xref: /linux/drivers/i2c/busses/i2c-bcm-iproc.c (revision 17b121ad0c43342bc894632f6710b894849ca372)
1 /*
2  * Copyright (C) 2014 Broadcom Corporation
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License as
6  * published by the Free Software Foundation version 2.
7  *
8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
9  * kind, whether express or implied; without even the implied warranty
10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  */
13 
14 #include <linux/delay.h>
15 #include <linux/i2c.h>
16 #include <linux/interrupt.h>
17 #include <linux/io.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/of_device.h>
21 #include <linux/platform_device.h>
22 #include <linux/slab.h>
23 
24 #define IDM_CTRL_DIRECT_OFFSET       0x00
25 #define CFG_OFFSET                   0x00
26 #define CFG_RESET_SHIFT              31
27 #define CFG_EN_SHIFT                 30
28 #define CFG_SLAVE_ADDR_0_SHIFT       28
29 #define CFG_M_RETRY_CNT_SHIFT        16
30 #define CFG_M_RETRY_CNT_MASK         0x0f
31 
32 #define TIM_CFG_OFFSET               0x04
33 #define TIM_CFG_MODE_400_SHIFT       31
34 #define TIM_RAND_SLAVE_STRETCH_SHIFT      24
35 #define TIM_RAND_SLAVE_STRETCH_MASK       0x7f
36 #define TIM_PERIODIC_SLAVE_STRETCH_SHIFT  16
37 #define TIM_PERIODIC_SLAVE_STRETCH_MASK   0x7f
38 
39 #define S_CFG_SMBUS_ADDR_OFFSET           0x08
40 #define S_CFG_EN_NIC_SMB_ADDR3_SHIFT      31
41 #define S_CFG_NIC_SMB_ADDR3_SHIFT         24
42 #define S_CFG_NIC_SMB_ADDR3_MASK          0x7f
43 #define S_CFG_EN_NIC_SMB_ADDR2_SHIFT      23
44 #define S_CFG_NIC_SMB_ADDR2_SHIFT         16
45 #define S_CFG_NIC_SMB_ADDR2_MASK          0x7f
46 #define S_CFG_EN_NIC_SMB_ADDR1_SHIFT      15
47 #define S_CFG_NIC_SMB_ADDR1_SHIFT         8
48 #define S_CFG_NIC_SMB_ADDR1_MASK          0x7f
49 #define S_CFG_EN_NIC_SMB_ADDR0_SHIFT      7
50 #define S_CFG_NIC_SMB_ADDR0_SHIFT         0
51 #define S_CFG_NIC_SMB_ADDR0_MASK          0x7f
52 
53 #define M_FIFO_CTRL_OFFSET           0x0c
54 #define M_FIFO_RX_FLUSH_SHIFT        31
55 #define M_FIFO_TX_FLUSH_SHIFT        30
56 #define M_FIFO_RX_CNT_SHIFT          16
57 #define M_FIFO_RX_CNT_MASK           0x7f
58 #define M_FIFO_RX_THLD_SHIFT         8
59 #define M_FIFO_RX_THLD_MASK          0x3f
60 
61 #define S_FIFO_CTRL_OFFSET           0x10
62 #define S_FIFO_RX_FLUSH_SHIFT        31
63 #define S_FIFO_TX_FLUSH_SHIFT        30
64 #define S_FIFO_RX_CNT_SHIFT          16
65 #define S_FIFO_RX_CNT_MASK           0x7f
66 #define S_FIFO_RX_THLD_SHIFT         8
67 #define S_FIFO_RX_THLD_MASK          0x3f
68 
69 #define M_CMD_OFFSET                 0x30
70 #define M_CMD_START_BUSY_SHIFT       31
71 #define M_CMD_STATUS_SHIFT           25
72 #define M_CMD_STATUS_MASK            0x07
73 #define M_CMD_STATUS_SUCCESS         0x0
74 #define M_CMD_STATUS_LOST_ARB        0x1
75 #define M_CMD_STATUS_NACK_ADDR       0x2
76 #define M_CMD_STATUS_NACK_DATA       0x3
77 #define M_CMD_STATUS_TIMEOUT         0x4
78 #define M_CMD_STATUS_FIFO_UNDERRUN   0x5
79 #define M_CMD_STATUS_RX_FIFO_FULL    0x6
80 #define M_CMD_PROTOCOL_SHIFT         9
81 #define M_CMD_PROTOCOL_MASK          0xf
82 #define M_CMD_PROTOCOL_QUICK         0x0
83 #define M_CMD_PROTOCOL_BLK_WR        0x7
84 #define M_CMD_PROTOCOL_BLK_RD        0x8
85 #define M_CMD_PROTOCOL_PROCESS       0xa
86 #define M_CMD_PEC_SHIFT              8
87 #define M_CMD_RD_CNT_SHIFT           0
88 #define M_CMD_RD_CNT_MASK            0xff
89 
90 #define S_CMD_OFFSET                 0x34
91 #define S_CMD_START_BUSY_SHIFT       31
92 #define S_CMD_STATUS_SHIFT           23
93 #define S_CMD_STATUS_MASK            0x07
94 #define S_CMD_STATUS_SUCCESS         0x0
95 #define S_CMD_STATUS_TIMEOUT         0x5
96 #define S_CMD_STATUS_MASTER_ABORT    0x7
97 
98 #define IE_OFFSET                    0x38
99 #define IE_M_RX_FIFO_FULL_SHIFT      31
100 #define IE_M_RX_THLD_SHIFT           30
101 #define IE_M_START_BUSY_SHIFT        28
102 #define IE_M_TX_UNDERRUN_SHIFT       27
103 #define IE_S_RX_FIFO_FULL_SHIFT      26
104 #define IE_S_RX_THLD_SHIFT           25
105 #define IE_S_RX_EVENT_SHIFT          24
106 #define IE_S_START_BUSY_SHIFT        23
107 #define IE_S_TX_UNDERRUN_SHIFT       22
108 #define IE_S_RD_EVENT_SHIFT          21
109 
110 #define IS_OFFSET                    0x3c
111 #define IS_M_RX_FIFO_FULL_SHIFT      31
112 #define IS_M_RX_THLD_SHIFT           30
113 #define IS_M_START_BUSY_SHIFT        28
114 #define IS_M_TX_UNDERRUN_SHIFT       27
115 #define IS_S_RX_FIFO_FULL_SHIFT      26
116 #define IS_S_RX_THLD_SHIFT           25
117 #define IS_S_RX_EVENT_SHIFT          24
118 #define IS_S_START_BUSY_SHIFT        23
119 #define IS_S_TX_UNDERRUN_SHIFT       22
120 #define IS_S_RD_EVENT_SHIFT          21
121 
122 #define M_TX_OFFSET                  0x40
123 #define M_TX_WR_STATUS_SHIFT         31
124 #define M_TX_DATA_SHIFT              0
125 #define M_TX_DATA_MASK               0xff
126 
127 #define M_RX_OFFSET                  0x44
128 #define M_RX_STATUS_SHIFT            30
129 #define M_RX_STATUS_MASK             0x03
130 #define M_RX_PEC_ERR_SHIFT           29
131 #define M_RX_DATA_SHIFT              0
132 #define M_RX_DATA_MASK               0xff
133 
134 #define S_TX_OFFSET                  0x48
135 #define S_TX_WR_STATUS_SHIFT         31
136 #define S_TX_DATA_SHIFT              0
137 #define S_TX_DATA_MASK               0xff
138 
139 #define S_RX_OFFSET                  0x4c
140 #define S_RX_STATUS_SHIFT            30
141 #define S_RX_STATUS_MASK             0x03
142 #define S_RX_PEC_ERR_SHIFT           29
143 #define S_RX_DATA_SHIFT              0
144 #define S_RX_DATA_MASK               0xff
145 
146 #define I2C_TIMEOUT_MSEC             50000
147 #define M_TX_RX_FIFO_SIZE            64
148 #define M_RX_FIFO_MAX_THLD_VALUE     (M_TX_RX_FIFO_SIZE - 1)
149 
150 #define M_RX_MAX_READ_LEN            255
151 #define M_RX_FIFO_THLD_VALUE         50
152 
153 #define IE_M_ALL_INTERRUPT_SHIFT     27
154 #define IE_M_ALL_INTERRUPT_MASK      0x1e
155 
156 #define SLAVE_READ_WRITE_BIT_MASK    0x1
157 #define SLAVE_READ_WRITE_BIT_SHIFT   0x1
158 #define SLAVE_MAX_SIZE_TRANSACTION   64
159 #define SLAVE_CLOCK_STRETCH_TIME     25
160 
161 #define IE_S_ALL_INTERRUPT_SHIFT     21
162 #define IE_S_ALL_INTERRUPT_MASK      0x3f
163 /*
164  * It takes ~18us to reading 10bytes of data, hence to keep tasklet
165  * running for less time, max slave read per tasklet is set to 10 bytes.
