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85b4fab2 MC |
1 | /* |
2 | * Copyright (C) 2013 STMicroelectronics | |
3 | * | |
4 | * I2C master mode controller driver, used in STMicroelectronics devices. | |
5 | * | |
6 | * Author: Maxime Coquelin <maxime.coquelin@st.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2, as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/platform_device.h> | |
15 | #include <linux/i2c.h> | |
16 | #include <linux/clk.h> | |
17 | #include <linux/io.h> | |
18 | #include <linux/delay.h> | |
19 | #include <linux/interrupt.h> | |
20 | #include <linux/err.h> | |
21 | #include <linux/of.h> | |
22 | #include <linux/of_address.h> | |
23 | #include <linux/of_irq.h> | |
24 | ||
25 | /* SSC registers */ | |
26 | #define SSC_BRG 0x000 | |
27 | #define SSC_TBUF 0x004 | |
28 | #define SSC_RBUF 0x008 | |
29 | #define SSC_CTL 0x00C | |
30 | #define SSC_IEN 0x010 | |
31 | #define SSC_STA 0x014 | |
32 | #define SSC_I2C 0x018 | |
33 | #define SSC_SLAD 0x01C | |
34 | #define SSC_REP_START_HOLD 0x020 | |
35 | #define SSC_START_HOLD 0x024 | |
36 | #define SSC_REP_START_SETUP 0x028 | |
37 | #define SSC_DATA_SETUP 0x02C | |
38 | #define SSC_STOP_SETUP 0x030 | |
39 | #define SSC_BUS_FREE 0x034 | |
40 | #define SSC_TX_FSTAT 0x038 | |
41 | #define SSC_RX_FSTAT 0x03C | |
42 | #define SSC_PRE_SCALER_BRG 0x040 | |
43 | #define SSC_CLR 0x080 | |
44 | #define SSC_NOISE_SUPP_WIDTH 0x100 | |
45 | #define SSC_PRSCALER 0x104 | |
46 | #define SSC_NOISE_SUPP_WIDTH_DATAOUT 0x108 | |
47 | #define SSC_PRSCALER_DATAOUT 0x10c | |
48 | ||
49 | /* SSC Control */ | |
50 | #define SSC_CTL_DATA_WIDTH_9 0x8 | |
51 | #define SSC_CTL_DATA_WIDTH_MSK 0xf | |
52 | #define SSC_CTL_BM 0xf | |
53 | #define SSC_CTL_HB BIT(4) | |
54 | #define SSC_CTL_PH BIT(5) | |
55 | #define SSC_CTL_PO BIT(6) | |
56 | #define SSC_CTL_SR BIT(7) | |
57 | #define SSC_CTL_MS BIT(8) | |
58 | #define SSC_CTL_EN BIT(9) | |
59 | #define SSC_CTL_LPB BIT(10) | |
60 | #define SSC_CTL_EN_TX_FIFO BIT(11) | |
61 | #define SSC_CTL_EN_RX_FIFO BIT(12) | |
62 | #define SSC_CTL_EN_CLST_RX BIT(13) | |
63 | ||
64 | /* SSC Interrupt Enable */ | |
65 | #define SSC_IEN_RIEN BIT(0) | |
66 | #define SSC_IEN_TIEN BIT(1) | |
67 | #define SSC_IEN_TEEN BIT(2) | |
68 | #define SSC_IEN_REEN BIT(3) | |
69 | #define SSC_IEN_PEEN BIT(4) | |
70 | #define SSC_IEN_AASEN BIT(6) | |
71 | #define SSC_IEN_STOPEN BIT(7) | |
72 | #define SSC_IEN_ARBLEN BIT(8) | |
73 | #define SSC_IEN_NACKEN BIT(10) | |
74 | #define SSC_IEN_REPSTRTEN BIT(11) | |
75 | #define SSC_IEN_TX_FIFO_HALF BIT(12) | |
76 | #define SSC_IEN_RX_FIFO_HALF_FULL BIT(14) | |
77 | ||
78 | /* SSC Status */ | |
79 | #define SSC_STA_RIR BIT(0) | |
80 | #define SSC_STA_TIR BIT(1) | |
81 | #define SSC_STA_TE BIT(2) | |
82 | #define SSC_STA_RE BIT(3) | |
83 | #define SSC_STA_PE BIT(4) | |
84 | #define SSC_STA_CLST BIT(5) | |
85 | #define SSC_STA_AAS BIT(6) | |
86 | #define SSC_STA_STOP BIT(7) | |
87 | #define SSC_STA_ARBL BIT(8) | |
88 | #define SSC_STA_BUSY BIT(9) | |
89 | #define SSC_STA_NACK BIT(10) | |
90 | #define SSC_STA_REPSTRT BIT(11) | |
91 | #define SSC_STA_TX_FIFO_HALF BIT(12) | |
92 | #define SSC_STA_TX_FIFO_FULL BIT(13) | |
93 | #define SSC_STA_RX_FIFO_HALF BIT(14) | |
94 | ||
95 | /* SSC I2C Control */ | |
96 | #define SSC_I2C_I2CM BIT(0) | |
97 | #define SSC_I2C_STRTG BIT(1) | |
98 | #define SSC_I2C_STOPG BIT(2) | |
99 | #define SSC_I2C_ACKG BIT(3) | |
100 | #define SSC_I2C_AD10 BIT(4) | |
101 | #define SSC_I2C_TXENB BIT(5) | |
102 | #define SSC_I2C_REPSTRTG BIT(11) | |
103 | #define SSC_I2C_SLAVE_DISABLE BIT(12) | |
104 | ||
105 | /* SSC Tx FIFO Status */ | |
106 | #define SSC_TX_FSTAT_STATUS 0x07 | |
107 | ||
