1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2013 STMicroelectronics
4 *
5 * I2C master mode controller driver, used in STMicroelectronics devices.
6 *
7 * Author: Maxime Coquelin <maxime.coquelin@st.com>
8 */
9
10 #include <linux/clk.h>
11 #include <linux/delay.h>
12 #include <linux/err.h>
13 #include <linux/i2c.h>
14 #include <linux/interrupt.h>
15 #include <linux/io.h>
16 #include <linux/module.h>
17 #include <linux/of_address.h>
18 #include <linux/of_irq.h>
19 #include <linux/of.h>
20 #include <linux/pinctrl/consumer.h>
21 #include <linux/platform_device.h>
22
23 /* SSC registers */
24 #define SSC_BRG 0x000
25 #define SSC_TBUF 0x004
26 #define SSC_RBUF 0x008
27 #define SSC_CTL 0x00C
28 #define SSC_IEN 0x010
29 #define SSC_STA 0x014
30 #define SSC_I2C 0x018
31 #define SSC_SLAD 0x01C
32 #define SSC_REP_START_HOLD 0x020
33 #define SSC_START_HOLD 0x024
34 #define SSC_REP_START_SETUP 0x028
35 #define SSC_DATA_SETUP 0x02C
36 #define SSC_STOP_SETUP 0x030
37 #define SSC_BUS_FREE 0x034
38 #define SSC_TX_FSTAT 0x038
39 #define SSC_RX_FSTAT 0x03C
40 #define SSC_PRE_SCALER_BRG 0x040
41 #define SSC_CLR 0x080
42 #define SSC_NOISE_SUPP_WIDTH 0x100
43 #define SSC_PRSCALER 0x104
44 #define SSC_NOISE_SUPP_WIDTH_DATAOUT 0x108
45 #define SSC_PRSCALER_DATAOUT 0x10c
46
47 /* SSC Control */
48 #define SSC_CTL_DATA_WIDTH_9 0x8
49 #define SSC_CTL_DATA_WIDTH_MSK 0xf
50 #define SSC_CTL_BM 0xf
51 #define SSC_CTL_HB BIT(4)
52 #define SSC_CTL_PH BIT(5)
53 #define SSC_CTL_PO BIT(6)
54 #define SSC_CTL_SR BIT(7)
55 #define SSC_CTL_MS BIT(8)
56 #define SSC_CTL_EN BIT(9)
57 #define SSC_CTL_LPB BIT(10)
58 #define SSC_CTL_EN_TX_FIFO BIT(11)
59 #define SSC_CTL_EN_RX_FIFO BIT(12)
60 #define SSC_CTL_EN_CLST_RX BIT(13)
61
62 /* SSC Interrupt Enable */
63 #define SSC_IEN_RIEN BIT(0)
64 #define SSC_IEN_TIEN BIT(1)
65 #define SSC_IEN_TEEN BIT(2)
66 #define SSC_IEN_REEN BIT(3)
67 #define SSC_IEN_PEEN BIT(4)
68 #define SSC_IEN_AASEN BIT(6)
69 #define SSC_IEN_STOPEN BIT(7)
70 #define SSC_IEN_ARBLEN BIT(8)
71 #define SSC_IEN_NACKEN BIT(10)
72 #define SSC_IEN_REPSTRTEN BIT(11)
73 #define SSC_IEN_TX_FIFO_HALF BIT(12)
74 #define SSC_IEN_RX_FIFO_HALF_FULL BIT(14)
75
76 /* SSC Status */
77 #define SSC_STA_RIR BIT(0)
78 #define SSC_STA_TIR BIT(1)
79 #define SSC_STA_TE BIT(2)
80 #define SSC_STA_RE BIT(3)
81 #define SSC_STA_PE BIT(4)
82 #define SSC_STA_CLST BIT(5)
83 #define SSC_STA_AAS BIT(6)
84 #define SSC_STA_STOP BIT(7)
85 #define SSC_STA_ARBL BIT(8)
86 #define SSC_STA_BUSY BIT(9)
87 #define SSC_STA_NACK BIT(10)
88 #define SSC_STA_REPSTRT BIT(11)
89 #define SSC_STA_TX_FIFO_HALF BIT(12)
90 #define SSC_STA_TX_FIFO_FULL BIT(13)
91 #define SSC_STA_RX_FIFO_HALF BIT(14)
92
93 /* SSC I2C Control */
94 #define SSC_I2C_I2CM BIT(0)
95 #define SSC_I2C_STRTG BIT(1)
96 #define SSC_I2C_STOPG BIT(2)
97 #define SSC_I2C_ACKG BIT(3)
98 #define SSC_I2C_AD10 BIT(4)
99 #define SSC_I2C_TXENB BIT(5)
100 #define SSC_I2C_REPSTRTG BIT(11)
101 #define SSC_I2C_SLAVE_DISABLE BIT(12)
102
103 /* SSC Tx FIFO Status */
104 #define SSC_TX_FSTAT_STATUS 0x07
105
106 /* SSC Rx FIFO Status */
