xref: /linux/drivers/i2c/busses/i2c-omap.c (revision f2ee442115c9b6219083c019939a9cc0c9abb2f8)
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/slab.h>
41 #include <linux/i2c-omap.h>
42 #include <linux/pm_runtime.h>
43 
44 /* I2C controller revisions */
45 #define OMAP_I2C_OMAP1_REV_2		0x20
46 
47 /* I2C controller revisions present on specific hardware */
48 #define OMAP_I2C_REV_ON_2430		0x36
49 #define OMAP_I2C_REV_ON_3430		0x3C
50 #define OMAP_I2C_REV_ON_3530_4430	0x40
51 
52 /* timeout waiting for the controller to respond */
53 #define OMAP_I2C_TIMEOUT (msecs_to_jiffies(1000))
54 
55 /* For OMAP3 I2C_IV has changed to I2C_WE (wakeup enable) */
56 enum {
57 	OMAP_I2C_REV_REG = 0,
58 	OMAP_I2C_IE_REG,
59 	OMAP_I2C_STAT_REG,
60 	OMAP_I2C_IV_REG,
61 	OMAP_I2C_WE_REG,
62 	OMAP_I2C_SYSS_REG,
63 	OMAP_I2C_BUF_REG,
64 	OMAP_I2C_CNT_REG,
65 	OMAP_I2C_DATA_REG,
66 	OMAP_I2C_SYSC_REG,
67 	OMAP_I2C_CON_REG,
68 	OMAP_I2C_OA_REG,
69 	OMAP_I2C_SA_REG,
70 	OMAP_I2C_PSC_REG,
71 	OMAP_I2C_SCLL_REG,
72 	OMAP_I2C_SCLH_REG,
73 	OMAP_I2C_SYSTEST_REG,
74 	OMAP_I2C_BUFSTAT_REG,
75 	/* only on OMAP4430 */
76 	OMAP_I2C_IP_V2_REVNB_LO,
77 	OMAP_I2C_IP_V2_REVNB_HI,
78 	OMAP_I2C_IP_V2_IRQSTATUS_RAW,
79 	OMAP_I2C_IP_V2_IRQENABLE_SET,
80 	OMAP_I2C_IP_V2_IRQENABLE_CLR,
81 };
82 
83 /* I2C Interrupt Enable Register (OMAP_I2C_IE): */
84 #define OMAP_I2C_IE_XDR		(1 << 14)	/* TX Buffer drain int enable */
85 #define OMAP_I2C_IE_RDR		(1 << 13)	/* RX Buffer drain int enable */
86 #define OMAP_I2C_IE_XRDY	(1 << 4)	/* TX data ready int enable */
87 #define OMAP_I2C_IE_RRDY	(1 << 3)	/* RX data ready int enable */
88 #define OMAP_I2C_IE_ARDY	(1 << 2)	/* Access ready int enable */
89 #define OMAP_I2C_IE_NACK	(1 << 1)	/* No ack interrupt enable */
90 #define OMAP_I2C_IE_AL		(1 << 0)	/* Arbitration lost int ena */
91 
92 /* I2C Status Register (OMAP_I2C_STAT): */
93 #define OMAP_I2C_STAT_XDR	(1 << 14)	/* TX Buffer draining */
94 #define OMAP_I2C_STAT_RDR	(1 << 13)	/* RX Buffer draining */
95 #define OMAP_I2C_STAT_BB	(1 << 12)	/* Bus busy */
96 #define OMAP_I2C_STAT_ROVR	(1 << 11)	/* Receive overrun */
97 #define OMAP_I2C_STAT_XUDF	(1 << 10)	/* Transmit underflow */
98 #define OMAP_I2C_STAT_AAS	(1 << 9)	/* Address as slave */
99 #define OMAP_I2C_STAT_AD0	(1 << 8)	/* Address zero */
100 #define OMAP_I2C_STAT_XRDY	(1 << 4)	/* Transmit data ready */
101 #define OMAP_I2C_STAT_RRDY	(1 << 3)	/* Receive data ready */
102 #define OMAP_I2C_STAT_ARDY	(1 << 2)	/* Register access ready */
103 #define OMAP_I2C_STAT_NACK	(1 << 1)	/* No ack interrupt enable */
104 #define OMAP_I2C_STAT_AL	(1 << 0)	/* Arbitration lost int ena */
105 
106 /* I2C WE wakeup enable register */
107 #define OMAP_I2C_WE_XDR_WE	(1 << 14)	/* TX drain wakup */
108 #define OMAP_I2C_WE_RDR_WE	(1 << 13)	/* RX drain wakeup */
109 #define OMAP_I2C_WE_AAS_WE	(1 << 9)	/* Address as slave wakeup*/
110 #define OMAP_I2C_WE_BF_WE	(1 << 8)	/* Bus free wakeup */
111 #define OMAP_I2C_WE_STC_WE	(1 << 6)	/* Start condition wakeup */
112 #define OMAP_I2C_WE_GC_WE	(1 << 5)	/* General call wakeup */
113 #define OMAP_I2C_WE_DRDY_WE	(1 << 3)	/* TX/RX data ready wakeup */
114 #define OMAP_I2C_WE_ARDY_WE	(1 << 2)	/* Reg access ready wakeup */
115 #define OMAP_I2C_WE_NACK_WE	(1 << 1)	/* No acknowledgment wakeup */
116 #define OMAP_I2C_WE_AL_WE	(1 << 0)	/* Arbitration lost wakeup */
117 
118 #define OMAP_I2C_WE_ALL		(OMAP_I2C_WE_XDR_WE | OMAP_I2C_WE_RDR_WE | \
119 				OMAP_I2C_WE_AAS_WE | OMAP_I2C_WE_BF_WE | \
120 				OMAP_I2C_WE_STC_WE | OMAP_I2C_WE_GC_WE | \
121 				OMAP_I2C_WE_DRDY_WE | OMAP_I2C_WE_ARDY_WE | \
122 				OMAP_I2C_WE_NACK_WE | OMAP_I2C_WE_AL_WE)
123 
124 /* I2C Buffer Configuration Register (OMAP_I2C_BUF): */
125 #define OMAP_I2C_BUF_RDMA_EN	(1 << 15)	/* RX DMA channel enable */
126 #define OMAP_I2C_BUF_RXFIF_CLR	(1 << 14)	/* RX FIFO Clear */
127 #define OMAP_I2C_BUF_XDMA_EN	(1 << 7)	/* TX DMA channel enable */
128 #define OMAP_I2C_BUF_TXFIF_CLR	(1 << 6)	/* TX FIFO Clear */
129 
130 /* I2C Configuration Register (OMAP_I2C_CON): */
131 #define OMAP_I2C_CON_EN		(1 << 15)	/* I2C module enable */
132 #define OMAP_I2C_CON_BE		(1 << 14)	/* Big endian mode */
133 #define OMAP_I2C_CON_OPMODE_HS	(1 << 12)	/* High Speed support */
134 #define OMAP_I2C_CON_STB	(1 << 11)	/* Start byte mode (master) */
135 #define OMAP_I2C_CON_MST	(1 << 10)	/* Master/slave mode */
136 #define OMAP_I2C_CON_TRX	(1 << 9)	/* TX/RX mode (master only) */
137 #define OMAP_I2C_CON_XA		(1 << 8)	/* Expand address */
138 #define OMAP_I2C_CON_RM		(1 << 2)	/* Repeat mode (master only) */
139 #define OMAP_I2C_CON_STP	(1 << 1)	/* Stop cond (master only) */
140 #define OMAP_I2C_CON_STT	(1 << 0)	/* Start condition (master) */
141 
142 /* I2C SCL time value when Master */
143 #define OMAP_I2C_SCLL_HSSCLL	8
144 #define OMAP_I2C_SCLH_HSSCLH	8
145 
146 /* I2C System Test Register (OMAP_I2C_SYSTEST): */
147 #ifdef DEBUG
148 #define OMAP_I2C_SYSTEST_ST_EN		(1 << 15)	/* System test enable */
149 #define OMAP_I2C_SYSTEST_FREE		(1 << 14)	/* Free running mode */
150 #define OMAP_I2C_SYSTEST_TMODE_MASK	(3 << 12)	/* Test mode select */
151 #define OMAP_I2C_SYSTEST_TMODE_SHIFT	(12)		/* Test mode select */
152 #define OMAP_I2C_SYSTEST_SCL_I		(1 << 3)	/* SCL line sense in */
153 #define OMAP_I2C_SYSTEST_SCL_O		(1 << 2)	/* SCL line drive out */
154 #define OMAP_I2C_SYSTEST_SDA_I		(1 << 1)	/* SDA line sense in */
155 #define OMAP_I2C_SYSTEST_SDA_O		(1 << 0)	/* SDA line drive out */
156 #endif
157 
158 /* OCP_SYSSTATUS bit definitions */
159 #define SYSS_RESETDONE_MASK		(1 << 0)
160 
161 /* OCP_SYSCONFIG bit definitions */
162 #define SYSC_CLOCKACTIVITY_MASK		(0x3 << 8)
163 #define SYSC_SIDLEMODE_MASK		(0x3 << 3)
164 #define SYSC_ENAWAKEUP_MASK		(1 << 2)
165 #define SYSC_SOFTRESET_MASK		(1 << 1)
166 #define SYSC_AUTOIDLE_MASK		(1 << 0)
167 
168 #define SYSC_IDLEMODE_SMART		0x2
169 #define SYSC_CLOCKACTIVITY_FCLK		0x2
170 
171 /* Errata definitions */
172 #define I2C_OMAP_ERRATA_I207		(1 << 0)
173 #define I2C_OMAP3_1P153			(1 << 1)
174 
175 struct omap_i2c_dev {
176 	struct device		*dev;
177 	void __iomem		*base;		/* virtual */
178 	int			irq;
179 	int			reg_shift;      /* bit shift for I2C register addresses */
180 	struct completion	cmd_complete;
181 	struct resource		*ioarea;
182 	u32			latency;	/* maximum mpu wkup latency */
183 	void			(*set_mpu_wkup_lat)(struct device *dev,
184 						    long latency);
185 	u32			speed;		/* