xref: /openbmc/linux/drivers/i2c/busses/i2c-omap.c (revision 63dc02bd)
1 /*
2  * TI OMAP I2C master mode driver
3  *
4  * Copyright (C) 2003 MontaVista Software, Inc.
5  * Copyright (C) 2005 Nokia Corporation
6  * Copyright (C) 2004 - 2007 Texas Instruments.
7  *
8  * Originally written by MontaVista Software, Inc.
9  * Additional contributions by:
10  *	Tony Lindgren <tony@atomide.com>
11  *	Imre Deak <imre.deak@nokia.com>
12  *	Juha Yrjölä <juha.yrjola@solidboot.com>
13  *	Syed Khasim <x0khasim@ti.com>
14  *	Nishant Menon <nm@ti.com>
15  *
16  * This program is free software; you can redistribute it and/or modify
17  * it under the terms of the GNU General Public License as published by
18  * the Free Software Foundation; either version 2 of the License, or
19  * (at your option) any later version.
20  *
21  * This program is distributed in the hope that it will be useful,
22  * but WITHOUT ANY WARRANTY; without even the implied warranty of
23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24  * GNU General Public License for more details.
25  *
26  * You should have received a copy of the GNU General Public License
27  * along with this program; if not, write to the Free Software
28  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
29  */
30 
31 #include <linux/module.h>
32 #include <linux/delay.h>
33 #include <linux/i2c.h>
34 #include <linux/err.h>
35 #include <linux/interrupt.h>
36 #include <linux/completion.h>
37 #include <linux/platform_device.h>
38 #include <linux/clk.h>
39 #include <linux/io.h>
40 #include <linux/of.h>
41 #include <linux/of_i2c.h>
42 #include <linux/of_device.h>
43 #include <linux/slab.h>
44 #include <linux/i2c-omap.h>
45 #include <linux/pm_runtime.h>
46 
47 /* I2C controller revisions */
48 #define OMAP_I2C_OMAP1_REV_2		0x20
49 
50 /* I2C controller revisions present on specific hardware */
51 #define OMAP_I2C_REV_ON_2430		0x36
52 #define OMAP_I2C_REV_ON_3430		0x3C
53 #define OMAP_I2C_REV_ON_3530_4430	0x40
54 
55 /* timeout waiting for the controller to respond */
56 #define OMAP_I2C_TIMEOUT (msecs_to_jiffies(1000))
57 
58 /* For OMAP3 I2C_IV has changed to I2C_WE (wakeup enable) */
59 enum {
60 	OMAP_I2C_REV_REG = 0,
61 	OMAP_I2C_IE_REG,
62 	OMAP_I2C_STAT_REG,
63 	OMAP_I2C_IV_REG,
64 	OMAP_I2C_WE_REG,
65 	OMAP_I2C_SYSS_REG,
66 	OMAP_I2C_BUF_REG,
67 	OMAP_I2C_CNT_REG,
68 	OMAP_I2C_DATA_REG,
69 	OMAP_I2C_SYSC_REG,
70 	OMAP_I2C_CON_REG,
71 	OMAP_I2C_OA_REG,
72 	OMAP_I2C_SA_REG,
73 	OMAP_I2C_PSC_REG,
74 	OMAP_I2C_SCLL_REG,
75 	OMAP_I2C_SCLH_REG,
76 	OMAP_I2C_SYSTEST_REG,
77 	OMAP_I2C_BUFSTAT_REG,
78 	/* only on OMAP4430 */
79 	OMAP_I2C_IP_V2_REVNB_LO,
80 	OMAP_I2C_IP_V2_REVNB_HI,
81 	OMAP_I2C_IP_V2_IRQSTATUS_RAW,
82 	OMAP_I2C_IP_V2_IRQENABLE_SET,
83 	OMAP_I2C_IP_V2_IRQENABLE_CLR,
84 };
85 
86 /* I2C Interrupt Enable Register (OMAP_I2C_IE): */
87 #define OMAP_I2C_IE_XDR		(1 << 14)	/* TX Buffer drain int enable */
88 #define OMAP_I2C_IE_RDR		(1 << 13)	/* RX Buffer drain int enable */
89 #define OMAP_I2C_IE_XRDY	(1 << 4)	/* TX data ready int enable */
90 #define OMAP_I2C_IE_RRDY	(1 << 3)	/* RX data ready int enable */
91 #define OMAP_I2C_IE_ARDY	(1 << 2)	/* Access ready int enable */
92 #define OMAP_I2C_IE_NACK	(1 << 1)	/* No ack interrupt enable */
93 #define OMAP_I2C_IE_AL		(1 << 0)	/* Arbitration lost int ena */
94 
95 /* I2C Status Register (OMAP_I2C_STAT): */
96 #define OMAP_I2C_STAT_XDR	(1 << 14)	/* TX Buffer draining */
97 #define OMAP_I2C_STAT_RDR	(1 << 13)	/* RX Buffer draining */
98 #define OMAP_I2C_STAT_BB	(1 << 12)	/* Bus busy */
99 #define OMAP_I2C_STAT_ROVR	(1 << 11)	/* Receive overrun */
100 #define OMAP_I2C_STAT_XUDF	(1 << 10)	/* Transmit underflow */
101 #define OMAP_I2C_STAT_AAS	(1 << 9)	/* Address as slave */
102 #define OMAP_I2C_STAT_AD0	(1 << 8)	/* Address zero */
103 #define OMAP_I2C_STAT_XRDY	(1 << 4)	/* Transmit data ready */
104 #define OMAP_I2C_STAT_RRDY	(1 << 3)	/* Receive data ready */
105 #define OMAP_I2C_STAT_ARDY	(1 << 2)	/* Register access ready */
106 #define OMAP_I2C_STAT_NACK	(1 << 1)	/* No ack interrupt enable */
107 #define OMAP_I2C_STAT_AL	(1 << 0)	/* Arbitration lost int ena */
108 
109 /* I2C WE wakeup enable register */
110 #define OMAP_I2C_WE_XDR_WE	(1 << 14)	/* TX drain wakup */
111 #define OMAP_I2C_WE_RDR_WE	(1 << 13)	/* RX drain wakeup */
112 #define OMAP_I2C_WE_AAS_WE	(1 << 9)	/* Address as slave wakeup*/
113 #define OMAP_I2C_WE_BF_WE	(1 << 8)	/* Bus free wakeup */
114 #define OMAP_I2C_WE_STC_WE	(1 << 6)	/* Start condition wakeup */
115 #define OMAP_I2C_WE_GC_WE	(1 << 5)	/* General call wakeup */
116 #define OMAP_I2C_WE_DRDY_WE	(1 << 3)	/* TX/RX data ready wakeup */
