1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * TI DAVINCI I2C adapter driver.
4 *
5 * Copyright (C) 2006 Texas Instruments.
6 * Copyright (C) 2007 MontaVista Software Inc.
7 *
8 * Updated by Vinod & Sudhakar Feb 2005
9 *
10 * ----------------------------------------------------------------------------
11 *
12 * ----------------------------------------------------------------------------
13 */
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/delay.h>
17#include <linux/i2c.h>
18#include <linux/clk.h>
19#include <linux/errno.h>
20#include <linux/sched.h>
21#include <linux/err.h>
22#include <linux/interrupt.h>
23#include <linux/platform_device.h>
24#include <linux/io.h>
25#include <linux/slab.h>
26#include <linux/cpufreq.h>
27#include <linux/gpio/consumer.h>
28#include <linux/of.h>
29#include <linux/platform_data/i2c-davinci.h>
30#include <linux/pm_runtime.h>
31
32/* ----- global defines ----------------------------------------------- */
33
34#define DAVINCI_I2C_TIMEOUT (1*HZ)
35#define DAVINCI_I2C_MAX_TRIES 2
36#define DAVINCI_I2C_OWN_ADDRESS 0x08
37#define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_SCD | \
38 DAVINCI_I2C_IMR_ARDY | \
39 DAVINCI_I2C_IMR_NACK | \
40 DAVINCI_I2C_IMR_AL)
41
42#define DAVINCI_I2C_OAR_REG 0x00
43#define DAVINCI_I2C_IMR_REG 0x04
44#define DAVINCI_I2C_STR_REG 0x08
45#define DAVINCI_I2C_CLKL_REG 0x0c
46#define DAVINCI_I2C_CLKH_REG 0x10
47#define DAVINCI_I2C_CNT_REG 0x14
48#define DAVINCI_I2C_DRR_REG 0x18
49#define DAVINCI_I2C_SAR_REG 0x1c
50#define DAVINCI_I2C_DXR_REG 0x20
51#define DAVINCI_I2C_MDR_REG 0x24
52#define DAVINCI_I2C_IVR_REG 0x28
53#define DAVINCI_I2C_EMDR_REG 0x2c
54#define DAVINCI_I2C_PSC_REG 0x30
55#define DAVINCI_I2C_FUNC_REG 0x48
56#define DAVINCI_I2C_DIR_REG 0x4c
57#define DAVINCI_I2C_DIN_REG 0x50
58#define DAVINCI_I2C_DOUT_REG 0x54
59#define DAVINCI_I2C_DSET_REG 0x58
60#define DAVINCI_I2C_DCLR_REG 0x5c
61
62#define DAVINCI_I2C_IVR_AAS 0x07
63#define DAVINCI_I2C_IVR_SCD 0x06
64#define DAVINCI_I2C_IVR_XRDY 0x05
65#define DAVINCI_I2C_IVR_RDR 0x04
66#define DAVINCI_I2C_IVR_ARDY 0x03
67#define DAVINCI_I2C_IVR_NACK 0x02
68#define DAVINCI_I2C_IVR_AL 0x01
69
70#define DAVINCI_I2C_STR_BB BIT(12)
71#define DAVINCI_I2C_STR_RSFULL BIT(11)
72#define DAVINCI_I2C_STR_SCD BIT(5)
73#define DAVINCI_I2C_STR_ARDY BIT(2)
74#define DAVINCI_I2C_STR_NACK BIT(1)
75#define DAVINCI_I2C_STR_AL BIT(0)
76
77#define DAVINCI_I2C_MDR_NACK BIT(15)
78#define DAVINCI_I2C_MDR_STT BIT(13)
79#define DAVINCI_I2C_MDR_STP BIT(11)
80#define DAVINCI_I2C_MDR_MST BIT(10)
81#define DAVINCI_I2C_MDR_TRX BIT(9)
82#define DAVINCI_I2C_MDR_XA BIT(8)
83#define DAVINCI_I2C_MDR_RM BIT(7)
84#define DAVINCI_I2C_MDR_IRS BIT(5)
85
86#define DAVINCI_I2C_IMR_AAS BIT(6)
87#define DAVINCI_I2C_IMR_SCD BIT(5)
88#define DAVINCI_I2C_IMR_XRDY BIT(4)
89#define DAVINCI_I2C_IMR_RRDY BIT(3)
90#define DAVINCI_I2C_IMR_ARDY BIT(2)
91#define DAVINCI_I2C_IMR_NACK BIT(1)
92#define DAVINCI_I2C_IMR_AL BIT(0)
93
94/* set SDA and SCL as GPIO */
95#define DAVINCI_I2C_FUNC_PFUNC0 BIT(0)
96
97/* set SCL as output when used as GPIO*/
98#define DAVINCI_I2C_DIR_PDIR0 BIT(0)
99/* set SDA as output when used as GPIO*/
100#define DAVINCI_I2C_DIR_PDIR1 BIT(1)
101
102/* read SCL GPIO level */
103#define DAVINCI_I2C_DIN_PDIN0 BIT(0)
104/* read SDA GPIO level */
105#define DAVINCI_I2C_DIN_PDIN1 BIT(1)
106
107/*set the SCL GPIO high */
108#define DAVINCI_I2C_DSET_PDSET0 BIT(0)
109/*set the SDA GPIO high */
