT(2)
320 
321 struct sc16is7xx_one_config {
322 	unsigned int			flags;
323 	u8				ier_mask;
324 	u8				ier_val;
325 };
326 
327 struct sc16is7xx_one {
328 	struct uart_port		port;
329 	struct regmap			*regmap;
330 	struct mutex			efr_lock; /* EFR registers access */
331 	struct kthread_work		tx_work;
332 	struct kthread_work		reg_work;
333 	struct kthread_delayed_work	ms_work;
334 	struct sc16is7xx_one_config	config;
335 	unsigned char			buf[SC16IS7XX_FIFO_SIZE]; /* Rx buffer. */
336 	unsigned int			old_mctrl;
337 	u8				old_lcr; /* Value before EFR access. */
338 	bool				irda_mode;
339 };
340 
341 struct sc16is7xx_port {
342 	const struct sc16is7xx_devtype	*devtype;
343 	struct clk			*clk;
344 #ifdef CONFIG_GPIOLIB
345 	struct gpio_chip		gpio;
346 	unsigned long			gpio_valid_mask;
347 #endif
348 	u8				mctrl_mask;
349 	struct kthread_worker		kworker;
350 	struct task_struct		*kworker_task;
351 	struct sc16is7xx_one		p[];
352 };
353 
354 static DEFINE_IDA(sc16is7xx_lines);
355 
356 static struct uart_driver sc16is7xx_uart = {
357 	.owner		= THIS_MODULE,
358 	.driver_name    = SC16IS7XX_NAME,
359 	.dev_name	= "ttySC",
360 	.nr		= SC16IS7XX_MAX_DEVS,
361 };
362 
363 #define to_sc16is7xx_one(p,e)	((container_of((p), struct sc16is7xx_one, e)))
364 
365 static u8 sc16is7xx_port_read(struct uart_port *port, u8 reg)
366 {
367 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
368 	unsigned int val = 0;
369 
370 	regmap_read(one->regmap, reg, &val);
371 
372 	return val;
373 }
374 
375 static void sc16is7xx_port_write(struct uart_port *port, u8 reg, u8 val)
376 {
377 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
378 
379 	regmap_write(one->regmap, reg, val);
380 }
381 
382 static void sc16is7xx_fifo_read(struct uart_port *port, u8 *rxbuf, unsigned int rxlen)
383 {
384 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
385 
386 	regmap_noinc_read(one->regmap, SC16IS7XX_RHR_REG, rxbuf, rxlen);
387 }
388 
389 static void sc16is7xx_fifo_write(struct uart_port *port, u8 *txbuf, u8 to_send)
390 {
391 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
392 
393 	/*
394 	 * Don't send zero-length data, at least on SPI it confuses the chip
395 	 * delivering wrong TXLVL data.
396 	 */
397 	if (unlikely(!to_send))
398 		return;
399 
400 	regmap_noinc_write(one->regmap, SC16IS7XX_THR_REG, txbuf, to_send);
401 }
402 
403 static void sc16is7xx_port_update(struct uart_port *port, u8 reg,
404 				  u8 mask, u8 val)
405 {
406 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
407 
408 	regmap_update_bits(one->regmap, reg, mask, val);
409 }
410 
411 static void sc16is7xx_power(struct uart_port *port, int on)
412 {
413 	sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
414 			      SC16IS7XX_IER_SLEEP_BIT,
415 			      on ? 0 : SC16IS7XX_IER_SLEEP_BIT);
416 }
417 
418 /*
419  * In an amazing feat of design, the Enhanced Features Register (EFR)
420  * shares the address of the Interrupt Identification Register (IIR).
421  * Access to EFR is switched on by writing a magic value (0xbf) to the
422  * Line Control Register (LCR). Any interrupt firing during this time will
423  * see the EFR where it expects the IIR to be, leading to
424  * "Unexpected interrupt" messages.
425  *
426  * Prevent this possibility by claiming a mutex while accessing the EFR,
427  * and claiming the same mutex from within the interrupt handler. This is
428  * similar to disabling the interrupt, but that doesn't work because the
429  * bulk of the interrupt processing is run as a workqueue job in thread
430  * context.
431  */
432 static void sc16is7xx_efr_lock(struct uart_port *port)
433 {
434 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
435 
436 	mutex_lock(&one->efr_lock);
437 
438 	/* Backup content of LCR. */
439 	one->old_lcr = sc16is7xx_port_read(port, SC16IS7XX_LCR_REG);
440 
441 	/* Enable access to Enhanced register set */
442 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_CONF_MODE_B);
443 
444 	/* Disable cache updates when writing to EFR registers */
445 	regcache_cache_bypass(one->regmap, true);
446 }
447 
448 static void sc16is7xx_efr_unlock(struct uart_port *port)
449 {
450 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
451 
452 	/* Re-enable cache updates when writing to normal registers */
453 	regcache_cache_bypass(one->regmap, false);
454 
455 	/* Restore original content of LCR */
456 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, one->old_lcr);
457 
458 	mutex_unlock(&one->efr_lock);
459 }
460 
461 static void sc16is7xx_ier_clear(struct uart_port *port, u8 bit)
462 {
463 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
464 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
465 
466 	lockdep_assert_held_once(&port->lock);
467 
468 	one->config.flags |= SC16IS7XX_RECONF_IER;
469 	one->config.ier_mask |= bit;
470 	one->config.ier_val &= ~bit;
471 	kthread_queue_work(&s->kworker, &one->reg_work);
472 }
473 
474 static void sc16is7xx_ier_set(struct uart_port *port, u8 bit)
475 {
476 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
477 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
478 
479 	lockdep_assert_held_once(&port->lock);
480 
481 	one->config.flags |= SC16IS7XX_RECONF_IER;
482 	one->config.ier_mask |= bit;
483 	one->config.ier_val |= bit;
484 	kthread_queue_work(&s->kworker, &one->reg_work);
485 }
486 
487 static void sc16is7xx_stop_tx(struct uart_port *port)
488 {
489 	sc16is7xx_ier_clear(port, SC16IS7XX_IER_THRI_BIT);
490 }
491 
492 static void sc16is7xx_stop_rx(struct uart_port *port)
493 {
494 	sc16is7xx_ier_clear(port, SC16IS7XX_IER_RDI_BIT);
495 }
496 
497 const struct sc16is7xx_devtype sc16is74x_devtype = {
498 	.name		= "SC16IS74X",
499 	.nr_gpio	= 0,
500 	.nr_uart	= 1,
501 };
502 EXPORT_SYMBOL_GPL(sc16is74x_devtype);
503 
504 const struct sc16is7xx_devtype sc16is750_devtype = {
505 	.name		= "SC16IS750",
506 	.nr_gpio	= 8,
507 	.nr_uart	= 1,
508 };
509 EXPORT_SYMBOL_GPL(sc16is750_devtype);
510 
511 const struct sc16is7xx_devtype sc16is752_devtype = {
512 	.name		= "SC16IS752",
513 	.nr_gpio	= 8,
514 	.nr_uart	= 2,
515 };
516 EXPORT_SYMBOL_GPL(sc16is752_devtype);
517 
518 const struct sc16is7xx_devtype sc16is760_devtype = {
519 	.name		= "SC16IS760",
520 	.nr_gpio	= 8,
521 	.nr_uart	= 1,
522 };
523 EXPORT_SYMBOL_GPL(sc16is760_devtype);
524 
525 const struct sc16is7xx_devtype sc16is762_devtype = {
526 	.name		= "SC16IS762",
527 	.nr_gpio	= 8,
528 	.nr_uart	= 2,
529 };
530 EXPORT_SYMBOL_GPL(sc16is762_devtype);
531 
532 static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg)
533 {
534 	switch (reg) {
535 	case SC16IS7XX_RHR_REG:
536 	case SC16IS7XX_IIR_REG:
537 	case SC16IS7XX_LSR_REG:
538 	case SC16IS7XX_MSR_REG:
539 	case SC16IS7XX_TXLVL_REG:
540 	case SC16IS7XX_RXLVL_REG:
541 	case SC16IS7XX_IOSTATE_REG:
542 	case SC16IS7XX_IOCONTROL_REG:
543 		return true;
544 	default:
545 		return false;
546 	}
547 }
548 
549 static bool sc16is7xx_regmap_precious(struct device *dev, unsigned int reg)
550 {
551 	switch (reg) {
552 	case SC16IS7XX_RHR_REG:
553 		return true;
554 	default:
555 		return false;
556 	}
557 }
558 
559 static bool sc16is7xx_regmap_noinc(struct device *dev, unsigned int reg)
560 {
561 	return reg == SC16IS7XX_RHR_REG;
562 }
563 
564 /*
565  * Configure programmable baud rate generator (divisor) according to the
566  * desired baud rate.
