1 /*
2 * TI DAVINCI I2C adapter driver.
3 *
4 * Copyright (C) 2006 Texas Instruments.
5 * Copyright (C) 2007 MontaVista Software Inc.
6 *
7 * Updated by Vinod & Sudhakar Feb 2005
8 *
9 * ----------------------------------------------------------------------------
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 * ----------------------------------------------------------------------------
21 *
22 */
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/delay.h>
26 #include <linux/i2c.h>
27 #include <linux/clk.h>
28 #include <linux/errno.h>
29 #include <linux/sched.h>
30 #include <linux/err.h>
31 #include <linux/interrupt.h>
32 #include <linux/platform_device.h>
33 #include <linux/io.h>
34 #include <linux/slab.h>
35 #include <linux/cpufreq.h>
36 #include <linux/gpio/consumer.h>
37 #include <linux/of_device.h>
38 #include <linux/platform_data/i2c-davinci.h>
39 #include <linux/pm_runtime.h>
40
41 /* ----- global defines ----------------------------------------------- */
42
43 #define DAVINCI_I2C_TIMEOUT (1*HZ)
44 #define DAVINCI_I2C_MAX_TRIES 2
45 #define DAVINCI_I2C_OWN_ADDRESS 0x08
46 #define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_SCD | \
47 DAVINCI_I2C_IMR_ARDY | \
48 DAVINCI_I2C_IMR_NACK | \
49 DAVINCI_I2C_IMR_AL)
50
51 #define DAVINCI_I2C_OAR_REG 0x00
52 #define DAVINCI_I2C_IMR_REG 0x04
53 #define DAVINCI_I2C_STR_REG 0x08
54 #define DAVINCI_I2C_CLKL_REG 0x0c
55 #define DAVINCI_I2C_CLKH_REG 0x10
56 #define DAVINCI_I2C_CNT_REG 0x14
57 #define DAVINCI_I2C_DRR_REG 0x18
58 #define DAVINCI_I2C_SAR_REG 0x1c
59 #define DAVINCI_I2C_DXR_REG 0x20
60 #define DAVINCI_I2C_MDR_REG 0x24
61 #define DAVINCI_I2C_IVR_REG 0x28
62 #define DAVINCI_I2C_EMDR_REG 0x2c
63 #define DAVINCI_I2C_PSC_REG 0x30
64 #define DAVINCI_I2C_FUNC_REG 0x48
65 #define DAVINCI_I2C_DIR_REG 0x4c
66 #define DAVINCI_I2C_DIN_REG 0x50
67 #define DAVINCI_I2C_DOUT_REG 0x54
68 #define DAVINCI_I2C_DSET_REG 0x58
69 #define DAVINCI_I2C_DCLR_REG 0x5c
70
71 #define DAVINCI_I2C_IVR_AAS 0x07
72 #define DAVINCI_I2C_IVR_SCD 0x06
73 #define DAVINCI_I2C_IVR_XRDY 0x05
74 #define DAVINCI_I2C_IVR_RDR 0x04
75 #define DAVINCI_I2C_IVR_ARDY 0x03
76 #define DAVINCI_I2C_IVR_NACK 0x02
77 #define DAVINCI_I2C_IVR_AL 0x01
78
79 #define DAVINCI_I2C_STR_BB BIT(12)
80 #define DAVINCI_I2C_STR_RSFULL BIT(11)
81 #define DAVINCI_I2C_STR_SCD BIT(5)
82 #define DAVINCI_I2C_STR_ARDY BIT(2)
83 #define DAVINCI_I2C_STR_NACK BIT(1)
84 #define DAVINCI_I2C_STR_AL BIT(0)
85
86 #define DAVINCI_I2C_MDR_NACK BIT(15)
87 #define DAVINCI_I2C_MDR_STT BIT(13)
88 #define DAVINCI_I2C_MDR_STP BIT(11)
89 #define DAVINCI_I2C_MDR_MST BIT(10)
90 #define DAVINCI_I2C_MDR_TRX BIT(9)
91 #define DAVINCI_I2C_MDR_XA BIT(8)
92 #define DAVINCI_I2C_MDR_RM BIT(7)
93 #define DAVINCI_I2C_MDR_IRS BIT(5)
94
95 #define DAVINCI_I2C_IMR_AAS BIT(6)
96 #define DAVINCI_I2C_IMR_SCD BIT(5)
97 #define DAVINCI_I2C_IMR_XRDY BIT(4)
98 #define DAVINCI_I2C_IMR_RRDY BIT(3)
99 #define DAVINCI_I2C_IMR_ARDY BIT(2)
100 #define DAVINCI_I2C_IMR_NACK BIT(1)
101 #define DAVINCI_I2C_IMR_AL BIT(0)
102
103 /* set SDA and SCL as GPIO */
104 #define DAVINCI_I2C_FUNC_PFUNC0 BIT(0)
105
106 /* set SCL as output when used as GPIO*/
107 #define DAVINCI_I2C_DIR_PDIR0 BIT(0)
108 /* set SDA as output when used as GPIO*/
109 #define DAVINCI_I2C_DIR_PDIR1 BIT(1)