110#define DAVINCI_I2C_DSET_PDSET1 BIT(1)
111
112/* set the SCL GPIO low */
113#define DAVINCI_I2C_DCLR_PDCLR0 BIT(0)
114/* set the SDA GPIO low */
115#define DAVINCI_I2C_DCLR_PDCLR1 BIT(1)
116
117/* timeout for pm runtime autosuspend */
118#define DAVINCI_I2C_PM_TIMEOUT 1000 /* ms */
119
120struct davinci_i2c_dev {
121 struct device *dev;
122 void __iomem *base;
123 struct completion cmd_complete;
124 struct clk *clk;
125 int cmd_err;
126 u8 *buf;
127 size_t buf_len;
128 int irq;
129 int stop;
130 u8 terminate;
131 struct i2c_adapter adapter;
132#ifdef CONFIG_CPU_FREQ
133 struct notifier_block freq_transition;
134#endif
135 struct davinci_i2c_platform_data *pdata;
136};
137
138/* default platform data to use if not supplied in the platform_device */
139static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
140 .bus_freq = 100,
141 .bus_delay = 0,
142};
143
144static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
145 int reg, u16 val)
146{
147 writew_relaxed(val, i2c_dev->base + reg);
148}
149
150static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
151{
152 return readw_relaxed(i2c_dev->base + reg);
153}
154
155static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
156 int val)
157{
158 u16 w;
159
160 w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG);
161 if (!val) /* put I2C into reset */
162 w &= ~DAVINCI_I2C_MDR_IRS;
163 else /* take I2C out of reset */
164 w |= DAVINCI_I2C_MDR_IRS;
165
166 davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, val: w);
167}
168
169static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
170{
171 struct davinci_i2c_platform_data *pdata = dev->pdata;
172 u16 psc;
173 u32 clk;
174 u32 d;
175 u32 clkh;
176 u32 clkl;
177 u32 input_clock = clk_get_rate(clk: dev->clk);
178 struct device_node *of_node = dev->dev->of_node;
179
180 /* NOTE: I2C Clock divider programming info
181 * As per I2C specs the following formulas provide prescaler
182 * and low/high divider values
183 * input clk --> PSC Div -----------> ICCL/H Div --> output clock
184 * module clk
185 *
186 * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
187 *
188 * Thus,
189 * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
190 *
191 * where if PSC == 0, d = 7,
192 * if PSC == 1, d = 6
193 * if PSC > 1 , d = 5
194 *
195 * Note:
196 * d is always 6 on Keystone I2C controller
197 */
198
199 /*
200 * Both Davinci and current Keystone User Guides recommend a value
201 * between 7MHz and 12MHz. In reality 7MHz module clock doesn't
202 * always produce enough margin between SDA and SCL transitions.
203 * Measurements show that the higher the module clock is, the
204 * bigger is the margin, providing more reliable communication.
205 * So we better target for 12MHz.
206 */
207 psc = (input_clock / 12000000) - 1;
208 if ((input_clock / (psc + 1)) > 12000000)
209 psc++; /* better to run under spec than over */
210 d = (psc >= 2) ? 5 : 7 - psc;
211
212 if (of_node && of_device_is_compatible(device: of_node, "ti,keystone-i2c"))
213 d = 6;
214
215 clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000));
216 /* Avoid driving the bus too fast because of rounding errors above */
217 if (input_clock / (psc + 1) / clk > pdata->bus_freq * 1000)
218 clk++;
219 /*
220 * According to I2C-BUS Spec 2.1, in FAST-MODE LOW period should be at
221 * least 1.3uS, which is not the case with 50% duty cycle. Driving HIGH
222 * to LOW ratio as 1 to 2 is more safe.
