xref: /linux/drivers/tty/serial/max310x.c (revision c0c914eca7f251c70facc37dfebeaf176601918d)
1 /*
2  *  Maxim (Dallas) MAX3107/8/9, MAX14830 serial driver
3  *
4  *  Copyright (C) 2012-2014 Alexander Shiyan <shc_work@mail.ru>
5  *
6  *  Based on max3100.c, by Christian Pellegrin <chripell@evolware.org>
7  *  Based on max3110.c, by Feng Tang <feng.tang@intel.com>
8  *  Based on max3107.c, by Aavamobile
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or
13  *  (at your option) any later version.
14  */
15 
16 #include <linux/bitops.h>
17 #include <linux/clk.h>
18 #include <linux/delay.h>
19 #include <linux/device.h>
20 #include <linux/gpio.h>
21 #include <linux/module.h>
22 #include <linux/of.h>
23 #include <linux/of_device.h>
24 #include <linux/regmap.h>
25 #include <linux/serial_core.h>
26 #include <linux/serial.h>
27 #include <linux/tty.h>
28 #include <linux/tty_flip.h>
29 #include <linux/spi/spi.h>
30 #include <linux/uaccess.h>
31 
32 #define MAX310X_NAME			"max310x"
33 #define MAX310X_MAJOR			204
34 #define MAX310X_MINOR			209
35 
36 /* MAX310X register definitions */
37 #define MAX310X_RHR_REG			(0x00) /* RX FIFO */
38 #define MAX310X_THR_REG			(0x00) /* TX FIFO */
39 #define MAX310X_IRQEN_REG		(0x01) /* IRQ enable */
40 #define MAX310X_IRQSTS_REG		(0x02) /* IRQ status */
41 #define MAX310X_LSR_IRQEN_REG		(0x03) /* LSR IRQ enable */
42 #define MAX310X_LSR_IRQSTS_REG		(0x04) /* LSR IRQ status */
43 #define MAX310X_REG_05			(0x05)
44 #define MAX310X_SPCHR_IRQEN_REG		MAX310X_REG_05 /* Special char IRQ en */
45 #define MAX310X_SPCHR_IRQSTS_REG	(0x06) /* Special char IRQ status */
46 #define MAX310X_STS_IRQEN_REG		(0x07) /* Status IRQ enable */
47 #define MAX310X_STS_IRQSTS_REG		(0x08) /* Status IRQ status */
48 #define MAX310X_MODE1_REG		(0x09) /* MODE1 */
49 #define MAX310X_MODE2_REG		(0x0a) /* MODE2 */
50 #define MAX310X_LCR_REG			(0x0b) /* LCR */
51 #define MAX310X_RXTO_REG		(0x0c) /* RX timeout */
52 #define MAX310X_HDPIXDELAY_REG		(0x0d) /* Auto transceiver delays */
53 #define MAX310X_IRDA_REG		(0x0e) /* IRDA settings */
54 #define MAX310X_FLOWLVL_REG		(0x0f) /* Flow control levels */
55 #define MAX310X_FIFOTRIGLVL_REG		(0x10) /* FIFO IRQ trigger levels */
56 #define MAX310X_TXFIFOLVL_REG		(0x11) /* TX FIFO level */
57 #define MAX310X_RXFIFOLVL_REG		(0x12) /* RX FIFO level */
58 #define MAX310X_FLOWCTRL_REG		(0x13) /* Flow control */
59 #define MAX310X_XON1_REG		(0x14) /* XON1 character */
60 #define MAX310X_XON2_REG		(0x15) /* XON2 character */
61 #define MAX310X_XOFF1_REG		(0x16) /* XOFF1 character */
62 #define MAX310X_XOFF2_REG		(0x17) /* XOFF2 character */
63 #define MAX310X_GPIOCFG_REG		(0x18) /* GPIO config */
64 #define MAX310X_GPIODATA_REG		(0x19) /* GPIO data */
65 #define MAX310X_PLLCFG_REG		(0x1a) /* PLL config */
66 #define MAX310X_BRGCFG_REG		(0x1b) /* Baud rate generator conf */
67 #define MAX310X_BRGDIVLSB_REG		(0x1c) /* Baud rate divisor LSB */
68 #define MAX310X_BRGDIVMSB_REG		(0x1d) /* Baud rate divisor MSB */
69 #define MAX310X_CLKSRC_REG		(0x1e) /* Clock source */
70 #define MAX310X_REG_1F			(0x1f)
71 
72 #define MAX310X_REVID_REG		MAX310X_REG_1F /* Revision ID */
73 
74 #define MAX310X_GLOBALIRQ_REG		MAX310X_REG_1F /* Global IRQ (RO) */
75 #define MAX310X_GLOBALCMD_REG		MAX310X_REG_1F /* Global Command (WO) */
76 
77 /* Extended registers */
78 #define MAX310X_REVID_EXTREG		MAX310X_REG_05 /* Revision ID */
79 
80 /* IRQ register bits */
81 #define MAX310X_IRQ_LSR_BIT		(1 << 0) /* LSR interrupt */
82 #define MAX310X_IRQ_SPCHR_BIT		(1 << 1) /* Special char interrupt */
83 #define MAX310X_IRQ_STS_BIT		(1 << 2) /* Status interrupt */
84 #define MAX310X_IRQ_RXFIFO_BIT		(1 << 3) /* RX FIFO interrupt */
85 #define MAX310X_IRQ_TXFIFO_BIT		(1 << 4) /* TX FIFO interrupt */
86 #define MAX310X_IRQ_TXEMPTY_BIT		(1 << 5) /* TX FIFO empty interrupt */
87 #define MAX310X_IRQ_RXEMPTY_BIT		(1 << 6) /* RX FIFO empty interrupt */
88 #define MAX310X_IRQ_CTS_BIT		(1 << 7) /* CTS interrupt */
89 
90 /* LSR register bits */
91 #define MAX310X_LSR_RXTO_BIT		(1 << 0) /* RX timeout */
92 #define MAX310X_LSR_RXOVR_BIT		(1 << 1) /* RX overrun */
93 #define MAX310X_LSR_RXPAR_BIT		(1 << 2) /* RX parity error */
94 #define MAX310X_LSR_FRERR_BIT		(1 << 3) /* Frame error */
95 #define MAX310X_LSR_RXBRK_BIT		(1 << 4) /* RX break */
96 #define MAX310X_LSR_RXNOISE_BIT		(1 << 5) /* RX noise */
97 #define MAX310X_LSR_CTS_BIT		(1 << 7) /* CTS pin state */
98 
99 /* Special character register bits */
100 #define MAX310X_SPCHR_XON1_BIT		(1 << 0) /* XON1 character */
101 #define MAX310X_SPCHR_XON2_BIT		(1 << 1) /* XON2 character */
102 #define MAX310X_SPCHR_XOFF1_BIT		(1 << 2) /* XOFF1 character */
103 #define MAX310X_SPCHR_XOFF2_BIT		(1 << 3) /* XOFF2 character */
104 #define MAX310X_SPCHR_BREAK_BIT		(1 << 4) /* RX break */
105 #define MAX310X_SPCHR_MULTIDROP_BIT	(1 << 5) /* 9-bit multidrop addr char */
106 
107 /* Status register bits */
108 #define MAX310X_STS_GPIO0_BIT		(1 << 0) /* GPIO 0 interrupt */
109 #define MAX310X_STS_GPIO1_BIT		(1 << 1) /* GPIO 1 interrupt */
110 #define MAX310X_STS_GPIO2_BIT		(1 << 2) /* GPIO 2 interrupt */
111 #define MAX310X_STS_GPIO3_BIT		(1 << 3) /* GPIO 3 interrupt */