107 #define SSC_RX_FSTAT_STATUS 0x07
108
109 /* SSC Clear bit operation */
110 #define SSC_CLR_SSCAAS BIT(6)
111 #define SSC_CLR_SSCSTOP BIT(7)
112 #define SSC_CLR_SSCARBL BIT(8)
113 #define SSC_CLR_NACK BIT(10)
114 #define SSC_CLR_REPSTRT BIT(11)
115
116 /* SSC Clock Prescaler */
117 #define SSC_PRSC_VALUE 0x0f
118
119
120 #define SSC_TXFIFO_SIZE 0x8
121 #define SSC_RXFIFO_SIZE 0x8
122
123 enum st_i2c_mode {
124 I2C_MODE_STANDARD,
125 I2C_MODE_FAST,
126 I2C_MODE_END,
127 };
128
129 /**
130 * struct st_i2c_timings - per-Mode tuning parameters
131 * @rate: I2C bus rate
132 * @rep_start_hold: I2C repeated start hold time requirement
133 * @rep_start_setup: I2C repeated start set up time requirement
134 * @start_hold: I2C start hold time requirement
135 * @data_setup_time: I2C data set up time requirement
136 * @stop_setup_time: I2C stop set up time requirement
137 * @bus_free_time: I2C bus free time requirement
138 * @sda_pulse_min_limit: I2C SDA pulse mini width limit
139 */
140 struct st_i2c_timings {
141 u32 rate;
142 u32 rep_start_hold;
143 u32 rep_start_setup;
144 u32 start_hold;
145 u32 data_setup_time;
146 u32 stop_setup_time;
147 u32 bus_free_time;
148 u32 sda_pulse_min_limit;
149 };
150
151 /**
152 * struct st_i2c_client - client specific data
153 * @addr: 8-bit slave addr, including r/w bit
154 * @count: number of bytes to be transfered
155 * @xfered: number of bytes already transferred
156 * @buf: data buffer
157 * @result: result of the transfer
158 * @stop: last I2C msg to be sent, i.e. STOP to be generated
159 */
160 struct st_i2c_client {
161 u8 addr;
162 u32 count;
163 u32 xfered;
164 u8 *buf;
165 int result;
166 bool stop;
167 };
168
169 /**
170 * struct st_i2c_dev - private data of the controller
171 * @adap: I2C adapter for this controller
172 * @dev: device for this controller
173 * @base: virtual memory area
174 * @complete: completion of I2C message
175 * @irq: interrupt line for th controller
176 * @clk: hw ssc block clock
177 * @mode: I2C mode of the controller. Standard or Fast only supported
178 * @scl_min_width_us: SCL line minimum pulse width in us
179 * @sda_min_width_us: SDA line minimum pulse width in us
180 * @client: I2C transfert information
181 * @busy: I2C transfer on-going
182 */
183 struct st_i2c_dev {
184 struct i2c_adapter adap;
185 struct device *dev;
186 void __iomem *base;
187 struct completion complete;
188 int irq;
189 struct clk *clk;
190 int mode;
191 u32 scl_min_width_us;
192 u32 sda_min_width_us;
193 struct st_i2c_client client;
194 bool busy;
195 };
196
st_i2c_set_bits(void __iomem * reg,u32 mask)197 static inline void st_i2c_set_bits(void __iomem *reg, u32 mask)
198 {
199 writel_relaxed(readl_relaxed(reg) | mask, reg);
200 }
201
st_i2c_clr_bits(void __iomem * reg,u32 mask)202 static inline void st_i2c_clr_bits(void __iomem *reg, u32 mask)
203 {
204 writel_relaxed(readl_relaxed(reg) & ~mask, reg);
205 }
206
207 /*
208 * From I2C Specifications v0.5.
209 *
210 * All the values below have +10% margin added to be
211 * compatible with some out-of-spec devices,
212 * like HDMI link of the Toshiba 19AV600 TV.
213 */
214 static struct st_i2c_timings i2c_timings[] = {
215 [I2C_MODE_STANDARD] = {
216 .rate = I2C_MAX_STANDARD_MODE_FREQ,
217 .rep_start_hold = 4400,
218 .rep_start_setup = 5170,
219 .start_hold = 4400,
220 .data_setup_time = 275,
221 .stop_setup_time = 4400,
222 .bus_free_time = 5170,
223 },
224 [I2C_MODE_FAST] = {
225 .rate = I2C_MAX_FAST_MODE_FREQ,
226 .rep_start_hold = 660,
227 .rep_start_setup = 660,
228 .start_hold = 660,
229 .data_setup_time = 110,
230 .stop_setup_time = 660,
231 .bus_free_time = 1430,
232 },
233 };
234
st_i2c_flush_rx_fifo(struct st_i2c_dev * i2c_dev)235 static void st_i2c_flush_rx_fifo(struct st_i2c_dev *i2c_dev)
236 {
237 int count, i;
238
239 /*
240 * Counter only counts up to 7 but fifo size is 8...
241 * When fifo is full, counter is 0 and RIR bit of status register is
242 * set
243 */
244 if (readl_relaxed(i2c_dev->base + SSC_STA) & SSC_STA_RIR)
245 count = SSC_RXFIFO_SIZE;
246 else
247 count = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT) &
248 SSC_RX_FSTAT_STATUS;
249
250 for (i = 0; i < count; i++)
251 readl_relaxed(i2c_dev->base + SSC_RBUF);
252 }
253
st_i2c_soft_reset(struct st_i2c_dev * i2c_dev)254 static void st_i2c_soft_reset(struct st_i2c_dev *i2c_dev)
255 {
256 /*
257 * FIFO needs to be emptied before reseting the IP,
258 * else the controller raises a BUSY error.
259 */
260 st_i2c_flush_rx_fifo(i2c_dev);
261
262 st_i2c_set_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR);
263 st_i2c_clr_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR);
264 }
265
266 /**
267 * st_i2c_hw_config() - Prepare SSC block, calculate and apply tuning timings
268 * @i2c_dev: Controller's private data
269 */
st_i2c_hw_config(struct st_i2c_dev * i2c_dev)270 static void st_i2c_hw_config(struct st_i2c_dev *i2c_dev)
271 {
272 unsigned long rate;
273 u32 val, ns_per_clk;
274 struct st_i2c_timings *t = &i2c_timings[i2c_dev->mode];
275
276 st_i2c_soft_reset(i2c_dev);
277
278 val = SSC_CLR_REPSTRT | SSC_CLR_NACK | SSC_CLR_SSCARBL |
279 SSC_CLR_SSCAAS | SSC_CLR_SSCSTOP;
280 writel_relaxed(val, i2c_dev->base + SSC_CLR);
281
282 /* SSC Control register setup */
283 val = SSC_CTL_PO | SSC_CTL_PH | SSC_CTL_HB | SSC_CTL_DATA_WIDTH_9;
284 writel_relaxed(val, i2c_dev->base + SSC_CTL);
285
286 rate = clk_get_rate(i2c_dev->clk);
287 ns_per_clk = 1000000000 / rate;
288
289 /* Baudrate */
290 val = rate / (2 * t->rate);
291 writel_relaxed(val, i2c_dev->base + SSC_BRG);
292
293 /* Pre-scaler baudrate */
294 writel_relaxed(1, i2c_dev->base + SSC_PRE_SCALER_BRG);
295
296 /* Enable I2C mode */
297 writel_relaxed(SSC_I2C_I2CM, i2c_dev->base + SSC_I2C);
298
299 /* Repeated start hold time */
300 val = t->rep_start_hold / ns_per_clk;
301 writel_relaxed(val, i2c_dev->base + SSC_REP_START_HOLD);
302
303 /* Repeated start set up time */
304 val = t->rep_start_setup / ns_per_clk;
305 writel_relaxed(val, i2c_dev->base + SSC_REP_START_SETUP);
306
307 /* Start hold time */
308 val = t->start_hold / ns_per_clk;
309 writel_relaxed(val, i2c_dev->base + SSC_START_HOLD);
310
311 /* Data set up time */
312 val = t->data_setup_time / ns_per_clk;
313 writel_relaxed(val, i2c_dev->base + SSC_DATA_SETUP);
314
315 /* Stop set up time */
316 val = t->stop_setup_time / ns_per_clk;
317 writel_relaxed(val, i2c_dev->base + SSC_STOP_SETUP);
318
319 /* Bus free time */
320 val = t->bus_free_time / ns_per_clk;
321 writel_relaxed(val, i2c_dev->base + SSC_BUS_FREE);
322
323 /* Prescalers set up */
324 val = rate / 10000000;
325 writel_relaxed(val, i2c_dev->base + SSC_PRSCALER);
326 writel_relaxed(val, i2c_dev->base + SSC_PRSCALER_DATAOUT);
327
328 /* Noise suppression witdh */
329 val = i2c_dev->scl_min_width_us * rate / 100000000;
330 writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH);
331
332 /* Noise suppression max output data delay width */
333 val = i2c_dev->sda_min_width_us * rate / 100000000;
334 writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH_DATAOUT);
335 }
336
st_i2c_recover_bus(struct i2c_adapter * i2c_adap)337 static int st_i2c_recover_bus(struct i2c_adapter *i2c_adap)
338 {
339 struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
340 u32 ctl;
341
342 dev_dbg(i2c_dev->dev, "Trying to recover bus\n");
343
344 /*
345 * SSP IP is dual role SPI/I2C to generate 9 clock pulses
346 * we switch to SPI node, 9 bit words and write a 0. This
347 * has been validate with a oscilloscope and is easier
348 * than switching to GPIO mode.