223 */
224 if (pdata->bus_freq > 100)
225 clkl = (clk << 1) / 3;
226 else
227 clkl = (clk >> 1);
228 /*
229 * It's not always possible to have 1 to 2 ratio when d=7, so fall back
230 * to minimal possible clkh in this case.
231 *
232 * Note:
233 * CLKH is not allowed to be 0, in this case I2C clock is not generated
234 * at all
235 */
236 if (clk > clkl + d) {
237 clkh = clk - clkl - d;
238 clkl -= d;
239 } else {
240 clkh = 1;
241 clkl = clk - (d << 1);
242 }
243
244 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_PSC_REG, val: psc);
245 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_CLKH_REG, val: clkh);
246 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_CLKL_REG, val: clkl);
247
248 dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
249}
250
251/*
252 * This function configures I2C and brings I2C out of reset.
253 * This function is called during I2C init function. This function
254 * also gets called if I2C encounters any errors.
255 */
256static int i2c_davinci_init(struct davinci_i2c_dev *dev)
257{
258 struct davinci_i2c_platform_data *pdata = dev->pdata;
259
260 /* put I2C into reset */
261 davinci_i2c_reset_ctrl(i2c_dev: dev, val: 0);
262
263 /* compute clock dividers */
264 i2c_davinci_calc_clk_dividers(dev);
265
266 /* Respond at reserved "SMBus Host" slave address" (and zero);
267 * we seem to have no option to not respond...
268 */
269 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_OAR_REG, DAVINCI_I2C_OWN_ADDRESS);
270
271 dev_dbg(dev->dev, "PSC = %d\n",
272 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
273 dev_dbg(dev->dev, "CLKL = %d\n",
274 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
275 dev_dbg(dev->dev, "CLKH = %d\n",
276 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
277 dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
278 pdata->bus_freq, pdata->bus_delay);
279
280
281 /* Take the I2C module out of reset: */
282 davinci_i2c_reset_ctrl(i2c_dev: dev, val: 1);
283
284 /* Enable interrupts */
285 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
286
287 return 0;
288}
289
290/*
291 * This routine does i2c bus recovery by using i2c_generic_scl_recovery
292 * which is provided by I2C Bus recovery infrastructure.
293 */
294static void davinci_i2c_prepare_recovery(struct i2c_adapter *adap)
295{
296 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
297
298 /* Disable interrupts */
299 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_IMR_REG, val: 0);
300
301 /* put I2C into reset */
302 davinci_i2c_reset_ctrl(i2c_dev: dev, val: 0);
303}
304
305static void davinci_i2c_unprepare_recovery(struct i2c_adapter *adap)
306{
307 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
308
309 i2c_davinci_init(dev);
310}
311
312static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info = {
313 .recover_bus = i2c_generic_scl_recovery,
314 .prepare_recovery = davinci_i2c_prepare_recovery,
315 .unprepare_recovery = davinci_i2c_unprepare_recovery,
316};
317
318static void davinci_i2c_set_scl(struct i2c_adapter *adap, int val)
319{
320 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
321
322 if (val)
323 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_DSET_REG,
324 DAVINCI_I2C_DSET_PDSET0);
325 else
326 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_DCLR_REG,
327 DAVINCI_I2C_DCLR_PDCLR0);
328}
329
330static int davinci_i2c_get_scl(struct i2c_adapter *adap)
331{
332 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
333 int val;
334
335 /* read the state of SCL */
336 val = davinci_i2c_read_reg(i2c_dev: dev, DAVINCI_I2C_DIN_REG);
337 return val & DAVINCI_I2C_DIN_PDIN0;
338}
339
340static int davinci_i2c_get_sda(struct i2c_adapter *adap)
341{
342 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
343 int val;
344
345 /* read the state of SDA */
346 val = davinci_i2c_read_reg(i2c_dev: dev, DAVINCI_I2C_DIN_REG);
347 return val & DAVINCI_I2C_DIN_PDIN1;
348}
349
350static void davinci_i2c_scl_prepare_recovery(struct i2c_adapter *adap)
351{
352 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
353
354 davinci_i2c_prepare_recovery(adap);
355
356 /* SCL output, SDA input */
357 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_DIR_REG, DAVINCI_I2C_DIR_PDIR0);
358
359 /* change to GPIO mode */
360 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_FUNC_REG,
361 DAVINCI_I2C_FUNC_PFUNC0);
362}
363
364static void davinci_i2c_scl_unprepare_recovery(struct i2c_adapter *adap)