567  *
568  * From the datasheet, the divisor is computed according to:
569  *
570  *              XTAL1 input frequency
571  *             -----------------------
572  *                    prescaler
573  * divisor = ---------------------------
574  *            baud-rate x sampling-rate
575  */
576 static int sc16is7xx_set_baud(struct uart_port *port, int baud)
577 {
578 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
579 	u8 lcr;
580 	unsigned int prescaler = 1;
581 	unsigned long clk = port->uartclk, div = clk / 16 / baud;
582 
583 	if (div >= BIT(16)) {
584 		prescaler = 4;
585 		div /= prescaler;
586 	}
587 
588 	/* Enable enhanced features */
589 	sc16is7xx_efr_lock(port);
590 	sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
591 			      SC16IS7XX_EFR_ENABLE_BIT,
592 			      SC16IS7XX_EFR_ENABLE_BIT);
593 	sc16is7xx_efr_unlock(port);
594 
595 	/* If bit MCR_CLKSEL is set, the divide by 4 prescaler is activated. */
596 	sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
597 			      SC16IS7XX_MCR_CLKSEL_BIT,
598 			      prescaler == 1 ? 0 : SC16IS7XX_MCR_CLKSEL_BIT);
599 
600 	mutex_lock(&one->efr_lock);
601 
602 	/* Backup LCR and access special register set (DLL/DLH) */
603 	lcr = sc16is7xx_port_read(port, SC16IS7XX_LCR_REG);
604 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
605 			     SC16IS7XX_LCR_CONF_MODE_A);
606 
607 	/* Write the new divisor */
608 	regcache_cache_bypass(one->regmap, true);
609 	sc16is7xx_port_write(port, SC16IS7XX_DLH_REG, div / 256);
610 	sc16is7xx_port_write(port, SC16IS7XX_DLL_REG, div % 256);
611 	regcache_cache_bypass(one->regmap, false);
612 
613 	/* Restore LCR and access to general register set */
614 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
615 
616 	mutex_unlock(&one->efr_lock);
617 
618 	return DIV_ROUND_CLOSEST((clk / prescaler) / 16, div);
619 }
620 
621 static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
622 				unsigned int iir)
623 {
624 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
625 	unsigned int lsr = 0, bytes_read, i;
626 	bool read_lsr = (iir == SC16IS7XX_IIR_RLSE_SRC) ? true : false;
627 	u8 ch, flag;
628 
629 	if (unlikely(rxlen >= sizeof(one->buf))) {
630 		dev_warn_ratelimited(port->dev,
631 				     "ttySC%i: Possible RX FIFO overrun: %d\n",
632 				     port->line, rxlen);
633 		port->icount.buf_overrun++;
634 		/* Ensure sanity of RX level */
635 		rxlen = sizeof(one->buf);
636 	}
637 
638 	while (rxlen) {
639 		/* Only read lsr if there are possible errors in FIFO */
640 		if (read_lsr) {
641 			lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
642 			if (!(lsr & SC16IS7XX_LSR_FIFOE_BIT))
643 				read_lsr = false; /* No errors left in FIFO */
644 		} else
645 			lsr = 0;
646 
647 		if (read_lsr) {
648 			one->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG);
649 			bytes_read = 1;
650 		} else {
651 			sc16is7xx_fifo_read(port, one->buf, rxlen);
652 			bytes_read = rxlen;
653 		}
654 
655 		lsr &= SC16IS7XX_LSR_BRK_ERROR_MASK;
656 
657 		port->icount.rx++;
658 		flag = TTY_NORMAL;
659 
660 		if (unlikely(lsr)) {
661 			if (lsr & SC16IS7XX_LSR_BI_BIT) {
662 				port->icount.brk++;
663 				if (uart_handle_break(port))
664 					continue;
665 			} else if (lsr & SC16IS7XX_LSR_PE_BIT)
666 				port->icount.parity++;
667 			else if (lsr & SC16IS7XX_LSR_FE_BIT)
668 				port->icount.frame++;
669 			else if (lsr & SC16IS7XX_LSR_OE_BIT)
670 				port->icount.overrun++;
671 
672 			lsr &= port->read_status_mask;
673 			if (lsr & SC16IS7XX_LSR_BI_BIT)
674 				flag = TTY_BREAK;
675 			else if (lsr & SC16IS7XX_LSR_PE_BIT)
676 				flag = TTY_PARITY;
677 			else if (lsr & SC16IS7XX_LSR_FE_BIT)
678 				flag = TTY_FRAME;
679 			else if (lsr & SC16IS7XX_LSR_OE_BIT)
680 				flag = TTY_OVERRUN;
681 		}
682 
683 		for (i = 0; i < bytes_read; ++i) {
684 			ch = one->buf[i];
685 			if (uart_handle_sysrq_char(port, ch))
686 				continue;
687 
688 			if (lsr & port->ignore_status_mask)
689 				continue;
690 
691 			uart_insert_char(port, lsr, SC16IS7XX_LSR_OE_BIT, ch,
692 					 flag);
693 		}
694 		rxlen -= bytes_read;
695 	}
696 
697 	tty_flip_buffer_push(&port->state->port);
698 }
699 
700 static void sc16is7xx_handle_tx(struct uart_port *port)
701 {
702 	struct tty_port *tport = &port->state->port;
703 	unsigned long flags;
704 	unsigned int txlen;
705 	unsigned char *tail;
706 
707 	if (unlikely(port->x_char)) {
708 		sc16is7xx_port_write(port, SC16IS7XX_THR_REG, port->x_char);
709 		port->icount.tx++;
710 		port->x_char = 0;
711 		return;
712 	}
713 
714 	if (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)) {
715 		uart_port_lock_irqsave(port, &flags);
716 		sc16is7xx_stop_tx(port);
717 		uart_port_unlock_irqrestore(port, flags);
718 		return;
719 	}
720 
721 	/* Limit to space available in TX FIFO */
722 	txlen = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
723 	if (txlen > SC16IS7XX_FIFO_SIZE) {
724 		dev_err_ratelimited(port->dev,
725 			"chip reports %d free bytes in TX fifo, but it only has %d",
726 			txlen, SC16IS7XX_FIFO_SIZE);
727 		txlen = 0;
728 	}
729 
730 	txlen = kfifo_out_linear_ptr(&tport->xmit_fifo, &tail, txlen);
731 	sc16is7xx_fifo_write(port, tail, txlen);
732 	uart_xmit_advance(port, txlen);
733 
734 	uart_port_lock_irqsave(port, &flags);
735 	if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
736 		uart_write_wakeup(port);
737 
738 	if (kfifo_is_empty(&tport->xmit_fifo))
739 		sc16is7xx_stop_tx(port);
740 	else
741 		sc16is7xx_ier_set(port, SC16IS7XX_IER_THRI_BIT);
742 	uart_port_unlock_irqrestore(port, flags);
743 }
744 
745 static unsigned int sc16is7xx_get_hwmctrl(struct uart_port *port)
746 {
747 	u8 msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
748 	unsigned int mctrl = 0;
749 
750 	mctrl |= (msr & SC16IS7XX_MSR_CTS_BIT) ? TIOCM_CTS : 0;
751 	mctrl |= (msr & SC16IS7XX_MSR_DSR_BIT) ? TIOCM_DSR : 0;
752 	mctrl |= (msr & SC16IS7XX_MSR_CD_BIT)  ? TIOCM_CAR : 0;