166  */
167 #define MAX_SLAVE_RX_PER_INT         10
168 
169 enum i2c_slave_read_status {
170 	I2C_SLAVE_RX_FIFO_EMPTY = 0,
171 	I2C_SLAVE_RX_START,
172 	I2C_SLAVE_RX_DATA,
173 	I2C_SLAVE_RX_END,
174 };
175 
176 enum bus_speed_index {
177 	I2C_SPD_100K = 0,
178 	I2C_SPD_400K,
179 };
180 
181 enum bcm_iproc_i2c_type {
182 	IPROC_I2C,
183 	IPROC_I2C_NIC
184 };
185 
186 struct bcm_iproc_i2c_dev {
187 	struct device *device;
188 	enum bcm_iproc_i2c_type type;
189 	int irq;
190 
191 	void __iomem *base;
192 	void __iomem *idm_base;
193 
194 	u32 ape_addr_mask;
195 
196 	/* lock for indirect access through IDM */
197 	spinlock_t idm_lock;
198 
199 	struct i2c_adapter adapter;
200 	unsigned int bus_speed;
201 
202 	struct completion done;
203 	int xfer_is_done;
204 
205 	struct i2c_msg *msg;
206 
207 	struct i2c_client *slave;
208 
209 	/* bytes that have been transferred */
210 	unsigned int tx_bytes;
211 	/* bytes that have been read */
212 	unsigned int rx_bytes;
213 	unsigned int thld_bytes;
214 
215 	bool slave_rx_only;
216 	bool rx_start_rcvd;
217 	bool slave_read_complete;
218 	u32 tx_underrun;
219 	u32 slave_int_mask;
220 	struct tasklet_struct slave_rx_tasklet;
221 };
222 
223 /* tasklet to process slave rx data */
224 static void slave_rx_tasklet_fn(unsigned long);
225 
226 /*
227  * Can be expanded in the future if more interrupt status bits are utilized
228  */
229 #define ISR_MASK (BIT(IS_M_START_BUSY_SHIFT) | BIT(IS_M_TX_UNDERRUN_SHIFT)\
230 		| BIT(IS_M_RX_THLD_SHIFT))
231 
232 #define ISR_MASK_SLAVE (BIT(IS_S_START_BUSY_SHIFT)\
233 		| BIT(IS_S_RX_EVENT_SHIFT) | BIT(IS_S_RD_EVENT_SHIFT)\
234 		| BIT(IS_S_TX_UNDERRUN_SHIFT) | BIT(IS_S_RX_FIFO_FULL_SHIFT)\
235 		| BIT(IS_S_RX_THLD_SHIFT))
236 
237 static int bcm_iproc_i2c_reg_slave(struct i2c_client *slave);
238 static int bcm_iproc_i2c_unreg_slave(struct i2c_client *slave);
239 static void bcm_iproc_i2c_enable_disable(struct bcm_iproc_i2c_dev *iproc_i2c,
240 					 bool enable);
241 
242 static inline u32 iproc_i2c_rd_reg(struct bcm_iproc_i2c_dev *iproc_i2c,
243 				   u32 offset)
244 {
245 	u32 val;
246 
247 	if (iproc_i2c->idm_base) {
248 		spin_lock(&iproc_i2c->idm_lock);
249 		writel(iproc_i2c->ape_addr_mask,
250 		       iproc_i2c->idm_base + IDM_CTRL_DIRECT_OFFSET);
251 		val = readl(iproc_i2c->base + offset);
252 		spin_unlock(&iproc_i2c->idm_lock);
253 	} else {
254 		val = readl(iproc_i2c->base + offset);
255 	}
256 
257 	return val;
258 }
259 
260 static inline void iproc_i2c_wr_reg(struct bcm_iproc_i2c_dev *iproc_i2c,
261 				    u32 offset, u32 val)
262 {
263 	if (iproc_i2c->idm_base) {
264 		spin_lock(&iproc_i2c->idm_lock);
265 		writel(iproc_i2c->ape_addr_mask,
266 		       iproc_i2c->idm_base + IDM_CTRL_DIRECT_OFFSET);
267 		writel(val, iproc_i2c->base + offset);
268 		spin_unlock(&iproc_i2c->idm_lock);
269 	} else {
270 		writel(val, iproc_i2c->base + offset);
271 	}
272 }
273 
274 static void bcm_iproc_i2c_slave_init(
275 	struct bcm_iproc_i2c_dev *iproc_i2c, bool need_reset)
276 {
277 	u32 val;
278 
279 	iproc_i2c->tx_underrun = 0;
280 	if (need_reset) {
281 		/* put controller in reset */
282 		val = iproc_i2c_rd_reg(iproc_i2c, CFG_OFFSET);
283 		val |= BIT(CFG_RESET_SHIFT);
284 		iproc_i2c_wr_reg(iproc_i2c, CFG_OFFSET, val);
285 
286 		/* wait 100 usec per spec */
287 		udelay(100);
288 
289 		/* bring controller out of reset */
290 		val &= ~(BIT(CFG_RESET_SHIFT));
291 		iproc_i2c_wr_reg(iproc_i2c, CFG_OFFSET, val);
292 	}
293 
294 	/* flush TX/RX FIFOs */
295 	val = (BIT(S_FIFO_RX_FLUSH_SHIFT) | BIT(S_FIFO_TX_FLUSH_SHIFT));
296 	iproc_i2c_wr_reg(iproc_i2c, S_FIFO_CTRL_OFFSET, val);
297 
298 	/* Maximum slave stretch time */
299 	val = iproc_i2c_rd_reg(iproc_i2c, TIM_CFG_OFFSET);
300 	val &= ~(TIM_RAND_SLAVE_STRETCH_MASK << TIM_RAND_SLAVE_STRETCH_SHIFT);
301 	val |= (SLAVE_CLOCK_STRETCH_TIME << TIM_RAND_SLAVE_STRETCH_SHIFT);
302 	iproc_i2c_wr_reg(iproc_i2c, TIM_CFG_OFFSET, val);
303 
304 	/* Configure the slave address */
305 	val = iproc_i2c_rd_reg(iproc_i2c, S_CFG_SMBUS_ADDR_OFFSET);
306 	val |= BIT(S_CFG_EN_NIC_SMB_ADDR3_SHIFT);
307 	val &= ~(S_CFG_NIC_SMB_ADDR3_MASK << S_CFG_NIC_SMB_ADDR3_SHIFT);
308 	val |= (iproc_i2c->slave->addr << S_CFG_NIC_SMB_ADDR3_SHIFT);
309 	iproc_i2c_wr_reg(iproc_i2c, S_CFG_SMBUS_ADDR_OFFSET, val);
310 
311 	/* clear all pending slave interrupts */
312 	iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, ISR_MASK_SLAVE);
313 
314 	/* Enable interrupt register to indicate a valid byte in receive fifo */
315 	val = BIT(IE_S_RX_EVENT_SHIFT);
316 	/* Enable interrupt register to indicate Slave Rx FIFO Full */
317 	val |= BIT(IE_S_RX_FIFO_FULL_SHIFT);