110
111 /* read SCL GPIO level */
112 #define DAVINCI_I2C_DIN_PDIN0 BIT(0)
113 /* read SDA GPIO level */
114 #define DAVINCI_I2C_DIN_PDIN1 BIT(1)
115
116 /*set the SCL GPIO high */
117 #define DAVINCI_I2C_DSET_PDSET0 BIT(0)
118 /*set the SDA GPIO high */
119 #define DAVINCI_I2C_DSET_PDSET1 BIT(1)
120
121 /* set the SCL GPIO low */
122 #define DAVINCI_I2C_DCLR_PDCLR0 BIT(0)
123 /* set the SDA GPIO low */
124 #define DAVINCI_I2C_DCLR_PDCLR1 BIT(1)
125
126 /* timeout for pm runtime autosuspend */
127 #define DAVINCI_I2C_PM_TIMEOUT 1000 /* ms */
128
129 struct davinci_i2c_dev {
130 struct device *dev;
131 void __iomem *base;
132 struct completion cmd_complete;
133 struct clk *clk;
134 int cmd_err;
135 u8 *buf;
136 size_t buf_len;
137 int irq;
138 int stop;
139 u8 terminate;
140 struct i2c_adapter adapter;
141 #ifdef CONFIG_CPU_FREQ
142 struct notifier_block freq_transition;
143 #endif
144 struct davinci_i2c_platform_data *pdata;
145 };
146
147 /* default platform data to use if not supplied in the platform_device */
148 static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
149 .bus_freq = 100,
150 .bus_delay = 0,
151 };
152
davinci_i2c_write_reg(struct davinci_i2c_dev * i2c_dev,int reg,u16 val)153 static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
154 int reg, u16 val)
155 {
156 writew_relaxed(val, i2c_dev->base + reg);
157 }
158
davinci_i2c_read_reg(struct davinci_i2c_dev * i2c_dev,int reg)159 static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
160 {
161 return readw_relaxed(i2c_dev->base + reg);
162 }
163
davinci_i2c_reset_ctrl(struct davinci_i2c_dev * i2c_dev,int val)164 static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
165 int val)
166 {
167 u16 w;
168
169 w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG);
170 if (!val) /* put I2C into reset */
171 w &= ~DAVINCI_I2C_MDR_IRS;
172 else /* take I2C out of reset */
173 w |= DAVINCI_I2C_MDR_IRS;
174
175 davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w);
176 }
177
i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev * dev)178 static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
179 {
180 struct davinci_i2c_platform_data *pdata = dev->pdata;
181 u16 psc;
182 u32 clk;
183 u32 d;
184 u32 clkh;
185 u32 clkl;
186 u32 input_clock = clk_get_rate(dev->clk);
187 struct device_node *of_node = dev->dev->of_node;
188
189 /* NOTE: I2C Clock divider programming info
190 * As per I2C specs the following formulas provide prescaler
191 * and low/high divider values
192 * input clk --> PSC Div -----------> ICCL/H Div --> output clock
193 * module clk
194 *
195 * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
196 *
197 * Thus,
198 * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
199 *
200 * where if PSC == 0, d = 7,
201 * if PSC == 1, d = 6
202 * if PSC > 1 , d = 5
203 *
204 * Note:
205 * d is always 6 on Keystone I2C controller
206 */
207
208 /*
209 * Both Davinci and current Keystone User Guides recommend a value
210 * between 7MHz and 12MHz. In reality 7MHz module clock doesn't
211 * always produce enough margin between SDA and SCL transitions.
212 * Measurements show that the higher the module clock is, the
213 * bigger is the margin, providing more reliable communication.
214 * So we better target for 12MHz.