349 */
350
351 /* Disable interrupts */
352 writel_relaxed(0, i2c_dev->base + SSC_IEN);
353
354 st_i2c_hw_config(i2c_dev);
355
356 ctl = SSC_CTL_EN | SSC_CTL_MS | SSC_CTL_EN_RX_FIFO | SSC_CTL_EN_TX_FIFO;
357 st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl);
358
359 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_I2CM);
360 usleep_range(8000, 10000);
361
362 writel_relaxed(0, i2c_dev->base + SSC_TBUF);
363 usleep_range(2000, 4000);
364 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_I2CM);
365
366 return 0;
367 }
368
st_i2c_wait_free_bus(struct st_i2c_dev * i2c_dev)369 static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev)
370 {
371 u32 sta;
372 int i, ret;
373
374 for (i = 0; i < 10; i++) {
375 sta = readl_relaxed(i2c_dev->base + SSC_STA);
376 if (!(sta & SSC_STA_BUSY))
377 return 0;
378
379 usleep_range(2000, 4000);
380 }
381
382 dev_err(i2c_dev->dev, "bus not free (status = 0x%08x)\n", sta);
383
384 ret = i2c_recover_bus(&i2c_dev->adap);
385 if (ret) {
386 dev_err(i2c_dev->dev, "Failed to recover the bus (%d)\n", ret);
387 return ret;
388 }
389
390 return -EBUSY;
391 }
392
393 /**
394 * st_i2c_write_tx_fifo() - Write a byte in the Tx FIFO
395 * @i2c_dev: Controller's private data
396 * @byte: Data to write in the Tx FIFO
397 */
st_i2c_write_tx_fifo(struct st_i2c_dev * i2c_dev,u8 byte)398 static inline void st_i2c_write_tx_fifo(struct st_i2c_dev *i2c_dev, u8 byte)
399 {
400 u16 tbuf = byte << 1;
401
402 writel_relaxed(tbuf | 1, i2c_dev->base + SSC_TBUF);
403 }
404
405 /**
406 * st_i2c_wr_fill_tx_fifo() - Fill the Tx FIFO in write mode
407 * @i2c_dev: Controller's private data
408 *
409 * This functions fills the Tx FIFO with I2C transfert buffer when
410 * in write mode.
411 */
st_i2c_wr_fill_tx_fifo(struct st_i2c_dev * i2c_dev)412 static void st_i2c_wr_fill_tx_fifo(struct st_i2c_dev *i2c_dev)
413 {
414 struct st_i2c_client *c = &i2c_dev->client;
415 u32 tx_fstat, sta;
416 int i;
417
418 sta = readl_relaxed(i2c_dev->base + SSC_STA);
419 if (sta & SSC_STA_TX_FIFO_FULL)
420 return;
421
422 tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT);
423 tx_fstat &= SSC_TX_FSTAT_STATUS;
424
425 if (c->count < (SSC_TXFIFO_SIZE - tx_fstat))
426 i = c->count;
427 else
428 i = SSC_TXFIFO_SIZE - tx_fstat;
429
430 for (; i > 0; i--, c->count--, c->buf++)
431 st_i2c_write_tx_fifo(i2c_dev, *c->buf);
432 }
433
434 /**
435 * st_i2c_rd_fill_tx_fifo() - Fill the Tx FIFO in read mode
436 * @i2c_dev: Controller's private data
437 * @max: Maximum amount of data to fill into the Tx FIFO
438 *
439 * This functions fills the Tx FIFO with fixed pattern when
440 * in read mode to trigger clock.
441 */
st_i2c_rd_fill_tx_fifo(struct st_i2c_dev * i2c_dev,int max)442 static void st_i2c_rd_fill_tx_fifo(struct st_i2c_dev *i2c_dev, int max)
443 {
444 struct st_i2c_client *c = &i2c_dev->client;
445 u32 tx_fstat, sta;
446 int i;
447
448 sta = readl_relaxed(i2c_dev->base + SSC_STA);
449 if (sta & SSC_STA_TX_FIFO_FULL)
450 return;
451
452 tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT);
453 tx_fstat &= SSC_TX_FSTAT_STATUS;
454
455 if (max < (SSC_TXFIFO_SIZE - tx_fstat))
456 i = max;
457 else
458 i = SSC_TXFIFO_SIZE - tx_fstat;
459
460 for (; i > 0; i--, c->xfered++)
461 st_i2c_write_tx_fifo(i2c_dev, 0xff);
462 }
463
st_i2c_read_rx_fifo(struct st_i2c_dev * i2c_dev)464 static void st_i2c_read_rx_fifo(struct st_i2c_dev *i2c_dev)
465 {
466 struct st_i2c_client *c = &i2c_dev->client;
467 u32 i, sta;
468 u16 rbuf;
469
470 sta = readl_relaxed(i2c_dev->base + SSC_STA);
471 if (sta & SSC_STA_RIR) {
472 i = SSC_RXFIFO_SIZE;
473 } else {
474 i = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT);
475 i &= SSC_RX_FSTAT_STATUS;
476 }
477
478 for (; (i > 0) && (c->count > 0); i--, c->count--) {
479 rbuf = readl_relaxed(i2c_dev->base + SSC_RBUF) >> 1;
480 *c->buf++ = (u8)rbuf & 0xff;
481 }
482
483 if (i) {
484 dev_err(i2c_dev->dev, "Unexpected %d bytes in rx fifo\n", i);
485 st_i2c_flush_rx_fifo(i2c_dev);
486 }
487 }
488
489 /**
490 * st_i2c_terminate_xfer() - Send either STOP or REPSTART condition
491 * @i2c_dev: Controller's private data
492 */
st_i2c_terminate_xfer(struct st_i2c_dev * i2c_dev)493 static void st_i2c_terminate_xfer(struct st_i2c_dev *i2c_dev)
494 {
495 struct st_i2c_client *c = &i2c_dev->client;
496
497 st_i2c_clr_bits(i2c_dev->base + SSC_IEN, SSC_IEN_TEEN);
498 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG);
499
500 if (c->stop) {
501 st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_STOPEN);
502 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG);
503 } else {
504 st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_REPSTRTEN);
505 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_REPSTRTG);
506 }
507 }
508
509 /**
510 * st_i2c_handle_write() - Handle FIFO empty interrupt in case of write
511 * @i2c_dev: Controller's private data
512 */
st_i2c_handle_write(struct st_i2c_dev * i2c_dev)513 static void st_i2c_handle_write(struct st_i2c_dev *i2c_dev)
514 {
515 struct st_i2c_client *c = &i2c_dev->client;
516
517 st_i2c_flush_rx_fifo(i2c_dev);
518
519 if (!c->count)
520 /* End of xfer, send stop or repstart */
521 st_i2c_terminate_xfer(i2c_dev);
522 else
523 st_i2c_wr_fill_tx_fifo(i2c_dev);
524 }
525
526 /**
527 * st_i2c_handle_read() - Handle FIFO empty interrupt in case of read
528 * @i2c_dev: Controller's private data
529 */
st_i2c_handle_read(struct st_i2c_dev * i2c_dev)530 static void st_i2c_handle_read(struct st_i2c_dev *i2c_dev)
531 {
532 struct st_i2c_client *c = &i2c_dev->client;
533 u32 ien;
534
535 /* Trash the address read back */
536 if (!c->xfered) {
537 readl_relaxed(i2c_dev->base + SSC_RBUF);
538 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_TXENB);
539 } else {
540 st_i2c_read_rx_fifo(i2c_dev);
541 }
542
543 if (!c->count) {
544 /* End of xfer, send stop or repstart */
545 st_i2c_terminate_xfer(i2c_dev);
546 } else if (c->count == 1) {
547 /* Penultimate byte to xfer, disable ACK gen. */
548 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_ACKG);
549