318 	/* Enable interrupt register to indicate a Master read transaction */
319 	val |= BIT(IE_S_RD_EVENT_SHIFT);
320 	/* Enable interrupt register for the Slave BUSY command */
321 	val |= BIT(IE_S_START_BUSY_SHIFT);
322 	iproc_i2c->slave_int_mask = val;
323 	iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val);
324 }
325 
326 static void bcm_iproc_i2c_check_slave_status(
327 	struct bcm_iproc_i2c_dev *iproc_i2c)
328 {
329 	u32 val;
330 
331 	val = iproc_i2c_rd_reg(iproc_i2c, S_CMD_OFFSET);
332 	/* status is valid only when START_BUSY is cleared after it was set */
333 	if (val & BIT(S_CMD_START_BUSY_SHIFT))
334 		return;
335 
336 	val = (val >> S_CMD_STATUS_SHIFT) & S_CMD_STATUS_MASK;
337 	if (val == S_CMD_STATUS_TIMEOUT || val == S_CMD_STATUS_MASTER_ABORT) {
338 		dev_err(iproc_i2c->device, (val == S_CMD_STATUS_TIMEOUT) ?
339 			"slave random stretch time timeout\n" :
340 			"Master aborted read transaction\n");
341 		/* re-initialize i2c for recovery */
342 		bcm_iproc_i2c_enable_disable(iproc_i2c, false);
343 		bcm_iproc_i2c_slave_init(iproc_i2c, true);
344 		bcm_iproc_i2c_enable_disable(iproc_i2c, true);
345 	}
346 }
347 
348 static void bcm_iproc_i2c_slave_read(struct bcm_iproc_i2c_dev *iproc_i2c)
349 {
350 	u8 rx_data, rx_status;
351 	u32 rx_bytes = 0;
352 	u32 val;
353 
354 	while (rx_bytes < MAX_SLAVE_RX_PER_INT) {
355 		val = iproc_i2c_rd_reg(iproc_i2c, S_RX_OFFSET);
356 		rx_status = (val >> S_RX_STATUS_SHIFT) & S_RX_STATUS_MASK;
357 		rx_data = ((val >> S_RX_DATA_SHIFT) & S_RX_DATA_MASK);
358 
359 		if (rx_status == I2C_SLAVE_RX_START) {
360 			/* Start of SMBUS Master write */
361 			i2c_slave_event(iproc_i2c->slave,
362 					I2C_SLAVE_WRITE_REQUESTED, &rx_data);
363 			iproc_i2c->rx_start_rcvd = true;
364 			iproc_i2c->slave_read_complete = false;
365 		} else if (rx_status == I2C_SLAVE_RX_DATA &&
366 			   iproc_i2c->rx_start_rcvd) {
367 			/* Middle of SMBUS Master write */
368 			i2c_slave_event(iproc_i2c->slave,
369 					I2C_SLAVE_WRITE_RECEIVED, &rx_data);
370 		} else if (rx_status == I2C_SLAVE_RX_END &&
371 			   iproc_i2c->rx_start_rcvd) {
372 			/* End of SMBUS Master write */
373 			if (iproc_i2c->slave_rx_only)
374 				i2c_slave_event(iproc_i2c->slave,
375 						I2C_SLAVE_WRITE_RECEIVED,
376 						&rx_data);
377 
378 			i2c_slave_event(iproc_i2c->slave, I2C_SLAVE_STOP,
379 					&rx_data);
380 		} else if (rx_status == I2C_SLAVE_RX_FIFO_EMPTY) {
381 			iproc_i2c->rx_start_rcvd = false;
382 			iproc_i2c->slave_read_complete = true;
383 			break;
384 		}
385 
386 		rx_bytes++;
387 	}
388 }
389 
390 static void slave_rx_tasklet_fn(unsigned long data)
391 {
392 	struct bcm_iproc_i2c_dev *iproc_i2c = (struct bcm_iproc_i2c_dev *)data;
393 	u32 int_clr;
394 
395 	bcm_iproc_i2c_slave_read(iproc_i2c);
396 
397 	/* clear pending IS_S_RX_EVENT_SHIFT interrupt */
398 	int_clr = BIT(IS_S_RX_EVENT_SHIFT);
399 
400 	if (!iproc_i2c->slave_rx_only && iproc_i2c->slave_read_complete) {
401 		/*
402 		 * In case of single byte master-read request,
403 		 * IS_S_TX_UNDERRUN_SHIFT event is generated before
404 		 * IS_S_START_BUSY_SHIFT event. Hence start slave data send
405 		 * from first IS_S_TX_UNDERRUN_SHIFT event.
406 		 *
407 		 * This means don't send any data from slave when
408 		 * IS_S_RD_EVENT_SHIFT event is generated else it will increment
409 		 * eeprom or other backend slave driver read pointer twice.
410 		 */
411 		iproc_i2c->tx_underrun = 0;
412 		iproc_i2c->slave_int_mask |= BIT(IE_S_TX_UNDERRUN_SHIFT);
413 
414 		/* clear IS_S_RD_EVENT_SHIFT interrupt */
415 		int_clr |= BIT(IS_S_RD_EVENT_SHIFT);
416 	}
417 
418 	/* clear slave interrupt */
419 	iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, int_clr);
420 	/* enable slave interrupts */
421 	iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, iproc_i2c->slave_int_mask);
422 }
423 
424 static bool bcm_iproc_i2c_slave_isr(struct bcm_iproc_i2c_dev *iproc_i2c,
425 				    u32 status)
426 {
427 	u32 val;
428 	u8 value;
429 
430 	/*
431 	 * Slave events in case of master-write, master-write-read and,
432 	 * master-read
433 	 *
434 	 * Master-write     : only IS_S_RX_EVENT_SHIFT event
435 	 * Master-write-read: both IS_S_RX_EVENT_SHIFT and IS_S_RD_EVENT_SHIFT
436 	 *                    events
437 	 * Master-read      : both IS_S_RX_EVENT_SHIFT and IS_S_RD_EVENT_SHIFT
438 	 *                    events or only IS_S_RD_EVENT_SHIFT
439 	 *
440 	 * iproc has a slave rx fifo size of 64 bytes. Rx fifo full interrupt
441 	 * (IS_S_RX_FIFO_FULL_SHIFT) will be generated when RX fifo becomes
442 	 * full. This can happen if Master issues write requests of more than
443 	 * 64 bytes.