108 | /* SSC Rx FIFO Status */ | |
109 | #define SSC_RX_FSTAT_STATUS 0x07 | |
110 | ||
111 | /* SSC Clear bit operation */ | |
112 | #define SSC_CLR_SSCAAS BIT(6) | |
113 | #define SSC_CLR_SSCSTOP BIT(7) | |
114 | #define SSC_CLR_SSCARBL BIT(8) | |
115 | #define SSC_CLR_NACK BIT(10) | |
116 | #define SSC_CLR_REPSTRT BIT(11) | |
117 | ||
118 | /* SSC Clock Prescaler */ | |
119 | #define SSC_PRSC_VALUE 0x0f | |
120 | ||
121 | ||
122 | #define SSC_TXFIFO_SIZE 0x8 | |
123 | #define SSC_RXFIFO_SIZE 0x8 | |
124 | ||
125 | enum st_i2c_mode { | |
126 | I2C_MODE_STANDARD, | |
127 | I2C_MODE_FAST, | |
128 | I2C_MODE_END, | |
129 | }; | |
130 | ||
131 | /** | |
132 | * struct st_i2c_timings - per-Mode tuning parameters | |
133 | * @rate: I2C bus rate | |
134 | * @rep_start_hold: I2C repeated start hold time requirement | |
135 | * @rep_start_setup: I2C repeated start set up time requirement | |
136 | * @start_hold: I2C start hold time requirement | |
137 | * @data_setup_time: I2C data set up time requirement | |
138 | * @stop_setup_time: I2C stop set up time requirement | |
139 | * @bus_free_time: I2C bus free time requirement | |
140 | * @sda_pulse_min_limit: I2C SDA pulse mini width limit | |
141 | */ | |
142 | struct st_i2c_timings { | |
143 | u32 rate; | |
144 | u32 rep_start_hold; | |
145 | u32 rep_start_setup; | |
146 | u32 start_hold; | |
147 | u32 data_setup_time; | |
148 | u32 stop_setup_time; | |
149 | u32 bus_free_time; | |
150 | u32 sda_pulse_min_limit; | |
151 | }; | |
152 | ||
153 | /** | |
154 | * struct st_i2c_client - client specific data | |
155 | * @addr: 8-bit slave addr, including r/w bit | |
156 | * @count: number of bytes to be transfered | |
157 | * @xfered: number of bytes already transferred | |
158 | * @buf: data buffer | |
159 | * @result: result of the transfer | |
160 | * @stop: last I2C msg to be sent, i.e. STOP to be generated | |
161 | */ | |
162 | struct st_i2c_client { | |
163 | u8 addr; | |
164 | u32 count; | |
165 | u32 xfered; | |
166 | u8 *buf; | |
167 | int result; | |
168 | bool stop; | |
169 | }; | |
170 | ||
171 | /** | |
172 | * struct st_i2c_dev - private data of the controller | |
173 | * @adap: I2C adapter for this controller | |
174 | * @dev: device for this controller | |
175 | * @base: virtual memory area | |
176 | * @complete: completion of I2C message | |
177 | * @irq: interrupt line for th controller | |
178 | * @clk: hw ssc block clock | |
179 | * @mode: I2C mode of the controller. Standard or Fast only supported | |
180 | * @scl_min_width_us: SCL line minimum pulse width in us | |
181 | * @sda_min_width_us: SDA line minimum pulse width in us | |
182 | * @client: I2C transfert information | |
183 | * @busy: I2C transfer on-going | |
184 | */ | |
185 | struct st_i2c_dev { | |
186 | struct i2c_adapter adap; | |
187 | struct device *dev; | |
188 | void __iomem *base; | |
189 | struct completion complete; | |
190 | int irq; | |
191 | struct clk *clk; | |
192 | int mode; | |
193 | u32 scl_min_width_us; | |
194 | u32 sda_min_width_us; | |
195 | struct st_i2c_client client; | |
196 | bool busy; | |
197 | }; | |
198 | ||
199 | static inline void st_i2c_set_bits(void __iomem *reg, u32 mask) | |
200 | { | |
201 | writel_relaxed(readl_relaxed(reg) | mask, reg); | |
202 | } | |
203 | ||
204 | static inline void st_i2c_clr_bits(void __iomem *reg, u32 mask) | |
205 | { | |
206 | writel_relaxed(readl_relaxed(reg) & ~mask, reg); | |
207 | } | |
208 | ||
209 | /* From I2C Specifications v0.5 */ | |
210 | static struct st_i2c_timings i2c_timings[] = { | |
211 | [I2C_MODE_STANDARD] = { | |
212 | .rate = 100000, | |
213 | .rep_start_hold = 4000, | |
214 | .rep_start_setup = 4700, | |
215 | .start_hold = 4000, | |