117 #define OMAP_I2C_WE_ARDY_WE	(1 << 2)	/* Reg access ready wakeup */
118 #define OMAP_I2C_WE_NACK_WE	(1 << 1)	/* No acknowledgment wakeup */
119 #define OMAP_I2C_WE_AL_WE	(1 << 0)	/* Arbitration lost wakeup */
120 
121 #define OMAP_I2C_WE_ALL		(OMAP_I2C_WE_XDR_WE | OMAP_I2C_WE_RDR_WE | \
122 				OMAP_I2C_WE_AAS_WE | OMAP_I2C_WE_BF_WE | \
123 				OMAP_I2C_WE_STC_WE | OMAP_I2C_WE_GC_WE | \
124 				OMAP_I2C_WE_DRDY_WE | OMAP_I2C_WE_ARDY_WE | \
125 				OMAP_I2C_WE_NACK_WE | OMAP_I2C_WE_AL_WE)
126 
127 /* I2C Buffer Configuration Register (OMAP_I2C_BUF): */
128 #define OMAP_I2C_BUF_RDMA_EN	(1 << 15)	/* RX DMA channel enable */
129 #define OMAP_I2C_BUF_RXFIF_CLR	(1 << 14)	/* RX FIFO Clear */
130 #define OMAP_I2C_BUF_XDMA_EN	(1 << 7)	/* TX DMA channel enable */
131 #define OMAP_I2C_BUF_TXFIF_CLR	(1 << 6)	/* TX FIFO Clear */
132 
133 /* I2C Configuration Register (OMAP_I2C_CON): */
134 #define OMAP_I2C_CON_EN		(1 << 15)	/* I2C module enable */
135 #define OMAP_I2C_CON_BE		(1 << 14)	/* Big endian mode */
136 #define OMAP_I2C_CON_OPMODE_HS	(1 << 12)	/* High Speed support */
137 #define OMAP_I2C_CON_STB	(1 << 11)	/* Start byte mode (master) */
138 #define OMAP_I2C_CON_MST	(1 << 10)	/* Master/slave mode */
139 #define OMAP_I2C_CON_TRX	(1 << 9)	/* TX/RX mode (master only) */
140 #define OMAP_I2C_CON_XA		(1 << 8)	/* Expand address */
141 #define OMAP_I2C_CON_RM		(1 << 2)	/* Repeat mode (master only) */
142 #define OMAP_I2C_CON_STP	(1 << 1)	/* Stop cond (master only) */
143 #define OMAP_I2C_CON_STT	(1 << 0)	/* Start condition (master) */
144 
145 /* I2C SCL time value when Master */
146 #define OMAP_I2C_SCLL_HSSCLL	8
147 #define OMAP_I2C_SCLH_HSSCLH	8
148 
149 /* I2C System Test Register (OMAP_I2C_SYSTEST): */
150 #ifdef DEBUG
151 #define OMAP_I2C_SYSTEST_ST_EN		(1 << 15)	/* System test enable */
152 #define OMAP_I2C_SYSTEST_FREE		(1 << 14)	/* Free running mode */
153 #define OMAP_I2C_SYSTEST_TMODE_MASK	(3 << 12)	/* Test mode select */
154 #define OMAP_I2C_SYSTEST_TMODE_SHIFT	(12)		/* Test mode select */
155 #define OMAP_I2C_SYSTEST_SCL_I		(1 << 3)	/* SCL line sense in */
156 #define OMAP_I2C_SYSTEST_SCL_O		(1 << 2)	/* SCL line drive out */
157 #define OMAP_I2C_SYSTEST_SDA_I		(1 << 1)	/* SDA line sense in */
158 #define OMAP_I2C_SYSTEST_SDA_O		(1 << 0)	/* SDA line drive out */
159 #endif
160 
161 /* OCP_SYSSTATUS bit definitions */
162 #define SYSS_RESETDONE_MASK		(1 << 0)
163 
164 /* OCP_SYSCONFIG bit definitions */
165 #define SYSC_CLOCKACTIVITY_MASK		(0x3 << 8)
166 #define SYSC_SIDLEMODE_MASK		(0x3 << 3)
167 #define SYSC_ENAWAKEUP_MASK		(1 << 2)
168 #define SYSC_SOFTRESET_MASK		(1 << 1)
169 #define SYSC_AUTOIDLE_MASK		(1 << 0)
170 
171 #define SYSC_IDLEMODE_SMART		0x2
172 #define SYSC_CLOCKACTIVITY_FCLK		0x2
173 
174 /* Errata definitions */
175 #define I2C_OMAP_ERRATA_I207		(1 << 0)
176 #define I2C_OMAP3_1P153			(1 << 1)
177 
178 struct omap_i2c_dev {
179 	struct device		*dev;
180 	void __iomem		*base;		/* virtual */
181 	int			irq;
182 	int			reg_shift;      /* bit shift for I2C register addresses */
183 	struct completion	cmd_complete;
184 	struct resource		*ioarea;
185 	u32			latency;	/* maximum mpu wkup latency */
186 	void			(*set_mpu_wkup_lat)(struct device *dev,
187 						    long latency);
188 	u32			speed;		/* Speed of bus in kHz */
189 	u32			dtrev;		/* extra revision from DT */
190 	u32			flags;
191 	u16			cmd_err;
192 	u8			*buf;
193 	u8			*regs;
194 	size_t			buf_len;
195 	struct i2c_adapter	adapter;
196 	u8			fifo_size;	/* use as flag and value
197 						 * fifo_size==0 implies no fifo
198 						 * if set, should be trsh+1
199 						 */
200 	u8			rev;
201 	unsigned		b_hw:1;		/* bad h/w fixes */
202 	u16			iestate;	/* Saved interrupt register */
203 	u16			pscstate;
204 	u16			scllstate;
205 	u16			sclhstate;
206 	u16			bufstate;
207 	u16			syscstate;
208 	u16			westate;
209 	u16			errata;
210 };
211 
212 static const u8 reg_map_ip_v1[] = {
213 	[OMAP_I2C_REV_REG] = 0x00,
214 	[OMAP_I2C_IE_REG] = 0x01,
215 	[OMAP_I2C_STAT_REG] = 0x02,
216 	[OMAP_I2C_IV_REG] = 0x03,
217 	[OMAP_I2C_WE_REG] = 0x03,
218 	[OMAP_I2C_SYSS_REG] = 0x04,
219 	[OMAP_I2C_BUF_REG] = 0x05,
220 	[OMAP_I2C_CNT_REG] = 0x06,
221 	[OMAP_I2C_DATA_REG] = 0x07,
222 	[OMAP_I2C_SYSC_REG] = 0x08,
223 	[OMAP_I2C_CON_REG] = 0x09,
224 	[OMAP_I2C_OA_REG] = 0x0a,
225 	[OMAP_I2C_SA_REG] = 0x0b,
226 	[OMAP_I2C_PSC_REG] = 0x0c,
227 	[OMAP_I2C_SCLL_REG] = 0x0d,
228 	[OMAP_I2C_SCLH_REG] = 0x0e,
229 	[OMAP_I2C_SYSTEST_REG] = 0x0f,
230 	[OMAP_I2C_BUFSTAT_REG] = 0x10,
231 };
232 
233 static const u8 reg_map_ip_v2[] = {