112 #define MAX310X_STS_CLKREADY_BIT	(1 << 5) /* Clock ready */
113 #define MAX310X_STS_SLEEP_BIT		(1 << 6) /* Sleep interrupt */
114 
115 /* MODE1 register bits */
116 #define MAX310X_MODE1_RXDIS_BIT		(1 << 0) /* RX disable */
117 #define MAX310X_MODE1_TXDIS_BIT		(1 << 1) /* TX disable */
118 #define MAX310X_MODE1_TXHIZ_BIT		(1 << 2) /* TX pin three-state */
119 #define MAX310X_MODE1_RTSHIZ_BIT	(1 << 3) /* RTS pin three-state */
120 #define MAX310X_MODE1_TRNSCVCTRL_BIT	(1 << 4) /* Transceiver ctrl enable */
121 #define MAX310X_MODE1_FORCESLEEP_BIT	(1 << 5) /* Force sleep mode */
122 #define MAX310X_MODE1_AUTOSLEEP_BIT	(1 << 6) /* Auto sleep enable */
123 #define MAX310X_MODE1_IRQSEL_BIT	(1 << 7) /* IRQ pin enable */
124 
125 /* MODE2 register bits */
126 #define MAX310X_MODE2_RST_BIT		(1 << 0) /* Chip reset */
127 #define MAX310X_MODE2_FIFORST_BIT	(1 << 1) /* FIFO reset */
128 #define MAX310X_MODE2_RXTRIGINV_BIT	(1 << 2) /* RX FIFO INT invert */
129 #define MAX310X_MODE2_RXEMPTINV_BIT	(1 << 3) /* RX FIFO empty INT invert */
130 #define MAX310X_MODE2_SPCHR_BIT		(1 << 4) /* Special chr detect enable */
131 #define MAX310X_MODE2_LOOPBACK_BIT	(1 << 5) /* Internal loopback enable */
132 #define MAX310X_MODE2_MULTIDROP_BIT	(1 << 6) /* 9-bit multidrop enable */
133 #define MAX310X_MODE2_ECHOSUPR_BIT	(1 << 7) /* ECHO suppression enable */
134 
135 /* LCR register bits */
136 #define MAX310X_LCR_LENGTH0_BIT		(1 << 0) /* Word length bit 0 */
137 #define MAX310X_LCR_LENGTH1_BIT		(1 << 1) /* Word length bit 1
138 						  *
139 						  * Word length bits table:
140 						  * 00 -> 5 bit words
141 						  * 01 -> 6 bit words
142 						  * 10 -> 7 bit words
143 						  * 11 -> 8 bit words
144 						  */
145 #define MAX310X_LCR_STOPLEN_BIT		(1 << 2) /* STOP length bit
146 						  *
147 						  * STOP length bit table:
148 						  * 0 -> 1 stop bit
149 						  * 1 -> 1-1.5 stop bits if
150 						  *      word length is 5,
151 						  *      2 stop bits otherwise
152 						  */
153 #define MAX310X_LCR_PARITY_BIT		(1 << 3) /* Parity bit enable */
154 #define MAX310X_LCR_EVENPARITY_BIT	(1 << 4) /* Even parity bit enable */
155 #define MAX310X_LCR_FORCEPARITY_BIT	(1 << 5) /* 9-bit multidrop parity */
156 #define MAX310X_LCR_TXBREAK_BIT		(1 << 6) /* TX break enable */
157 #define MAX310X_LCR_RTS_BIT		(1 << 7) /* RTS pin control */
158 #define MAX310X_LCR_WORD_LEN_5		(0x00)
159 #define MAX310X_LCR_WORD_LEN_6		(0x01)
160 #define MAX310X_LCR_WORD_LEN_7		(0x02)
161 #define MAX310X_LCR_WORD_LEN_8		(0x03)
162 
163 /* IRDA register bits */
164 #define MAX310X_IRDA_IRDAEN_BIT		(1 << 0) /* IRDA mode enable */
165 #define MAX310X_IRDA_SIR_BIT		(1 << 1) /* SIR mode enable */
166 
167 /* Flow control trigger level register masks */
168 #define MAX310X_FLOWLVL_HALT_MASK	(0x000f) /* Flow control halt level */
169 #define MAX310X_FLOWLVL_RES_MASK	(0x00f0) /* Flow control resume level */
170 #define MAX310X_FLOWLVL_HALT(words)	((words / 8) & 0x0f)
171 #define MAX310X_FLOWLVL_RES(words)	(((words / 8) & 0x0f) << 4)
172 
173 /* FIFO interrupt trigger level register masks */
174 #define MAX310X_FIFOTRIGLVL_TX_MASK	(0x0f) /* TX FIFO trigger level */
175 #define MAX310X_FIFOTRIGLVL_RX_MASK	(0xf0) /* RX FIFO trigger level */
176 #define MAX310X_FIFOTRIGLVL_TX(words)	((words / 8) & 0x0f)
177 #define MAX310X_FIFOTRIGLVL_RX(words)	(((words / 8) & 0x0f) << 4)
178 
179 /* Flow control register bits */
180 #define MAX310X_FLOWCTRL_AUTORTS_BIT	(1 << 0) /* Auto RTS flow ctrl enable */
181 #define MAX310X_FLOWCTRL_AUTOCTS_BIT	(1 << 1) /* Auto CTS flow ctrl enable */
182 #define MAX310X_FLOWCTRL_GPIADDR_BIT	(1 << 2) /* Enables that GPIO inputs
183 						  * are used in conjunction with
184 						  * XOFF2 for definition of
185 						  * special character */
186 #define MAX310X_FLOWCTRL_SWFLOWEN_BIT	(1 << 3) /* Auto SW flow ctrl enable */
187 #define MAX310X_FLOWCTRL_SWFLOW0_BIT	(1 << 4) /* SWFLOW bit 0 */
188 #define MAX310X_FLOWCTRL_SWFLOW1_BIT	(1 << 5) /* SWFLOW bit 1
189 						  *
190 						  * SWFLOW bits 1 & 0 table:
191 						  * 00 -> no transmitter flow
192 						  *       control
193 						  * 01 -> receiver compares
194 						  *       XON2 and XOFF2
195 						  *       and controls
196 						  *       transmitter
197 						  * 10 -> receiver compares
198 						  *       XON1 and XOFF1
199 						  *       and controls
200 						  *       transmitter
201 						  * 11 -> receiver compares
202 						  *       XON1, XON2, XOFF1 and
203 						  *       XOFF2 and controls
204 						  *       transmitter
205 						  */
206 #define MAX310X_FLOWCTRL_SWFLOW2_BIT	(1 << 6) /* SWFLOW bit 2 */
207 #define MAX310X_FLOWCTRL_SWFLOW3_BIT	(1 << 7) /* SWFLOW bit 3
208 						  *
209 						  * SWFLOW bits 3 & 2 table:
210 						  * 00 -> no received flow
211 						  *       control
212 						  * 01 -> transmitter generates
213 						  *       XON2 and XOFF2
214 						  * 10 -> transmitter generates
215 						  *       XON1 and XOFF1
216 						  * 11 -> transmitter generates
217 						  *       XON1, XON2, XOFF1 and
218 						  *       XOFF2
219 						  */
220 
221 /* PLL configuration register masks */
222 #define MAX310X_PLLCFG_PREDIV_MASK	(0x3f) /* PLL predivision value */
223 #define MAX310X_PLLCFG_PLLFACTOR_MASK	(0xc0) /* PLL multiplication factor */
224 
225 /* Baud rate generator configuration register bits */
226 #define MAX310X_BRGCFG_2XMODE_BIT	(1 << 4) /* Double baud rate */
227 #define MAX310X_BRGCFG_4XMODE_BIT	(1 << 5) /* Quadruple baud rate */
228 
229 /* Clock source register bits */
230 #define MAX310X_CLKSRC_CRYST_BIT	(1 << 1) /* Crystal osc enable */
231 #define MAX310X_CLKSRC_PLL_BIT		(1 << 2) /* PLL enable */
232 #define MAX310X_CLKSRC_PLLBYP_BIT	(1 << 3) /* PLL bypass */
233 #define MAX310X_CLKSRC_EXTCLK_BIT	(1 << 4) /* External clock enable */
234 #define MAX310X_CLKSRC_CLK2RTS_BIT	(1 << 7) /* Baud clk to RTS pin */
235 
236 /* Global commands */
237 #define MAX310X_EXTREG_ENBL		(0xce)
238 #define MAX310X_EXTREG_DSBL		(0xcd)
239 
240 /* Misc definitions */
241 #define MAX310X_FIFO_SIZE		(128)
242 #define MAX310x_REV_MASK		(0xfc)
243 
244 /* MAX3107 specific */
245 #define MAX3107_REV_ID			(0xa0)
246 
247 /* MAX3109 specific */
248 #define MAX3109_REV_ID			(0xc0)
249 
250 /* MAX14830 specific */
251 #define MAX14830_BRGCFG_CLKDIS_BIT	(1 << 6) /* Clock Disable */
252 #define MAX14830_REV_ID			(0xb0)
253 
254 struct max310x_devtype {
255 	char	name[9];
256 	int	nr;
257 	int	(*detect)(struct device *);
258 	void	(*power)(struct uart_port *, int);
259 };
260 
261 struct max310x_one {
262 	struct uart_port	port;
263 	struct work_struct	tx_work;
264 	struct work_struct	md_work;
265 };
266 
267 struct max310x_port {
268 	struct uart_driver	uart;
269 	struct max310x_devtype	*devtype;
270 	struct regmap		*regmap;
271 	struct mutex		mutex;
272 	struct clk		*clk;
273 #ifdef CONFIG_GPIOLIB
274 	struct gpio_chip	gpio;
275 #endif
276 	struct max310x_one	p[0];
277 };
278 
279 static u8 max310x_port_read(struct uart_port *port, u8 reg)
280 {
281 	struct max310x_port *s = dev_get_drvdata(port->dev);
282 	unsigned int val = 0;
283 
284 	regmap_read(s->regmap, port->iobase + reg, &val);
285 
286 	return val;
287 }
288 
289 static void max310x_port_write(struct uart_port *port, u8 reg, u8 val)
290 {
291 	struct max310x_port *s = dev_get_drvdata(port->dev);
292 
293 	regmap_write(s->regmap, port->iobase + reg, val);
294 }
295 
296 static void max310x_port_update(struct uart_port *port, u8 reg, u8 mask, u8 val)
297 {
298 	struct max310x_port *s = dev_get_drvdata(port->dev);
299 
300 	regmap_update_bits(s->regmap, port->iobase + reg, mask, val);
301 }
302 
303 static int max3107_detect(struct device *dev)
304 {
305 	struct max310x_port *s = dev_get_drvdata(dev);
306 	unsigned int val = 0;
307 	int ret;
308 
309 	ret = regmap_read(s->regmap, MAX310X_REVID_REG, &val);
310 	if (ret)
311 		return ret;
312 
313 	if (((val & MAX310x_REV_MASK) != MAX3107_REV_ID)) {
314 		dev_err(dev,
315 			"%s ID 0x%02x does not match\n", s->devtype->name, val);
316 		return -ENODEV;
317 	}
318 
319 	return 0;
320 }
321 
322 static int max3108_detect(struct device *dev)
323 {
324 	struct max310x_port *s = dev_get_drvdata(dev);
325 	unsigned int val = 0;
326 	int ret;
327 
328 	/* MAX3108 have not REV ID register, we just check default value
329 	 * from clocksource register to make sure everything works.
330 	 */
331 	ret = regmap_read(s->regmap, MAX310X_CLKSRC_REG, &val);
332 	if (ret)
333 		return ret;
334 
335 	if (val != (MAX310X_CLKSRC_EXTCLK_BIT | MAX310X_CLKSRC_PLLBYP_BIT)) {
336 		dev_err(dev, "%s not present\n", s->devtype->name);
337 		return -ENODEV;
338 	}
339 
340 	return 0;
341 }
342 
343 static int max3109_detect(struct device *dev)
344 {
345 	struct max310x_port *s = dev_get_drvdata(dev);
346 	unsigned int val = 0;
347 	int ret;
348 
349 	ret = regmap_write(s->regmap, MAX310X_GLOBALCMD_REG,
350 			   MAX310X_EXTREG_ENBL);
351 	if (ret)
352 		return ret;
353 
354 	regmap_read(s->regmap, MAX310X_REVID_EXTREG, &val);
355 	regmap_write(s->regmap, MAX310X_GLOBALCMD_REG, MAX310X_EXTREG_DSBL);
356 	if (((val & MAX310x_REV_MASK) != MAX3109_REV_ID)) {
357 		dev_err(dev,
358 			"%s ID 0x%02x does not match\n", s->devtype->name, val);
359 		return -ENODEV;
360 	}
361 
362 	return 0;
363 }
364 
365 static void max310x_power(struct uart_port *port, int on)
366 {
367 	max310x_port_update(port, MAX310X_MODE1_REG,
368 			    MAX310X_MODE1_FORCESLEEP_BIT,
369 			    on ? 0 : MAX310X_MODE1_FORCESLEEP_BIT);
370 	if (on)
371 		msleep(50);
372 }
373 
374 static int max14830_detect(struct device *dev)
375 {
376 	struct max310x_port *s = dev_get_drvdata(dev);
377 	unsigned int val = 0;
378 	int ret;
379 
380 	ret = regmap_write(s->regmap, MAX310X_GLOBALCMD_REG,
381 			   MAX310X_EXTREG_ENBL);
382 	if (ret)
383 		return ret;
384 
385 	regmap_read(s->regmap, MAX310X_REVID_EXTREG, &val);
386 	regmap_write(s->regmap, MAX310X_GLOBALCMD_REG, MAX310X_EXTREG_DSBL);
387 	if (((val & MAX310x_REV_MASK) != MAX14830_REV_ID)) {
388 		dev_err(dev,
389 			"%s ID 0x%02x does not match\n", s->devtype->name, val);
390 		return -ENODEV;
391 	}
392 
393 	return 0;
394 }
395 
396 static void max14830_power(struct uart_port *port, int on)
397 {
398 	max310x_port_update(port, MAX310X_BRGCFG_REG,
399 			    MAX14830_BRGCFG_CLKDIS_BIT,
400 			    on ? 0 : MAX14830_BRGCFG_CLKDIS_BIT);
401 	if (on)
402 		msleep(50);
403 }
404 
405 static const struct max310x_devtype max3107_devtype = {