215 */
216 psc = (input_clock / 12000000) - 1;
217 if ((input_clock / (psc + 1)) > 12000000)
218 psc++; /* better to run under spec than over */
219 d = (psc >= 2) ? 5 : 7 - psc;
220
221 if (of_node && of_device_is_compatible(of_node, "ti,keystone-i2c"))
222 d = 6;
223
224 clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000));
225 /* Avoid driving the bus too fast because of rounding errors above */
226 if (input_clock / (psc + 1) / clk > pdata->bus_freq * 1000)
227 clk++;
228 /*
229 * According to I2C-BUS Spec 2.1, in FAST-MODE LOW period should be at
230 * least 1.3uS, which is not the case with 50% duty cycle. Driving HIGH
231 * to LOW ratio as 1 to 2 is more safe.
232 */
233 if (pdata->bus_freq > 100)
234 clkl = (clk << 1) / 3;
235 else
236 clkl = (clk >> 1);
237 /*
238 * It's not always possible to have 1 to 2 ratio when d=7, so fall back
239 * to minimal possible clkh in this case.
240 *
241 * Note:
242 * CLKH is not allowed to be 0, in this case I2C clock is not generated
243 * at all
244 */
245 if (clk > clkl + d) {
246 clkh = clk - clkl - d;
247 clkl -= d;
248 } else {
249 clkh = 1;
250 clkl = clk - (d << 1);
251 }
252
253 davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
254 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
255 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
256
257 dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
258 }
259
260 /*
261 * This function configures I2C and brings I2C out of reset.
262 * This function is called during I2C init function. This function
263 * also gets called if I2C encounters any errors.
264 */
i2c_davinci_init(struct davinci_i2c_dev * dev)265 static int i2c_davinci_init(struct davinci_i2c_dev *dev)
266 {
267 struct davinci_i2c_platform_data *pdata = dev->pdata;
268
269 /* put I2C into reset */
270 davinci_i2c_reset_ctrl(dev, 0);
271
272 /* compute clock dividers */
273 i2c_davinci_calc_clk_dividers(dev);
274
275 /* Respond at reserved "SMBus Host" slave address" (and zero);
276 * we seem to have no option to not respond...
277 */
278 davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, DAVINCI_I2C_OWN_ADDRESS);
279
280 dev_dbg(dev->dev, "PSC = %d\n",
281 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
282 dev_dbg(dev->dev, "CLKL = %d\n",
283 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
284 dev_dbg(dev->dev, "CLKH = %d\n",
285 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
286 dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
287 pdata->bus_freq, pdata->bus_delay);
288
289
290 /* Take the I2C module out of reset: */
291 davinci_i2c_reset_ctrl(dev, 1);
292
293 /* Enable interrupts */
294 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
295
296 return 0;
297 }
298
299 /*
300 * This routine does i2c bus recovery by using i2c_generic_scl_recovery
301 * which is provided by I2C Bus recovery infrastructure.
302 */
davinci_i2c_prepare_recovery(struct i2c_adapter * adap)303 static void davinci_i2c_prepare_recovery(struct i2c_adapter *adap)
304 {
305 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
306
307 /* Disable interrupts */
308 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, 0);
309
310 /* put I2C into reset */
311 davinci_i2c_reset_ctrl(dev, 0);
312 }
313
davinci_i2c_unprepare_recovery(struct i2c_adapter * adap)314 static void davinci_i2c_unprepare_recovery(struct i2c_adapter *adap)
315 {
316 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
317
318 i2c_davinci_init(dev);
319 }
320
321 static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info = {
322 .recover_bus = i2c_generic_scl_recovery,
323 .prepare_recovery = davinci_i2c_prepare_recovery,
324 .unprepare_recovery = davinci_i2c_unprepare_recovery,
325 };
326
davinci_i2c_set_scl(struct i2c_adapter * adap,int val)327 static void davinci_i2c_set_scl(struct i2c_adapter *adap, int val)
328 {
329 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
330
331 if (val)
332 davinci_i2c_write_reg(dev, DAVINCI_I2C_DSET_REG,
333 DAVINCI_I2C_DSET_PDSET0);
334 else
335 davinci_i2c_write_reg(dev, DAVINCI_I2C_DCLR_REG,
336 DAVINCI_I2C_DCLR_PDCLR0);
337 }
338
davinci_i2c_get_scl(struct i2c_adapter * adap)339 static int davinci_i2c_get_scl(struct i2c_adapter *adap)