753 	mctrl |= (msr & SC16IS7XX_MSR_RI_BIT)  ? TIOCM_RNG : 0;
754 	return mctrl;
755 }
756 
757 static void sc16is7xx_update_mlines(struct sc16is7xx_one *one)
758 {
759 	struct uart_port *port = &one->port;
760 	unsigned long flags;
761 	unsigned int status, changed;
762 
763 	lockdep_assert_held_once(&one->efr_lock);
764 
765 	status = sc16is7xx_get_hwmctrl(port);
766 	changed = status ^ one->old_mctrl;
767 
768 	if (changed == 0)
769 		return;
770 
771 	one->old_mctrl = status;
772 
773 	uart_port_lock_irqsave(port, &flags);
774 	if ((changed & TIOCM_RNG) && (status & TIOCM_RNG))
775 		port->icount.rng++;
776 	if (changed & TIOCM_DSR)
777 		port->icount.dsr++;
778 	if (changed & TIOCM_CAR)
779 		uart_handle_dcd_change(port, status & TIOCM_CAR);
780 	if (changed & TIOCM_CTS)
781 		uart_handle_cts_change(port, status & TIOCM_CTS);
782 
783 	wake_up_interruptible(&port->state->port.delta_msr_wait);
784 	uart_port_unlock_irqrestore(port, flags);
785 }
786 
787 static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
788 {
789 	bool rc = true;
790 	unsigned int iir, rxlen;
791 	struct uart_port *port = &s->p[portno].port;
792 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
793 
794 	mutex_lock(&one->efr_lock);
795 
796 	iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
797 	if (iir & SC16IS7XX_IIR_NO_INT_BIT) {
798 		rc = false;
799 		goto out_port_irq;
800 	}
801 
802 	iir &= SC16IS7XX_IIR_ID_MASK;
803 
804 	switch (iir) {
805 	case SC16IS7XX_IIR_RDI_SRC:
806 	case SC16IS7XX_IIR_RLSE_SRC:
807 	case SC16IS7XX_IIR_RTOI_SRC:
808 	case SC16IS7XX_IIR_XOFFI_SRC:
809 		rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG);
810 
811 		/*
812 		 * There is a silicon bug that makes the chip report a
813 		 * time-out interrupt but no data in the FIFO. This is
814 		 * described in errata section 18.1.4.
815 		 *
816 		 * When this happens, read one byte from the FIFO to
817 		 * clear the interrupt.
818 		 */
819 		if (iir == SC16IS7XX_IIR_RTOI_SRC && !rxlen)
820 			rxlen = 1;
821 
822 		if (rxlen)
823 			sc16is7xx_handle_rx(port, rxlen, iir);
824 		break;
825 		/* CTSRTS interrupt comes only when CTS goes inactive */
826 	case SC16IS7XX_IIR_CTSRTS_SRC:
827 	case SC16IS7XX_IIR_MSI_SRC:
828 		sc16is7xx_update_mlines(one);
829 		break;
830 	case SC16IS7XX_IIR_THRI_SRC:
831 		sc16is7xx_handle_tx(port);
832 		break;
833 	default:
834 		dev_err_ratelimited(port->dev,
835 				    "ttySC%i: Unexpected interrupt: %x",
836 				    port->line, iir);
837 		break;
838 	}
839 
840 out_port_irq:
841 	mutex_unlock(&one->efr_lock);
842 
843 	return rc;
844 }
845 
846 static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
847 {
848 	bool keep_polling;
849 
850 	struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
851 
852 	do {
853 		int i;
854 
855 		keep_polling = false;
856 
857 		for (i = 0; i < s->devtype->nr_uart; ++i)
858 			keep_polling |= sc16is7xx_port_irq(s, i);
859 	} while (keep_polling);
860 
861 	return IRQ_HANDLED;
862 }
863 
864 static void sc16is7xx_tx_proc(struct kthread_work *ws)
865 {
866 	struct uart_port *port = &(to_sc16is7xx_one(ws, tx_work)->port);
867 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
868 
869 	if ((port->rs485.flags & SER_RS485_ENABLED) &&
870 	    (port->rs485.delay_rts_before_send > 0))
871 		msleep(port->rs485.delay_rts_before_send);
872 
873 	mutex_lock(&one->efr_lock);
874 	sc16is7xx_handle_tx(port);
875 	mutex_unlock(&one->efr_lock);
876 }
877 
878 static void sc16is7xx_reconf_rs485(struct uart_port *port)
879 {
880 	const u32 mask = SC16IS7XX_EFCR_AUTO_RS485_BIT |
881 			 SC16IS7XX_EFCR_RTS_INVERT_BIT;
882 	u32 efcr = 0;
883 	struct serial_rs485 *rs485 = &port->rs485;
884 	unsigned long irqflags;
885 
886 	uart_port_lock_irqsave(port, &irqflags);
887 	if (rs485->flags & SER_RS485_ENABLED) {
888 		efcr |=	SC16IS7XX_EFCR_AUTO_RS485_BIT;
889 
890 		if (rs485->flags & SER_RS485_RTS_AFTER_SEND)
891 			efcr |= SC16IS7XX_EFCR_RTS_INVERT_BIT;
892 	}
893 	uart_port_unlock_irqrestore(port, irqflags);
894 
895 	sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr);
896 }
897 
898 static void sc16is7xx_reg_proc(struct kthread_work *ws)
899 {
900 	struct sc16is7xx_one *one = to_sc16is7xx_one(ws, reg_work);
901 	struct sc16is7xx_one_config config;
902 	unsigned long irqflags;
903 
904 	uart_port_lock_irqsave(&one->port, &irqflags);
905 	config = one->config;
906 	memset(&one->config, 0, sizeof(one->config));
907 	uart_port_unlock_irqrestore(&one->port, irqflags);
908 
909 	if (config.flags & SC16IS7XX_RECONF_MD) {
910 		u8 mcr = 0;
911 
912 		/* Device ignores RTS setting when hardware flow is enabled */
913 		if (one->port.mctrl & TIOCM_RTS)
914 			mcr |= SC16IS7XX_MCR_RTS_BIT;
915 
916 		if (one->port.mctrl & TIOCM_DTR)
917 			mcr |= SC16IS7XX_MCR_DTR_BIT;
918 
919 		if (one->port.mctrl & TIOCM_LOOP)
920 			mcr |= SC16IS7XX_MCR_LOOP_BIT;
921 		sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
922 				      SC16IS7XX_MCR_RTS_BIT |
923 				      SC16IS7XX_MCR_DTR_BIT |
924 				      SC16IS7XX_MCR_LOOP_BIT,
925 				      mcr);
926 	}
927 
928 	if (config.flags & SC16IS7XX_RECONF_IER)
929 		sc16is7xx_port_update(&one->port, SC16IS7XX_IER_REG,
930 				      config.ier_mask, config.ier_val);
931 
932 	if (config.flags & SC16IS7XX_RECONF_RS485)
933 		sc16is7xx_reconf_rs485(&one->port);
934 }
935 
936 static void sc16is7xx_ms_proc(struct kthread_work *ws)
937 {
938 	struct sc16is7xx_one *one = to_sc16is7xx_one(ws, ms_work.work);
939 	struct sc16is7xx_port *s = dev_get_drvdata(one->port.dev);
940 
941 	if (one->port.state) {
942 		mutex_lock(&one->efr_lock);
943 		sc16is7xx_update_mlines(one);
944 		mutex_unlock(&one->efr_lock);
945 
946 		kthread_queue_delayed_work(&s->kworker, &one->ms_work, HZ);
947 	}
948 }
949 
950 static void sc16is7xx_enable_ms(struct uart_port *port)
951 {
952 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
953 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