406 	.name	= "MAX3107",
407 	.nr	= 1,
408 	.detect	= max3107_detect,
409 	.power	= max310x_power,
410 };
411 
412 static const struct max310x_devtype max3108_devtype = {
413 	.name	= "MAX3108",
414 	.nr	= 1,
415 	.detect	= max3108_detect,
416 	.power	= max310x_power,
417 };
418 
419 static const struct max310x_devtype max3109_devtype = {
420 	.name	= "MAX3109",
421 	.nr	= 2,
422 	.detect	= max3109_detect,
423 	.power	= max310x_power,
424 };
425 
426 static const struct max310x_devtype max14830_devtype = {
427 	.name	= "MAX14830",
428 	.nr	= 4,
429 	.detect	= max14830_detect,
430 	.power	= max14830_power,
431 };
432 
433 static bool max310x_reg_writeable(struct device *dev, unsigned int reg)
434 {
435 	switch (reg & 0x1f) {
436 	case MAX310X_IRQSTS_REG:
437 	case MAX310X_LSR_IRQSTS_REG:
438 	case MAX310X_SPCHR_IRQSTS_REG:
439 	case MAX310X_STS_IRQSTS_REG:
440 	case MAX310X_TXFIFOLVL_REG:
441 	case MAX310X_RXFIFOLVL_REG:
442 		return false;
443 	default:
444 		break;
445 	}
446 
447 	return true;
448 }
449 
450 static bool max310x_reg_volatile(struct device *dev, unsigned int reg)
451 {
452 	switch (reg & 0x1f) {
453 	case MAX310X_RHR_REG:
454 	case MAX310X_IRQSTS_REG:
455 	case MAX310X_LSR_IRQSTS_REG:
456 	case MAX310X_SPCHR_IRQSTS_REG:
457 	case MAX310X_STS_IRQSTS_REG:
458 	case MAX310X_TXFIFOLVL_REG:
459 	case MAX310X_RXFIFOLVL_REG:
460 	case MAX310X_GPIODATA_REG:
461 	case MAX310X_BRGDIVLSB_REG:
462 	case MAX310X_REG_05:
463 	case MAX310X_REG_1F:
464 		return true;
465 	default:
466 		break;
467 	}
468 
469 	return false;
470 }
471 
472 static bool max310x_reg_precious(struct device *dev, unsigned int reg)
473 {
474 	switch (reg & 0x1f) {
475 	case MAX310X_RHR_REG:
476 	case MAX310X_IRQSTS_REG:
477 	case MAX310X_SPCHR_IRQSTS_REG:
478 	case MAX310X_STS_IRQSTS_REG:
479 		return true;
480 	default:
481 		break;
482 	}
483 
484 	return false;
485 }
486 
487 static int max310x_set_baud(struct uart_port *port, int baud)
488 {
489 	unsigned int mode = 0, clk = port->uartclk, div = clk / baud;
490 
491 	/* Check for minimal value for divider */
492 	if (div < 16)
493 		div = 16;
494 
495 	if (clk % baud && (div / 16) < 0x8000) {
496 		/* Mode x2 */
497 		mode = MAX310X_BRGCFG_2XMODE_BIT;
498 		clk = port->uartclk * 2;
499 		div = clk / baud;
500 
501 		if (clk % baud && (div / 16) < 0x8000) {
502 			/* Mode x4 */
503 			mode = MAX310X_BRGCFG_4XMODE_BIT;
504 			clk = port->uartclk * 4;
505 			div = clk / baud;
506 		}
507 	}
508 
509 	max310x_port_write(port, MAX310X_BRGDIVMSB_REG, (div / 16) >> 8);
510 	max310x_port_write(port, MAX310X_BRGDIVLSB_REG, div / 16);
511 	max310x_port_write(port, MAX310X_BRGCFG_REG, (div % 16) | mode);
512 
513 	return DIV_ROUND_CLOSEST(clk, div);
514 }
515 
516 static int max310x_update_best_err(unsigned long f, long *besterr)
517 {
518 	/* Use baudrate 115200 for calculate error */
519 	long err = f % (115200 * 16);
520 
521 	if ((*besterr < 0) || (*besterr > err)) {
522 		*besterr = err;
523 		return 0;
524 	}
525 
526 	return 1;
527 }
528 
529 static int max310x_set_ref_clk(struct max310x_port *s, unsigned long freq,
530 			       bool xtal)
531 {
532 	unsigned int div, clksrc, pllcfg = 0;
533 	long besterr = -1;
534 	unsigned long fdiv, fmul, bestfreq = freq;
535 
536 	/* First, update error without PLL */
537 	max310x_update_best_err(freq, &besterr);
538 
539 	/* Try all possible PLL dividers */
540 	for (div = 1; (div <= 63) && besterr; div++) {
541 		fdiv = DIV_ROUND_CLOSEST(freq, div);
542 
543 		/* Try multiplier 6 */
544 		fmul = fdiv * 6;
545 		if ((fdiv >= 500000) && (fdiv <= 800000))
546 			if (!max310x_update_best_err(fmul, &besterr)) {
547 				pllcfg = (0 << 6) | div;
548 				bestfreq = fmul;
549 			}
550 		/* Try multiplier 48 */
551 		fmul = fdiv * 48;
552 		if ((fdiv >= 850000) && (fdiv <= 1200000))
553 			if (!max310x_update_best_err(fmul, &besterr)) {
554 				pllcfg = (1 << 6) | div;
555 				bestfreq = fmul;
556 			}
557 		/* Try multiplier 96 */
558 		fmul = fdiv * 96;
559 		if ((fdiv >= 425000) && (fdiv <= 1000000))
560 			if (!max310x_update_best_err(fmul, &besterr)) {
561 				pllcfg = (2 << 6) | div;
562 				bestfreq = fmul;
563 			}
564 		/* Try multiplier 144 */
565 		fmul = fdiv * 144;
566 		if ((fdiv >= 390000) && (fdiv <= 667000))
567 			if (!max310x_update_best_err(fmul, &besterr)) {
568 				pllcfg = (3 << 6) | div;
569 				bestfreq = fmul;
570 			}
571 	}
572 
573 	/* Configure clock source */
574 	clksrc = xtal ? MAX310X_CLKSRC_CRYST_BIT : MAX310X_CLKSRC_EXTCLK_BIT;
575 
576 	/* Configure PLL */
577 	if (pllcfg) {
578 		clksrc |= MAX310X_CLKSRC_PLL_BIT;
579 		regmap_write(s->regmap, MAX310X_PLLCFG_REG, pllcfg);
580 	} else
581 		clksrc |= MAX310X_CLKSRC_PLLBYP_BIT;
582 
583 	regmap_write(s->regmap, MAX310X_CLKSRC_REG, clksrc);
584 
585 	/* Wait for crystal */
586 	if (pllcfg && xtal)
587 		msleep(10);
588 
589 	return (int)bestfreq;
590 }
591 
592 static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen)
593 {
594 	unsigned int sts, ch, flag;
595 
596 	if (unlikely(rxlen >= port->fifosize)) {
597 		dev_warn_ratelimited(port->dev,
598 				     "Port %i: Possible RX FIFO overrun\n",
599 				     port->line);
600 		port->icount.buf_overrun++;