340 {
341 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
342 int val;
343
344 /* read the state of SCL */
345 val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG);
346 return val & DAVINCI_I2C_DIN_PDIN0;
347 }
348
davinci_i2c_get_sda(struct i2c_adapter * adap)349 static int davinci_i2c_get_sda(struct i2c_adapter *adap)
350 {
351 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
352 int val;
353
354 /* read the state of SDA */
355 val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG);
356 return val & DAVINCI_I2C_DIN_PDIN1;
357 }
358
davinci_i2c_scl_prepare_recovery(struct i2c_adapter * adap)359 static void davinci_i2c_scl_prepare_recovery(struct i2c_adapter *adap)
360 {
361 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
362
363 davinci_i2c_prepare_recovery(adap);
364
365 /* SCL output, SDA input */
366 davinci_i2c_write_reg(dev, DAVINCI_I2C_DIR_REG, DAVINCI_I2C_DIR_PDIR0);
367
368 /* change to GPIO mode */
369 davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG,
370 DAVINCI_I2C_FUNC_PFUNC0);
371 }
372
davinci_i2c_scl_unprepare_recovery(struct i2c_adapter * adap)373 static void davinci_i2c_scl_unprepare_recovery(struct i2c_adapter *adap)
374 {
375 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
376
377 /* change back to I2C mode */
378 davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG, 0);
379
380 davinci_i2c_unprepare_recovery(adap);
381 }
382
383 static struct i2c_bus_recovery_info davinci_i2c_scl_recovery_info = {
384 .recover_bus = i2c_generic_scl_recovery,
385 .set_scl = davinci_i2c_set_scl,
386 .get_scl = davinci_i2c_get_scl,
387 .get_sda = davinci_i2c_get_sda,
388 .prepare_recovery = davinci_i2c_scl_prepare_recovery,
389 .unprepare_recovery = davinci_i2c_scl_unprepare_recovery,
390 };
391
392 /*
393 * Waiting for bus not busy
394 */
i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev * dev)395 static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev)
396 {
397 unsigned long timeout = jiffies + dev->adapter.timeout;
398
399 do {
400 if (!(davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB))
401 return 0;
402 schedule_timeout_uninterruptible(1);
403 } while (time_before_eq(jiffies, timeout));
404
405 dev_warn(dev->dev, "timeout waiting for bus ready\n");
406 i2c_recover_bus(&dev->adapter);
407
408 /*
409 * if bus is still "busy" here, it's most probably a HW problem like
410 * short-circuit
411 */
412 if (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB)
413 return -EIO;
414
415 return 0;
416 }
417
418 /*
419 * Low level master read/write transaction. This function is called
420 * from i2c_davinci_xfer.
421 */
422 static int
i2c_davinci_xfer_msg(struct i2c_adapter * adap,struct i2c_msg * msg,int stop)423 i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
424 {
425 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
426 struct davinci_i2c_platform_data *pdata = dev->pdata;
427 u32 flag;
428 u16 w;
429 unsigned long time_left;
430
431 if (msg->addr == DAVINCI_I2C_OWN_ADDRESS) {
432 dev_warn(dev->dev, "transfer to own address aborted\n");
433 return -EADDRNOTAVAIL;
434 }
435
436 /* Introduce a delay, required for some boards (e.g Davinci EVM) */
437 if (pdata->bus_delay)
438 udelay(pdata->bus_delay);
439
440 /* set the slave address */
441 davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
442
443 dev->buf = msg->buf;
444 dev->buf_len = msg->len;
445 dev->stop = stop;
446
447 davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
448
449 reinit_completion(&dev->cmd_complete);
450 dev->cmd_err = 0;
451
452 /* Take I2C out of reset and configure it as master */
453 flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST;
454
455 /* if the slave address is ten bit address, enable XA bit */
456 if (msg->flags & I2C_M_TEN)
457 flag |= DAVINCI_I2C_MDR_XA;
458 if (!(msg->flags & I2C_M_RD))
459 flag |= DAVINCI_I2C_MDR_TRX;
460 if (msg->len == 0)
461 flag |= DAVINCI_I2C_MDR_RM;
462
463 /* Enable receive or transmit interrupts */
464 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
465 if (msg->flags & I2C_M_RD)
466 w |= DAVINCI_I2C_IMR_RRDY;
467 else
468 w |= DAVINCI_I2C_IMR_XRDY;