954 
955 	lockdep_assert_held_once(&port->lock);
956 
957 	kthread_queue_delayed_work(&s->kworker, &one->ms_work, 0);
958 }
959 
960 static void sc16is7xx_start_tx(struct uart_port *port)
961 {
962 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
963 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
964 
965 	kthread_queue_work(&s->kworker, &one->tx_work);
966 }
967 
968 static void sc16is7xx_throttle(struct uart_port *port)
969 {
970 	unsigned long flags;
971 
972 	/*
973 	 * Hardware flow control is enabled and thus the device ignores RTS
974 	 * value set in MCR register. Stop reading data from RX FIFO so the
975 	 * AutoRTS feature will de-activate RTS output.
976 	 */
977 	uart_port_lock_irqsave(port, &flags);
978 	sc16is7xx_ier_clear(port, SC16IS7XX_IER_RDI_BIT);
979 	uart_port_unlock_irqrestore(port, flags);
980 }
981 
982 static void sc16is7xx_unthrottle(struct uart_port *port)
983 {
984 	unsigned long flags;
985 
986 	uart_port_lock_irqsave(port, &flags);
987 	sc16is7xx_ier_set(port, SC16IS7XX_IER_RDI_BIT);
988 	uart_port_unlock_irqrestore(port, flags);
989 }
990 
991 static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
992 {
993 	unsigned int lsr;
994 
995 	lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
996 
997 	return (lsr & SC16IS7XX_LSR_TEMT_BIT) ? TIOCSER_TEMT : 0;
998 }
999 
1000 static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
1001 {
1002 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
1003 
1004 	/* Called with port lock taken so we can only return cached value */
1005 	return one->old_mctrl;
1006 }
1007 
1008 static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
1009 {
1010 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
1011 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
1012 
1013 	one->config.flags |= SC16IS7XX_RECONF_MD;
1014 	kthread_queue_work(&s->kworker, &one->reg_work);
1015 }
1016 
1017 static void sc16is7xx_break_ctl(struct uart_port *port, int break_state)
1018 {
1019 	sc16is7xx_port_update(port, SC16IS7XX_LCR_REG,
1020 			      SC16IS7XX_LCR_TXBREAK_BIT,
1021 			      break_state ? SC16IS7XX_LCR_TXBREAK_BIT : 0);
1022 }
1023 
1024 static void sc16is7xx_set_termios(struct uart_port *port,
1025 				  struct ktermios *termios,
1026 				  const struct ktermios *old)
1027 {
1028 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
1029 	unsigned int lcr, flow = 0;
1030 	int baud;
1031 	unsigned long flags;
1032 
1033 	kthread_cancel_delayed_work_sync(&one->ms_work);
1034 
1035 	/* Mask termios capabilities we don't support */
1036 	termios->c_cflag &= ~CMSPAR;
1037 
1038 	/* Word size */
1039 	switch (termios->c_cflag & CSIZE) {
1040 	case CS5:
1041 		lcr = SC16IS7XX_LCR_WORD_LEN_5;
1042 		break;
1043 	case CS6:
1044 		lcr = SC16IS7XX_LCR_WORD_LEN_6;
1045 		break;
1046 	case CS7:
1047 		lcr = SC16IS7XX_LCR_WORD_LEN_7;
1048 		break;
1049 	case CS8:
1050 		lcr = SC16IS7XX_LCR_WORD_LEN_8;
1051 		break;
1052 	default:
1053 		lcr = SC16IS7XX_LCR_WORD_LEN_8;
1054 		termios->c_cflag &= ~CSIZE;
1055 		termios->c_cflag |= CS8;
1056 		break;
1057 	}
1058 
1059 	/* Parity */
1060 	if (termios->c_cflag & PARENB) {
1061 		lcr |= SC16IS7XX_LCR_PARITY_BIT;
1062 		if (!(termios->c_cflag & PARODD))
1063 			lcr |= SC16IS7XX_LCR_EVENPARITY_BIT;
1064 	}
1065 
1066 	/* Stop bits */
1067 	if (termios->c_cflag & CSTOPB)
1068 		lcr |= SC16IS7XX_LCR_STOPLEN_BIT; /* 2 stops */
1069 
1070 	/* Set read status mask */
1071 	port->read_status_mask = SC16IS7XX_LSR_OE_BIT;
1072 	if (termios->c_iflag & INPCK)
1073 		port->read_status_mask |= SC16IS7XX_LSR_PE_BIT |
1074 					  SC16IS7XX_LSR_FE_BIT;
1075 	if (termios->c_iflag & (BRKINT | PARMRK))
1076 		port->read_status_mask |= SC16IS7XX_LSR_BI_BIT;
1077 
1078 	/* Set status ignore mask */
1079 	port->ignore_status_mask = 0;
1080 	if (termios->c_iflag & IGNBRK)
1081 		port->ignore_status_mask |= SC16IS7XX_LSR_BI_BIT;
1082 	if (!(termios->c_cflag & CREAD))
1083 		port->ignore_status_mask |= SC16IS7XX_LSR_BRK_ERROR_MASK;
1084 
1085 	/* Configure flow control */
1086 	port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
1087 	if (termios->c_cflag & CRTSCTS) {
1088 		flow |= SC16IS7XX_EFR_AUTOCTS_BIT |
1089 			SC16IS7XX_EFR_AUTORTS_BIT;
1090 		port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
1091 	}
1092 	if (termios->c_iflag & IXON)
1093 		flow |= SC16IS7XX_EFR_SWFLOW3_BIT;
1094 	if (termios->c_iflag & IXOFF)
1095 		flow |= SC16IS7XX_EFR_SWFLOW1_BIT;
1096 
1097 	/* Update LCR register */
1098 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
1099 
1100 	/* Update EFR registers */
1101 	sc16is7xx_efr_lock(port);
1102 	sc16is7xx_port_write(port, SC16IS7XX_XON1_REG, termios->c_cc[VSTART]);
1103 	sc16is7xx_port_write(port, SC16IS7XX_XOFF1_REG, termios->c_cc[VSTOP]);
1104 	sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
1105 			      SC16IS7XX_EFR_FLOWCTRL_BITS, flow);
1106 	sc16is7xx_efr_unlock(port);
1107 
1108 	/* Get baud rate generator configuration */
1109 	baud = uart_get_baud_rate(port, termios, old,
1110 				  port->uartclk / 16 / 4 / 0xffff,
1111 				  port->uartclk / 16);
1112 
1113 	/* Setup baudrate generator */
1114 	baud = sc16is7xx_set_baud(port, baud);
1115 
1116 	uart_port_lock_irqsave(port, &flags);
1117 
1118 	/* Update timeout according to new baud rate */
1119 	uart_update_timeout(port, termios->c_cflag, baud);
1120 
1121 	if (UART_ENABLE_MS(port, termios->c_cflag))
1122 		sc16is7xx_enable_ms(port);
1123 
1124 	uart_port_unlock_irqrestore(port, flags);
1125 }
1126 
1127 static int sc16is7xx_config_rs485(struct uart_port *port, struct ktermios *termios,
1128 				  struct serial_rs485 *rs485)
1129 {
1130 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
1131 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
1132 
1133 	if (rs485->flags & SER_RS485_ENABLED) {
1134 		/*
1135 		 * RTS signal is handled by HW, it's timing can't be influenced.