365{
366 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
367
368 /* change back to I2C mode */
369 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_FUNC_REG, val: 0);
370
371 davinci_i2c_unprepare_recovery(adap);
372}
373
374static struct i2c_bus_recovery_info davinci_i2c_scl_recovery_info = {
375 .recover_bus = i2c_generic_scl_recovery,
376 .set_scl = davinci_i2c_set_scl,
377 .get_scl = davinci_i2c_get_scl,
378 .get_sda = davinci_i2c_get_sda,
379 .prepare_recovery = davinci_i2c_scl_prepare_recovery,
380 .unprepare_recovery = davinci_i2c_scl_unprepare_recovery,
381};
382
383/*
384 * Waiting for bus not busy
385 */
386static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev)
387{
388 unsigned long timeout = jiffies + dev->adapter.timeout;
389
390 do {
391 if (!(davinci_i2c_read_reg(i2c_dev: dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB))
392 return 0;
393 schedule_timeout_uninterruptible(timeout: 1);
394 } while (time_before_eq(jiffies, timeout));
395
396 dev_warn(dev->dev, "timeout waiting for bus ready\n");
397 i2c_recover_bus(adap: &dev->adapter);
398
399 /*
400 * if bus is still "busy" here, it's most probably a HW problem like
401 * short-circuit
402 */
403 if (davinci_i2c_read_reg(i2c_dev: dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB)
404 return -EIO;
405
406 return 0;
407}
408
409/*
410 * Low level master read/write transaction. This function is called
411 * from i2c_davinci_xfer.
412 */
413static int
414i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
415{
416 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
417 struct davinci_i2c_platform_data *pdata = dev->pdata;
418 u32 flag;
419 u16 w;
420 unsigned long time_left;
421
422 if (msg->addr == DAVINCI_I2C_OWN_ADDRESS) {
423 dev_warn(dev->dev, "transfer to own address aborted\n");
424 return -EADDRNOTAVAIL;
425 }
426
427 /* Introduce a delay, required for some boards (e.g Davinci EVM) */
428 if (pdata->bus_delay)
429 udelay(pdata->bus_delay);
430
431 /* set the slave address */
432 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_SAR_REG, val: msg->addr);
433
434 dev->buf = msg->buf;
435 dev->buf_len = msg->len;
436 dev->stop = stop;
437
438 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_CNT_REG, val: dev->buf_len);
439
440 reinit_completion(x: &dev->cmd_complete);
441 dev->cmd_err = 0;
442
443 /* Take I2C out of reset and configure it as master */
444 flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST;
445
446 /* if the slave address is ten bit address, enable XA bit */
447 if (msg->flags & I2C_M_TEN)
448 flag |= DAVINCI_I2C_MDR_XA;
449 if (!(msg->flags & I2C_M_RD))
450 flag |= DAVINCI_I2C_MDR_TRX;
451 if (msg->len == 0)
452 flag |= DAVINCI_I2C_MDR_RM;
453
454 /* Enable receive or transmit interrupts */
455 w = davinci_i2c_read_reg(i2c_dev: dev, DAVINCI_I2C_IMR_REG);
456 if (msg->flags & I2C_M_RD)
457 w |= DAVINCI_I2C_IMR_RRDY;
458 else
459 w |= DAVINCI_I2C_IMR_XRDY;
460 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_IMR_REG, val: w);
461
462 dev->terminate = 0;
463
464 /*
465 * Write mode register first as needed for correct behaviour
466 * on OMAP-L138, but don't set STT yet to avoid a race with XRDY
467 * occurring before we have loaded DXR
468 */
469 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_MDR_REG, val: flag);
470
471 /*
472 * First byte should be set here, not after interrupt,
473 * because transmit-data-ready interrupt can come before
474 * NACK-interrupt during sending of previous message and
475 * ICDXR may have wrong data
476 * It also saves us one interrupt, slightly faster
477 */
478 if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
479 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_DXR_REG, val: *dev->buf++);
480 dev->buf_len--;
481 }
482
483 /* Set STT to begin transmit now DXR is loaded */
484 flag |= DAVINCI_I2C_MDR_STT;
485 if (stop && msg->len != 0)
486 flag |= DAVINCI_I2C_MDR_STP;
487 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_MDR_REG, val: flag);
488
489 time_left = wait_for_completion_timeout(x: &dev->cmd_complete,
490 timeout: dev->adapter.timeout);
491 if (!time_left) {
492 dev_err(dev->dev, "controller timed out\n");
493 i2c_recover_bus(adap);
494 dev->buf_len = 0;
495 return -ETIMEDOUT;
496 }
497 if (dev->buf_len) {
498 /* This should be 0 if all bytes were transferred
499 * or dev->cmd_err denotes an error.