550 /* Last received byte is to be handled by NACK interrupt */
551 ien = SSC_IEN_NACKEN | SSC_IEN_ARBLEN;
552 writel_relaxed(ien, i2c_dev->base + SSC_IEN);
553
554 st_i2c_rd_fill_tx_fifo(i2c_dev, c->count);
555 } else {
556 st_i2c_rd_fill_tx_fifo(i2c_dev, c->count - 1);
557 }
558 }
559
560 /**
561 * st_i2c_isr_thread() - Interrupt routine
562 * @irq: interrupt number
563 * @data: Controller's private data
564 */
st_i2c_isr_thread(int irq,void * data)565 static irqreturn_t st_i2c_isr_thread(int irq, void *data)
566 {
567 struct st_i2c_dev *i2c_dev = data;
568 struct st_i2c_client *c = &i2c_dev->client;
569 u32 sta, ien;
570 int it;
571
572 ien = readl_relaxed(i2c_dev->base + SSC_IEN);
573 sta = readl_relaxed(i2c_dev->base + SSC_STA);
574
575 /* Use __fls() to check error bits first */
576 it = __fls(sta & ien);
577 if (it < 0) {
578 dev_dbg(i2c_dev->dev, "spurious it (sta=0x%04x, ien=0x%04x)\n",
579 sta, ien);
580 return IRQ_NONE;
581 }
582
583 switch (1 << it) {
584 case SSC_STA_TE:
585 if (c->addr & I2C_M_RD)
586 st_i2c_handle_read(i2c_dev);
587 else
588 st_i2c_handle_write(i2c_dev);
589 break;
590
591 case SSC_STA_STOP:
592 case SSC_STA_REPSTRT:
593 writel_relaxed(0, i2c_dev->base + SSC_IEN);
594 complete(&i2c_dev->complete);
595 break;
596
597 case SSC_STA_NACK:
598 writel_relaxed(SSC_CLR_NACK, i2c_dev->base + SSC_CLR);
599
600 /* Last received byte handled by NACK interrupt */
601 if ((c->addr & I2C_M_RD) && (c->count == 1) && (c->xfered)) {
602 st_i2c_handle_read(i2c_dev);
603 break;
604 }
605
606 it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN;
607 writel_relaxed(it, i2c_dev->base + SSC_IEN);
608
609 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG);
610 c->result = -EIO;
611 break;
612
613 case SSC_STA_ARBL:
614 writel_relaxed(SSC_CLR_SSCARBL, i2c_dev->base + SSC_CLR);
615
616 it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN;
617 writel_relaxed(it, i2c_dev->base + SSC_IEN);
618
619 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG);
620 c->result = -EAGAIN;
621 break;
622
623 default:
624 dev_err(i2c_dev->dev,
625 "it %d unhandled (sta=0x%04x)\n", it, sta);
626 }
627
628 /*
629 * Read IEN register to ensure interrupt mask write is effective
630 * before re-enabling interrupt at GIC level, and thus avoid spurious
631 * interrupts.
632 */
633 readl(i2c_dev->base + SSC_IEN);
634
635 return IRQ_HANDLED;
636 }
637
638 /**
639 * st_i2c_xfer_msg() - Transfer a single I2C message
640 * @i2c_dev: Controller's private data
641 * @msg: I2C message to transfer
642 * @is_first: first message of the sequence
643 * @is_last: last message of the sequence
644 */
st_i2c_xfer_msg(struct st_i2c_dev * i2c_dev,struct i2c_msg * msg,bool is_first,bool is_last)645 static int st_i2c_xfer_msg(struct st_i2c_dev *i2c_dev, struct i2c_msg *msg,
646 bool is_first, bool is_last)
647 {
648 struct st_i2c_client *c = &i2c_dev->client;
649 u32 ctl, i2c, it;
650 unsigned long timeout;
651 int ret;
652
653 c->addr = i2c_8bit_addr_from_msg(msg);
654 c->buf = msg->buf;
655 c->count = msg->len;
656 c->xfered = 0;
657 c->result = 0;
658 c->stop = is_last;
659
660 reinit_completion(&i2c_dev->complete);
661
662 ctl = SSC_CTL_EN | SSC_CTL_MS | SSC_CTL_EN_RX_FIFO | SSC_CTL_EN_TX_FIFO;
663 st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl);
664
665 i2c = SSC_I2C_TXENB;
666 if (c->addr & I2C_M_RD)
667 i2c |= SSC_I2C_ACKG;
668 st_i2c_set_bits(i2c_dev->base + SSC_I2C, i2c);
669
670 /* Write slave address */
671 st_i2c_write_tx_fifo(i2c_dev, c->addr);
672
673 /* Pre-fill Tx fifo with data in case of write */
674 if (!(c->addr & I2C_M_RD))
675 st_i2c_wr_fill_tx_fifo(i2c_dev);
676
677 it = SSC_IEN_NACKEN | SSC_IEN_TEEN | SSC_IEN_ARBLEN;
678 writel_relaxed(it, i2c_dev->base + SSC_IEN);
679
680 if (is_first) {
681 ret = st_i2c_wait_free_bus(i2c_dev);
682 if (ret)
683 return ret;
684
685 st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG);
686 }
687
688 timeout = wait_for_completion_timeout(&i2c_dev->complete,
689 i2c_dev->adap.timeout);
690 ret = c->result;
691
692 if (!timeout) {
693 dev_err(i2c_dev->dev, "Write to slave 0x%x timed out\n",
694 c->addr);
695 ret = -ETIMEDOUT;
696 }
697
698 i2c = SSC_I2C_STOPG | SSC_I2C_REPSTRTG;
699 st_i2c_clr_bits(i2c_dev->base + SSC_I2C, i2c);
700
701 writel_relaxed(SSC_CLR_SSCSTOP | SSC_CLR_REPSTRT,
702 i2c_dev->base + SSC_CLR);
703
704 return ret;
705 }
706
707 /**
708 * st_i2c_xfer() - Transfer a single I2C message
709 * @i2c_adap: Adapter pointer to the controller
710 * @msgs: Pointer to data to be written.
711 * @num: Number of messages to be executed
712 */
st_i2c_xfer(struct i2c_adapter * i2c_adap,struct i2c_msg msgs[],int num)713 static int st_i2c_xfer(struct i2c_adapter *i2c_adap,
714 struct i2c_msg msgs[], int num)
715 {
716 struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
717 int ret, i;
718
719 i2c_dev->busy = true;
720
721 ret = clk_prepare_enable(i2c_dev->clk);
722 if (ret) {
723 dev_err(i2c_dev->dev, "Failed to prepare_enable clock\n");
724 return ret;
725 }
726
727 pinctrl_pm_select_default_state(i2c_dev->dev);
728
729 st_i2c_hw_config(i2c_dev);
730
731 for (i = 0; (i < num) && !ret; i++)
732 ret = st_i2c_xfer_msg(i2c_dev, &msgs[i], i == 0, i == num - 1);
733
734 pinctrl_pm_select_idle_state(i2c_dev->dev);
735
736 clk_disable_unprepare(i2c_dev->clk);
737
738 i2c_dev->busy = false;
739
740 return (ret < 0) ? ret : i;
741 }
742
st_i2c_suspend(struct device * dev)743 static int st_i2c_suspend(struct device *dev)
744 {
745 struct st_i2c_dev *i2c_dev = dev_get_drvdata(dev);
746
747 if (i2c_dev->busy)
748 return -EBUSY;
749
750 pinctrl_pm_select_sleep_state(dev);
751
752 return 0;
753 }
754
st_i2c_resume(struct device * dev)755 static int st_i2c_resume(struct device *dev)
756 {
757 pinctrl_pm_select_default_state(dev);
758 /* Go in idle state if available */
759 pinctrl_pm_select_idle_state(dev);
760
761 return 0;
762 }
763
764 static DEFINE_SIMPLE_DEV_PM_OPS(st_i2c_pm, st_i2c_suspend, st_i2c_resume);
765
st_i2c_func(struct i2c_adapter * adap)766 static u32 st_i2c_func(struct i2c_adapter *adap)
767 {
768 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
769 }
770
771 static const struct i2c_algorithm st_i2c_algo = {
772 .master_xfer = st_i2c_xfer,
773 .functionality = st_i2c_func,
774 };
775
776 static struct i2c_bus_recovery_info st_i2c_recovery_info = {
777 .recover_bus = st_i2c_recover_bus,
778 };
779
st_i2c_of_get_deglitch(struct device_node * np,struct st_i2c_dev * i2c_dev)780 static int st_i2c_of_get_deglitch(struct device_node *np,
781 struct st_i2c_dev *i2c_dev)
782 {
783 int ret;
784
785 ret = of_property_read_u32(np, "st,i2c-min-scl-pulse-width-us",
786 &i2c_dev->scl_min_width_us);
787 if ((ret == -ENODATA) || (ret == -EOVERFLOW)) {
788 dev_err(i2c_dev->dev, "st,i2c-min-scl-pulse-width-us invalid\n");