469 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
470
471 dev->terminate = 0;
472
473 /*
474 * Write mode register first as needed for correct behaviour
475 * on OMAP-L138, but don't set STT yet to avoid a race with XRDY
476 * occurring before we have loaded DXR
477 */
478 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
479
480 /*
481 * First byte should be set here, not after interrupt,
482 * because transmit-data-ready interrupt can come before
483 * NACK-interrupt during sending of previous message and
484 * ICDXR may have wrong data
485 * It also saves us one interrupt, slightly faster
486 */
487 if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
488 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
489 dev->buf_len--;
490 }
491
492 /* Set STT to begin transmit now DXR is loaded */
493 flag |= DAVINCI_I2C_MDR_STT;
494 if (stop && msg->len != 0)
495 flag |= DAVINCI_I2C_MDR_STP;
496 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
497
498 time_left = wait_for_completion_timeout(&dev->cmd_complete,
499 dev->adapter.timeout);
500 if (!time_left) {
501 dev_err(dev->dev, "controller timed out\n");
502 i2c_recover_bus(adap);
503 dev->buf_len = 0;
504 return -ETIMEDOUT;
505 }
506 if (dev->buf_len) {
507 /* This should be 0 if all bytes were transferred
508 * or dev->cmd_err denotes an error.
509 */
510 dev_err(dev->dev, "abnormal termination buf_len=%zu\n",
511 dev->buf_len);
512 dev->terminate = 1;
513 wmb();
514 dev->buf_len = 0;
515 return -EREMOTEIO;
516 }
517
518 /* no error */
519 if (likely(!dev->cmd_err))
520 return msg->len;
521
522 /* We have an error */
523 if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
524 i2c_davinci_init(dev);
525 return -EIO;
526 }
527
528 if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
529 if (msg->flags & I2C_M_IGNORE_NAK)
530 return msg->len;
531 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
532 w |= DAVINCI_I2C_MDR_STP;
533 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
534 return -EREMOTEIO;
535 }
536 return -EIO;
537 }
538
539 /*
540 * Prepare controller for a transaction and call i2c_davinci_xfer_msg
541 */
542 static int
i2c_davinci_xfer(struct i2c_adapter * adap,struct i2c_msg msgs[],int num)543 i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
544 {
545 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
546 int i;
547 int ret;
548
549 dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
550
551 ret = pm_runtime_get_sync(dev->dev);
552 if (ret < 0) {
553 dev_err(dev->dev, "Failed to runtime_get device: %d\n", ret);
554 pm_runtime_put_noidle(dev->dev);
555 return ret;
556 }
557
558 ret = i2c_davinci_wait_bus_not_busy(dev);
559 if (ret < 0) {
560 dev_warn(dev->dev, "timeout waiting for bus ready\n");
561 goto out;
562 }
563
564 for (i = 0; i < num; i++) {
565 ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
566 dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
567 ret);
568 if (ret < 0)
569 goto out;
570 }
571
572 ret = num;
573
574 out:
575 pm_runtime_mark_last_busy(dev->dev);
576 pm_runtime_put_autosuspend(dev->dev);
577
578 return ret;
579 }
580
i2c_davinci_func(struct i2c_adapter * adap)581 static u32 i2c_davinci_func(struct i2c_adapter *adap)
582 {
583 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
584 }
585
terminate_read(struct davinci_i2c_dev * dev)586 static void terminate_read(struct davinci_i2c_dev *dev)
587 {
588 u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
589 w |= DAVINCI_I2C_MDR_NACK;
590 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
591
592 /* Throw away data */
593 davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG);
594 if (!dev->terminate)
595 dev_err(dev->dev, "RDR IRQ while no data requested\n");
596 }
terminate_write(struct davinci_i2c_dev * dev)597 static void terminate_write(struct davinci_i2c_dev *dev)
598 {
599 u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
600 w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
601 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
602
603 if (!dev->terminate)
604 dev_dbg(dev->dev, "TDR IRQ while no data to send\n");
605 }
606
607 /*
608 * Interrupt service routine. This gets called whenever an I2C interrupt
609 * occurs.
