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, 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(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(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(dev, DAVINCI_I2C_PSC_REG, psc);
245	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
246	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, 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(dev, 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(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(dev, 1);
283
284	/* Enable interrupts */
285	davinci_i2c_write_reg(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(dev, DAVINCI_I2C_IMR_REG, 0);
300
301	/* put I2C into reset */
302	davinci_i2c_reset_ctrl(dev, 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(dev, DAVINCI_I2C_DSET_REG,
324				      DAVINCI_I2C_DSET_PDSET0);
325	else
326		davinci_i2c_write_reg(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(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(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(dev, DAVINCI_I2C_DIR_REG, DAVINCI_I2C_DIR_PDIR0);
358
359	/* change to GPIO mode */
360	davinci_i2c_write_reg(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(dev, DAVINCI_I2C_FUNC_REG, 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(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB))
392			return 0;
393		schedule_timeout_uninterruptible(1);
394	} while (time_before_eq(jiffies, timeout));
395
396	dev_warn(dev->dev, "timeout waiting for bus ready\n");
397	i2c_recover_bus(&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(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(dev, DAVINCI_I2C_SAR_REG, msg->addr);
433
434	dev->buf = msg->buf;
435	dev->buf_len = msg->len;
436	dev->stop = stop;
437
438	davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
439
440	reinit_completion(&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(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(dev, DAVINCI_I2C_IMR_REG, 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(dev, DAVINCI_I2C_MDR_REG, 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(dev, DAVINCI_I2C_DXR_REG, *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(dev, DAVINCI_I2C_MDR_REG, flag);
488
489	time_left = wait_for_completion_timeout(&dev->cmd_complete,
490						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(dev, DAVINCI_I2C_MDR_REG);
523		w |= DAVINCI_I2C_MDR_STP;
524		davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 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);
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, &msgs[i], (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);
566	pm_runtime_put_autosuspend(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(dev, DAVINCI_I2C_MDR_REG);
579	w |= DAVINCI_I2C_MDR_NACK;
580	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
581
582	/* Throw away data */
583	davinci_i2c_read_reg(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(dev, DAVINCI_I2C_MDR_REG);
590	w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
591	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 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))
609		return IRQ_NONE;
610
611	while ((stat = davinci_i2c_read_reg(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(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(dev,
638							 DAVINCI_I2C_MDR_REG);
639				w |= DAVINCI_I2C_MDR_STP;
640				davinci_i2c_write_reg(dev,
641						      DAVINCI_I2C_MDR_REG, 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(dev,
650							 DAVINCI_I2C_DRR_REG);
651				dev->buf_len--;
652				if (dev->buf_len)
653					continue;
654
655				davinci_i2c_write_reg(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(dev, DAVINCI_I2C_DXR_REG,
667						      *dev->buf++);
668				dev->buf_len--;
669				if (dev->buf_len)
670					continue;
671
672				w = davinci_i2c_read_reg(dev,
673							 DAVINCI_I2C_IMR_REG);
674				w &= ~DAVINCI_I2C_IMR_XRDY;
675				davinci_i2c_write_reg(dev,
676						      DAVINCI_I2C_IMR_REG,
677						      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(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(&dev->adapter, I2C_LOCK_ROOT_ADAPTER);
712	if (val == CPUFREQ_PRECHANGE) {
713		davinci_i2c_reset_ctrl(dev, 0);
714	} else if (val == CPUFREQ_POSTCHANGE) {
715		i2c_davinci_calc_clk_dividers(dev);
716		davinci_i2c_reset_ctrl(dev, 1);
717	}
718	i2c_unlock_bus(&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(&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(&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(&pdev->dev, sizeof(*dev), GFP_KERNEL);
771	if (!dev)
772		return -ENOMEM;
773
774	init_completion(&dev->cmd_complete);
775
776	dev->dev = &pdev->dev;
777	dev->irq = irq;
778	dev->pdata = dev_get_platdata(&pdev->dev);
779	platform_set_drvdata(pdev, dev);
780
781	if (!dev->pdata && pdev->dev.of_node) {
782		u32 prop;
783
784		dev->pdata = devm_kzalloc(&pdev->dev,
785			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(pdev->dev.of_node, "clock-frequency",
792			&prop))
793			dev->pdata->bus_freq = prop / 1000;
794
795		dev->pdata->has_pfunc =
796			of_property_read_bool(pdev->dev.of_node,
797					      "ti,has-pfunc");
798	} else if (!dev->pdata) {
799		dev->pdata = &davinci_i2c_platform_data_default;
800	}
801
802	dev->clk = devm_clk_get(&pdev->dev, NULL);
803	if (IS_ERR(dev->clk))
804		return PTR_ERR(dev->clk);
805
806	dev->base = devm_platform_ioremap_resource(pdev, 0);
807	if (IS_ERR(dev->base)) {
808		return PTR_ERR(dev->base);
809	}
810
811	pm_runtime_set_autosuspend_delay(dev->dev,
812					 DAVINCI_I2C_PM_TIMEOUT);
813	pm_runtime_use_autosuspend(dev->dev);
814
815	pm_runtime_enable(dev->dev);
816
817	r = pm_runtime_resume_and_get(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(&pdev->dev, dev->irq, i2c_davinci_isr, 0,
826			pdev->name, 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, dev);
840	adap->owner = THIS_MODULE;
841	adap->class = I2C_CLASS_DEPRECATED;
842	strscpy(adap->name, "DaVinci I2C adapter", 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(&pdev->dev, "scl",
854						  GPIOD_OUT_HIGH_OPEN_DRAIN);
855		if (IS_ERR(rinfo->scl_gpiod)) {
856			r = PTR_ERR(rinfo->scl_gpiod);
857			goto err_unuse_clocks;
858		}
859		rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN);
860		if (IS_ERR(rinfo->sda_gpiod)) {
861			r = PTR_ERR(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);
872	pm_runtime_put_autosuspend(dev->dev);
873
874	return 0;
875
876err_unuse_clocks:
877	pm_runtime_dont_use_autosuspend(dev->dev);
878	pm_runtime_put_sync(dev->dev);
879err_pm:
880	pm_runtime_disable(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(&dev->adapter);
893
894	ret = pm_runtime_get_sync(&pdev->dev);
895	if (ret < 0)
896		dev_err(&pdev->dev, "Failed to resume device\n");
897	else
898		davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
899
900	pm_runtime_dont_use_autosuspend(dev->dev);
901	pm_runtime_put_sync(dev->dev);
902	pm_runtime_disable(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, 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, 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");