789 return ret;
790 }
791
792 ret = of_property_read_u32(np, "st,i2c-min-sda-pulse-width-us",
793 &i2c_dev->sda_min_width_us);
794 if ((ret == -ENODATA) || (ret == -EOVERFLOW)) {
795 dev_err(i2c_dev->dev, "st,i2c-min-sda-pulse-width-us invalid\n");
796 return ret;
797 }
798
799 return 0;
800 }
801
st_i2c_probe(struct platform_device * pdev)802 static int st_i2c_probe(struct platform_device *pdev)
803 {
804 struct device_node *np = pdev->dev.of_node;
805 struct st_i2c_dev *i2c_dev;
806 struct resource *res;
807 u32 clk_rate;
808 struct i2c_adapter *adap;
809 int ret;
810
811 i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
812 if (!i2c_dev)
813 return -ENOMEM;
814
815 i2c_dev->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
816 if (IS_ERR(i2c_dev->base))
817 return PTR_ERR(i2c_dev->base);
818
819 i2c_dev->irq = irq_of_parse_and_map(np, 0);
820 if (!i2c_dev->irq) {
821 dev_err(&pdev->dev, "IRQ missing or invalid\n");
822 return -EINVAL;
823 }
824
825 i2c_dev->clk = of_clk_get_by_name(np, "ssc");
826 if (IS_ERR(i2c_dev->clk)) {
827 dev_err(&pdev->dev, "Unable to request clock\n");
828 return PTR_ERR(i2c_dev->clk);
829 }
830
831 i2c_dev->mode = I2C_MODE_STANDARD;
832 ret = of_property_read_u32(np, "clock-frequency", &clk_rate);
833 if (!ret && (clk_rate == I2C_MAX_FAST_MODE_FREQ))
834 i2c_dev->mode = I2C_MODE_FAST;
835
836 i2c_dev->dev = &pdev->dev;
837
838 ret = devm_request_threaded_irq(&pdev->dev, i2c_dev->irq,
839 NULL, st_i2c_isr_thread,
840 IRQF_ONESHOT, pdev->name, i2c_dev);
841 if (ret) {
842 dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq);
843 return ret;
844 }
845
846 pinctrl_pm_select_default_state(i2c_dev->dev);
847 /* In case idle state available, select it */
848 pinctrl_pm_select_idle_state(i2c_dev->dev);
849
850 ret = st_i2c_of_get_deglitch(np, i2c_dev);
851 if (ret)
852 return ret;
853
854 adap = &i2c_dev->adap;
855 i2c_set_adapdata(adap, i2c_dev);
856 snprintf(adap->name, sizeof(adap->name), "ST I2C(%pa)", &res->start);
857 adap->owner = THIS_MODULE;
858 adap->timeout = 2 * HZ;
859 adap->retries = 0;
860 adap->algo = &st_i2c_algo;
861 adap->bus_recovery_info = &st_i2c_recovery_info;
862 adap->dev.parent = &pdev->dev;
863 adap->dev.of_node = pdev->dev.of_node;
864
865 init_completion(&i2c_dev->complete);
866
867 ret = i2c_add_adapter(adap);
868 if (ret)
869 return ret;
870
871 platform_set_drvdata(pdev, i2c_dev);
872
873 dev_info(i2c_dev->dev, "%s initialized\n", adap->name);
874
875 return 0;
876 }
877
st_i2c_remove(struct platform_device * pdev)878 static void st_i2c_remove(struct platform_device *pdev)
879 {
880 struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
881
882 i2c_del_adapter(&i2c_dev->adap);
883 }
884
885 static const struct of_device_id st_i2c_match[] = {
886 { .compatible = "st,comms-ssc-i2c", },
887 { .compatible = "st,comms-ssc4-i2c", },
888 {},
889 };
890 MODULE_DEVICE_TABLE(of, st_i2c_match);
891
892 static struct platform_driver st_i2c_driver = {
893 .driver = {
894 .name = "st-i2c",
895 .of_match_table = st_i2c_match,
896 .pm = pm_sleep_ptr(&st_i2c_pm),
897 },
898 .probe = st_i2c_probe,
899 .remove_new = st_i2c_remove,
900 };
901
902 module_platform_driver(st_i2c_driver);
903
904 MODULE_AUTHOR("Maxime Coquelin <maxime.coquelin@st.com>");
905 MODULE_DESCRIPTION("STMicroelectronics I2C driver");
906 MODULE_LICENSE("GPL v2");
907