500 */
501 dev_err(dev->dev, "abnormal termination buf_len=%zu\n",
502 dev->buf_len);
503 dev->terminate = 1;
504 wmb();
505 dev->buf_len = 0;
506 return -EREMOTEIO;
507 }
508
509 /* no error */
510 if (likely(!dev->cmd_err))
511 return msg->len;
512
513 /* We have an error */
514 if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
515 i2c_davinci_init(dev);
516 return -EIO;
517 }
518
519 if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
520 if (msg->flags & I2C_M_IGNORE_NAK)
521 return msg->len;
522 w = davinci_i2c_read_reg(i2c_dev: dev, DAVINCI_I2C_MDR_REG);
523 w |= DAVINCI_I2C_MDR_STP;
524 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_MDR_REG, val: w);
525 return -EREMOTEIO;
526 }
527 return -EIO;
528}
529
530/*
531 * Prepare controller for a transaction and call i2c_davinci_xfer_msg
532 */
533static int
534i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
535{
536 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
537 int i;
538 int ret;
539
540 dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
541
542 ret = pm_runtime_resume_and_get(dev: dev->dev);
543 if (ret < 0) {
544 dev_err(dev->dev, "Failed to runtime_get device: %d\n", ret);
545 return ret;
546 }
547
548 ret = i2c_davinci_wait_bus_not_busy(dev);
549 if (ret < 0) {
550 dev_warn(dev->dev, "timeout waiting for bus ready\n");
551 goto out;
552 }
553
554 for (i = 0; i < num; i++) {
555 ret = i2c_davinci_xfer_msg(adap, msg: &msgs[i], stop: (i == (num - 1)));
556 dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
557 ret);
558 if (ret < 0)
559 goto out;
560 }
561
562 ret = num;
563
564out:
565 pm_runtime_mark_last_busy(dev: dev->dev);
566 pm_runtime_put_autosuspend(dev: dev->dev);
567
568 return ret;
569}
570
571static u32 i2c_davinci_func(struct i2c_adapter *adap)
572{
573 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
574}
575
576static void terminate_read(struct davinci_i2c_dev *dev)
577{
578 u16 w = davinci_i2c_read_reg(i2c_dev: dev, DAVINCI_I2C_MDR_REG);
579 w |= DAVINCI_I2C_MDR_NACK;
580 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_MDR_REG, val: w);
581
582 /* Throw away data */
583 davinci_i2c_read_reg(i2c_dev: dev, DAVINCI_I2C_DRR_REG);
584 if (!dev->terminate)
585 dev_err(dev->dev, "RDR IRQ while no data requested\n");
586}
587static void terminate_write(struct davinci_i2c_dev *dev)
588{
589 u16 w = davinci_i2c_read_reg(i2c_dev: dev, DAVINCI_I2C_MDR_REG);
590 w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
591 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_MDR_REG, val: w);
592
593 if (!dev->terminate)
594 dev_dbg(dev->dev, "TDR IRQ while no data to send\n");
595}
596
597/*
598 * Interrupt service routine. This gets called whenever an I2C interrupt
599 * occurs.