444 	 */
445 	if (status & BIT(IS_S_RX_EVENT_SHIFT) ||
446 	    status & BIT(IS_S_RD_EVENT_SHIFT) ||
447 	    status & BIT(IS_S_RX_FIFO_FULL_SHIFT)) {
448 		/* disable slave interrupts */
449 		val = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET);
450 		val &= ~iproc_i2c->slave_int_mask;
451 		iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val);
452 
453 		if (status & BIT(IS_S_RD_EVENT_SHIFT))
454 			/* Master-write-read request */
455 			iproc_i2c->slave_rx_only = false;
456 		else
457 			/* Master-write request only */
458 			iproc_i2c->slave_rx_only = true;
459 
460 		/* schedule tasklet to read data later */
461 		tasklet_schedule(&iproc_i2c->slave_rx_tasklet);
462 
463 		/*
464 		 * clear only IS_S_RX_EVENT_SHIFT and
465 		 * IS_S_RX_FIFO_FULL_SHIFT interrupt.
466 		 */
467 		val = BIT(IS_S_RX_EVENT_SHIFT);
468 		if (status & BIT(IS_S_RX_FIFO_FULL_SHIFT))
469 			val |= BIT(IS_S_RX_FIFO_FULL_SHIFT);
470 		iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, val);
471 	}
472 
473 	if (status & BIT(IS_S_TX_UNDERRUN_SHIFT)) {
474 		iproc_i2c->tx_underrun++;
475 		if (iproc_i2c->tx_underrun == 1)
476 			/* Start of SMBUS for Master Read */
477 			i2c_slave_event(iproc_i2c->slave,
478 					I2C_SLAVE_READ_REQUESTED,
479 					&value);
480 		else
481 			/* Master read other than start */
482 			i2c_slave_event(iproc_i2c->slave,
483 					I2C_SLAVE_READ_PROCESSED,
484 					&value);
485 
486 		iproc_i2c_wr_reg(iproc_i2c, S_TX_OFFSET, value);
487 		/* start transfer */
488 		val = BIT(S_CMD_START_BUSY_SHIFT);
489 		iproc_i2c_wr_reg(iproc_i2c, S_CMD_OFFSET, val);
490 
491 		/* clear interrupt */
492 		iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET,
493 				 BIT(IS_S_TX_UNDERRUN_SHIFT));
494 	}
495 
496 	/* Stop received from master in case of master read transaction */
497 	if (status & BIT(IS_S_START_BUSY_SHIFT)) {
498 		/*
499 		 * Disable interrupt for TX FIFO becomes empty and
500 		 * less than PKT_LENGTH bytes were output on the SMBUS
501 		 */
502 		iproc_i2c->slave_int_mask &= ~BIT(IE_S_TX_UNDERRUN_SHIFT);
503 		iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET,
504 				 iproc_i2c->slave_int_mask);
505 
506 		/* End of SMBUS for Master Read */
507 		val = BIT(S_TX_WR_STATUS_SHIFT);
508 		iproc_i2c_wr_reg(iproc_i2c, S_TX_OFFSET, val);
509 
510 		val = BIT(S_CMD_START_BUSY_SHIFT);
511 		iproc_i2c_wr_reg(iproc_i2c, S_CMD_OFFSET, val);
512 
513 		/* flush TX FIFOs */
514 		val = iproc_i2c_rd_reg(iproc_i2c, S_FIFO_CTRL_OFFSET);
515 		val |= (BIT(S_FIFO_TX_FLUSH_SHIFT));
516 		iproc_i2c_wr_reg(iproc_i2c, S_FIFO_CTRL_OFFSET, val);
517 
518 		i2c_slave_event(iproc_i2c->slave, I2C_SLAVE_STOP, &value);
519 
520 		/* clear interrupt */
521 		iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET,
522 				 BIT(IS_S_START_BUSY_SHIFT));
523 	}
524 
525 	/* check slave transmit status only if slave is transmitting */
526 	if (!iproc_i2c->slave_rx_only)
527 		bcm_iproc_i2c_check_slave_status(iproc_i2c);
528 
529 	return true;
530 }
531 
532 static void bcm_iproc_i2c_read_valid_bytes(struct bcm_iproc_i2c_dev *iproc_i2c)
533 {
534 	struct i2c_msg *msg = iproc_i2c->msg;
535 	uint32_t val;
536 
537 	/* Read valid data from RX FIFO */
538 	while (iproc_i2c->rx_bytes < msg->len) {
539 		val = iproc_i2c_rd_reg(iproc_i2c, M_RX_OFFSET);
540 
541 		/* rx fifo empty */
542 		if (!((val >> M_RX_STATUS_SHIFT) & M_RX_STATUS_MASK))
543 			break;
544 
545 		msg->buf[iproc_i2c->rx_bytes] =
546 			(val >> M_RX_DATA_SHIFT) & M_RX_DATA_MASK;
547 		iproc_i2c->rx_bytes++;
548 	}
549 }
550 
551 static void bcm_iproc_i2c_send(struct bcm_iproc_i2c_dev *iproc_i2c)
552 {
553 	struct i2c_msg *msg = iproc_i2c->msg;
554 	unsigned int tx_bytes = msg->len - iproc_i2c->tx_bytes;
555 	unsigned int i;
556 	u32 val;
557 
558 	/* can only fill up to the FIFO size */
559 	tx_bytes = min_t(unsigned int, tx_bytes, M_TX_RX_FIFO_SIZE);
560 	for (i = 0; i < tx_bytes; i++) {
561 		/* start from where we left over */
562 		unsigned int idx = iproc_i2c->tx_bytes + i;
563 
564 		val = msg->buf[idx];
565 
566 		/* mark the last byte */
567 		if (idx == msg->len - 1) {
568 			val |= BIT(M_TX_WR_STATUS_SHIFT);
569 
570 			if (iproc_i2c->irq) {
571 				u32 tmp;
572 
573 				/*
574 				 * Since this is the last byte, we should now
575 				 * disable TX FIFO underrun interrupt
576 				 */
577 				tmp = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET);
578 				tmp &= ~BIT(IE_M_TX_UNDERRUN_SHIFT);
579 				iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET,
580 						 tmp);
581 			}
582 		}
583 
584 		/* load data into TX FIFO */
585 		iproc_i2c_wr_reg(iproc_i2c, M_TX_OFFSET, val);
586 	}
587 
588 	/* update number of transferred bytes */
589 	iproc_i2c->tx_bytes += tx_bytes;
590 }
591 
592 static void bcm_iproc_i2c_read(struct bcm_iproc_i2c_dev *iproc_i2c)
593 {
594 	struct i2c_msg *msg = iproc_i2c->msg;
595 	u32 bytes_left, val;
596 
597 	bcm_iproc_i2c_read_valid_bytes(iproc_i2c);
598 	bytes_left = msg->len - iproc_i2c->rx_bytes;
599 	if (bytes_left == 0) {
600 		if (iproc_i2c->irq) {
601 			/* finished reading all data, disable rx thld event */
602 			val = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET);
603 			val &= ~BIT(IS_M_RX_THLD_SHIFT);
604 			iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val);
605 		}
606 	} else if (bytes_left < iproc_i2c->thld_bytes) {
607 		/* set bytes left as threshold */
608 		val = iproc_i2c_rd_reg(iproc_i2c, M_FIFO_CTRL_OFFSET);
609 		val &= ~(M_FIFO_RX_THLD_MASK << M_FIFO_RX_THLD_SHIFT);
610 		val |= (bytes_left << M_FIFO_RX_THLD_SHIFT);
611 		iproc_i2c_wr_reg(iproc_i2c, M_FIFO_CTRL_OFFSET, val);
612 		iproc_i2c->thld_bytes = bytes_left;
613 	}
614 	/*
615 	 * bytes_left >= iproc_i2c->thld_bytes,
616 	 * hence no need to change the THRESHOLD SET.