234 	[OMAP_I2C_REV_REG] = 0x04,
235 	[OMAP_I2C_IE_REG] = 0x2c,
236 	[OMAP_I2C_STAT_REG] = 0x28,
237 	[OMAP_I2C_IV_REG] = 0x34,
238 	[OMAP_I2C_WE_REG] = 0x34,
239 	[OMAP_I2C_SYSS_REG] = 0x90,
240 	[OMAP_I2C_BUF_REG] = 0x94,
241 	[OMAP_I2C_CNT_REG] = 0x98,
242 	[OMAP_I2C_DATA_REG] = 0x9c,
243 	[OMAP_I2C_SYSC_REG] = 0x10,
244 	[OMAP_I2C_CON_REG] = 0xa4,
245 	[OMAP_I2C_OA_REG] = 0xa8,
246 	[OMAP_I2C_SA_REG] = 0xac,
247 	[OMAP_I2C_PSC_REG] = 0xb0,
248 	[OMAP_I2C_SCLL_REG] = 0xb4,
249 	[OMAP_I2C_SCLH_REG] = 0xb8,
250 	[OMAP_I2C_SYSTEST_REG] = 0xbC,
251 	[OMAP_I2C_BUFSTAT_REG] = 0xc0,
252 	[OMAP_I2C_IP_V2_REVNB_LO] = 0x00,
253 	[OMAP_I2C_IP_V2_REVNB_HI] = 0x04,
254 	[OMAP_I2C_IP_V2_IRQSTATUS_RAW] = 0x24,
255 	[OMAP_I2C_IP_V2_IRQENABLE_SET] = 0x2c,
256 	[OMAP_I2C_IP_V2_IRQENABLE_CLR] = 0x30,
257 };
258 
259 static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev,
260 				      int reg, u16 val)
261 {
262 	__raw_writew(val, i2c_dev->base +
263 			(i2c_dev->regs[reg] << i2c_dev->reg_shift));
264 }
265 
266 static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
267 {
268 	return __raw_readw(i2c_dev->base +
269 				(i2c_dev->regs[reg] << i2c_dev->reg_shift));
270 }
271 
272 static void omap_i2c_unidle(struct omap_i2c_dev *dev)
273 {
274 	if (dev->flags & OMAP_I2C_FLAG_RESET_REGS_POSTIDLE) {
275 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
276 		omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, dev->pscstate);
277 		omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, dev->scllstate);
278 		omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, dev->sclhstate);
279 		omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, dev->bufstate);
280 		omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, dev->syscstate);
281 		omap_i2c_write_reg(dev, OMAP_I2C_WE_REG, dev->westate);
282 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
283 	}
284 
285 	/*
286 	 * Don't write to this register if the IE state is 0 as it can
287 	 * cause deadlock.
288 	 */
289 	if (dev->iestate)
290 		omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
291 }
292 
293 static void omap_i2c_idle(struct omap_i2c_dev *dev)
294 {
295 	u16 iv;
296 
297 	dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
298 	if (dev->dtrev == OMAP_I2C_IP_VERSION_2)
299 		omap_i2c_write_reg(dev, OMAP_I2C_IP_V2_IRQENABLE_CLR, 1);
300 	else
301 		omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0);
302 
303 	if (dev->rev < OMAP_I2C_OMAP1_REV_2) {
304 		iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG); /* Read clears */
305 	} else {
306 		omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate);
307 
308 		/* Flush posted write */
309 		omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
310 	}
311 }
312 
313 static int omap_i2c_init(struct omap_i2c_dev *dev)
314 {
315 	u16 psc = 0, scll = 0, sclh = 0, buf = 0;
316 	u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0;
317 	unsigned long fclk_rate = 12000000;
318 	unsigned long timeout;
319 	unsigned long internal_clk = 0;
320 	struct clk *fclk;
321 
322 	if (dev->rev >= OMAP_I2C_OMAP1_REV_2) {
323 		/* Disable I2C controller before soft reset */
324 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
325 			omap_i2c_read_reg(dev, OMAP_I2C_CON_REG) &
326 				~(OMAP_I2C_CON_EN));
327 
328 		omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, SYSC_SOFTRESET_MASK);
329 		/* For some reason we need to set the EN bit before the
330 		 * reset done bit gets set. */
331 		timeout = jiffies + OMAP_I2C_TIMEOUT;
332 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
333 		while (!(omap_i2c_read_reg(dev, OMAP_I2C_SYSS_REG) &
334 			 SYSS_RESETDONE_MASK)) {
335 			if (time_after(jiffies, timeout)) {
336 				dev_warn(dev->dev, "timeout waiting "
337 						"for controller reset\n");
338 				return -ETIMEDOUT;
339 			}
340 			msleep(1);
341 		}
342 
343 		/* SYSC register is cleared by the reset; rewrite it */
344 		if (dev->rev == OMAP_I2C_REV_ON_2430) {
345 
346 			omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
347 					   SYSC_AUTOIDLE_MASK);
348 
349 		} else if (dev->rev >= OMAP_I2C_REV_ON_3430) {
350 			dev->syscstate = SYSC_AUTOIDLE_MASK;
351 			dev->syscstate |= SYSC_ENAWAKEUP_MASK;
352 			dev->syscstate |= (SYSC_IDLEMODE_SMART <<
353 			      __ffs(SYSC_SIDLEMODE_MASK));
354 			dev->syscstate |= (SYSC_CLOCKACTIVITY_FCLK <<
355 			      __ffs(SYSC_CLOCKACTIVITY_MASK));
356 
357 			omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
358 							dev->syscstate);
359 			/*
360 			 * Enabling all wakup sources to stop I2C freezing on
361 			 * WFI instruction.