600 */
601static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
602{
603 struct davinci_i2c_dev *dev = dev_id;
604 u32 stat;
605 int count = 0;
606 u16 w;
607
608 if (pm_runtime_suspended(dev: dev->dev))
609 return IRQ_NONE;
610
611 while ((stat = davinci_i2c_read_reg(i2c_dev: dev, DAVINCI_I2C_IVR_REG))) {
612 dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
613 if (count++ == 100) {
614 dev_warn(dev->dev, "Too much work in one IRQ\n");
615 break;
616 }
617
618 switch (stat) {
619 case DAVINCI_I2C_IVR_AL:
620 /* Arbitration lost, must retry */
621 dev->cmd_err |= DAVINCI_I2C_STR_AL;
622 dev->buf_len = 0;
623 complete(&dev->cmd_complete);
624 break;
625
626 case DAVINCI_I2C_IVR_NACK:
627 dev->cmd_err |= DAVINCI_I2C_STR_NACK;
628 dev->buf_len = 0;
629 complete(&dev->cmd_complete);
630 break;
631
632 case DAVINCI_I2C_IVR_ARDY:
633 davinci_i2c_write_reg(i2c_dev: dev,
634 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
635 if (((dev->buf_len == 0) && (dev->stop != 0)) ||
636 (dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
637 w = davinci_i2c_read_reg(i2c_dev: dev,
638 DAVINCI_I2C_MDR_REG);
639 w |= DAVINCI_I2C_MDR_STP;
640 davinci_i2c_write_reg(i2c_dev: dev,
641 DAVINCI_I2C_MDR_REG, val: w);
642 }
643 complete(&dev->cmd_complete);
644 break;
645
646 case DAVINCI_I2C_IVR_RDR:
647 if (dev->buf_len) {
648 *dev->buf++ =
649 davinci_i2c_read_reg(i2c_dev: dev,
650 DAVINCI_I2C_DRR_REG);
651 dev->buf_len--;
652 if (dev->buf_len)
653 continue;
654
655 davinci_i2c_write_reg(i2c_dev: dev,
656 DAVINCI_I2C_STR_REG,
657 DAVINCI_I2C_IMR_RRDY);
658 } else {
659 /* signal can terminate transfer */
660 terminate_read(dev);
661 }
662 break;
663
664 case DAVINCI_I2C_IVR_XRDY:
665 if (dev->buf_len) {
666 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_DXR_REG,
667 val: *dev->buf++);
668 dev->buf_len--;
669 if (dev->buf_len)
670 continue;
671
672 w = davinci_i2c_read_reg(i2c_dev: dev,
673 DAVINCI_I2C_IMR_REG);
674 w &= ~DAVINCI_I2C_IMR_XRDY;
675 davinci_i2c_write_reg(i2c_dev: dev,
676 DAVINCI_I2C_IMR_REG,
677 val: w);
678 } else {
679 /* signal can terminate transfer */
680 terminate_write(dev);
681 }
682 break;
683
684 case DAVINCI_I2C_IVR_SCD:
685 davinci_i2c_write_reg(i2c_dev: dev,
686 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
687 complete(&dev->cmd_complete);
688 break;
689
690 case DAVINCI_I2C_IVR_AAS:
691 dev_dbg(dev->dev, "Address as slave interrupt\n");
692 break;
693
694 default:
695 dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat);
696 break;
697 }
698 }
699
700 return count ? IRQ_HANDLED : IRQ_NONE;
701}
702
703#ifdef CONFIG_CPU_FREQ
704static int i2c_davinci_cpufreq_transition(struct notifier_block *nb,
705 unsigned long val, void *data)
706{
707 struct davinci_i2c_dev *dev;
708
709 dev = container_of(nb, struct davinci_i2c_dev, freq_transition);
710
711 i2c_lock_bus(adapter: &dev->adapter, I2C_LOCK_ROOT_ADAPTER);
712 if (val == CPUFREQ_PRECHANGE) {
713 davinci_i2c_reset_ctrl(i2c_dev: dev, val: 0);
714 } else if (val == CPUFREQ_POSTCHANGE) {
715 i2c_davinci_calc_clk_dividers(dev);
716 davinci_i2c_reset_ctrl(i2c_dev: dev, val: 1);
717 }
718 i2c_unlock_bus(adapter: &dev->adapter, I2C_LOCK_ROOT_ADAPTER);
719
720 return 0;
721}
722
723static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
724{
725 dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition;
726
727 return cpufreq_register_notifier(nb: &dev->freq_transition,