617 	 * It will remain as iproc_i2c->thld_bytes itself
618 	 */
619 }
620 
621 static void bcm_iproc_i2c_process_m_event(struct bcm_iproc_i2c_dev *iproc_i2c,
622 					  u32 status)
623 {
624 	/* TX FIFO is empty and we have more data to send */
625 	if (status & BIT(IS_M_TX_UNDERRUN_SHIFT))
626 		bcm_iproc_i2c_send(iproc_i2c);
627 
628 	/* RX FIFO threshold is reached and data needs to be read out */
629 	if (status & BIT(IS_M_RX_THLD_SHIFT))
630 		bcm_iproc_i2c_read(iproc_i2c);
631 
632 	/* transfer is done */
633 	if (status & BIT(IS_M_START_BUSY_SHIFT)) {
634 		iproc_i2c->xfer_is_done = 1;
635 		if (iproc_i2c->irq)
636 			complete(&iproc_i2c->done);
637 	}
638 }
639 
640 static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data)
641 {
642 	struct bcm_iproc_i2c_dev *iproc_i2c = data;
643 	u32 slave_status;
644 	u32 status;
645 	bool ret;
646 
647 	status = iproc_i2c_rd_reg(iproc_i2c, IS_OFFSET);
648 	/* process only slave interrupt which are enabled */
649 	slave_status = status & iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET) &
650 		       ISR_MASK_SLAVE;
651 
652 	if (slave_status) {
653 		ret = bcm_iproc_i2c_slave_isr(iproc_i2c, slave_status);
654 		if (ret)
655 			return IRQ_HANDLED;
656 		else
657 			return IRQ_NONE;
658 	}
659 
660 	status &= ISR_MASK;
661 	if (!status)
662 		return IRQ_NONE;
663 
664 	/* process all master based events */
665 	bcm_iproc_i2c_process_m_event(iproc_i2c, status);
666 	iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, status);
667 
668 	return IRQ_HANDLED;
669 }
670 
671 static int bcm_iproc_i2c_init(struct bcm_iproc_i2c_dev *iproc_i2c)
672 {
673 	u32 val;
674 
675 	/* put controller in reset */
676 	val = iproc_i2c_rd_reg(iproc_i2c, CFG_OFFSET);
677 	val |= BIT(CFG_RESET_SHIFT);
678 	val &= ~(BIT(CFG_EN_SHIFT));
679 	iproc_i2c_wr_reg(iproc_i2c, CFG_OFFSET, val);
680 
681 	/* wait 100 usec per spec */
682 	udelay(100);
683 
684 	/* bring controller out of reset */
685 	val &= ~(BIT(CFG_RESET_SHIFT));
686 	iproc_i2c_wr_reg(iproc_i2c, CFG_OFFSET, val);
687 
688 	/* flush TX/RX FIFOs and set RX FIFO threshold to zero */
689 	val = (BIT(M_FIFO_RX_FLUSH_SHIFT) | BIT(M_FIFO_TX_FLUSH_SHIFT));
690 	iproc_i2c_wr_reg(iproc_i2c, M_FIFO_CTRL_OFFSET, val);
691 	/* disable all interrupts */
692 	val = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET);
693 	val &= ~(IE_M_ALL_INTERRUPT_MASK <<
694 			IE_M_ALL_INTERRUPT_SHIFT);
695 	iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val);
696 
697 	/* clear all pending interrupts */
698 	iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, 0xffffffff);
699 
700 	return 0;
701 }
702 
703 static void bcm_iproc_i2c_enable_disable(struct bcm_iproc_i2c_dev *iproc_i2c,
704 					 bool enable)
705 {
706 	u32 val;
707 
708 	val = iproc_i2c_rd_reg(iproc_i2c, CFG_OFFSET);
709 	if (enable)
710 		val |= BIT(CFG_EN_SHIFT);
711 	else
712 		val &= ~BIT(CFG_EN_SHIFT);
713 	iproc_i2c_wr_reg(iproc_i2c, CFG_OFFSET, val);
714 }
715 
716 static int bcm_iproc_i2c_check_status(struct bcm_iproc_i2c_dev *iproc_i2c,
717 				      struct i2c_msg *msg)
718 {
719 	u32 val;
720 
721 	val = iproc_i2c_rd_reg(iproc_i2c, M_CMD_OFFSET);
722 	val = (val >> M_CMD_STATUS_SHIFT) & M_CMD_STATUS_MASK;
723 
724 	switch (val) {
725 	case M_CMD_STATUS_SUCCESS:
726 		return 0;
727 
728 	case M_CMD_STATUS_LOST_ARB:
729 		dev_dbg(iproc_i2c->device, "lost bus arbitration\n");
730 		return -EAGAIN;
731 
732 	case M_CMD_STATUS_NACK_ADDR:
733 		dev_dbg(iproc_i2c->device, "NAK addr:0x%02x\n", msg->addr);
734 		return -ENXIO;
735 
736 	case M_CMD_STATUS_NACK_DATA:
737 		dev_dbg(iproc_i2c->device, "NAK data\n");
738 		return -ENXIO;
739 
740 	case M_CMD_STATUS_TIMEOUT:
741 		dev_dbg(iproc_i2c->device, "bus timeout\n");
742 		return -ETIMEDOUT;
743 
744 	case M_CMD_STATUS_FIFO_UNDERRUN:
745 		dev_dbg(iproc_i2c->device, "FIFO under-run\n");
746 		return -ENXIO;
747 
748 	case M_CMD_STATUS_RX_FIFO_FULL:
749 		dev_dbg(iproc_i2c->device, "RX FIFO full\n");
750 		return -ETIMEDOUT;
751 
752 	default:
753 		dev_dbg(iproc_i2c->device, "unknown error code=%d\n", val);
754 
755 		/* re-initialize i2c for recovery */
756 		bcm_iproc_i2c_enable_disable(iproc_i2c, false);
757 		bcm_iproc_i2c_init(iproc_i2c);
758 		bcm_iproc_i2c_enable_disable(iproc_i2c, true);
759 
760 		return -EIO;
761 	}
762 }
763 
764 static int bcm_iproc_i2c_xfer_wait(struct bcm_iproc_i2c_dev *iproc_i2c,
765 				   struct i2c_msg *msg,
766 				   u32 cmd)
767 {
768 	unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MSEC);
769 	u32 val, status;
770 	int ret;
771 
772 	iproc_i2c_wr_reg(iproc_i2c, M_CMD_OFFSET, cmd);
773 
774 	if (iproc_i2c->irq) {
775 		time_left = wait_for_completion_timeout(&iproc_i2c->done,
776 							time_left);
777 		/* disable all interrupts */
778 		iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, 0);
779 		/* read it back to flush the write */
780 		iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET);
781 		/* make sure the interrupt handler isn't running */