362 			 * REVISIT: Some wkup sources might not be needed.
363 			 */
364 			dev->westate = OMAP_I2C_WE_ALL;
365 			omap_i2c_write_reg(dev, OMAP_I2C_WE_REG,
366 							dev->westate);
367 		}
368 	}
369 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
370 
371 	if (dev->flags & OMAP_I2C_FLAG_ALWAYS_ARMXOR_CLK) {
372 		/*
373 		 * The I2C functional clock is the armxor_ck, so there's
374 		 * no need to get "armxor_ck" separately.  Now, if OMAP2420
375 		 * always returns 12MHz for the functional clock, we can
376 		 * do this bit unconditionally.
377 		 */
378 		fclk = clk_get(dev->dev, "fck");
379 		fclk_rate = clk_get_rate(fclk);
380 		clk_put(fclk);
381 
382 		/* TRM for 5912 says the I2C clock must be prescaled to be
383 		 * between 7 - 12 MHz. The XOR input clock is typically
384 		 * 12, 13 or 19.2 MHz. So we should have code that produces:
385 		 *
386 		 * XOR MHz	Divider		Prescaler
387 		 * 12		1		0
388 		 * 13		2		1
389 		 * 19.2		2		1
390 		 */
391 		if (fclk_rate > 12000000)
392 			psc = fclk_rate / 12000000;
393 	}
394 
395 	if (!(dev->flags & OMAP_I2C_FLAG_SIMPLE_CLOCK)) {
396 
397 		/*
398 		 * HSI2C controller internal clk rate should be 19.2 Mhz for
399 		 * HS and for all modes on 2430. On 34xx we can use lower rate
400 		 * to get longer filter period for better noise suppression.
401 		 * The filter is iclk (fclk for HS) period.
402 		 */
403 		if (dev->speed > 400 ||
404 			       dev->flags & OMAP_I2C_FLAG_FORCE_19200_INT_CLK)
405 			internal_clk = 19200;
406 		else if (dev->speed > 100)
407 			internal_clk = 9600;
408 		else
409 			internal_clk = 4000;
410 		fclk = clk_get(dev->dev, "fck");
411 		fclk_rate = clk_get_rate(fclk) / 1000;
412 		clk_put(fclk);
413 
414 		/* Compute prescaler divisor */
415 		psc = fclk_rate / internal_clk;
416 		psc = psc - 1;
417 
418 		/* If configured for High Speed */
419 		if (dev->speed > 400) {
420 			unsigned long scl;
421 
422 			/* For first phase of HS mode */
423 			scl = internal_clk / 400;
424 			fsscll = scl - (scl / 3) - 7;
425 			fssclh = (scl / 3) - 5;
426 
427 			/* For second phase of HS mode */
428 			scl = fclk_rate / dev->speed;
429 			hsscll = scl - (scl / 3) - 7;
430 			hssclh = (scl / 3) - 5;
431 		} else if (dev->speed > 100) {
432 			unsigned long scl;
433 
434 			/* Fast mode */
435 			scl = internal_clk / dev->speed;
436 			fsscll = scl - (scl / 3) - 7;
437 			fssclh = (scl / 3) - 5;
438 		} else {
439 			/* Standard mode */
440 			fsscll = internal_clk / (dev->speed * 2) - 7;
441 			fssclh = internal_clk / (dev->speed * 2) - 5;
442 		}
443 		scll = (hsscll << OMAP_I2C_SCLL_HSSCLL) | fsscll;
444 		sclh = (hssclh << OMAP_I2C_SCLH_HSSCLH) | fssclh;
445 	} else {
446 		/* Program desired operating rate */
447 		fclk_rate /= (psc + 1) * 1000;
448 		if (psc > 2)
449 			psc = 2;
450 		scll = fclk_rate / (dev->speed * 2) - 7 + psc;
451 		sclh = fclk_rate / (dev->speed * 2) - 7 + psc;
452 	}
453 
454 	/* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
455 	omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, psc);
456 
457 	/* SCL low and high time values */
458 	omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll);
459 	omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh);
460 
461 	if (dev->fifo_size) {
462 		/* Note: setup required fifo size - 1. RTRSH and XTRSH */
463 		buf = (dev->fifo_size - 1) << 8 | OMAP_I2C_BUF_RXFIF_CLR |
464 			(dev->fifo_size - 1) | OMAP_I2C_BUF_TXFIF_CLR;
465 		omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, buf);
466 	}
467 
468 	/* Take the I2C module out of reset: */
469 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
470 
471 	dev->errata = 0;
472 
473 	if (dev->flags & OMAP_I2C_FLAG_APPLY_ERRATA_I207)
474 		dev->errata |= I2C_OMAP_ERRATA_I207;
475 
476 	/* Enable interrupts */
477 	dev->iestate = (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
478 			OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK |
479 			OMAP_I2C_IE_AL)  | ((dev->fifo_size) ?
480 				(OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0);
481 	omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
482 	if (dev->flags & OMAP_I2C_FLAG_RESET_REGS_POSTIDLE) {
483 		dev->pscstate = psc;
484 		dev->scllstate = scll;
485 		dev->sclhstate = sclh;
486 		dev->bufstate = buf;
487 	}
488 	return 0;
489 }
490 
491 /*
492  * Waiting on Bus Busy
493  */
494 static int omap_i2c_wait_for_bb(struct omap_i2c_dev *dev)
495 {
496 	unsigned long timeout;
497 
498 	timeout = jiffies + OMAP_I2C_TIMEOUT;
499 	while (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_BB) {
500 		if (time_after(jiffies, timeout)) {
501 			dev_warn(dev->dev, "timeout waiting for bus ready\n");
502 			return -ETIMEDOUT;
503 		}
504 		msleep(1);
505 	}
506 
507 	return 0;
508 }
509 
510 /*
511  * Low level master read/write transaction.