610 */
i2c_davinci_isr(int this_irq,void * dev_id)611 static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
612 {
613 struct davinci_i2c_dev *dev = dev_id;
614 u32 stat;
615 int count = 0;
616 u16 w;
617
618 if (pm_runtime_suspended(dev->dev))
619 return IRQ_NONE;
620
621 while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
622 dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
623 if (count++ == 100) {
624 dev_warn(dev->dev, "Too much work in one IRQ\n");
625 break;
626 }
627
628 switch (stat) {
629 case DAVINCI_I2C_IVR_AL:
630 /* Arbitration lost, must retry */
631 dev->cmd_err |= DAVINCI_I2C_STR_AL;
632 dev->buf_len = 0;
633 complete(&dev->cmd_complete);
634 break;
635
636 case DAVINCI_I2C_IVR_NACK:
637 dev->cmd_err |= DAVINCI_I2C_STR_NACK;
638 dev->buf_len = 0;
639 complete(&dev->cmd_complete);
640 break;
641
642 case DAVINCI_I2C_IVR_ARDY:
643 davinci_i2c_write_reg(dev,
644 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
645 if (((dev->buf_len == 0) && (dev->stop != 0)) ||
646 (dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
647 w = davinci_i2c_read_reg(dev,
648 DAVINCI_I2C_MDR_REG);
649 w |= DAVINCI_I2C_MDR_STP;
650 davinci_i2c_write_reg(dev,
651 DAVINCI_I2C_MDR_REG, w);
652 }
653 complete(&dev->cmd_complete);
654 break;
655
656 case DAVINCI_I2C_IVR_RDR:
657 if (dev->buf_len) {
658 *dev->buf++ =
659 davinci_i2c_read_reg(dev,
660 DAVINCI_I2C_DRR_REG);
661 dev->buf_len--;
662 if (dev->buf_len)
663 continue;
664
665 davinci_i2c_write_reg(dev,
666 DAVINCI_I2C_STR_REG,
667 DAVINCI_I2C_IMR_RRDY);
668 } else {
669 /* signal can terminate transfer */
670 terminate_read(dev);
671 }
672 break;
673
674 case DAVINCI_I2C_IVR_XRDY:
675 if (dev->buf_len) {
676 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
677 *dev->buf++);
678 dev->buf_len--;
679 if (dev->buf_len)
680 continue;
681
682 w = davinci_i2c_read_reg(dev,
683 DAVINCI_I2C_IMR_REG);
684 w &= ~DAVINCI_I2C_IMR_XRDY;
685 davinci_i2c_write_reg(dev,
686 DAVINCI_I2C_IMR_REG,
687 w);
688 } else {
689 /* signal can terminate transfer */
690 terminate_write(dev);
691 }
692 break;
693
694 case DAVINCI_I2C_IVR_SCD:
695 davinci_i2c_write_reg(dev,
696 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
697 complete(&dev->cmd_complete);
698 break;
699
700 case DAVINCI_I2C_IVR_AAS:
701 dev_dbg(dev->dev, "Address as slave interrupt\n");
702 break;
703
704 default:
705 dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat);
706 break;
707 }
708 }
709
710 return count ? IRQ_HANDLED : IRQ_NONE;
711 }
712
713 #ifdef CONFIG_CPU_FREQ
i2c_davinci_cpufreq_transition(struct notifier_block * nb,unsigned long val,void * data)714 static int i2c_davinci_cpufreq_transition(struct notifier_block *nb,
715 unsigned long val, void *data)
716 {
717 struct davinci_i2c_dev *dev;
718
719 dev = container_of(nb, struct davinci_i2c_dev, freq_transition);
720
721 i2c_lock_bus(&dev->adapter, I2C_LOCK_ROOT_ADAPTER);
722 if (val == CPUFREQ_PRECHANGE) {
723 davinci_i2c_reset_ctrl(dev, 0);
724 } else if (val == CPUFREQ_POSTCHANGE) {
725 i2c_davinci_calc_clk_dividers(dev);
726 davinci_i2c_reset_ctrl(dev, 1);
727 }
728 i2c_unlock_bus(&dev->adapter, I2C_LOCK_ROOT_ADAPTER);
729
730 return 0;
731 }
732
i2c_davinci_cpufreq_register(struct davinci_i2c_dev * dev)733 static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
734 {
735 dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition;
736
737 return cpufreq_register_notifier(&dev->freq_transition,
738 CPUFREQ_TRANSITION_NOTIFIER);
739 }
740