601 		/* Ensure sanity of RX level */
602 		rxlen = port->fifosize;
603 	}
604 
605 	while (rxlen--) {
606 		ch = max310x_port_read(port, MAX310X_RHR_REG);
607 		sts = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
608 
609 		sts &= MAX310X_LSR_RXPAR_BIT | MAX310X_LSR_FRERR_BIT |
610 		       MAX310X_LSR_RXOVR_BIT | MAX310X_LSR_RXBRK_BIT;
611 
612 		port->icount.rx++;
613 		flag = TTY_NORMAL;
614 
615 		if (unlikely(sts)) {
616 			if (sts & MAX310X_LSR_RXBRK_BIT) {
617 				port->icount.brk++;
618 				if (uart_handle_break(port))
619 					continue;
620 			} else if (sts & MAX310X_LSR_RXPAR_BIT)
621 				port->icount.parity++;
622 			else if (sts & MAX310X_LSR_FRERR_BIT)
623 				port->icount.frame++;
624 			else if (sts & MAX310X_LSR_RXOVR_BIT)
625 				port->icount.overrun++;
626 
627 			sts &= port->read_status_mask;
628 			if (sts & MAX310X_LSR_RXBRK_BIT)
629 				flag = TTY_BREAK;
630 			else if (sts & MAX310X_LSR_RXPAR_BIT)
631 				flag = TTY_PARITY;
632 			else if (sts & MAX310X_LSR_FRERR_BIT)
633 				flag = TTY_FRAME;
634 			else if (sts & MAX310X_LSR_RXOVR_BIT)
635 				flag = TTY_OVERRUN;
636 		}
637 
638 		if (uart_handle_sysrq_char(port, ch))
639 			continue;
640 
641 		if (sts & port->ignore_status_mask)
642 			continue;
643 
644 		uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, ch, flag);
645 	}
646 
647 	tty_flip_buffer_push(&port->state->port);
648 }
649 
650 static void max310x_handle_tx(struct uart_port *port)
651 {
652 	struct circ_buf *xmit = &port->state->xmit;
653 	unsigned int txlen, to_send;
654 
655 	if (unlikely(port->x_char)) {
656 		max310x_port_write(port, MAX310X_THR_REG, port->x_char);
657 		port->icount.tx++;
658 		port->x_char = 0;
659 		return;
660 	}
661 
662 	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
663 		return;
664 
665 	/* Get length of data pending in circular buffer */
666 	to_send = uart_circ_chars_pending(xmit);
667 	if (likely(to_send)) {
668 		/* Limit to size of TX FIFO */
669 		txlen = max310x_port_read(port, MAX310X_TXFIFOLVL_REG);
670 		txlen = port->fifosize - txlen;
671 		to_send = (to_send > txlen) ? txlen : to_send;
672 
673 		/* Add data to send */
674 		port->icount.tx += to_send;
675 		while (to_send--) {
676 			max310x_port_write(port, MAX310X_THR_REG,
677 					   xmit->buf[xmit->tail]);
678 			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
679 		}
680 	}
681 
682 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
683 		uart_write_wakeup(port);
684 }
685 
686 static void max310x_port_irq(struct max310x_port *s, int portno)
687 {
688 	struct uart_port *port = &s->p[portno].port;
689 
690 	do {
691 		unsigned int ists, lsr, rxlen;
692 
693 		/* Read IRQ status & RX FIFO level */
694 		ists = max310x_port_read(port, MAX310X_IRQSTS_REG);
695 		rxlen = max310x_port_read(port, MAX310X_RXFIFOLVL_REG);
696 		if (!ists && !rxlen)
697 			break;
698 
699 		if (ists & MAX310X_IRQ_CTS_BIT) {
700 			lsr = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
701 			uart_handle_cts_change(port,
702 					       !!(lsr & MAX310X_LSR_CTS_BIT));
703 		}
704 		if (rxlen)
705 			max310x_handle_rx(port, rxlen);
706 		if (ists & MAX310X_IRQ_TXEMPTY_BIT) {
707 			mutex_lock(&s->mutex);
708 			max310x_handle_tx(port);
709 			mutex_unlock(&s->mutex);
710 		}
711 	} while (1);
712 }
713 
714 static irqreturn_t max310x_ist(int irq, void *dev_id)
715 {
716 	struct max310x_port *s = (struct max310x_port *)dev_id;
717 
718 	if (s->uart.nr > 1) {
719 		do {
720 			unsigned int val = ~0;
721 
722 			WARN_ON_ONCE(regmap_read(s->regmap,
723 						 MAX310X_GLOBALIRQ_REG, &val));
724 			val = ((1 << s->uart.nr) - 1) & ~val;
725 			if (!val)
726 				break;
727 			max310x_port_irq(s, fls(val) - 1);
728 		} while (1);
729 	} else
730 		max310x_port_irq(s, 0);
731 
732 	return IRQ_HANDLED;
733 }
734 
735 static void max310x_wq_proc(struct work_struct *ws)
736 {
737 	struct max310x_one *one = container_of(ws, struct max310x_one, tx_work);
738 	struct max310x_port *s = dev_get_drvdata(one->port.dev);
739 
740 	mutex_lock(&s->mutex);
741 	max310x_handle_tx(&one->port);
742 	mutex_unlock(&s->mutex);
743 }
744 
745 static void max310x_start_tx(struct uart_port *port)
746 {
747 	struct max310x_one *one = container_of(port, struct max310x_one, port);
748 
749 	if (!work_pending(&one->tx_work))
750 		schedule_work(&one->tx_work);
751 }
752 
753 static unsigned int max310x_tx_empty(struct uart_port *port)
754 {
755 	unsigned int lvl, sts;
756 
757 	lvl = max310x_port_read(port, MAX310X_TXFIFOLVL_REG);
758 	sts = max310x_port_read(port, MAX310X_IRQSTS_REG);
759 
760 	return ((sts & MAX310X_IRQ_TXEMPTY_BIT) && !lvl) ? TIOCSER_TEMT : 0;
761 }
762 
763 static unsigned int max310x_get_mctrl(struct uart_port *port)
764 {
765 	/* DCD and DSR are not wired and CTS/RTS is handled automatically
766 	 * so just indicate DSR and CAR asserted
767 	 */
768 	return TIOCM_DSR | TIOCM_CAR;
769 }
770 
771 static void max310x_md_proc(struct work_struct *ws)
772 {
773 	struct max310x_one *one = container_of(ws, struct max310x_one, md_work);
774 
775 	max310x_port_update(&one->port, MAX310X_MODE2_REG,
776 			    MAX310X_MODE2_LOOPBACK_BIT,
777 			    (one->port.mctrl & TIOCM_LOOP) ?