1136 		 * However, it's sometimes useful to delay TX even without RTS
1137 		 * control therefore we try to handle .delay_rts_before_send.
1138 		 */
1139 		if (rs485->delay_rts_after_send)
1140 			return -EINVAL;
1141 	}
1142 
1143 	one->config.flags |= SC16IS7XX_RECONF_RS485;
1144 	kthread_queue_work(&s->kworker, &one->reg_work);
1145 
1146 	return 0;
1147 }
1148 
1149 static int sc16is7xx_startup(struct uart_port *port)
1150 {
1151 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
1152 	unsigned int val;
1153 	unsigned long flags;
1154 
1155 	sc16is7xx_power(port, 1);
1156 
1157 	/* Reset FIFOs*/
1158 	val = SC16IS7XX_FCR_RXRESET_BIT | SC16IS7XX_FCR_TXRESET_BIT;
1159 	sc16is7xx_port_write(port, SC16IS7XX_FCR_REG, val);
1160 	udelay(5);
1161 	sc16is7xx_port_write(port, SC16IS7XX_FCR_REG,
1162 			     SC16IS7XX_FCR_FIFO_BIT);
1163 
1164 	/* Enable EFR */
1165 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
1166 			     SC16IS7XX_LCR_CONF_MODE_B);
1167 
1168 	regcache_cache_bypass(one->regmap, true);
1169 
1170 	/* Enable write access to enhanced features and internal clock div */
1171 	sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
1172 			      SC16IS7XX_EFR_ENABLE_BIT,
1173 			      SC16IS7XX_EFR_ENABLE_BIT);
1174 
1175 	/* Enable TCR/TLR */
1176 	sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
1177 			      SC16IS7XX_MCR_TCRTLR_BIT,
1178 			      SC16IS7XX_MCR_TCRTLR_BIT);
1179 
1180 	/* Configure flow control levels */
1181 	/* Flow control halt level 48, resume level 24 */
1182 	sc16is7xx_port_write(port, SC16IS7XX_TCR_REG,
1183 			     SC16IS7XX_TCR_RX_RESUME(24) |
1184 			     SC16IS7XX_TCR_RX_HALT(48));
1185 
1186 	regcache_cache_bypass(one->regmap, false);
1187 
1188 	/* Now, initialize the UART */
1189 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_WORD_LEN_8);
1190 
1191 	/* Enable IrDA mode if requested in DT */
1192 	/* This bit must be written with LCR[7] = 0 */
1193 	sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
1194 			      SC16IS7XX_MCR_IRDA_BIT,
1195 			      one->irda_mode ?
1196 				SC16IS7XX_MCR_IRDA_BIT : 0);
1197 
1198 	/* Enable the Rx and Tx FIFO */
1199 	sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
1200 			      SC16IS7XX_EFCR_RXDISABLE_BIT |
1201 			      SC16IS7XX_EFCR_TXDISABLE_BIT,
1202 			      0);
1203 
1204 	/* Enable RX, CTS change and modem lines interrupts */
1205 	val = SC16IS7XX_IER_RDI_BIT | SC16IS7XX_IER_CTSI_BIT |
1206 	      SC16IS7XX_IER_MSI_BIT;
1207 	sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val);
1208 
1209 	/* Enable modem status polling */
1210 	uart_port_lock_irqsave(port, &flags);
1211 	sc16is7xx_enable_ms(port);
1212 	uart_port_unlock_irqrestore(port, flags);
1213 
1214 	return 0;
1215 }
1216 
1217 static void sc16is7xx_shutdown(struct uart_port *port)
1218 {
1219 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
1220 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
1221 
1222 	kthread_cancel_delayed_work_sync(&one->ms_work);
1223 
1224 	/* Disable all interrupts */
1225 	sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
1226 	/* Disable TX/RX */
1227 	sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
1228 			      SC16IS7XX_EFCR_RXDISABLE_BIT |
1229 			      SC16IS7XX_EFCR_TXDISABLE_BIT,
1230 			      SC16IS7XX_EFCR_RXDISABLE_BIT |
1231 			      SC16IS7XX_EFCR_TXDISABLE_BIT);
1232 
1233 	sc16is7xx_power(port, 0);
1234 
1235 	kthread_flush_worker(&s->kworker);
1236 }
1237 
1238 static const char *sc16is7xx_type(struct uart_port *port)
1239 {
1240 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
1241 
1242 	return (port->type == PORT_SC16IS7XX) ? s->devtype->name : NULL;
1243 }
1244 
1245 static int sc16is7xx_request_port(struct uart_port *port)
1246 {
1247 	/* Do nothing */
1248 	return 0;
1249 }
1250 
1251 static void sc16is7xx_config_port(struct uart_port *port, int flags)
1252 {
1253 	if (flags & UART_CONFIG_TYPE)
1254 		port->type = PORT_SC16IS7XX;
1255 }
1256 
1257 static int sc16is7xx_verify_port(struct uart_port *port,
1258 				 struct serial_struct *s)
1259 {
1260 	if ((s->type != PORT_UNKNOWN) && (s->type != PORT_SC16IS7XX))
1261 		return -EINVAL;
1262 	if (s->irq != port->irq)
1263 		return -EINVAL;
1264 
1265 	return 0;
1266 }
1267 
1268 static void sc16is7xx_pm(struct uart_port *port, unsigned int state,
1269 			 unsigned int oldstate)
1270 {
1271 	sc16is7xx_power(port, (state == UART_PM_STATE_ON) ? 1 : 0);
1272 }
1273 
1274 static void sc16is7xx_null_void(struct uart_port *port)
1275 {
1276 	/* Do nothing */
1277 }
1278 
1279 static const struct uart_ops sc16is7xx_ops = {
1280 	.tx_empty	= sc16is7xx_tx_empty,
1281 	.set_mctrl	= sc16is7xx_set_mctrl,
1282 	.get_mctrl	= sc16is7xx_get_mctrl,
1283 	.stop_tx	= sc16is7xx_stop_tx,