728 CPUFREQ_TRANSITION_NOTIFIER);
729}
730
731static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
732{
733 cpufreq_unregister_notifier(nb: &dev->freq_transition,
734 CPUFREQ_TRANSITION_NOTIFIER);
735}
736#else
737static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
738{
739 return 0;
740}
741
742static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
743{
744}
745#endif
746
747static const struct i2c_algorithm i2c_davinci_algo = {
748 .master_xfer = i2c_davinci_xfer,
749 .functionality = i2c_davinci_func,
750};
751
752static const struct of_device_id davinci_i2c_of_match[] = {
753 {.compatible = "ti,davinci-i2c", },
754 {.compatible = "ti,keystone-i2c", },
755 {},
756};
757MODULE_DEVICE_TABLE(of, davinci_i2c_of_match);
758
759static int davinci_i2c_probe(struct platform_device *pdev)
760{
761 struct davinci_i2c_dev *dev;
762 struct i2c_adapter *adap;
763 struct i2c_bus_recovery_info *rinfo;
764 int r, irq;
765
766 irq = platform_get_irq(pdev, 0);
767 if (irq < 0)
768 return irq;
769
770 dev = devm_kzalloc(dev: &pdev->dev, size: sizeof(*dev), GFP_KERNEL);
771 if (!dev)
772 return -ENOMEM;
773
774 init_completion(x: &dev->cmd_complete);
775
776 dev->dev = &pdev->dev;
777 dev->irq = irq;
778 dev->pdata = dev_get_platdata(dev: &pdev->dev);
779 platform_set_drvdata(pdev, data: dev);
780
781 if (!dev->pdata && pdev->dev.of_node) {
782 u32 prop;
783
784 dev->pdata = devm_kzalloc(dev: &pdev->dev,
785 size: sizeof(struct davinci_i2c_platform_data), GFP_KERNEL);
786 if (!dev->pdata)
787 return -ENOMEM;
788
789 memcpy(dev->pdata, &davinci_i2c_platform_data_default,
790 sizeof(struct davinci_i2c_platform_data));
791 if (!of_property_read_u32(np: pdev->dev.of_node, propname: "clock-frequency",
792 out_value: &prop))
793 dev->pdata->bus_freq = prop / 1000;
794
795 dev->pdata->has_pfunc =
796 of_property_read_bool(np: pdev->dev.of_node,
797 propname: "ti,has-pfunc");
798 } else if (!dev->pdata) {
799 dev->pdata = &davinci_i2c_platform_data_default;
800 }
801
802 dev->clk = devm_clk_get(dev: &pdev->dev, NULL);
803 if (IS_ERR(ptr: dev->clk))
804 return PTR_ERR(ptr: dev->clk);
805
806 dev->base = devm_platform_ioremap_resource(pdev, index: 0);
807 if (IS_ERR(ptr: dev->base)) {
808 return PTR_ERR(ptr: dev->base);
809 }
810
811 pm_runtime_set_autosuspend_delay(dev: dev->dev,
812 DAVINCI_I2C_PM_TIMEOUT);
813 pm_runtime_use_autosuspend(dev: dev->dev);
814
815 pm_runtime_enable(dev: dev->dev);
816
817 r = pm_runtime_resume_and_get(dev: dev->dev);
818 if (r < 0) {
819 dev_err(dev->dev, "failed to runtime_get device: %d\n", r);
820 goto err_pm;
821 }
822
823 i2c_davinci_init(dev);
824
825 r = devm_request_irq(dev: &pdev->dev, irq: dev->irq, handler: i2c_davinci_isr, irqflags: 0,
826 devname: pdev->name, dev_id: dev);
827 if (r) {
828 dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
829 goto err_unuse_clocks;
830 }
831
832 r = i2c_davinci_cpufreq_register(dev);
833 if (r) {
834 dev_err(&pdev->dev, "failed to register cpufreq\n");
835 goto err_unuse_clocks;
836 }
837
838 adap = &dev->adapter;
839 i2c_set_adapdata(adap, data: dev);
840 adap->owner = THIS_MODULE;
841 adap->class = I2C_CLASS_DEPRECATED;
842 strscpy(p: adap->name, q: "DaVinci I2C adapter", size: sizeof(adap->name));
843 adap->algo = &i2c_davinci_algo;
844 adap->dev.parent = &pdev->dev;
845 adap->timeout = DAVINCI_I2C_TIMEOUT;
846 adap->dev.of_node = pdev->dev.of_node;