778 			    MAX310X_MODE2_LOOPBACK_BIT : 0);
779 }
780 
781 static void max310x_set_mctrl(struct uart_port *port, unsigned int mctrl)
782 {
783 	struct max310x_one *one = container_of(port, struct max310x_one, port);
784 
785 	schedule_work(&one->md_work);
786 }
787 
788 static void max310x_break_ctl(struct uart_port *port, int break_state)
789 {
790 	max310x_port_update(port, MAX310X_LCR_REG,
791 			    MAX310X_LCR_TXBREAK_BIT,
792 			    break_state ? MAX310X_LCR_TXBREAK_BIT : 0);
793 }
794 
795 static void max310x_set_termios(struct uart_port *port,
796 				struct ktermios *termios,
797 				struct ktermios *old)
798 {
799 	unsigned int lcr, flow = 0;
800 	int baud;
801 
802 	/* Mask termios capabilities we don't support */
803 	termios->c_cflag &= ~CMSPAR;
804 
805 	/* Word size */
806 	switch (termios->c_cflag & CSIZE) {
807 	case CS5:
808 		lcr = MAX310X_LCR_WORD_LEN_5;
809 		break;
810 	case CS6:
811 		lcr = MAX310X_LCR_WORD_LEN_6;
812 		break;
813 	case CS7:
814 		lcr = MAX310X_LCR_WORD_LEN_7;
815 		break;
816 	case CS8:
817 	default:
818 		lcr = MAX310X_LCR_WORD_LEN_8;
819 		break;
820 	}
821 
822 	/* Parity */
823 	if (termios->c_cflag & PARENB) {
824 		lcr |= MAX310X_LCR_PARITY_BIT;
825 		if (!(termios->c_cflag & PARODD))
826 			lcr |= MAX310X_LCR_EVENPARITY_BIT;
827 	}
828 
829 	/* Stop bits */
830 	if (termios->c_cflag & CSTOPB)
831 		lcr |= MAX310X_LCR_STOPLEN_BIT; /* 2 stops */
832 
833 	/* Update LCR register */
834 	max310x_port_write(port, MAX310X_LCR_REG, lcr);
835 
836 	/* Set read status mask */
837 	port->read_status_mask = MAX310X_LSR_RXOVR_BIT;
838 	if (termios->c_iflag & INPCK)
839 		port->read_status_mask |= MAX310X_LSR_RXPAR_BIT |
840 					  MAX310X_LSR_FRERR_BIT;
841 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
842 		port->read_status_mask |= MAX310X_LSR_RXBRK_BIT;
843 
844 	/* Set status ignore mask */
845 	port->ignore_status_mask = 0;
846 	if (termios->c_iflag & IGNBRK)
847 		port->ignore_status_mask |= MAX310X_LSR_RXBRK_BIT;
848 	if (!(termios->c_cflag & CREAD))
849 		port->ignore_status_mask |= MAX310X_LSR_RXPAR_BIT |
850 					    MAX310X_LSR_RXOVR_BIT |
851 					    MAX310X_LSR_FRERR_BIT |
852 					    MAX310X_LSR_RXBRK_BIT;
853 
854 	/* Configure flow control */
855 	max310x_port_write(port, MAX310X_XON1_REG, termios->c_cc[VSTART]);
856 	max310x_port_write(port, MAX310X_XOFF1_REG, termios->c_cc[VSTOP]);
857 	if (termios->c_cflag & CRTSCTS)
858 		flow |= MAX310X_FLOWCTRL_AUTOCTS_BIT |
859 			MAX310X_FLOWCTRL_AUTORTS_BIT;
860 	if (termios->c_iflag & IXON)
861 		flow |= MAX310X_FLOWCTRL_SWFLOW3_BIT |
862 			MAX310X_FLOWCTRL_SWFLOWEN_BIT;
863 	if (termios->c_iflag & IXOFF)
864 		flow |= MAX310X_FLOWCTRL_SWFLOW1_BIT |
865 			MAX310X_FLOWCTRL_SWFLOWEN_BIT;
866 	max310x_port_write(port, MAX310X_FLOWCTRL_REG, flow);
867 
868 	/* Get baud rate generator configuration */
869 	baud = uart_get_baud_rate(port, termios, old,
870 				  port->uartclk / 16 / 0xffff,
871 				  port->uartclk / 4);
872 
873 	/* Setup baudrate generator */
874 	baud = max310x_set_baud(port, baud);
875 
876 	/* Update timeout according to new baud rate */
877 	uart_update_timeout(port, termios->c_cflag, baud);
878 }
879 
880 static int max310x_rs485_config(struct uart_port *port,
881 				struct serial_rs485 *rs485)
882 {
883 	unsigned int val;
884 
885 	if (rs485->delay_rts_before_send > 0x0f ||
886 		    rs485->delay_rts_after_send > 0x0f)
887 		return -ERANGE;
888 
889 	val = (rs485->delay_rts_before_send << 4) |
890 		rs485->delay_rts_after_send;
891 	max310x_port_write(port, MAX310X_HDPIXDELAY_REG, val);
892 	if (rs485->flags & SER_RS485_ENABLED) {
893 		max310x_port_update(port, MAX310X_MODE1_REG,
894 				MAX310X_MODE1_TRNSCVCTRL_BIT,
895 				MAX310X_MODE1_TRNSCVCTRL_BIT);
896 		max310x_port_update(port, MAX310X_MODE2_REG,
897 				MAX310X_MODE2_ECHOSUPR_BIT,
898 				MAX310X_MODE2_ECHOSUPR_BIT);
899 	} else {
900 		max310x_port_update(port, MAX310X_MODE1_REG,
901 				MAX310X_MODE1_TRNSCVCTRL_BIT, 0);
902 		max310x_port_update(port, MAX310X_MODE2_REG,
903 				MAX310X_MODE2_ECHOSUPR_BIT, 0);
904 	}
905 
906 	rs485->flags &= SER_RS485_RTS_ON_SEND | SER_RS485_ENABLED;
907 	memset(rs485->padding, 0, sizeof(rs485->padding));
908 	port->rs485 = *rs485;
909 
910 	return 0;
911 }
912 
913 static int max310x_startup(struct uart_port *port)
914 {
915 	struct max310x_port *s = dev_get_drvdata(port->dev);
916 	unsigned int val;
917 
918 	s->devtype->power(port, 1);
919 
920 	/* Configure MODE1 register */
921 	max310x_port_update(port, MAX310X_MODE1_REG,
922 			    MAX310X_MODE1_TRNSCVCTRL_BIT, 0);
923 
924 	/* Configure MODE2 register & Reset FIFOs*/
925 	val = MAX310X_MODE2_RXEMPTINV_BIT | MAX310X_MODE2_FIFORST_BIT;
926 	max310x_port_write(port, MAX310X_MODE2_REG, val);
927 	max310x_port_update(port, MAX310X_MODE2_REG,
928 			    MAX310X_MODE2_FIFORST_BIT, 0);
929 
930 	/* Configure flow control levels */
931 	/* Flow control halt level 96, resume level 48 */
932 	max310x_port_write(port, MAX310X_FLOWLVL_REG,
933 			   MAX310X_FLOWLVL_RES(48) | MAX310X_FLOWLVL_HALT(96));
934 
935 	/* Clear IRQ status register */
936 	max310x_port_read(port, MAX310X_IRQSTS_REG);
937 
938 	/* Enable RX, TX, CTS change interrupts */
939 	val = MAX310X_IRQ_RXEMPTY_BIT | MAX310X_IRQ_TXEMPTY_BIT;
940 	max310x_port_write(port, MAX310X_IRQEN_REG, val | MAX310X_IRQ_CTS_BIT);
941 
942 	return 0;
943 }
944 
945 static void max310x_shutdown(struct uart_port *port)
946 {
947 	struct max310x_port *s = dev_get_drvdata(port->dev);
948 
949 	/* Disable all interrupts */
950 	max310x_port_write(port, MAX310X_IRQEN_REG, 0);
951 
952 	s->devtype->power(port, 0);
953 }
954 
955 static const char *max310x_type(struct uart_port *port)
956 {
957 	struct max310x_port *s = dev_get_drvdata(port->dev);
958 
959 	return (port->type == PORT_MAX310X) ? s->devtype->name : NULL;
960 }
961 
962 static int max310x_request_port(struct uart_port *port)
963 {
964 	/* Do nothing */
965 	return 0;