216 | .data_setup_time = 250, | |
217 | .stop_setup_time = 4000, | |
218 | .bus_free_time = 4700, | |
219 | }, | |
220 | [I2C_MODE_FAST] = { | |
221 | .rate = 400000, | |
222 | .rep_start_hold = 600, | |
223 | .rep_start_setup = 600, | |
224 | .start_hold = 600, | |
225 | .data_setup_time = 100, | |
226 | .stop_setup_time = 600, | |
227 | .bus_free_time = 1300, | |
228 | }, | |
229 | }; | |
230 | ||
231 | static void st_i2c_flush_rx_fifo(struct st_i2c_dev *i2c_dev) | |
232 | { | |
233 | int count, i; | |
234 | ||
235 | /* | |
236 | * Counter only counts up to 7 but fifo size is 8... | |
237 | * When fifo is full, counter is 0 and RIR bit of status register is | |
238 | * set | |
239 | */ | |
240 | if (readl_relaxed(i2c_dev->base + SSC_STA) & SSC_STA_RIR) | |
241 | count = SSC_RXFIFO_SIZE; | |
242 | else | |
243 | count = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT) & | |
244 | SSC_RX_FSTAT_STATUS; | |
245 | ||
246 | for (i = 0; i < count; i++) | |
247 | readl_relaxed(i2c_dev->base + SSC_RBUF); | |
248 | } | |
249 | ||
250 | static void st_i2c_soft_reset(struct st_i2c_dev *i2c_dev) | |
251 | { | |
252 | /* | |
253 | * FIFO needs to be emptied before reseting the IP, | |
254 | * else the controller raises a BUSY error. | |
255 | */ | |
256 | st_i2c_flush_rx_fifo(i2c_dev); | |
257 | ||
258 | st_i2c_set_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR); | |
259 | st_i2c_clr_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR); | |
260 | } | |
261 | ||
262 | /** | |
263 | * st_i2c_hw_config() - Prepare SSC block, calculate and apply tuning timings | |
264 | * @i2c_dev: Controller's private data | |
265 | */ | |
266 | static void st_i2c_hw_config(struct st_i2c_dev *i2c_dev) | |
267 | { | |
268 | unsigned long rate; | |
269 | u32 val, ns_per_clk; | |
270 | struct st_i2c_timings *t = &i2c_timings[i2c_dev->mode]; | |
271 | ||
272 | st_i2c_soft_reset(i2c_dev); | |
273 | ||
274 | val = SSC_CLR_REPSTRT | SSC_CLR_NACK | SSC_CLR_SSCARBL | | |
275 | SSC_CLR_SSCAAS | SSC_CLR_SSCSTOP; | |
276 | writel_relaxed(val, i2c_dev->base + SSC_CLR); | |
277 | ||
278 | /* SSC Control register setup */ | |
279 | val = SSC_CTL_PO | SSC_CTL_PH | SSC_CTL_HB | SSC_CTL_DATA_WIDTH_9; | |
280 | writel_relaxed(val, i2c_dev->base + SSC_CTL); | |
281 | ||
282 | rate = clk_get_rate(i2c_dev->clk); | |
283 | ns_per_clk = 1000000000 / rate; | |
284 | ||
285 | /* Baudrate */ | |
286 | val = rate / (2 * t->rate); | |
287 | writel_relaxed(val, i2c_dev->base + SSC_BRG); | |
288 | ||
289 | /* Pre-scaler baudrate */ | |
290 | writel_relaxed(1, i2c_dev->base + SSC_PRE_SCALER_BRG); | |
291 | ||
292 | /* Enable I2C mode */ | |
293 | writel_relaxed(SSC_I2C_I2CM, i2c_dev->base + SSC_I2C); | |
294 | ||
295 | /* Repeated start hold time */ | |
296 | val = t->rep_start_hold / ns_per_clk; | |
297 | writel_relaxed(val, i2c_dev->base + SSC_REP_START_HOLD); | |
298 | ||
299 | /* Repeated start set up time */ | |
300 | val = t->rep_start_setup / ns_per_clk; | |
301 | writel_relaxed(val, i2c_dev->base + SSC_REP_START_SETUP); | |
302 | ||
303 | /* Start hold time */ | |
304 | val = t->start_hold / ns_per_clk; | |
305 | writel_relaxed(val, i2c_dev->base + SSC_START_HOLD); | |
306 | ||
307 | /* Data set up time */ | |
308 | val = t->data_setup_time / ns_per_clk; | |
309 | writel_relaxed(val, i2c_dev->base + SSC_DATA_SETUP); | |
310 | ||
311 | /* Stop set up time */ | |
312 | val = t->stop_setup_time / ns_per_clk; | |
313 | writel_relaxed(val, i2c_dev->base + SSC_STOP_SETUP); | |
314 | ||
315 | /* Bus free time */ | |
316 | val = t->bus_free_time / ns_per_clk; | |
317 | writel_relaxed(val, i2c_dev->base + SSC_BUS_FREE); | |
318 | ||
319 | /* Prescalers set up */ | |
320 | val = rate / 10000000; | |
321 | writel_relaxed(val, i2c_dev->base + SSC_PRSCALER); | |
322 | writel_relaxed(val, i2c_dev->base + SSC_PRSCALER_DATAOUT); | |
323 | ||
324 | /* Noise suppression witdh */ | |
325 | val = i2c_dev->scl_min_width_us * rate / 100000000; | |
326 | writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH); | |
327 | ||
328 | /* Noise suppression max output data delay width */ | |
329 | val = i2c_dev->sda_min_width_us * rate / 100000000; | |
330 | writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH_DATAOUT); | |
331 | } | |
332 | ||
333 | static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev) | |
334 | { | |
335 | u32 sta; | |
336 | int i; | |
337 | ||
338 | for (i = 0; i < 10; i++) { | |
339 | sta = readl_relaxed(i2c_dev->base + SSC_STA); | |
340 | if (!(sta & SSC_STA_BUSY)) | |
341 | return 0; | |
342 | ||
343 | usleep_range(2000, 4000); | |
344 | } | |
345 | ||
346 | dev_err(i2c_dev->dev, "bus not free (status = 0x%08x)\n", sta); | |
347 | ||
348 | return -EBUSY; | |
349 | } | |
350 | ||
351 | /** | |
352 | * st_i2c_write_tx_fifo() - Write a byte in the Tx FIFO | |
353 | * @i2c_dev: Controller's private data | |
354 | * @byte: Data to write in the Tx FIFO | |
355 | */ | |
356 | static inline void st_i2c_write_tx_fifo(struct st_i2c_dev *i2c_dev, u8 byte) | |
357 | { | |
358 | u16 tbuf = byte << 1; | |
359 | ||
360 | writel_relaxed(tbuf | 1, i2c_dev->base + SSC_TBUF); | |
361 | } | |
362 | ||
363 | /** | |
364 | * st_i2c_wr_fill_tx_fifo() - Fill the Tx FIFO in write mode | |
365 | * @i2c_dev: Controller's private data | |
366 | * | |
367 | * This functions fills the Tx FIFO with I2C transfert buffer when | |
368 | * in write mode. | |
369 | */ | |
370 | static void st_i2c_wr_fill_tx_fifo(struct st_i2c_dev *i2c_dev) | |
371 | { | |
372 | struct st_i2c_client *c = &i2c_dev->client; | |
373 | u32 tx_fstat, sta; | |
374 | int i; | |
375 | ||
376 | sta = readl_relaxed(i2c_dev->base + SSC_STA); | |
377 | if (sta & SSC_STA_TX_FIFO_FULL) | |
378 | return; | |
379 | ||
380 | tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT); | |
381 | tx_fstat &= SSC_TX_FSTAT_STATUS; | |
382 | ||
383 | if (c->count < (SSC_TXFIFO_SIZE - tx_fstat)) | |
384 | i = c->count; | |
385 | else | |
386 | i = SSC_TXFIFO_SIZE - tx_fstat; | |
387 | ||
388 | for (; i > 0; i--, c->count--, c->buf++) | |
389 | st_i2c_write_tx_fifo(i2c_dev, *c->buf); | |
390 | } | |
391 | ||
392 | /** | |
393 | * st_i2c_rd_fill_tx_fifo() - Fill the Tx FIFO in read mode | |
394 | * @i2c_dev: Controller's private data | |
395 | * | |
396 | * This functions fills the Tx FIFO with fixed pattern when | |
397 | * in read mode to trigger clock. | |
398 | */ | |
399 | static void st_i2c_rd_fill_tx_fifo(struct st_i2c_dev *i2c_dev, int max) | |
400 | { | |
401 | struct st_i2c_client *c = &i2c_dev->client; | |
402 | u32 tx_fstat, sta; | |
403 | int i; | |
404 | ||
405 | sta = readl_relaxed(i2c_dev->base + SSC_STA); | |
406 | if (sta & SSC_STA_TX_FIFO_FULL) | |
407 | return; | |
408 | ||
409 | tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT); | |
410 | tx_fstat &= SSC_TX_FSTAT_STATUS; | |
411 | ||
412 | if (max < (SSC_TXFIFO_SIZE - tx_fstat)) | |
413 | i = max; | |
414 | else | |
415 | i = SSC_TXFIFO_SIZE - tx_fstat; | |
416 | ||
417 | for (; i > 0; i--, c->xfered++) | |
418 | st_i2c_write_tx_fifo(i2c_dev, 0xff); | |
419 | } | |
420 | ||
421 | static void st_i2c_read_rx_fifo(struct st_i2c_dev *i2c_dev) | |
422 | { | |
423 | struct st_i2c_client *c = &i2c_dev->client; | |
424 | u32 i, sta; | |
425 | u16 rbuf; | |
426 | ||
427 | sta = readl_relaxed(i2c_dev->base + SSC_STA); | |
428 | if (sta & SSC_STA_RIR) { | |
429 | i = SSC_RXFIFO_SIZE; | |
430 | } else { | |
431 | i = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT); | |
432 | i &= SSC_RX_FSTAT_STATUS; | |
433 | } | |
434 | ||
435 | for (; (i > 0) && (c->count > 0); i--, c->count--) { | |
436 | rbuf = readl_relaxed(i2c_dev->base + SSC_RBUF) >> 1; | |
437 | *c->buf++ = (u8)rbuf & 0xff; | |
438 | } | |
439 | ||
440 | if (i) { | |
441 | dev_err(i2c_dev->dev, "Unexpected %d bytes in rx fifo\n", i); | |
442 | st_i2c_flush_rx_fifo(i2c_dev); | |
443 | } | |
444 | } | |
445 | ||
446 | /** | |
447 | * st_i2c_terminate_xfer() - Send either STOP or REPSTART condition | |
448 | * @i2c_dev: Controller's private data | |
449 | */ | |
450 | static void st_i2c_terminate_xfer(struct st_i2c_dev *i2c_dev) | |
451 | { | |
452 | struct st_i2c_client *c = &i2c_dev->client; | |
453 | ||
454 | st_i2c_clr_bits(i2c_dev->base + SSC_IEN, SSC_IEN_TEEN); | |
455 | st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG); | |
456 | ||
457 | if (c->stop) { | |
458 | st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_STOPEN); | |
459 | st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); | |
460 | } else { | |
461 | st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_REPSTRTEN); | |
462 | st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_REPSTRTG); | |
463 | } | |
464 | } | |
465 | ||
466 | /** | |
467 | * st_i2c_handle_write() - Handle FIFO empty interrupt in case of write | |
468 | * @i2c_dev: Controller's private data | |
469 | */ | |
470 | static void st_i2c_handle_write(struct st_i2c_dev *i2c_dev) | |
471 | { | |
472 | struct st_i2c_client *c = &i2c_dev->client; | |
473 | ||
474 | st_i2c_flush_rx_fifo(i2c_dev); | |
475 | ||
476 | if (!c->count) | |
477 | /* End of xfer, send stop or repstart */ | |
478 | st_i2c_terminate_xfer(i2c_dev); | |
479 | else | |
480 | st_i2c_wr_fill_tx_fifo(i2c_dev); | |
481 | } | |
482 | ||
483 | /** | |
484 | * st_i2c_handle_write() - Handle FIFO enmpty interrupt in case of read | |
485 | * @i2c_dev: Controller's private data | |
486 | */ | |
487 | static void st_i2c_handle_read(struct st_i2c_dev *i2c_dev) | |
488 | { | |
489 | struct st_i2c_client *c = &i2c_dev->client; | |
490 | u32 ien; | |
491 | ||
492 | /* Trash the address read back */ | |
493 | if (!c->xfered) { | |
494 | readl_relaxed(i2c_dev->base + SSC_RBUF); | |
495 | st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_TXENB); | |
496 | } else { | |
497 | st_i2c_read_rx_fifo(i2c_dev); | |
498 | } | |
499 | ||
500 | if (!c->count) { | |
501 | /* End of xfer, send stop or repstart */ | |
502 | st_i2c_terminate_xfer(i2c_dev); | |
503 | } else if (c->count == 1) { | |
504 | /* Penultimate byte to xfer, disable ACK gen. */ | |
505 | st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_ACKG); | |
506 | ||
507 | /* Last received byte is to be handled by NACK interrupt */ | |
508 | ien = SSC_IEN_NACKEN | SSC_IEN_ARBLEN; | |
509 | writel_relaxed(ien, i2c_dev->base + SSC_IEN); | |
510 | ||
511 | st_i2c_rd_fill_tx_fifo(i2c_dev, c->count); | |
512 | } else { | |
513 | st_i2c_rd_fill_tx_fifo(i2c_dev, c->count - 1); | |
514 | } | |
515 | } | |
516 | ||
517 | /** | |
518 | * st_i2c_isr() - Interrupt routine | |
519 | * @irq: interrupt number | |
520 | * @data: Controller's private data | |
521 | */ | |
522 | static irqreturn_t st_i2c_isr_thread(int irq, void *data) | |
523 | { | |
524 | struct st_i2c_dev *i2c_dev = data; | |
525 | struct st_i2c_client *c = &i2c_dev->client; | |
526 | u32 sta, ien; | |
527 | int it; | |
528 | ||
529 | ien = readl_relaxed(i2c_dev->base + SSC_IEN); | |
530 | sta = readl_relaxed(i2c_dev->base + SSC_STA); | |
531 | ||
532 | /* Use __fls() to check error bits first */ | |
533 | it = __fls(sta & ien); | |
534 | if (it < 0) { | |
535 | dev_dbg(i2c_dev->dev, "spurious it (sta=0x%04x, ien=0x%04x)\n", | |
536 | sta, ien); | |
537 | return IRQ_NONE; | |
538 | } | |
539 | ||
540 | switch (1 << it) { | |
541 | case SSC_STA_TE: | |
542 | if (c->addr & I2C_M_RD) | |
543 | st_i2c_handle_read(i2c_dev); | |
544 | else | |
545 | st_i2c_handle_write(i2c_dev); | |
546 | break; | |
547 | ||
548 | case SSC_STA_STOP: | |
549 | case SSC_STA_REPSTRT: | |
550 | writel_relaxed(0, i2c_dev->base + SSC_IEN); | |
551 | complete(&i2c_dev->complete); | |
552 | break; | |
553 | ||
554 | case SSC_STA_NACK: | |
555 | writel_relaxed(SSC_CLR_NACK, i2c_dev->base + SSC_CLR); | |
556 | ||
557 | /* Last received byte handled by NACK interrupt */ | |
558 | if ((c->addr & I2C_M_RD) && (c->count == 1) && (c->xfered)) { | |
559 | st_i2c_handle_read(i2c_dev); | |
560 | break; | |
561 | } | |
562 | ||
563 | it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN; | |
564 | writel_relaxed(it, i2c_dev->base + SSC_IEN); | |
565 | ||
566 | st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); | |
567 | c->result = -EIO; | |
568 | break; | |
569 | ||
570 | case SSC_STA_ARBL: | |
571 | writel_relaxed(SSC_CLR_SSCARBL, i2c_dev->base + SSC_CLR); | |
572 | ||
573 | it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN; | |
574 | writel_relaxed(it, i2c_dev->base + SSC_IEN); | |
575 | ||
576 | st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); | |
577 | c->result = -EIO; | |
578 | break; | |
579 | ||
580 | default: | |
581 | dev_err(i2c_dev->dev, | |
582 | "it %d unhandled (sta=0x%04x)\n", it, sta); | |
583 | } | |
584 | ||
585 | /* | |
586 | * Read IEN register to ensure interrupt mask write is effective | |
587 | * before re-enabling interrupt at GIC level, and thus avoid spurious | |
588 | * interrupts. | |
589 | */ | |
590 | readl(i2c_dev->base + SSC_IEN); | |
591 | ||
592 | return IRQ_HANDLED; | |
593 | } | |
594 | ||
595 | /** | |
596 | * st_i2c_xfer_msg() - Transfer a single I2C message | |
597 | * @i2c_dev: Controller's private data | |
598 | * @msg: I2C message to transfer | |
599 | * @is_first: first message of the sequence | |
600 | * @is_last: last message of the sequence | |
601 | */ | |
602 | static int st_i2c_xfer_msg(struct st_i2c_dev *i2c_dev, struct i2c_msg *msg, | |
603 | bool is_first, bool is_last) | |
604 | { | |
605 | struct st_i2c_client *c = &i2c_dev->client; | |
606 | u32 ctl, i2c, it; | |
607 | unsigned long timeout; | |
608 | int ret; | |
609 | ||
610 | c->addr = (u8)(msg->addr << 1); | |
611 | c->addr |= (msg->flags & I2C_M_RD); | |
612 | c->buf = msg->buf; | |
613 | c->count = msg->len; | |
614 | c->xfered = 0; | |
615 | c->result = 0; | |
616 | c->stop = is_last; | |
617 | ||
618 | INIT_COMPLETION(i2c_dev->complete); | |
619 | ||
620 | ctl = SSC_CTL_EN | SSC_CTL_MS | SSC_CTL_EN_RX_FIFO | SSC_CTL_EN_TX_FIFO; | |
621 | st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl); | |
622 | ||
623 | i2c = SSC_I2C_TXENB; | |
624 | if (c->addr & I2C_M_RD) | |
625 | i2c |= SSC_I2C_ACKG; | |
626 | st_i2c_set_bits(i2c_dev->base + SSC_I2C, i2c); | |
627 | ||
628 | /* Write slave address */ | |
629 | st_i2c_write_tx_fifo(i2c_dev, c->addr); | |
630 | ||
631 | /* Pre-fill Tx fifo with data in case of write */ | |
632 | if (!(c->addr & I2C_M_RD)) | |
633 | st_i2c_wr_fill_tx_fifo(i2c_dev); | |
634 | ||
635 | it = SSC_IEN_NACKEN | SSC_IEN_TEEN | SSC_IEN_ARBLEN; | |
636 | writel_relaxed(it, i2c_dev->base + SSC_IEN); | |
637 | ||
638 | if (is_first) { | |
639 | ret = st_i2c_wait_free_bus(i2c_dev); | |
640 | if (ret) | |
641 | return ret; | |
642 | ||
643 | st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG); | |