782 		synchronize_irq(iproc_i2c->irq);
783 
784 	} else { /* polling mode */
785 		unsigned long timeout = jiffies + time_left;
786 
787 		do {
788 			status = iproc_i2c_rd_reg(iproc_i2c,
789 						  IS_OFFSET) & ISR_MASK;
790 			bcm_iproc_i2c_process_m_event(iproc_i2c, status);
791 			iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, status);
792 
793 			if (time_after(jiffies, timeout)) {
794 				time_left = 0;
795 				break;
796 			}
797 
798 			cpu_relax();
799 			cond_resched();
800 		} while (!iproc_i2c->xfer_is_done);
801 	}
802 
803 	if (!time_left && !iproc_i2c->xfer_is_done) {
804 		dev_err(iproc_i2c->device, "transaction timed out\n");
805 
806 		/* flush both TX/RX FIFOs */
807 		val = BIT(M_FIFO_RX_FLUSH_SHIFT) | BIT(M_FIFO_TX_FLUSH_SHIFT);
808 		iproc_i2c_wr_reg(iproc_i2c, M_FIFO_CTRL_OFFSET, val);
809 		return -ETIMEDOUT;
810 	}
811 
812 	ret = bcm_iproc_i2c_check_status(iproc_i2c, msg);
813 	if (ret) {
814 		/* flush both TX/RX FIFOs */
815 		val = BIT(M_FIFO_RX_FLUSH_SHIFT) | BIT(M_FIFO_TX_FLUSH_SHIFT);
816 		iproc_i2c_wr_reg(iproc_i2c, M_FIFO_CTRL_OFFSET, val);
817 		return ret;
818 	}
819 
820 	return 0;
821 }
822 
823 /*
824  * If 'process_call' is true, then this is a multi-msg transfer that requires
825  * a repeated start between the messages.
826  * More specifically, it must be a write (reg) followed by a read (data).
827  * The i2c quirks are set to enforce this rule.
828  */
829 static int bcm_iproc_i2c_xfer_internal(struct bcm_iproc_i2c_dev *iproc_i2c,
830 					struct i2c_msg *msgs, bool process_call)
831 {
832 	int i;
833 	u8 addr;
834 	u32 val, tmp, val_intr_en;
835 	unsigned int tx_bytes;
836 	struct i2c_msg *msg = &msgs[0];
837 
838 	/* check if bus is busy */
839 	if (!!(iproc_i2c_rd_reg(iproc_i2c,
840 				M_CMD_OFFSET) & BIT(M_CMD_START_BUSY_SHIFT))) {
841 		dev_warn(iproc_i2c->device, "bus is busy\n");
842 		return -EBUSY;
843 	}
844 
845 	iproc_i2c->msg = msg;
846 
847 	/* format and load slave address into the TX FIFO */
848 	addr = i2c_8bit_addr_from_msg(msg);
849 	iproc_i2c_wr_reg(iproc_i2c, M_TX_OFFSET, addr);
850 
851 	/*
852 	 * For a write transaction, load data into the TX FIFO. Only allow
853 	 * loading up to TX FIFO size - 1 bytes of data since the first byte
854 	 * has been used up by the slave address
855 	 */
856 	tx_bytes = min_t(unsigned int, msg->len, M_TX_RX_FIFO_SIZE - 1);
857 	if (!(msg->flags & I2C_M_RD)) {
858 		for (i = 0; i < tx_bytes; i++) {
859 			val = msg->buf[i];
860 
861 			/* mark the last byte */
862 			if (!process_call && (i == msg->len - 1))
863 				val |= BIT(M_TX_WR_STATUS_SHIFT);
864 
865 			iproc_i2c_wr_reg(iproc_i2c, M_TX_OFFSET, val);
866 		}
867 		iproc_i2c->tx_bytes = tx_bytes;
868 	}
869 
870 	/* Process the read message if this is process call */
871 	if (process_call) {
872 		msg++;
873 		iproc_i2c->msg = msg;  /* point to second msg */
874 
875 		/*
876 		 * The last byte to be sent out should be a slave
877 		 * address with read operation
878 		 */
879 		addr = i2c_8bit_addr_from_msg(msg);
880 		/* mark it the last byte out */
881 		val = addr | BIT(M_TX_WR_STATUS_SHIFT);
882 		iproc_i2c_wr_reg(iproc_i2c, M_TX_OFFSET, val);
883 	}
884 
885 	/* mark as incomplete before starting the transaction */
886 	if (iproc_i2c->irq)
887 		reinit_completion(&iproc_i2c->done);
888 
889 	iproc_i2c->xfer_is_done = 0;
890 
891 	/*
892 	 * Enable the "start busy" interrupt, which will be triggered after the
893 	 * transaction is done, i.e., the internal start_busy bit, transitions
894 	 * from 1 to 0.
895 	 */
896 	val_intr_en = BIT(IE_M_START_BUSY_SHIFT);
897 
898 	/*
899 	 * If TX data size is larger than the TX FIFO, need to enable TX
900 	 * underrun interrupt, which will be triggerred when the TX FIFO is
901 	 * empty. When that happens we can then pump more data into the FIFO
902 	 */
903 	if (!process_call && !(msg->flags & I2C_M_RD) &&
904 	    msg->len > iproc_i2c->tx_bytes)
905 		val_intr_en |= BIT(IE_M_TX_UNDERRUN_SHIFT);
906 
907 	/*
908 	 * Now we can activate the transfer. For a read operation, specify the
909 	 * number of bytes to read
910 	 */
911 	val = BIT(M_CMD_START_BUSY_SHIFT);
912 
913 	if (msg->len == 0) {
914 		/* SMBUS QUICK Command (Read/Write) */
915 		val |= (M_CMD_PROTOCOL_QUICK << M_CMD_PROTOCOL_SHIFT);
916 	} else if (msg->flags & I2C_M_RD) {
917 		u32 protocol;
918 
919 		iproc_i2c->rx_bytes = 0;
920 		if (msg->len > M_RX_FIFO_MAX_THLD_VALUE)
921 			iproc_i2c->thld_bytes = M_RX_FIFO_THLD_VALUE;
922 		else
923 			iproc_i2c->thld_bytes = msg->len;
924 
925 		/* set threshold value */
926 		tmp = iproc_i2c_rd_reg(iproc_i2c, M_FIFO_CTRL_OFFSET);
927 		tmp &= ~(M_FIFO_RX_THLD_MASK << M_FIFO_RX_THLD_SHIFT);
928 		tmp |= iproc_i2c->thld_bytes << M_FIFO_RX_THLD_SHIFT;
929 		iproc_i2c_wr_reg(iproc_i2c, M_FIFO_CTRL_OFFSET, tmp);
930 
931 		/* enable the RX threshold interrupt */
932 		val_intr_en |= BIT(IE_M_RX_THLD_SHIFT);
933 
934 		protocol = process_call ?