1284 	.start_tx	= sc16is7xx_start_tx,
1285 	.throttle	= sc16is7xx_throttle,
1286 	.unthrottle	= sc16is7xx_unthrottle,
1287 	.stop_rx	= sc16is7xx_stop_rx,
1288 	.enable_ms	= sc16is7xx_enable_ms,
1289 	.break_ctl	= sc16is7xx_break_ctl,
1290 	.startup	= sc16is7xx_startup,
1291 	.shutdown	= sc16is7xx_shutdown,
1292 	.set_termios	= sc16is7xx_set_termios,
1293 	.type		= sc16is7xx_type,
1294 	.request_port	= sc16is7xx_request_port,
1295 	.release_port	= sc16is7xx_null_void,
1296 	.config_port	= sc16is7xx_config_port,
1297 	.verify_port	= sc16is7xx_verify_port,
1298 	.pm		= sc16is7xx_pm,
1299 };
1300 
1301 #ifdef CONFIG_GPIOLIB
1302 static int sc16is7xx_gpio_get(struct gpio_chip *chip, unsigned offset)
1303 {
1304 	unsigned int val;
1305 	struct sc16is7xx_port *s = gpiochip_get_data(chip);
1306 	struct uart_port *port = &s->p[0].port;
1307 
1308 	val = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG);
1309 
1310 	return !!(val & BIT(offset));
1311 }
1312 
1313 static void sc16is7xx_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
1314 {
1315 	struct sc16is7xx_port *s = gpiochip_get_data(chip);
1316 	struct uart_port *port = &s->p[0].port;
1317 
1318 	sc16is7xx_port_update(port, SC16IS7XX_IOSTATE_REG, BIT(offset),
1319 			      val ? BIT(offset) : 0);
1320 }
1321 
1322 static int sc16is7xx_gpio_direction_input(struct gpio_chip *chip,
1323 					  unsigned offset)
1324 {
1325 	struct sc16is7xx_port *s = gpiochip_get_data(chip);
1326 	struct uart_port *port = &s->p[0].port;
1327 
1328 	sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset), 0);
1329 
1330 	return 0;
1331 }
1332 
1333 static int sc16is7xx_gpio_direction_output(struct gpio_chip *chip,
1334 					   unsigned offset, int val)
1335 {
1336 	struct sc16is7xx_port *s = gpiochip_get_data(chip);
1337 	struct uart_port *port = &s->p[0].port;
1338 	u8 state = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG);
1339 
1340 	if (val)
1341 		state |= BIT(offset);
1342 	else
1343 		state &= ~BIT(offset);
1344 
1345 	/*
1346 	 * If we write IOSTATE first, and then IODIR, the output value is not
1347 	 * transferred to the corresponding I/O pin.
1348 	 * The datasheet states that each register bit will be transferred to
1349 	 * the corresponding I/O pin programmed as output when writing to
1350 	 * IOSTATE. Therefore, configure direction first with IODIR, and then
1351 	 * set value after with IOSTATE.
1352 	 */
1353 	sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset),
1354 			      BIT(offset));
1355 	sc16is7xx_port_write(port, SC16IS7XX_IOSTATE_REG, state);
1356 
1357 	return 0;
1358 }
1359 
1360 static int sc16is7xx_gpio_init_valid_mask(struct gpio_chip *chip,
1361 					  unsigned long *valid_mask,
1362 					  unsigned int ngpios)
1363 {
1364 	struct sc16is7xx_port *s = gpiochip_get_data(chip);
1365 
1366 	*valid_mask = s->gpio_valid_mask;
1367 
1368 	return 0;
1369 }
1370 
1371 static int sc16is7xx_setup_gpio_chip(struct sc16is7xx_port *s)
1372 {
1373 	struct device *dev = s->p[0].port.dev;
1374 
1375 	if (!s->devtype->nr_gpio)
1376 		return 0;
1377 
1378 	switch (s->mctrl_mask) {
1379 	case 0:
1380 		s->gpio_valid_mask = GENMASK(7, 0);
1381 		break;
1382 	case SC16IS7XX_IOCONTROL_MODEM_A_BIT:
1383 		s->gpio_valid_mask = GENMASK(3, 0);
1384 		break;
1385 	case SC16IS7XX_IOCONTROL_MODEM_B_BIT:
1386 		s->gpio_valid_mask = GENMASK(7, 4);
1387 		break;
1388 	default:
1389 		break;
1390 	}
1391 
1392 	if (s->gpio_valid_mask == 0)
1393 		return 0;
1394 
1395 	s->gpio.owner		 = THIS_MODULE;
1396 	s->gpio.parent		 = dev;
1397 	s->gpio.label		 = dev_name(dev);
1398 	s->gpio.init_valid_mask	 = sc16is7xx_gpio_init_valid_mask;
1399 	s->gpio.direction_input	 = sc16is7xx_gpio_direction_input;
1400 	s->gpio.get		 = sc16is7xx_gpio_get;
1401 	s->gpio.direction_output = sc16is7xx_gpio_direction_output;
1402 	s->gpio.set		 = sc16is7xx_gpio_set;
1403 	s->gpio.base		 = -1;
1404 	s->gpio.ngpio		 = s->devtype->nr_gpio;
1405 	s->gpio.can_sleep	 = 1;
1406 
1407 	return gpiochip_add_data(&s->gpio, s);
1408 }
1409 #endif
1410 
1411 static void sc16is7xx_setup_irda_ports(struct sc16is7xx_port *s)
1412 {
1413 	int i;
1414 	int ret;
1415 	int count;
1416 	u32 irda_port[SC16IS7XX_MAX_PORTS];
1417 	struct device *dev = s->p[0].port.dev;
1418 
1419 	count = device_property_count_u32(dev, "irda-mode-ports");
1420 	if (count < 0 || count > ARRAY_SIZE(irda_port))
1421 		return;
1422 
1423 	ret = device_property_read_u32_array(dev, "irda-mode-ports",
1424 					     irda_port, count);
1425 	if (ret)
1426 		return;
1427 
1428 	for (i = 0; i < count; i++) {
1429 		if (irda_port[i] < s->devtype->nr_uart)
1430 			s->p[irda_port[i]].irda_mode = true;
1431 	}
1432 }
1433 
1434 /*
1435  * Configure ports designated to operate as modem control lines.