512  */
513 static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
514 			     struct i2c_msg *msg, int stop)
515 {
516 	struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
517 	int r;
518 	u16 w;
519 
520 	dev_dbg(dev->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
521 		msg->addr, msg->len, msg->flags, stop);
522 
523 	if (msg->len == 0)
524 		return -EINVAL;
525 
526 	omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr);
527 
528 	/* REVISIT: Could the STB bit of I2C_CON be used with probing? */
529 	dev->buf = msg->buf;
530 	dev->buf_len = msg->len;
531 
532 	omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len);
533 
534 	/* Clear the FIFO Buffers */
535 	w = omap_i2c_read_reg(dev, OMAP_I2C_BUF_REG);
536 	w |= OMAP_I2C_BUF_RXFIF_CLR | OMAP_I2C_BUF_TXFIF_CLR;
537 	omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, w);
538 
539 	init_completion(&dev->cmd_complete);
540 	dev->cmd_err = 0;
541 
542 	w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;
543 
544 	/* High speed configuration */
545 	if (dev->speed > 400)
546 		w |= OMAP_I2C_CON_OPMODE_HS;
547 
548 	if (msg->flags & I2C_M_TEN)
549 		w |= OMAP_I2C_CON_XA;
550 	if (!(msg->flags & I2C_M_RD))
551 		w |= OMAP_I2C_CON_TRX;
552 
553 	if (!dev->b_hw && stop)
554 		w |= OMAP_I2C_CON_STP;
555 
556 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
557 
558 	/*
559 	 * Don't write stt and stp together on some hardware.
560 	 */
561 	if (dev->b_hw && stop) {
562 		unsigned long delay = jiffies + OMAP_I2C_TIMEOUT;
563 		u16 con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
564 		while (con & OMAP_I2C_CON_STT) {
565 			con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
566 
567 			/* Let the user know if i2c is in a bad state */
568 			if (time_after(jiffies, delay)) {
569 				dev_err(dev->dev, "controller timed out "
570 				"waiting for start condition to finish\n");
571 				return -ETIMEDOUT;
572 			}
573 			cpu_relax();
574 		}
575 
576 		w |= OMAP_I2C_CON_STP;
577 		w &= ~OMAP_I2C_CON_STT;
578 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
579 	}
580 
581 	/*
582 	 * REVISIT: We should abort the transfer on signals, but the bus goes
583 	 * into arbitration and we're currently unable to recover from it.
584 	 */
585 	r = wait_for_completion_timeout(&dev->cmd_complete,
586 					OMAP_I2C_TIMEOUT);
587 	dev->buf_len = 0;
588 	if (r < 0)
589 		return r;
590 	if (r == 0) {
591 		dev_err(dev->dev, "controller timed out\n");
592 		omap_i2c_init(dev);
593 		return -ETIMEDOUT;
594 	}
595 
596 	if (likely(!dev->cmd_err))
597 		return 0;
598 
599 	/* We have an error */
600 	if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR |
601 			    OMAP_I2C_STAT_XUDF)) {
602 		omap_i2c_init(dev);
603 		return -EIO;
604 	}
605 
606 	if (dev->cmd_err & OMAP_I2C_STAT_NACK) {
607 		if (msg->flags & I2C_M_IGNORE_NAK)
608 			return 0;
609 		if (stop) {
610 			w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
611 			w |= OMAP_I2C_CON_STP;
612 			omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
613 		}
614 		return -EREMOTEIO;
615 	}
616 	return -EIO;
617 }
618 
619 
620 /*
621  * Prepare controller for a transaction and call omap_i2c_xfer_msg
622  * to do the work during IRQ processing.
623  */
624 static int
625 omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
626 {
627 	struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
628 	int i;
629 	int r;
630 
631 	pm_runtime_get_sync(dev->dev);
632 
633 	r = omap_i2c_wait_for_bb(dev);
634 	if (r < 0)
635 		goto out;
636 
637 	if (dev->set_mpu_wkup_lat != NULL)
638 		dev->set_mpu_wkup_lat(dev->dev, dev->latency);
639 
640 	for (i = 0; i < num; i++) {
641 		r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
642 		if (r != 0)
643 			break;
644 	}
645 
646 	if (dev->set_mpu_wkup_lat != NULL)
647 		dev->set_mpu_wkup_lat(dev->dev, -1);
648 
649 	if (r == 0)
650 		r = num;
651 
652 	omap_i2c_wait_for_bb(dev);
653 out:
654 	pm_runtime_put(dev->dev);
655 	return r;
656 }
657 
658 static u32
659 omap_i2c_func(struct i2c_adapter *adap)
660 {
661 	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
662 }
663 
664 static inline void
665 omap_i2c_complete_cmd(struct omap_i2c_dev *dev, u16 err)
666 {
667 	dev->cmd_err |= err;
668 	complete(&dev->cmd_complete);
669 }
670 
671 static inline void
672 omap_i2c_ack_stat(struct omap_i2c_dev *dev, u16 stat)
673 {
674 	omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
675 }
676 
677 static inline void i2c_omap_errata_i207(struct omap_i2c_dev *dev, u16 stat)
678 {
679 	/*
680 	 * I2C Errata(Errata Nos. OMAP2: 1.67, OMAP3: 1.8)
681 	 * Not applicable for OMAP4.
682 	 * Under certain rare conditions, RDR could be set again
683 	 * when the bus is busy, then ignore the interrupt and
684 	 * clear the interrupt.