966 }
967 
968 static void max310x_config_port(struct uart_port *port, int flags)
969 {
970 	if (flags & UART_CONFIG_TYPE)
971 		port->type = PORT_MAX310X;
972 }
973 
974 static int max310x_verify_port(struct uart_port *port, struct serial_struct *s)
975 {
976 	if ((s->type != PORT_UNKNOWN) && (s->type != PORT_MAX310X))
977 		return -EINVAL;
978 	if (s->irq != port->irq)
979 		return -EINVAL;
980 
981 	return 0;
982 }
983 
984 static void max310x_null_void(struct uart_port *port)
985 {
986 	/* Do nothing */
987 }
988 
989 static const struct uart_ops max310x_ops = {
990 	.tx_empty	= max310x_tx_empty,
991 	.set_mctrl	= max310x_set_mctrl,
992 	.get_mctrl	= max310x_get_mctrl,
993 	.stop_tx	= max310x_null_void,
994 	.start_tx	= max310x_start_tx,
995 	.stop_rx	= max310x_null_void,
996 	.break_ctl	= max310x_break_ctl,
997 	.startup	= max310x_startup,
998 	.shutdown	= max310x_shutdown,
999 	.set_termios	= max310x_set_termios,
1000 	.type		= max310x_type,
1001 	.request_port	= max310x_request_port,
1002 	.release_port	= max310x_null_void,
1003 	.config_port	= max310x_config_port,
1004 	.verify_port	= max310x_verify_port,
1005 };
1006 
1007 static int __maybe_unused max310x_suspend(struct device *dev)
1008 {
1009 	struct max310x_port *s = dev_get_drvdata(dev);
1010 	int i;
1011 
1012 	for (i = 0; i < s->uart.nr; i++) {
1013 		uart_suspend_port(&s->uart, &s->p[i].port);
1014 		s->devtype->power(&s->p[i].port, 0);
1015 	}
1016 
1017 	return 0;
1018 }
1019 
1020 static int __maybe_unused max310x_resume(struct device *dev)
1021 {
1022 	struct max310x_port *s = dev_get_drvdata(dev);
1023 	int i;
1024 
1025 	for (i = 0; i < s->uart.nr; i++) {
1026 		s->devtype->power(&s->p[i].port, 1);
1027 		uart_resume_port(&s->uart, &s->p[i].port);
1028 	}
1029 
1030 	return 0;
1031 }
1032 
1033 static SIMPLE_DEV_PM_OPS(max310x_pm_ops, max310x_suspend, max310x_resume);
1034 
1035 #ifdef CONFIG_GPIOLIB
1036 static int max310x_gpio_get(struct gpio_chip *chip, unsigned offset)
1037 {
1038 	unsigned int val;
1039 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1040 	struct uart_port *port = &s->p[offset / 4].port;
1041 
1042 	val = max310x_port_read(port, MAX310X_GPIODATA_REG);
1043 
1044 	return !!((val >> 4) & (1 << (offset % 4)));
1045 }
1046 
1047 static void max310x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
1048 {
1049 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1050 	struct uart_port *port = &s->p[offset / 4].port;
1051 
1052 	max310x_port_update(port, MAX310X_GPIODATA_REG, 1 << (offset % 4),
1053 			    value ? 1 << (offset % 4) : 0);
1054 }
1055 
1056 static int max310x_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
1057 {
1058 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1059 	struct uart_port *port = &s->p[offset / 4].port;
1060 
1061 	max310x_port_update(port, MAX310X_GPIOCFG_REG, 1 << (offset % 4), 0);
1062 
1063 	return 0;
1064 }
1065 
1066 static int max310x_gpio_direction_output(struct gpio_chip *chip,
1067 					 unsigned offset, int value)
1068 {
1069 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1070 	struct uart_port *port = &s->p[offset / 4].port;
1071 
1072 	max310x_port_update(port, MAX310X_GPIODATA_REG, 1 << (offset % 4),
1073 			    value ? 1 << (offset % 4) : 0);
1074 	max310x_port_update(port, MAX310X_GPIOCFG_REG, 1 << (offset % 4),
1075 			    1 << (offset % 4));
1076 
1077 	return 0;
1078 }
1079 #endif
1080 
1081 static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,
1082 			 struct regmap *regmap, int irq, unsigned long flags)
1083 {
1084 	int i, ret, fmin, fmax, freq, uartclk;
1085 	struct clk *clk_osc, *clk_xtal;
1086 	struct max310x_port *s;
1087 	bool xtal = false;
1088 
1089 	if (IS_ERR(regmap))
1090 		return PTR_ERR(regmap);
1091 
1092 	/* Alloc port structure */
1093 	s = devm_kzalloc(dev, sizeof(*s) +
1094 			 sizeof(struct max310x_one) * devtype->nr, GFP_KERNEL);
1095 	if (!s) {
1096 		dev_err(dev, "Error allocating port structure\n");
1097 		return -ENOMEM;
1098 	}
1099 
1100 	clk_osc = devm_clk_get(dev, "osc");
1101 	clk_xtal = devm_clk_get(dev, "xtal");
1102 	if (!IS_ERR(clk_osc)) {
1103 		s->clk = clk_osc;
1104 		fmin = 500000;
1105 		fmax = 35000000;
1106 	} else if (!IS_ERR(clk_xtal)) {
1107 		s->clk = clk_xtal;
1108 		fmin = 1000000;
1109 		fmax = 4000000;
1110 		xtal = true;
1111 	} else if (PTR_ERR(clk_osc) == -EPROBE_DEFER ||
1112 		   PTR_ERR(clk_xtal) == -EPROBE_DEFER) {
1113 		return -EPROBE_DEFER;
1114 	} else {
1115 		dev_err(dev, "Cannot get clock\n");
1116 		return -EINVAL;
1117 	}
1118 
1119 	ret = clk_prepare_enable(s->clk);
1120 	if (ret)
1121 		return ret;
1122 
1123 	freq = clk_get_rate(s->clk);
1124 	/* Check frequency limits */
1125 	if (freq < fmin || freq > fmax) {
1126 		ret = -ERANGE;
1127 		goto out_clk;
1128 	}
1129 
1130 	s->regmap = regmap;
1131 	s->devtype = devtype;
1132 	dev_set_drvdata(dev, s);
1133 
1134 	/* Check device to ensure we are talking to what we expect */
1135 	ret = devtype->detect(dev);
1136 	if (ret)
1137 		goto out_clk;
1138 
1139 	for (i = 0; i < devtype->nr; i++) {
1140 		unsigned int offs = i << 5;
1141 
1142 		/* Reset port */
1143 		regmap_write(s->regmap, MAX310X_MODE2_REG + offs,
1144 			     MAX310X_MODE2_RST_BIT);
1145 		/* Clear port reset */
1146 		regmap_write(s->regmap, MAX310X_MODE2_REG + offs, 0);
1147 
1148 		/* Wait for port startup */
1149 		do {
1150 			regmap_read(s->regmap,
1151 				    MAX310X_BRGDIVLSB_REG + offs, &ret);
1152 		} while (ret != 0x01);
1153 
1154 		regmap_update_bits(s->regmap, MAX310X_MODE1_REG + offs,
1155 				   MAX310X_MODE1_AUTOSLEEP_BIT,
1156 				   MAX310X_MODE1_AUTOSLEEP_BIT);
1157 	}
1158 
1159 	uartclk = max310x_set_ref_clk(s, freq, xtal);
1160 	dev_dbg(dev, "Reference clock set to %i Hz\n", uartclk);
1161 
1162 	/* Register UART driver */
1163 	s->uart.owner		= THIS_MODULE;
1164 	s->uart.dev_name	= "ttyMAX";
1165 	s->uart.major		= MAX310X_MAJOR;
1166 	s->uart.minor		= MAX310X_MINOR;
1167 	s->uart.nr		= devtype->nr;
1168 	ret = uart_register_driver(&s->uart);
1169 	if (ret) {
1170 		dev_err(dev, "Registering UART driver failed\n");
1171 		goto out_clk;
1172 	}
1173 
1174 #ifdef CONFIG_GPIOLIB
1175 	/* Setup GPIO cotroller */
1176 	s->gpio.owner		= THIS_MODULE;
1177 	s->gpio.parent		= dev;
1178 	s->gpio.label		= dev_name(dev);
1179 	s->gpio.direction_input	= max310x_gpio_direction_input;
1180 	s->gpio.get		= max310x_gpio_get;
1181 	s->gpio.direction_output= max310x_gpio_direction_output;
1182 	s->gpio.set		= max310x_gpio_set;
1183 	s->gpio.base		= -1;
1184 	s->gpio.ngpio		= devtype->nr * 4;
1185 	s->gpio.can_sleep	= 1;
1186 	ret = gpiochip_add(&s->gpio);
1187 	if (ret)
1188 		goto out_uart;
1189 #endif
1190 
1191 	mutex_init(&s->mutex);
1192 
1193 	for (i = 0; i < devtype->nr; i++) {
1194 		/* Initialize port data */
1195 		s->p[i].port.line	= i;
1196 		s->p[i].port.dev	= dev;
1197 		s->p[i].port.irq	= irq;
1198 		s->p[i].port.type	= PORT_MAX310X;
1199 		s->p[i].port.fifosize	= MAX310X_FIFO_SIZE;
1200 		s->p[i].port.flags	= UPF_FIXED_TYPE | UPF_LOW_LATENCY;
1201 		s->p[i].port.iotype	= UPIO_PORT;
1202 		s->p[i].port.iobase	= i * 0x20;
1203 		s->p[i].port.membase	= (void __iomem *)~0;
1204 		s->p[i].port.uartclk	= uartclk;
1205 		s->p[i].port.rs485_config = max310x_rs485_config;
1206 		s->p[i].port.ops	= &max310x_ops;
1207 		/* Disable all interrupts */
1208 		max310x_port_write(&s->p[i].port, MAX310X_IRQEN_REG, 0);
1209 		/* Clear IRQ status register */
1210 		max310x_port_read(&s->p[i].port, MAX310X_IRQSTS_REG);
1211 		/* Enable IRQ pin */
1212 		max310x_port_update(&s->p[i].port, MAX310X_MODE1_REG,
1213 				    MAX310X_MODE1_IRQSEL_BIT,
1214 				    MAX310X_MODE1_IRQSEL_BIT);
1215 		/* Initialize queue for start TX */
1216 		INIT_WORK(&s->p[i].tx_work, max310x_wq_proc);
1217 		/* Initialize queue for changing mode */
1218 		INIT_WORK(&s->p[i].md_work, max310x_md_proc);
1219 		/* Register port */
1220 		uart_add_one_port(&s->uart, &s->p[i].port);
1221 		/* Go to suspend mode */
1222 		devtype->power(&s->p[i].port, 0);
1223 	}
1224 
1225 	/* Setup interrupt */
1226 	ret = devm_request_threaded_irq(dev, irq, NULL, max310x_ist,
1227 					IRQF_ONESHOT | flags, dev_name(dev), s);
1228 	if (!ret)
1229 		return 0;
1230 
1231 	dev_err(dev, "Unable to reguest IRQ %i\n", irq);
1232 
1233 	mutex_destroy(&s->mutex);
1234 
1235 #ifdef CONFIG_GPIOLIB
1236 	gpiochip_remove(&s->gpio);
1237 
1238 out_uart:
1239 #endif
1240 	uart_unregister_driver(&s->uart);
1241 
1242 out_clk:
1243 	clk_disable_unprepare(s->clk);
1244 
1245 	return ret;
1246 }
1247 
1248 static int max310x_remove(struct device *dev)
1249 {
1250 	struct max310x_port *s = dev_get_drvdata(dev);
1251 	int i;
1252 
1253 #ifdef CONFIG_GPIOLIB
1254 	gpiochip_remove(&s->gpio);
1255 #endif
1256 
1257 	for (i = 0; i < s->uart.nr; i++) {
1258 		cancel_work_sync(&s->p[i].tx_work);
1259 		cancel_work_sync(&s->p[i].md_work);
1260 		uart_remove_one_port(&s->uart, &s->p[i].port);
1261 		s->devtype->power(&s->p[i].port, 0);
1262 	}
1263 
1264 	mutex_destroy(&s->mutex);
1265 	uart_unregister_driver(&s->uart);
1266 	clk_disable_unprepare(s->clk);
1267 
1268 	return 0;
1269 }
1270 
1271 static const struct of_device_id __maybe_unused max310x_dt_ids[] = {
1272 	{ .compatible = "maxim,max3107",	.data = &max3107_devtype, },
1273 	{ .compatible = "maxim,max3108",	.data = &max3108_devtype, },
1274 	{ .compatible = "maxim,max3109",	.data = &max3109_devtype, },
1275 	{ .compatible = "maxim,max14830",	.data = &max14830_devtype },
1276 	{ }
1277 };
1278 MODULE_DEVICE_TABLE(of, max310x_dt_ids);
1279 
1280 static struct regmap_config regcfg = {
1281 	.reg_bits = 8,
1282 	.val_bits = 8,
1283 	.write_flag_mask = 0x80,
1284 	.cache_type = REGCACHE_RBTREE,
1285 	.writeable_reg = max310x_reg_writeable,
1286 	.volatile_reg = max310x_reg_volatile,
1287 	.precious_reg = max310x_reg_precious,
1288 };
1289 
1290 #ifdef CONFIG_SPI_MASTER
1291 static int max310x_spi_probe(struct spi_device *spi)
1292 {
1293 	struct max310x_devtype *devtype;
1294 	unsigned long flags = 0;
1295 	struct regmap *regmap;
1296 	int ret;
1297 
1298 	/* Setup SPI bus */
1299 	spi->bits_per_word	= 8;
1300 	spi->mode		= spi->mode ? : SPI_MODE_0;
1301 	spi->max_speed_hz	= spi->max_speed_hz ? : 26000000;
1302 	ret = spi_setup(spi);
1303 	if (ret)
1304 		return ret;
1305 
1306 	if (spi->dev.of_node) {
1307 		const struct of_device_id *of_id =
1308 			of_match_device(max310x_dt_ids, &spi->dev);
1309 
1310 		devtype = (struct max310x_devtype *)of_id->data;
1311 	} else {
1312 		const struct spi_device_id *id_entry = spi_get_device_id(spi);
1313 
1314 		devtype = (struct max310x_devtype *)id_entry->driver_data;
1315 		flags = IRQF_TRIGGER_FALLING;
1316 	}
1317 
1318 	regcfg.max_register = devtype->nr * 0x20 - 1;
1319 	regmap = devm_regmap_init_spi(spi, &regcfg);
1320 
1321 	return max310x_probe(&spi->dev, devtype, regmap, spi->irq, flags);
1322 }
1323 
1324 static int max310x_spi_remove(struct spi_device *spi)
1325 {
1326 	return max310x_remove(&spi->dev);
1327 }
1328 
1329 static const struct spi_device_id max310x_id_table[] = {
1330 	{ "max3107",	(kernel_ulong_t)&max3107_devtype, },
1331 	{ "max3108",	(kernel_ulong_t)&max3108_devtype, },
1332 	{ "max3109",	(kernel_ulong_t)&max3109_devtype, },
1333 	{ "max14830",	(kernel_ulong_t)&max14830_devtype, },
1334 	{ }
1335 };
1336 MODULE_DEVICE_TABLE(spi, max310x_id_table);
1337 
1338 static struct spi_driver max310x_uart_driver = {
1339 	.driver = {
1340 		.name		= MAX310X_NAME,
1341 		.of_match_table	= of_match_ptr(max310x_dt_ids),
1342 		.pm		= &max310x_pm_ops,
1343 	},
1344 	.probe		= max310x_spi_probe,
1345 	.remove		= max310x_spi_remove,
1346 	.id_table	= max310x_id_table,
1347 };
1348 module_spi_driver(max310x_uart_driver);
1349 #endif
1350 
1351 MODULE_LICENSE("GPL");
1352 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
1353 MODULE_DESCRIPTION("MAX310X serial driver");
1354