i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev * dev)741 static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
742 {
743 cpufreq_unregister_notifier(&dev->freq_transition,
744 CPUFREQ_TRANSITION_NOTIFIER);
745 }
746 #else
i2c_davinci_cpufreq_register(struct davinci_i2c_dev * dev)747 static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
748 {
749 return 0;
750 }
751
i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev * dev)752 static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
753 {
754 }
755 #endif
756
757 static const struct i2c_algorithm i2c_davinci_algo = {
758 .master_xfer = i2c_davinci_xfer,
759 .functionality = i2c_davinci_func,
760 };
761
762 static const struct of_device_id davinci_i2c_of_match[] = {
763 {.compatible = "ti,davinci-i2c", },
764 {.compatible = "ti,keystone-i2c", },
765 {},
766 };
767 MODULE_DEVICE_TABLE(of, davinci_i2c_of_match);
768
davinci_i2c_probe(struct platform_device * pdev)769 static int davinci_i2c_probe(struct platform_device *pdev)
770 {
771 struct davinci_i2c_dev *dev;
772 struct i2c_adapter *adap;
773 struct resource *mem;
774 struct i2c_bus_recovery_info *rinfo;
775 int r, irq;
776
777 irq = platform_get_irq(pdev, 0);
778 if (irq <= 0) {
779 if (!irq)
780 irq = -ENXIO;
781 if (irq != -EPROBE_DEFER)
782 dev_err(&pdev->dev,
783 "can't get irq resource ret=%d\n", irq);
784 return irq;
785 }
786
787 dev = devm_kzalloc(&pdev->dev, sizeof(struct davinci_i2c_dev),
788 GFP_KERNEL);
789 if (!dev) {
790 dev_err(&pdev->dev, "Memory allocation failed\n");
791 return -ENOMEM;
792 }
793
794 init_completion(&dev->cmd_complete);
795
796 dev->dev = &pdev->dev;
797 dev->irq = irq;
798 dev->pdata = dev_get_platdata(&pdev->dev);
799 platform_set_drvdata(pdev, dev);
800
801 if (!dev->pdata && pdev->dev.of_node) {
802 u32 prop;
803
804 dev->pdata = devm_kzalloc(&pdev->dev,
805 sizeof(struct davinci_i2c_platform_data), GFP_KERNEL);
806 if (!dev->pdata)
807 return -ENOMEM;
808
809 memcpy(dev->pdata, &davinci_i2c_platform_data_default,
810 sizeof(struct davinci_i2c_platform_data));
811 if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency",
812 &prop))
813 dev->pdata->bus_freq = prop / 1000;
814
815 dev->pdata->has_pfunc =
816 of_property_read_bool(pdev->dev.of_node,
817 "ti,has-pfunc");
818 } else if (!dev->pdata) {
819 dev->pdata = &davinci_i2c_platform_data_default;
820 }
821
822 dev->clk = devm_clk_get(&pdev->dev, NULL);
823 if (IS_ERR(dev->clk))
824 return PTR_ERR(dev->clk);
825
826 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
827 dev->base = devm_ioremap_resource(&pdev->dev, mem);
828 if (IS_ERR(dev->base)) {
829 return PTR_ERR(dev->base);
830 }
831
832 pm_runtime_set_autosuspend_delay(dev->dev,
833 DAVINCI_I2C_PM_TIMEOUT);
834 pm_runtime_use_autosuspend(dev->dev);
835
836 pm_runtime_enable(dev->dev);
837
838 r = pm_runtime_get_sync(dev->dev);
839 if (r < 0) {
840 dev_err(dev->dev, "failed to runtime_get device: %d\n", r);
841 pm_runtime_put_noidle(dev->dev);
842 return r;
843 }
844
845 i2c_davinci_init(dev);
846
847 r = devm_request_irq(&pdev->dev, dev->irq, i2c_davinci_isr, 0,
848 pdev->name, dev);
849 if (r) {
850 dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
851 goto err_unuse_clocks;
852 }
853
854 r = i2c_davinci_cpufreq_register(dev);
855 if (r) {
856 dev_err(&pdev->dev, "failed to register cpufreq\n");
857 goto err_unuse_clocks;
858 }
859
860 adap = &dev->adapter;
861 i2c_set_adapdata(adap, dev);
862 adap->owner = THIS_MODULE;
863 adap->class = I2C_CLASS_DEPRECATED;
864 strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