1436  */
1437 static int sc16is7xx_setup_mctrl_ports(struct sc16is7xx_port *s,
1438 				       struct regmap *regmap)
1439 {
1440 	int i;
1441 	int ret;
1442 	int count;
1443 	u32 mctrl_port[SC16IS7XX_MAX_PORTS];
1444 	struct device *dev = s->p[0].port.dev;
1445 
1446 	count = device_property_count_u32(dev, "nxp,modem-control-line-ports");
1447 	if (count < 0 || count > ARRAY_SIZE(mctrl_port))
1448 		return 0;
1449 
1450 	ret = device_property_read_u32_array(dev, "nxp,modem-control-line-ports",
1451 					     mctrl_port, count);
1452 	if (ret)
1453 		return ret;
1454 
1455 	s->mctrl_mask = 0;
1456 
1457 	for (i = 0; i < count; i++) {
1458 		/* Use GPIO lines as modem control lines */
1459 		if (mctrl_port[i] == 0)
1460 			s->mctrl_mask |= SC16IS7XX_IOCONTROL_MODEM_A_BIT;
1461 		else if (mctrl_port[i] == 1)
1462 			s->mctrl_mask |= SC16IS7XX_IOCONTROL_MODEM_B_BIT;
1463 	}
1464 
1465 	if (s->mctrl_mask)
1466 		regmap_update_bits(
1467 			regmap,
1468 			SC16IS7XX_IOCONTROL_REG,
1469 			SC16IS7XX_IOCONTROL_MODEM_A_BIT |
1470 			SC16IS7XX_IOCONTROL_MODEM_B_BIT, s->mctrl_mask);
1471 
1472 	return 0;
1473 }
1474 
1475 static const struct serial_rs485 sc16is7xx_rs485_supported = {
1476 	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND,
1477 	.delay_rts_before_send = 1,
1478 	.delay_rts_after_send = 1,	/* Not supported but keep returning -EINVAL */
1479 };
1480 
1481 /* Reset device, purging any pending irq / data */
1482 static int sc16is7xx_reset(struct device *dev, struct regmap *regmap)
1483 {
1484 	struct gpio_desc *reset_gpio;
1485 
1486 	/* Assert reset GPIO if defined and valid. */
1487 	reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
1488 	if (IS_ERR(reset_gpio))
1489 		return dev_err_probe(dev, PTR_ERR(reset_gpio), "Failed to get reset GPIO\n");
1490 
1491 	if (reset_gpio) {
1492 		/* The minimum reset pulse width is 3 us. */
1493 		fsleep(5);
1494 		gpiod_set_value_cansleep(reset_gpio, 0); /* Deassert GPIO */
1495 	} else {
1496 		/* Software reset */
1497 		regmap_write(regmap, SC16IS7XX_IOCONTROL_REG,
1498 			     SC16IS7XX_IOCONTROL_SRESET_BIT);
1499 	}
1500 
1501 	return 0;
1502 }
1503 
1504 int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
1505 		    struct regmap *regmaps[], int irq)
1506 {
1507 	unsigned long freq = 0, *pfreq = dev_get_platdata(dev);
1508 	unsigned int val;
1509 	u32 uartclk = 0;
1510 	int i, ret;
1511 	struct sc16is7xx_port *s;
1512 	bool port_registered[SC16IS7XX_MAX_PORTS];
1513 
1514 	for (i = 0; i < devtype->nr_uart; i++)
1515 		if (IS_ERR(regmaps[i]))
1516 			return PTR_ERR(regmaps[i]);
1517 
1518 	/*
1519 	 * This device does not have an identification register that would
1520 	 * tell us if we are really connected to the correct device.
1521 	 * The best we can do is to check if communication is at all possible.
1522 	 *
1523 	 * Note: regmap[0] is used in the probe function to access registers
1524 	 * common to all channels/ports, as it is guaranteed to be present on
1525 	 * all variants.
1526 	 */
1527 	ret = regmap_read(regmaps[0], SC16IS7XX_LSR_REG, &val);
1528 	if (ret < 0)
1529 		return -EPROBE_DEFER;
1530 
1531 	/* Alloc port structure */
1532 	s = devm_kzalloc(dev, struct_size(s, p, devtype->nr_uart), GFP_KERNEL);
1533 	if (!s) {
1534 		dev_err(dev, "Error allocating port structure\n");
1535 		return -ENOMEM;
1536 	}
1537 
1538 	/* Always ask for fixed clock rate from a property. */
1539 	device_property_read_u32(dev, "clock-frequency", &uartclk);
1540 
1541 	s->clk = devm_clk_get_optional(dev, NULL);
1542 	if (IS_ERR(s->clk))
1543 		return PTR_ERR(s->clk);
1544 
1545 	ret = clk_prepare_enable(s->clk);
1546 	if (ret)
1547 		return ret;
1548 
1549 	freq = clk_get_rate(s->clk);
1550 	if (freq == 0) {
1551 		if (uartclk)
1552 			freq = uartclk;
1553 		if (pfreq)
1554 			freq = *pfreq;
1555 		if (freq)
1556 			dev_dbg(dev, "Clock frequency: %luHz\n", freq);
1557 		else
1558 			return -EINVAL;
1559 	}
1560 
1561 	s->devtype = devtype;
1562 	dev_set_drvdata(dev, s);
1563 
1564 	kthread_init_worker(&s->kworker);
1565 	s->kworker_task = kthread_run(kthread_worker_fn, &s->kworker,
1566 				      "sc16is7xx");
1567 	if (IS_ERR(s->kworker_task)) {
1568 		ret = PTR_ERR(s->kworker_task);
1569 		goto out_clk;
1570 	}
1571 	sched_set_fifo(s->kworker_task);
1572 
1573 	ret = sc16is7xx_reset(dev, regmaps[0]);
1574 	if (ret)
1575 		goto out_kthread;
1576 
1577 	/* Mark each port line and status as uninitialised. */
1578 	for (i = 0; i < devtype->nr_uart; ++i) {
1579 		s->p[i].port.line = SC16IS7XX_MAX_DEVS;
1580 		port_registered[i] = false;
1581 	}
1582 
1583 	for (i = 0; i < devtype->nr_uart; ++i) {
1584 		ret = ida_alloc_max(&sc16is7xx_lines,
1585 				    SC16IS7XX_MAX_DEVS - 1, GFP_KERNEL);
1586 		if (ret < 0)
1587 			goto out_ports;
1588 
1589 		s->p[i].port.line = ret;
1590 
1591 		/* Initialize port data */
1592 		s->p[i].port.dev	= dev;
1593 		s->p[i].port.irq	= irq;
1594 		s->p[i].port.type	= PORT_SC16IS7XX;
1595 		s->p[i].port.fifosize	= SC16IS7XX_FIFO_SIZE;
1596 		s->p[i].port.flags	= UPF_FIXED_TYPE | UPF_LOW_LATENCY;
1597 		s->p[i].port.iobase	= i;
1598 		/*
1599 		 * Use all ones as membase to make sure uart_configure_port() in
1600 		 * serial_core.c does not abort for SPI/I2C devices where the
1601 		 * membase address is not applicable.