644 | } | |
645 | ||
646 | timeout = wait_for_completion_timeout(&i2c_dev->complete, | |
647 | i2c_dev->adap.timeout); | |
648 | ret = c->result; | |
649 | ||
650 | if (!timeout) { | |
651 | dev_err(i2c_dev->dev, "Write to slave 0x%x timed out\n", | |
652 | c->addr); | |
653 | ret = -ETIMEDOUT; | |
654 | } | |
655 | ||
656 | i2c = SSC_I2C_STOPG | SSC_I2C_REPSTRTG; | |
657 | st_i2c_clr_bits(i2c_dev->base + SSC_I2C, i2c); | |
658 | ||
659 | writel_relaxed(SSC_CLR_SSCSTOP | SSC_CLR_REPSTRT, | |
660 | i2c_dev->base + SSC_CLR); | |
661 | ||
662 | return ret; | |
663 | } | |
664 | ||
665 | /** | |
666 | * st_i2c_xfer() - Transfer a single I2C message | |
667 | * @i2c_adap: Adapter pointer to the controller | |
668 | * @msgs: Pointer to data to be written. | |
669 | * @num: Number of messages to be executed | |
670 | */ | |
671 | static int st_i2c_xfer(struct i2c_adapter *i2c_adap, | |
672 | struct i2c_msg msgs[], int num) | |
673 | { | |
674 | struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap); | |
675 | int ret, i; | |
676 | ||
677 | i2c_dev->busy = true; | |
678 | ||
679 | ret = clk_prepare_enable(i2c_dev->clk); | |
680 | if (ret) { | |
681 | dev_err(i2c_dev->dev, "Failed to prepare_enable clock\n"); | |
682 | return ret; | |
683 | } | |
684 | ||
685 | pinctrl_pm_select_default_state(i2c_dev->dev); | |
686 | ||
687 | st_i2c_hw_config(i2c_dev); | |
688 | ||
689 | for (i = 0; (i < num) && !ret; i++) | |
690 | ret = st_i2c_xfer_msg(i2c_dev, &msgs[i], i == 0, i == num - 1); | |
691 | ||
692 | pinctrl_pm_select_idle_state(i2c_dev->dev); | |
693 | ||
694 | clk_disable_unprepare(i2c_dev->clk); | |
695 | ||
696 | i2c_dev->busy = false; | |
697 | ||
698 | return (ret < 0) ? ret : i; | |
699 | } | |
700 | ||
701 | #ifdef CONFIG_PM_SLEEP | |
702 | static int st_i2c_suspend(struct device *dev) | |
703 | { | |
704 | struct platform_device *pdev = | |
705 | container_of(dev, struct platform_device, dev); | |
706 | struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev); | |
707 | ||
708 | if (i2c_dev->busy) | |
709 | return -EBUSY; | |
710 | ||
711 | pinctrl_pm_select_sleep_state(dev); | |
712 | ||
713 | return 0; | |
714 | } | |
715 | ||
716 | static int st_i2c_resume(struct device *dev) | |
717 | { | |
718 | pinctrl_pm_select_default_state(dev); | |
719 | /* Go in idle state if available */ | |
720 | pinctrl_pm_select_idle_state(dev); | |
721 | ||
722 | return 0; | |
723 | } | |
724 | ||
725 | static SIMPLE_DEV_PM_OPS(st_i2c_pm, st_i2c_suspend, st_i2c_resume); | |
726 | #define ST_I2C_PM (&st_i2c_pm) | |
727 | #else | |
728 | #define ST_I2C_PM NULL | |
729 | #endif | |
730 | ||
731 | static u32 st_i2c_func(struct i2c_adapter *adap) | |
732 | { | |
733 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; | |
734 | } | |
735 | ||
736 | static struct i2c_algorithm st_i2c_algo = { | |
737 | .master_xfer = st_i2c_xfer, | |
738 | .functionality = st_i2c_func, | |
739 | }; | |
740 | ||
741 | static int st_i2c_of_get_deglitch(struct device_node *np, | |
742 | struct st_i2c_dev *i2c_dev) | |
743 | { | |
744 | int ret; | |
745 | ||
746 | ret = of_property_read_u32(np, "st,i2c-min-scl-pulse-width-us", | |
747 | &i2c_dev->scl_min_width_us); | |
748 | if ((ret == -ENODATA) || (ret == -EOVERFLOW)) { | |
749 | dev_err(i2c_dev->dev, "st,i2c-min-scl-pulse-width-us invalid\n"); | |
750 | return ret; | |
751 | } | |
752 | ||
753 | ret = of_property_read_u32(np, "st,i2c-min-sda-pulse-width-us", | |
754 | &i2c_dev->sda_min_width_us); | |
755 | if ((ret == -ENODATA) || (ret == -EOVERFLOW)) { | |
756 | dev_err(i2c_dev->dev, "st,i2c-min-sda-pulse-width-us invalid\n"); | |
757 | return ret; | |
758 | } | |
759 | ||
760 | return 0; | |