935 				M_CMD_PROTOCOL_PROCESS : M_CMD_PROTOCOL_BLK_RD;
936 
937 		val |= (protocol << M_CMD_PROTOCOL_SHIFT) |
938 		       (msg->len << M_CMD_RD_CNT_SHIFT);
939 	} else {
940 		val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT);
941 	}
942 
943 	if (iproc_i2c->irq)
944 		iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val_intr_en);
945 
946 	return bcm_iproc_i2c_xfer_wait(iproc_i2c, msg, val);
947 }
948 
949 static int bcm_iproc_i2c_xfer(struct i2c_adapter *adapter,
950 			      struct i2c_msg msgs[], int num)
951 {
952 	struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adapter);
953 	bool process_call = false;
954 	int ret;
955 
956 	if (num == 2) {
957 		/* Repeated start, use process call */
958 		process_call = true;
959 		if (msgs[1].flags & I2C_M_NOSTART) {
960 			dev_err(iproc_i2c->device, "Invalid repeated start\n");
961 			return -EOPNOTSUPP;
962 		}
963 	}
964 
965 	ret = bcm_iproc_i2c_xfer_internal(iproc_i2c, msgs, process_call);
966 	if (ret) {
967 		dev_dbg(iproc_i2c->device, "xfer failed\n");
968 		return ret;
969 	}
970 
971 	return num;
972 }
973 
974 static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap)
975 {
976 	u32 val;
977 
978 	val = I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
979 
980 	if (adap->algo->reg_slave)
981 		val |= I2C_FUNC_SLAVE;
982 
983 	return val;
984 }
985 
986 static struct i2c_algorithm bcm_iproc_algo = {
987 	.master_xfer = bcm_iproc_i2c_xfer,
988 	.functionality = bcm_iproc_i2c_functionality,
989 	.reg_slave = bcm_iproc_i2c_reg_slave,
990 	.unreg_slave = bcm_iproc_i2c_unreg_slave,
991 };
992 
993 static const struct i2c_adapter_quirks bcm_iproc_i2c_quirks = {
994 	.flags = I2C_AQ_COMB_WRITE_THEN_READ,
995 	.max_comb_1st_msg_len = M_TX_RX_FIFO_SIZE,
996 	.max_read_len = M_RX_MAX_READ_LEN,
997 };
998 
999 static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *iproc_i2c)
1000 {
1001 	unsigned int bus_speed;
1002 	u32 val;
1003 	int ret = of_property_read_u32(iproc_i2c->device->of_node,
1004 				       "clock-frequency", &bus_speed);
1005 	if (ret < 0) {
1006 		dev_info(iproc_i2c->device,
1007 			"unable to interpret clock-frequency DT property\n");
1008 		bus_speed = I2C_MAX_STANDARD_MODE_FREQ;
1009 	}
1010 
1011 	if (bus_speed < I2C_MAX_STANDARD_MODE_FREQ) {
1012 		dev_err(iproc_i2c->device, "%d Hz bus speed not supported\n",
1013 			bus_speed);
1014 		dev_err(iproc_i2c->device,
1015 			"valid speeds are 100khz and 400khz\n");
1016 		return -EINVAL;
1017 	} else if (bus_speed < I2C_MAX_FAST_MODE_FREQ) {
1018 		bus_speed = I2C_MAX_STANDARD_MODE_FREQ;
1019 	} else {
1020 		bus_speed = I2C_MAX_FAST_MODE_FREQ;
1021 	}
1022 
1023 	iproc_i2c->bus_speed = bus_speed;
1024 	val = iproc_i2c_rd_reg(iproc_i2c, TIM_CFG_OFFSET);
1025 	val &= ~BIT(TIM_CFG_MODE_400_SHIFT);
1026 	val |= (bus_speed == I2C_MAX_FAST_MODE_FREQ) << TIM_CFG_MODE_400_SHIFT;
1027 	iproc_i2c_wr_reg(iproc_i2c, TIM_CFG_OFFSET, val);
1028 
1029 	dev_info(iproc_i2c->device, "bus set to %u Hz\n", bus_speed);
1030 
1031 	return 0;
1032 }
1033 
1034 static int bcm_iproc_i2c_probe(struct platform_device *pdev)
1035 {
1036 	int irq, ret = 0;
1037 	struct bcm_iproc_i2c_dev *iproc_i2c;
1038 	struct i2c_adapter *adap;
1039 	struct resource *res;
1040 
1041 	iproc_i2c = devm_kzalloc(&pdev->dev, sizeof(*iproc_i2c),
1042 				 GFP_KERNEL);
1043 	if (!iproc_i2c)
1044 		return -ENOMEM;
1045 
1046 	platform_set_drvdata(pdev, iproc_i2c);
1047 	iproc_i2c->device = &pdev->dev;
1048 	iproc_i2c->type =
1049 		(enum bcm_iproc_i2c_type)of_device_get_match_data(&pdev->dev);
1050 	init_completion(&iproc_i2c->done);
1051 
1052 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1053 	iproc_i2c->base = devm_ioremap_resource(iproc_i2c->device, res);
1054 	if (IS_ERR(iproc_i2c->base))
1055 		return PTR_ERR(iproc_i2c->base);
1056 
1057 	if (iproc_i2c->type == IPROC_I2C_NIC) {
1058 		res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
1059 		iproc_i2c->idm_base = devm_ioremap_resource(iproc_i2c->device,
1060 							    res);
1061 		if (IS_ERR(iproc_i2c->idm_base))
1062 			return PTR_ERR(iproc_i2c->idm_base);
1063 
1064 		ret = of_property_read_u32(iproc_i2c->device->of_node,
1065 					   "brcm,ape-hsls-addr-mask",
1066 					   &iproc_i2c->ape_addr_mask);
1067 		if (ret < 0) {
1068 			dev_err(iproc_i2c->device,
1069 				"'brcm,ape-hsls-addr-mask' missing\n");
1070 			return -EINVAL;
1071 		}
1072 
1073 		spin_lock_init(&iproc_i2c->idm_lock);
1074 
1075 		/* no slave support */
1076 		bcm_iproc_algo.reg_slave = NULL;
1077 		bcm_iproc_algo.unreg_slave = NULL;
1078 	}
1079 
1080 	ret = bcm_iproc_i2c_init(iproc_i2c);
1081 	if (ret)
1082 		return ret;
1083 
1084 	ret = bcm_iproc_i2c_cfg_speed(iproc_i2c);
1085 	if (ret)
1086 		return ret;
1087 
1088 	irq = platform_get_irq(pdev, 0);
1089 	if (irq > 0) {
1090 		ret = devm_request_irq(iproc_i2c->device, irq,
1091 				       bcm_iproc_i2c_isr, 0, pdev->name,
1092 				       iproc_i2c);
1093 		if (ret < 0) {
1094 			dev_err(iproc_i2c->device,
1095 				"unable to request irq %i\n", irq);
1096 			return ret;
1097 		}
1098 
1099 		iproc_i2c->irq = irq;
1100 	} else {
1101 		dev_warn(iproc_i2c->device,
1102 			 "no irq resource, falling back to poll mode\n");
1103 	}
1104 
1105 	bcm_iproc_i2c_enable_disable(iproc_i2c, true);
1106 
1107 	adap = &iproc_i2c->adapter;