685 	 */
686 	if (stat & OMAP_I2C_STAT_RDR) {
687 		/* Step 1: If RDR is set, clear it */
688 		omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RDR);
689 
690 		/* Step 2: */
691 		if (!(omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG)
692 						& OMAP_I2C_STAT_BB)) {
693 
694 			/* Step 3: */
695 			if (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG)
696 						& OMAP_I2C_STAT_RDR) {
697 				omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RDR);
698 				dev_dbg(dev->dev, "RDR when bus is busy.\n");
699 			}
700 
701 		}
702 	}
703 }
704 
705 /* rev1 devices are apparently only on some 15xx */
706 #ifdef CONFIG_ARCH_OMAP15XX
707 
708 static irqreturn_t
709 omap_i2c_omap1_isr(int this_irq, void *dev_id)
710 {
711 	struct omap_i2c_dev *dev = dev_id;
712 	u16 iv, w;
713 
714 	if (pm_runtime_suspended(dev->dev))
715 		return IRQ_NONE;
716 
717 	iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
718 	switch (iv) {
719 	case 0x00:	/* None */
720 		break;
721 	case 0x01:	/* Arbitration lost */
722 		dev_err(dev->dev, "Arbitration lost\n");
723 		omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
724 		break;
725 	case 0x02:	/* No acknowledgement */
726 		omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
727 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_STP);
728 		break;
729 	case 0x03:	/* Register access ready */
730 		omap_i2c_complete_cmd(dev, 0);
731 		break;
732 	case 0x04:	/* Receive data ready */
733 		if (dev->buf_len) {
734 			w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
735 			*dev->buf++ = w;
736 			dev->buf_len--;
737 			if (dev->buf_len) {
738 				*dev->buf++ = w >> 8;
739 				dev->buf_len--;
740 			}
741 		} else
742 			dev_err(dev->dev, "RRDY IRQ while no data requested\n");
743 		break;
744 	case 0x05:	/* Transmit data ready */
745 		if (dev->buf_len) {
746 			w = *dev->buf++;
747 			dev->buf_len--;
748 			if (dev->buf_len) {
749 				w |= *dev->buf++ << 8;
750 				dev->buf_len--;
751 			}
752 			omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
753 		} else
754 			dev_err(dev->dev, "XRDY IRQ while no data to send\n");
755 		break;
756 	default:
757 		return IRQ_NONE;
758 	}
759 
760 	return IRQ_HANDLED;
761 }
762 #else
763 #define omap_i2c_omap1_isr		NULL
764 #endif
765 
766 /*
767  * OMAP3430 Errata 1.153: When an XRDY/XDR is hit, wait for XUDF before writing
768  * data to DATA_REG. Otherwise some data bytes can be lost while transferring
769  * them from the memory to the I2C interface.
770  */
771 static int errata_omap3_1p153(struct omap_i2c_dev *dev, u16 *stat, int *err)
772 {
773 	unsigned long timeout = 10000;
774 
775 	while (--timeout && !(*stat & OMAP_I2C_STAT_XUDF)) {
776 		if (*stat & (OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) {
777 			omap_i2c_ack_stat(dev, *stat & (OMAP_I2C_STAT_XRDY |
778 							OMAP_I2C_STAT_XDR));
779 			*err |= OMAP_I2C_STAT_XUDF;
780 			return -ETIMEDOUT;
781 		}
782 
783 		cpu_relax();
784 		*stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
785 	}
786 
787 	if (!timeout) {
788 		dev_err(dev->dev, "timeout waiting on XUDF bit\n");
789 		return 0;
790 	}
791 
792 	return 0;
793 }
794 
795 static irqreturn_t
796 omap_i2c_isr(int this_irq, void *dev_id)
797 {
798 	struct omap_i2c_dev *dev = dev_id;
799 	u16 bits;
800 	u16 stat, w;
801 	int err, count = 0;
802 
803 	if (pm_runtime_suspended(dev->dev))
804 		return IRQ_NONE;
805 
806 	bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
807 	while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) {
808 		dev_dbg(dev->dev, "IRQ (ISR = 0x%04x)\n", stat);
809 		if (count++ == 100) {
810 			dev_warn(dev->dev, "Too much work in one IRQ\n");
811 			break;
812 		}
813 
814 		err = 0;
815 complete:
816 		/*
817 		 * Ack the stat in one go, but [R/X]DR and [R/X]RDY should be
818 		 * acked after the data operation is complete.
819 		 * Ref: TRM SWPU114Q Figure 18-31
820 		 */
821 		omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat &
822 				~(OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
823 				OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
824 
825 		if (stat & OMAP_I2C_STAT_NACK)
826 			err |= OMAP_I2C_STAT_NACK;
827 
828 		if (stat & OMAP_I2C_STAT_AL) {
829 			dev_err(dev->dev, "Arbitration lost\n");
830 			err |= OMAP_I2C_STAT_AL;
831 		}
832 		/*
833 		 * ProDB0017052: Clear ARDY bit twice
834 		 */
835 		if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK |
836 					OMAP_I2C_STAT_AL)) {
837 			omap_i2c_ack_stat(dev, stat &
838 				(OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
839 				OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR |
840 				OMAP_I2C_STAT_ARDY));
841 			omap_i2c_complete_cmd(dev, err);
842 			return IRQ_HANDLED;
843 		}
844 		if (stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR)) {
845 			u8 num_bytes = 1;
846 
847 			if (dev->errata & I2C_OMAP_ERRATA_I207)
848 				i2c_omap_errata_i207(dev, stat);
849 
850 			if (dev->fifo_size) {
851 				if (stat & OMAP_I2C_STAT_RRDY)
852 					num_bytes = dev->fifo_size;
853 				else    /* read RXSTAT on RDR interrupt */
854 					num_bytes = (omap_i2c_read_reg(dev,
855 							OMAP_I2C_BUFSTAT_REG)
856 							>> 8) & 0x3F;
857 			}
858 			while (num_bytes) {
859 				num_bytes--;
860 				w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
861 				if (dev->buf_len) {
862 					*dev->buf++ = w;
863 					dev->buf_len--;
864 					/*
865 					 * Data reg in 2430, omap3 and
866 					 * omap4 is 8 bit wide
867 					 */
868 					if (dev->flags &
869 						 OMAP_I2C_FLAG_16BIT_DATA_REG) {
870 						if (dev->buf_len) {
871 							*dev->buf++ = w >> 8;
872 							dev->buf_len--;
873 						}
874 					}
875 				} else {
876 					if (stat & OMAP_I2C_STAT_RRDY)
877 						dev_err(dev->dev,