761 | } | |
762 | ||
763 | static int st_i2c_probe(struct platform_device *pdev) | |
764 | { | |
765 | struct device_node *np = pdev->dev.of_node; | |
766 | struct st_i2c_dev *i2c_dev; | |
767 | struct resource *res; | |
768 | u32 clk_rate; | |
769 | struct i2c_adapter *adap; | |
770 | int ret; | |
771 | ||
772 | i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL); | |
773 | if (!i2c_dev) | |
774 | return -ENOMEM; | |
775 | ||
776 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
777 | i2c_dev->base = devm_ioremap_resource(&pdev->dev, res); | |
778 | if (IS_ERR(i2c_dev->base)) | |
779 | return PTR_ERR(i2c_dev->base); | |
780 | ||
781 | i2c_dev->irq = irq_of_parse_and_map(np, 0); | |
782 | if (!i2c_dev->irq) { | |
783 | dev_err(&pdev->dev, "IRQ missing or invalid\n"); | |
784 | return -EINVAL; | |
785 | } | |
786 | ||
787 | i2c_dev->clk = of_clk_get_by_name(np, "ssc"); | |
788 | if (IS_ERR(i2c_dev->clk)) { | |
789 | dev_err(&pdev->dev, "Unable to request clock\n"); | |
790 | return PTR_ERR(i2c_dev->clk); | |
791 | } | |
792 | ||
793 | i2c_dev->mode = I2C_MODE_STANDARD; | |
794 | ret = of_property_read_u32(np, "clock-frequency", &clk_rate); | |
795 | if ((!ret) && (clk_rate == 400000)) | |
796 | i2c_dev->mode = I2C_MODE_FAST; | |
797 | ||
798 | i2c_dev->dev = &pdev->dev; | |
799 | ||
800 | ret = devm_request_threaded_irq(&pdev->dev, i2c_dev->irq, | |
801 | NULL, st_i2c_isr_thread, | |
802 | IRQF_ONESHOT, pdev->name, i2c_dev); | |
803 | if (ret) { | |
804 | dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq); | |
805 | return ret; | |
806 | } | |
807 | ||
808 | pinctrl_pm_select_default_state(i2c_dev->dev); | |
809 | /* In case idle state available, select it */ | |
810 | pinctrl_pm_select_idle_state(i2c_dev->dev); | |
811 | ||
812 | ret = st_i2c_of_get_deglitch(np, i2c_dev); | |
813 | if (ret) | |
814 | return ret; | |
815 | ||
816 | adap = &i2c_dev->adap; | |
817 | i2c_set_adapdata(adap, i2c_dev); | |
818 | snprintf(adap->name, sizeof(adap->name), "ST I2C(0x%x)", res->start); | |
819 | adap->owner = THIS_MODULE; | |
820 | adap->timeout = 2 * HZ; | |
821 | adap->retries = 0; | |
822 | adap->algo = &st_i2c_algo; | |
823 | adap->dev.parent = &pdev->dev; | |
824 | adap->dev.of_node = pdev->dev.of_node; | |
825 | ||
826 | init_completion(&i2c_dev->complete); | |
827 | ||
828 | ret = i2c_add_adapter(adap); | |
829 | if (ret) { | |
830 | dev_err(&pdev->dev, "Failed to add adapter\n"); | |
831 | return ret; | |
832 | } | |
833 | ||
834 | platform_set_drvdata(pdev, i2c_dev); | |
835 | ||
836 | dev_info(i2c_dev->dev, "%s initialized\n", adap->name); | |
837 | ||
838 | return 0; | |
839 | } | |
840 | ||
841 | static int st_i2c_remove(struct platform_device *pdev) | |
842 | { | |
843 | struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev); | |
844 | ||
845 | i2c_del_adapter(&i2c_dev->adap); | |
846 | ||
847 | return 0; | |
848 | } | |
849 | ||
850 | static struct of_device_id st_i2c_match[] = { | |
851 | { .compatible = "st,comms-ssc-i2c", }, | |
852 | { .compatible = "st,comms-ssc4-i2c", }, | |
853 | {}, | |
854 | }; | |
855 | MODULE_DEVICE_TABLE(of, st_i2c_match); | |
856 | ||
857 | static struct platform_driver st_i2c_driver = { | |
858 | .driver = { | |
859 | .name = "st-i2c", | |
860 | .owner = THIS_MODULE, | |
861 | .of_match_table = st_i2c_match, | |
862 | .pm = ST_I2C_PM, | |
863 | }, | |
864 | .probe = st_i2c_probe, | |
865 | .remove = st_i2c_remove, | |
866 | }; | |
867 | ||
868 | module_platform_driver(st_i2c_driver); | |
869 | ||
870 | MODULE_AUTHOR("Maxime Coquelin <maxime.coquelin@st.com>"); | |
871 | MODULE_DESCRIPTION("STMicroelectronics I2C driver"); | |
872 | MODULE_LICENSE("GPL v2"); |