865 adap->algo = &i2c_davinci_algo;
866 adap->dev.parent = &pdev->dev;
867 adap->timeout = DAVINCI_I2C_TIMEOUT;
868 adap->dev.of_node = pdev->dev.of_node;
869
870 if (dev->pdata->has_pfunc)
871 adap->bus_recovery_info = &davinci_i2c_scl_recovery_info;
872 else if (dev->pdata->gpio_recovery) {
873 rinfo = &davinci_i2c_gpio_recovery_info;
874 adap->bus_recovery_info = rinfo;
875 rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl",
876 GPIOD_OUT_HIGH_OPEN_DRAIN);
877 if (IS_ERR(rinfo->scl_gpiod)) {
878 r = PTR_ERR(rinfo->scl_gpiod);
879 goto err_unuse_clocks;
880 }
881 rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN);
882 if (IS_ERR(rinfo->sda_gpiod)) {
883 r = PTR_ERR(rinfo->sda_gpiod);
884 goto err_unuse_clocks;
885 }
886 }
887
888 adap->nr = pdev->id;
889 r = i2c_add_numbered_adapter(adap);
890 if (r)
891 goto err_unuse_clocks;
892
893 pm_runtime_mark_last_busy(dev->dev);
894 pm_runtime_put_autosuspend(dev->dev);
895
896 return 0;
897
898 err_unuse_clocks:
899 pm_runtime_dont_use_autosuspend(dev->dev);
900 pm_runtime_put_sync(dev->dev);
901 pm_runtime_disable(dev->dev);
902
903 return r;
904 }
905
davinci_i2c_remove(struct platform_device * pdev)906 static int davinci_i2c_remove(struct platform_device *pdev)
907 {
908 struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
909 int ret;
910
911 i2c_davinci_cpufreq_deregister(dev);
912
913 i2c_del_adapter(&dev->adapter);
914
915 ret = pm_runtime_get_sync(&pdev->dev);
916 if (ret < 0) {
917 pm_runtime_put_noidle(&pdev->dev);
918 return ret;
919 }
920
921 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
922
923 pm_runtime_dont_use_autosuspend(dev->dev);
924 pm_runtime_put_sync(dev->dev);
925 pm_runtime_disable(dev->dev);
926
927 return 0;
928 }
929
930 #ifdef CONFIG_PM
davinci_i2c_suspend(struct device * dev)931 static int davinci_i2c_suspend(struct device *dev)
932 {
933 struct davinci_i2c_dev *i2c_dev = dev_get_drvdata(dev);
934
935 /* put I2C into reset */
936 davinci_i2c_reset_ctrl(i2c_dev, 0);
937
938 return 0;
939 }
940
davinci_i2c_resume(struct device * dev)941 static int davinci_i2c_resume(struct device *dev)
942 {
943 struct davinci_i2c_dev *i2c_dev = dev_get_drvdata(dev);
944
945 /* take I2C out of reset */
946 davinci_i2c_reset_ctrl(i2c_dev, 1);
947
948 return 0;
949 }
950
951 static const struct dev_pm_ops davinci_i2c_pm = {
952 .suspend = davinci_i2c_suspend,
953 .resume = davinci_i2c_resume,
954 SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
955 pm_runtime_force_resume)
956 };
957
958 #define davinci_i2c_pm_ops (&davinci_i2c_pm)
959 #else
960 #define davinci_i2c_pm_ops NULL
961 #endif
962
963 /* work with hotplug and coldplug */
964 MODULE_ALIAS("platform:i2c_davinci");
965
966 static struct platform_driver davinci_i2c_driver = {
967 .probe = davinci_i2c_probe,
968 .remove = davinci_i2c_remove,
969 .driver = {
970 .name = "i2c_davinci",
971 .pm = davinci_i2c_pm_ops,
972 .of_match_table = davinci_i2c_of_match,
973 },
974 };
975
976 /* I2C may be needed to bring up other drivers */
davinci_i2c_init_driver(void)977 static int __init davinci_i2c_init_driver(void)
978 {
979 return platform_driver_register(&davinci_i2c_driver);
980 }
981 subsys_initcall(davinci_i2c_init_driver);
982
davinci_i2c_exit_driver(void)983 static void __exit davinci_i2c_exit_driver(void)
984 {
985 platform_driver_unregister(&davinci_i2c_driver);
986 }
987 module_exit(davinci_i2c_exit_driver);
988
989 MODULE_AUTHOR("Texas Instruments India");
990 MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
991 MODULE_LICENSE("GPL");
992