847
848 if (dev->pdata->has_pfunc)
849 adap->bus_recovery_info = &davinci_i2c_scl_recovery_info;
850 else if (dev->pdata->gpio_recovery) {
851 rinfo = &davinci_i2c_gpio_recovery_info;
852 adap->bus_recovery_info = rinfo;
853 rinfo->scl_gpiod = devm_gpiod_get(dev: &pdev->dev, con_id: "scl",
854 flags: GPIOD_OUT_HIGH_OPEN_DRAIN);
855 if (IS_ERR(ptr: rinfo->scl_gpiod)) {
856 r = PTR_ERR(ptr: rinfo->scl_gpiod);
857 goto err_unuse_clocks;
858 }
859 rinfo->sda_gpiod = devm_gpiod_get(dev: &pdev->dev, con_id: "sda", flags: GPIOD_IN);
860 if (IS_ERR(ptr: rinfo->sda_gpiod)) {
861 r = PTR_ERR(ptr: rinfo->sda_gpiod);
862 goto err_unuse_clocks;
863 }
864 }
865
866 adap->nr = pdev->id;
867 r = i2c_add_numbered_adapter(adap);
868 if (r)
869 goto err_unuse_clocks;
870
871 pm_runtime_mark_last_busy(dev: dev->dev);
872 pm_runtime_put_autosuspend(dev: dev->dev);
873
874 return 0;
875
876err_unuse_clocks:
877 pm_runtime_dont_use_autosuspend(dev: dev->dev);
878 pm_runtime_put_sync(dev: dev->dev);
879err_pm:
880 pm_runtime_disable(dev: dev->dev);
881
882 return r;
883}
884
885static void davinci_i2c_remove(struct platform_device *pdev)
886{
887 struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
888 int ret;
889
890 i2c_davinci_cpufreq_deregister(dev);
891
892 i2c_del_adapter(adap: &dev->adapter);
893
894 ret = pm_runtime_get_sync(dev: &pdev->dev);
895 if (ret < 0)
896 dev_err(&pdev->dev, "Failed to resume device\n");
897 else
898 davinci_i2c_write_reg(i2c_dev: dev, DAVINCI_I2C_MDR_REG, val: 0);
899
900 pm_runtime_dont_use_autosuspend(dev: dev->dev);
901 pm_runtime_put_sync(dev: dev->dev);
902 pm_runtime_disable(dev: dev->dev);
903}
904
905static int davinci_i2c_suspend(struct device *dev)
906{
907 struct davinci_i2c_dev *i2c_dev = dev_get_drvdata(dev);
908
909 /* put I2C into reset */
910 davinci_i2c_reset_ctrl(i2c_dev, val: 0);
911
912 return 0;
913}
914
915static int davinci_i2c_resume(struct device *dev)
916{
917 struct davinci_i2c_dev *i2c_dev = dev_get_drvdata(dev);
918
919 /* take I2C out of reset */
920 davinci_i2c_reset_ctrl(i2c_dev, val: 1);
921
922 return 0;
923}
924
925static const struct dev_pm_ops davinci_i2c_pm = {
926 .suspend = davinci_i2c_suspend,
927 .resume = davinci_i2c_resume,
928 NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
929 pm_runtime_force_resume)
930};
931
932static const struct platform_device_id davinci_i2c_driver_ids[] = {
933 { .name = "i2c_davinci", },
934 { /* sentinel */ }
935};
936MODULE_DEVICE_TABLE(platform, davinci_i2c_driver_ids);
937
938static struct platform_driver davinci_i2c_driver = {
939 .probe = davinci_i2c_probe,
940 .remove_new = davinci_i2c_remove,
941 .id_table = davinci_i2c_driver_ids,
942 .driver = {
943 .name = "i2c_davinci",
944 .pm = pm_sleep_ptr(&davinci_i2c_pm),
945 .of_match_table = davinci_i2c_of_match,
946 },
947};
948
949/* I2C may be needed to bring up other drivers */
950static int __init davinci_i2c_init_driver(void)
951{
952 return platform_driver_register(&davinci_i2c_driver);
953}
954subsys_initcall(davinci_i2c_init_driver);
955
956static void __exit davinci_i2c_exit_driver(void)
957{
958 platform_driver_unregister(&davinci_i2c_driver);
959}
960module_exit(davinci_i2c_exit_driver);
961
962MODULE_AUTHOR("Texas Instruments India");
963MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
964MODULE_LICENSE("GPL");
965

source code of linux/drivers/i2c/busses/i2c-davinci.c