1108 	i2c_set_adapdata(adap, iproc_i2c);
1109 	snprintf(adap->name, sizeof(adap->name),
1110 		"Broadcom iProc (%s)",
1111 		of_node_full_name(iproc_i2c->device->of_node));
1112 	adap->algo = &bcm_iproc_algo;
1113 	adap->quirks = &bcm_iproc_i2c_quirks;
1114 	adap->dev.parent = &pdev->dev;
1115 	adap->dev.of_node = pdev->dev.of_node;
1116 
1117 	return i2c_add_adapter(adap);
1118 }
1119 
1120 static int bcm_iproc_i2c_remove(struct platform_device *pdev)
1121 {
1122 	struct bcm_iproc_i2c_dev *iproc_i2c = platform_get_drvdata(pdev);
1123 
1124 	if (iproc_i2c->irq) {
1125 		/*
1126 		 * Make sure there's no pending interrupt when we remove the
1127 		 * adapter
1128 		 */
1129 		iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, 0);
1130 		iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET);
1131 		synchronize_irq(iproc_i2c->irq);
1132 	}
1133 
1134 	i2c_del_adapter(&iproc_i2c->adapter);
1135 	bcm_iproc_i2c_enable_disable(iproc_i2c, false);
1136 
1137 	return 0;
1138 }
1139 
1140 #ifdef CONFIG_PM_SLEEP
1141 
1142 static int bcm_iproc_i2c_suspend(struct device *dev)
1143 {
1144 	struct bcm_iproc_i2c_dev *iproc_i2c = dev_get_drvdata(dev);
1145 
1146 	if (iproc_i2c->irq) {
1147 		/*
1148 		 * Make sure there's no pending interrupt when we go into
1149 		 * suspend
1150 		 */
1151 		iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, 0);
1152 		iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET);
1153 		synchronize_irq(iproc_i2c->irq);
1154 	}
1155 
1156 	/* now disable the controller */
1157 	bcm_iproc_i2c_enable_disable(iproc_i2c, false);
1158 
1159 	return 0;
1160 }
1161 
1162 static int bcm_iproc_i2c_resume(struct device *dev)
1163 {
1164 	struct bcm_iproc_i2c_dev *iproc_i2c = dev_get_drvdata(dev);
1165 	int ret;
1166 	u32 val;
1167 
1168 	/*
1169 	 * Power domain could have been shut off completely in system deep
1170 	 * sleep, so re-initialize the block here
1171 	 */
1172 	ret = bcm_iproc_i2c_init(iproc_i2c);
1173 	if (ret)
1174 		return ret;
1175 
1176 	/* configure to the desired bus speed */
1177 	val = iproc_i2c_rd_reg(iproc_i2c, TIM_CFG_OFFSET);
1178 	val &= ~BIT(TIM_CFG_MODE_400_SHIFT);
1179 	val |= (iproc_i2c->bus_speed == I2C_MAX_FAST_MODE_FREQ) << TIM_CFG_MODE_400_SHIFT;
1180 	iproc_i2c_wr_reg(iproc_i2c, TIM_CFG_OFFSET, val);
1181 
1182 	bcm_iproc_i2c_enable_disable(iproc_i2c, true);
1183 
1184 	return 0;
1185 }
1186 
1187 static const struct dev_pm_ops bcm_iproc_i2c_pm_ops = {
1188 	.suspend_late = &bcm_iproc_i2c_suspend,
1189 	.resume_early = &bcm_iproc_i2c_resume
1190 };
1191 
1192 #define BCM_IPROC_I2C_PM_OPS (&bcm_iproc_i2c_pm_ops)
1193 #else
1194 #define BCM_IPROC_I2C_PM_OPS NULL
1195 #endif /* CONFIG_PM_SLEEP */
1196 
1197 
1198 static int bcm_iproc_i2c_reg_slave(struct i2c_client *slave)
1199 {
1200 	struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(slave->adapter);
1201 
1202 	if (iproc_i2c->slave)
1203 		return -EBUSY;
1204 
1205 	if (slave->flags & I2C_CLIENT_TEN)
1206 		return -EAFNOSUPPORT;
1207 
1208 	iproc_i2c->slave = slave;
1209 
1210 	tasklet_init(&iproc_i2c->slave_rx_tasklet, slave_rx_tasklet_fn,
1211 		     (unsigned long)iproc_i2c);
1212 
1213 	bcm_iproc_i2c_slave_init(iproc_i2c, false);
1214 	return 0;
1215 }
1216 
1217 static int bcm_iproc_i2c_unreg_slave(struct i2c_client *slave)
1218 {
1219 	u32 tmp;
1220 	struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(slave->adapter);
1221 
1222 	if (!iproc_i2c->slave)
1223 		return -EINVAL;
1224 
1225 	disable_irq(iproc_i2c->irq);
1226 
1227 	tasklet_kill(&iproc_i2c->slave_rx_tasklet);
1228 
1229 	/* disable all slave interrupts */
1230 	tmp = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET);
1231 	tmp &= ~(IE_S_ALL_INTERRUPT_MASK <<
1232 			IE_S_ALL_INTERRUPT_SHIFT);
1233 	iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, tmp);
1234 
1235 	/* Erase the slave address programmed */
1236 	tmp = iproc_i2c_rd_reg(iproc_i2c, S_CFG_SMBUS_ADDR_OFFSET);
1237 	tmp &= ~BIT(S_CFG_EN_NIC_SMB_ADDR3_SHIFT);
1238 	iproc_i2c_wr_reg(iproc_i2c, S_CFG_SMBUS_ADDR_OFFSET, tmp);
1239 
1240 	/* flush TX/RX FIFOs */
1241 	tmp = (BIT(S_FIFO_RX_FLUSH_SHIFT) | BIT(S_FIFO_TX_FLUSH_SHIFT));
1242 	iproc_i2c_wr_reg(iproc_i2c, S_FIFO_CTRL_OFFSET, tmp);
1243 
1244 	/* clear all pending slave interrupts */
1245 	iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, ISR_MASK_SLAVE);
1246 
1247 	iproc_i2c->slave = NULL;
1248 
1249 	enable_irq(iproc_i2c->irq);
1250 
1251 	return 0;
1252 }
1253 
1254 static const struct of_device_id bcm_iproc_i2c_of_match[] = {
1255 	{
1256 		.compatible = "brcm,iproc-i2c",
1257 		.data = (int *)IPROC_I2C,
1258 	}, {
1259 		.compatible = "brcm,iproc-nic-i2c",
1260 		.data = (int *)IPROC_I2C_NIC,
1261 	},
1262 	{ /* sentinel */ }
1263 };
1264 MODULE_DEVICE_TABLE(of, bcm_iproc_i2c_of_match);
1265 
1266 static struct platform_driver bcm_iproc_i2c_driver = {
1267 	.driver = {
1268 		.name = "bcm-iproc-i2c",
1269 		.of_match_table = bcm_iproc_i2c_of_match,
1270 		.pm = BCM_IPROC_I2C_PM_OPS,
1271 	},
1272 	.probe = bcm_iproc_i2c_probe,
1273 	.remove = bcm_iproc_i2c_remove,
1274 };
1275 module_platform_driver(bcm_iproc_i2c_driver);
1276 
1277 MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>");
1278 MODULE_DESCRIPTION("Broadcom iProc I2C Driver");
1279 MODULE_LICENSE("GPL v2");
1280