1602 		 */
1603 		s->p[i].port.membase	= (void __iomem *)~0;
1604 		s->p[i].port.iotype	= UPIO_PORT;
1605 		s->p[i].port.uartclk	= freq;
1606 		s->p[i].port.rs485_config = sc16is7xx_config_rs485;
1607 		s->p[i].port.rs485_supported = sc16is7xx_rs485_supported;
1608 		s->p[i].port.ops	= &sc16is7xx_ops;
1609 		s->p[i].old_mctrl	= 0;
1610 		s->p[i].regmap		= regmaps[i];
1611 
1612 		mutex_init(&s->p[i].efr_lock);
1613 
1614 		ret = uart_get_rs485_mode(&s->p[i].port);
1615 		if (ret)
1616 			goto out_ports;
1617 
1618 		/* Disable all interrupts */
1619 		sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_IER_REG, 0);
1620 		/* Disable TX/RX */
1621 		sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFCR_REG,
1622 				     SC16IS7XX_EFCR_RXDISABLE_BIT |
1623 				     SC16IS7XX_EFCR_TXDISABLE_BIT);
1624 
1625 		/* Initialize kthread work structs */
1626 		kthread_init_work(&s->p[i].tx_work, sc16is7xx_tx_proc);
1627 		kthread_init_work(&s->p[i].reg_work, sc16is7xx_reg_proc);
1628 		kthread_init_delayed_work(&s->p[i].ms_work, sc16is7xx_ms_proc);
1629 
1630 		/* Register port */
1631 		ret = uart_add_one_port(&sc16is7xx_uart, &s->p[i].port);
1632 		if (ret)
1633 			goto out_ports;
1634 
1635 		port_registered[i] = true;
1636 
1637 		/* Enable EFR */
1638 		sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG,
1639 				     SC16IS7XX_LCR_CONF_MODE_B);
1640 
1641 		regcache_cache_bypass(regmaps[i], true);
1642 
1643 		/* Enable write access to enhanced features */
1644 		sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFR_REG,
1645 				     SC16IS7XX_EFR_ENABLE_BIT);
1646 
1647 		regcache_cache_bypass(regmaps[i], false);
1648 
1649 		/* Restore access to general registers */
1650 		sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG, 0x00);
1651 
1652 		/* Go to suspend mode */
1653 		sc16is7xx_power(&s->p[i].port, 0);
1654 	}
1655 
1656 	sc16is7xx_setup_irda_ports(s);
1657 
1658 	ret = sc16is7xx_setup_mctrl_ports(s, regmaps[0]);
1659 	if (ret)
1660 		goto out_ports;
1661 
1662 #ifdef CONFIG_GPIOLIB
1663 	ret = sc16is7xx_setup_gpio_chip(s);
1664 	if (ret)
1665 		goto out_ports;
1666 #endif
1667 
1668 	/*
1669 	 * Setup interrupt. We first try to acquire the IRQ line as level IRQ.
1670 	 * If that succeeds, we can allow sharing the interrupt as well.
1671 	 * In case the interrupt controller doesn't support that, we fall
1672 	 * back to a non-shared falling-edge trigger.
1673 	 */
1674 	ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq,
1675 					IRQF_TRIGGER_LOW | IRQF_SHARED |
1676 					IRQF_ONESHOT,
1677 					dev_name(dev), s);
1678 	if (!ret)
1679 		return 0;
1680 
1681 	ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq,
1682 					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
1683 					dev_name(dev), s);
1684 	if (!ret)
1685 		return 0;
1686 
1687 #ifdef CONFIG_GPIOLIB
1688 	if (s->gpio_valid_mask)
1689 		gpiochip_remove(&s->gpio);
1690 #endif
1691 
1692 out_ports:
1693 	for (i = 0; i < devtype->nr_uart; i++) {
1694 		if (s->p[i].port.line < SC16IS7XX_MAX_DEVS)
1695 			ida_free(&sc16is7xx_lines, s->p[i].port.line);
1696 		if (port_registered[i])
1697 			uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
1698 	}
1699 
1700 out_kthread:
1701 	kthread_stop(s->kworker_task);
1702 
1703 out_clk:
1704 	clk_disable_unprepare(s->clk);
1705 
1706 	return ret;
1707 }
1708 EXPORT_SYMBOL_GPL(sc16is7xx_probe);
1709 
1710 void sc16is7xx_remove(struct device *dev)
1711 {
1712 	struct sc16is7xx_port *s = dev_get_drvdata(dev);
1713 	int i;
1714 
1715 #ifdef CONFIG_GPIOLIB
1716 	if (s->gpio_valid_mask)
1717 		gpiochip_remove(&s->gpio);
1718 #endif
1719 
1720 	for (i = 0; i < s->devtype->nr_uart; i++) {
1721 		kthread_cancel_delayed_work_sync(&s->p[i].ms_work);
1722 		ida_free(&sc16is7xx_lines, s->p[i].port.line);
1723 		uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
1724 		sc16is7xx_power(&s->p[i].port, 0);
1725 	}
1726 
1727 	kthread_flush_worker(&s->kworker);
1728 	kthread_stop(s->kworker_task);
1729 
1730 	clk_disable_unprepare(s->clk);
1731 }
1732 EXPORT_SYMBOL_GPL(sc16is7xx_remove);
1733 
1734 const struct of_device_id __maybe_unused sc16is7xx_dt_ids[] = {
1735 	{ .compatible = "nxp,sc16is740",	.data = &sc16is74x_devtype, },
1736 	{ .compatible = "nxp,sc16is741",	.data = &sc16is74x_devtype, },
1737 	{ .compatible = "nxp,sc16is750",	.data = &sc16is750_devtype, },
1738 	{ .compatible = "nxp,sc16is752",	.data = &sc16is752_devtype, },
1739 	{ .compatible = "nxp,sc16is760",	.data = &sc16is760_devtype, },
1740 	{ .compatible = "nxp,sc16is762",	.data = &sc16is762_devtype, },
1741 	{ }
1742 };
1743 EXPORT_SYMBOL_GPL(sc16is7xx_dt_ids);
1744 MODULE_DEVICE_TABLE(of, sc16is7xx_dt_ids);
1745 
1746 const struct regmap_config sc16is7xx_regcfg = {
1747 	.reg_bits = 5,
1748 	.pad_bits = 3,
1749 	.val_bits = 8,
1750 	.cache_type = REGCACHE_MAPLE,
1751 	.volatile_reg = sc16is7xx_regmap_volatile,
1752 	.precious_reg = sc16is7xx_regmap_precious,
1753 	.writeable_noinc_reg = sc16is7xx_regmap_noinc,
1754 	.readable_noinc_reg = sc16is7xx_regmap_noinc,
1755 	.max_raw_read = SC16IS7XX_FIFO_SIZE,
1756 	.max_raw_write = SC16IS7XX_FIFO_SIZE,
1757 	.max_register = SC16IS7XX_EFCR_REG,
1758 };
1759 EXPORT_SYMBOL_GPL(sc16is7xx_regcfg);
1760 
1761 const char *sc16is7xx_regmap_name(u8 port_id)
1762 {
1763 	switch (port_id) {
1764 	case 0:	return "port0";
1765 	case 1:	return "port1";
1766 	default:
1767 		WARN_ON(true);
1768 		return NULL;
1769 	}
1770 }
1771 EXPORT_SYMBOL_GPL(sc16is7xx_regmap_name);
1772 
1773 unsigned int sc16is7xx_regmap_port_mask(unsigned int port_id)
1774 {
1775 	/* CH1,CH0 are at bits 2:1. */
1776 	return port_id << 1;
1777 }
1778 EXPORT_SYMBOL_GPL(sc16is7xx_regmap_port_mask);
1779 
1780 static int __init sc16is7xx_init(void)
1781 {
1782 	return uart_register_driver(&sc16is7xx_uart);
1783 }
1784 module_init(sc16is7xx_init);
1785 
1786 static void __exit sc16is7xx_exit(void)
1787 {
1788 	uart_unregister_driver(&sc16is7xx_uart);
1789 }
1790 module_exit(sc16is7xx_exit);
1791 
1792 MODULE_LICENSE("GPL");
1793 MODULE_AUTHOR("Jon Ringle <jringle@gridpoint.com>");
1794 MODULE_DESCRIPTION("SC16IS7xx tty serial core driver");
1795