878 							"RRDY IRQ while no data"
879 								" requested\n");
880 					if (stat & OMAP_I2C_STAT_RDR)
881 						dev_err(dev->dev,
882 							"RDR IRQ while no data"
883 								" requested\n");
884 					break;
885 				}
886 			}
887 			omap_i2c_ack_stat(dev,
888 				stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR));
889 			continue;
890 		}
891 		if (stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR)) {
892 			u8 num_bytes = 1;
893 			if (dev->fifo_size) {
894 				if (stat & OMAP_I2C_STAT_XRDY)
895 					num_bytes = dev->fifo_size;
896 				else    /* read TXSTAT on XDR interrupt */
897 					num_bytes = omap_i2c_read_reg(dev,
898 							OMAP_I2C_BUFSTAT_REG)
899 							& 0x3F;
900 			}
901 			while (num_bytes) {
902 				num_bytes--;
903 				w = 0;
904 				if (dev->buf_len) {
905 					w = *dev->buf++;
906 					dev->buf_len--;
907 					/*
908 					 * Data reg in 2430, omap3 and
909 					 * omap4 is 8 bit wide
910 					 */
911 					if (dev->flags &
912 						 OMAP_I2C_FLAG_16BIT_DATA_REG) {
913 						if (dev->buf_len) {
914 							w |= *dev->buf++ << 8;
915 							dev->buf_len--;
916 						}
917 					}
918 				} else {
919 					if (stat & OMAP_I2C_STAT_XRDY)
920 						dev_err(dev->dev,
921 							"XRDY IRQ while no "
922 							"data to send\n");
923 					if (stat & OMAP_I2C_STAT_XDR)
924 						dev_err(dev->dev,
925 							"XDR IRQ while no "
926 							"data to send\n");
927 					break;
928 				}
929 
930 				if ((dev->errata & I2C_OMAP3_1P153) &&
931 				    errata_omap3_1p153(dev, &stat, &err))
932 					goto complete;
933 
934 				omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
935 			}
936 			omap_i2c_ack_stat(dev,
937 				stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
938 			continue;
939 		}
940 		if (stat & OMAP_I2C_STAT_ROVR) {
941 			dev_err(dev->dev, "Receive overrun\n");
942 			dev->cmd_err |= OMAP_I2C_STAT_ROVR;
943 		}
944 		if (stat & OMAP_I2C_STAT_XUDF) {
945 			dev_err(dev->dev, "Transmit underflow\n");
946 			dev->cmd_err |= OMAP_I2C_STAT_XUDF;
947 		}
948 	}
949 
950 	return count ? IRQ_HANDLED : IRQ_NONE;
951 }
952 
953 static const struct i2c_algorithm omap_i2c_algo = {
954 	.master_xfer	= omap_i2c_xfer,
955 	.functionality	= omap_i2c_func,
956 };
957 
958 #ifdef CONFIG_OF
959 static struct omap_i2c_bus_platform_data omap3_pdata = {
960 	.rev = OMAP_I2C_IP_VERSION_1,
961 	.flags = OMAP_I2C_FLAG_APPLY_ERRATA_I207 |
962 		 OMAP_I2C_FLAG_RESET_REGS_POSTIDLE |
963 		 OMAP_I2C_FLAG_BUS_SHIFT_2,
964 };
965 
966 static struct omap_i2c_bus_platform_data omap4_pdata = {
967 	.rev = OMAP_I2C_IP_VERSION_2,
968 };
969 
970 static const struct of_device_id omap_i2c_of_match[] = {
971 	{
972 		.compatible = "ti,omap4-i2c",
973 		.data = &omap4_pdata,
974 	},
975 	{
976 		.compatible = "ti,omap3-i2c",
977 		.data = &omap3_pdata,
978 	},
979 	{ },
980 };
981 MODULE_DEVICE_TABLE(of, omap_i2c_of_match);
982 #endif
983 
984 static int __devinit
985 omap_i2c_probe(struct platform_device *pdev)
986 {
987 	struct omap_i2c_dev	*dev;
988 	struct i2c_adapter	*adap;
989 	struct resource		*mem, *irq, *ioarea;
990 	struct omap_i2c_bus_platform_data *pdata = pdev->dev.platform_data;
991 	struct device_node	*node = pdev->dev.of_node;
992 	const struct of_device_id *match;
993 	irq_handler_t isr;
994 	int r;
995 
996 	/* NOTE: driver uses the static register mapping */
997 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
998 	if (!mem) {
999 		dev_err(&pdev->dev, "no mem resource?\n");
1000 		return -ENODEV;
1001 	}
1002 	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
1003 	if (!irq) {
1004 		dev_err(&pdev->dev, "no irq resource?\n");
1005 		return -ENODEV;
1006 	}
1007 
1008 	ioarea = request_mem_region(mem->start, resource_size(mem),
1009 			pdev->name);
1010 	if (!ioarea) {
1011 		dev_err(&pdev->dev, "I2C region already claimed\n");
1012 		return -EBUSY;
1013 	}
1014 
1015 	dev = kzalloc(sizeof(struct omap_i2c_dev), GFP_KERNEL);
1016 	if (!dev) {
1017 		r = -ENOMEM;
1018 		goto err_release_region;
1019 	}
1020 
1021 	match = of_match_device(of_match_ptr(omap_i2c_of_match), &pdev->dev);
1022 	if (match) {
1023 		u32 freq = 100000; /* default to 100000 Hz */
1024 
1025 		pdata = match->data;
1026 		dev->dtrev = pdata->rev;
1027 		dev->flags = pdata->flags;
1028 
1029 		of_property_read_u32(node, "clock-frequency", &freq);
1030 		/* convert DT freq value in Hz into kHz for speed */
1031 		dev->speed = freq / 1000;
1032 	} else if (pdata != NULL) {
1033 		dev->speed = pdata->clkrate;
1034 		dev->flags = pdata->flags;
1035 		dev->set_mpu_wkup_lat = pdata->set_mpu_wkup_lat;
1036 		dev->dtrev = pdata->rev;
1037 	}
1038 
1039 	dev->dev = &pdev->dev;
1040 	dev->irq = irq->start;
1041 	dev->base = ioremap(mem->start, resource_size(mem));
1042 	if (!dev->base) {
1043 		r = -ENOMEM;
1044 		goto err_free_mem;
1045 	}
1046 
1047 	platform_set_drvdata(pdev, dev);
1048 
1049 	dev->reg_shift = (dev->flags >> OMAP_I2C_FLAG_BUS_SHIFT__SHIFT) & 3;
1050 
1051 	if (dev->dtrev == OMAP_I2C_IP_VERSION_2)
1052 		dev->regs = (u8 *)reg_map_ip_v2;
1053 	else
1054 		dev->regs = (u8 *)reg_map_ip_v1;
1055 
1056 	pm_runtime_enable(dev->dev);
1057 	pm_runtime_get_sync(dev->dev);
1058 
1059 	dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
1060 
1061 	if (dev->rev <= OMAP_I2C_REV_ON_3430)
1062 		dev->errata |= I2C_OMAP3_1P153;
1063 
1064 	if (!(dev->flags & OMAP_I2C_FLAG_NO_FIFO)) {
1065 		u16 s;
1066 
1067 		/* Set up the fifo size - Get total size */
1068 		s = (omap_i2c_read_reg(dev, OMAP_I2C_BUFSTAT_REG) >> 14) & 0x3;
1069 		dev->fifo_size = 0x8 << s;
1070 
1071 		/*
1072 		 * Set up notification threshold as half the total available
1073 		 * size. This is to ensure that we can handle the status on int
1074 		 * call back latencies.
1075 		 */
1076 
1077 		dev->fifo_size = (dev->fifo_size / 2);
1078 
1079 		if (dev->rev >= OMAP_I2C_REV_ON_3530_4430)
1080 			dev->b_hw = 0; /* Disable hardware fixes */
1081 		else
1082 			dev->b_hw = 1; /* Enable hardware fixes */
1083 
1084 		/* calculate wakeup latency constraint for MPU */
1085 		if (dev->set_mpu_wkup_lat != NULL)
1086 			dev->latency = (1000000 * dev->fifo_size) /
1087 				       (1000 * dev->speed / 8);
1088 	}
1089 
1090 	/* reset ASAP, clearing any IRQs */
1091 	omap_i2c_init(dev);
1092 
1093 	isr = (dev->rev < OMAP_I2C_OMAP1_REV_2) ? omap_i2c_omap1_isr :
1094 								   omap_i2c_isr;
1095 	r = request_irq(dev->irq, isr, 0, pdev->name, dev);
1096 
1097 	if (r) {
1098 		dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
1099 		goto err_unuse_clocks;
1100 	}
1101 
1102 	dev_info(dev->dev, "bus %d rev%d.%d.%d at %d kHz\n", pdev->id,
1103 		 dev->dtrev, dev->rev >> 4, dev->rev & 0xf, dev->speed);
1104 
1105 	pm_runtime_put(dev->dev);
1106 
1107 	adap = &dev->adapter;
1108 	i2c_set_adapdata(adap, dev);
1109 	adap->owner = THIS_MODULE;
1110 	adap->class = I2C_CLASS_HWMON;
1111 	strlcpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
1112 	adap->algo = &omap_i2c_algo;
1113 	adap->dev.parent = &pdev->dev;
1114 	adap->dev.of_node = pdev->dev.of_node;
1115 
1116 	/* i2c device drivers may be active on return from add_adapter() */
1117 	adap->nr = pdev->id;
1118 	r = i2c_add_numbered_adapter(adap);
1119 	if (r) {
1120 		dev_err(dev->dev, "failure adding adapter\n");
1121 		goto err_free_irq;
1122 	}
1123 
1124 	of_i2c_register_devices(adap);
1125 
1126 	return 0;
1127 
1128 err_free_irq:
1129 	free_irq(dev->irq, dev);
1130 err_unuse_clocks:
1131 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
1132 	pm_runtime_put(dev->dev);
1133 	iounmap(dev->base);
1134 err_free_mem:
1135 	platform_set_drvdata(pdev, NULL);
1136 	kfree(dev);
1137 err_release_region:
1138 	release_mem_region(mem->start, resource_size(mem));
1139 
1140 	return r;
1141 }
1142 
1143 static int
1144 omap_i2c_remove(struct platform_device *pdev)
1145 {
1146 	struct omap_i2c_dev	*dev = platform_get_drvdata(pdev);
1147 	struct resource		*mem;
1148 
1149 	platform_set_drvdata(pdev, NULL);
1150 
1151 	free_irq(dev->irq, dev);
1152 	i2c_del_adapter(&dev->adapter);
1153 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
1154 	iounmap(dev->base);
1155 	kfree(dev);
1156 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1157 	release_mem_region(mem->start, resource_size(mem));
1158 	return 0;
1159 }
1160 
1161 #ifdef CONFIG_PM_RUNTIME
1162 static int omap_i2c_runtime_suspend(struct device *dev)
1163 {
1164 	struct platform_device *pdev = to_platform_device(dev);
1165 	struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);
1166 
1167 	omap_i2c_idle(_dev);
1168 
1169 	return 0;
1170 }
1171 
1172 static int omap_i2c_runtime_resume(struct device *dev)
1173 {
1174 	struct platform_device *pdev = to_platform_device(dev);
1175 	struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);
1176 
1177 	omap_i2c_unidle(_dev);
1178 
1179 	return 0;
1180 }
1181 
1182 static struct dev_pm_ops omap_i2c_pm_ops = {
1183 	.runtime_suspend = omap_i2c_runtime_suspend,
1184 	.runtime_resume = omap_i2c_runtime_resume,
1185 };
1186 #define OMAP_I2C_PM_OPS (&omap_i2c_pm_ops)
1187 #else
1188 #define OMAP_I2C_PM_OPS NULL
1189 #endif
1190 
1191 static struct platform_driver omap_i2c_driver = {
1192 	.probe		= omap_i2c_probe,
1193 	.remove		= omap_i2c_remove,
1194 	.driver		= {
1195 		.name	= "omap_i2c",
1196 		.owner	= THIS_MODULE,
1197 		.pm	= OMAP_I2C_PM_OPS,
1198 		.of_match_table = of_match_ptr(omap_i2c_of_match),
1199 	},
1200 };
1201 
1202 /* I2C may be needed to bring up other drivers */
1203 static int __init
1204 omap_i2c_init_driver(void)
1205 {
1206 	return platform_driver_register(&omap_i2c_driver);
1207 }
1208 subsys_initcall(omap_i2c_init_driver);
1209 
1210 static void __exit omap_i2c_exit_driver(void)
1211 {
1212 	platform_driver_unregister(&omap_i2c_driver);
1213 }
1214 module_exit(omap_i2c_exit_driver);
1215 
1216 MODULE_AUTHOR("MontaVista Software, Inc. (and others)");
1217 MODULE_DESCRIPTION("TI OMAP I2C bus adapter");
1218 MODULE_LICENSE("GPL");
1219 MODULE_ALIAS("platform:omap_i2c");
1220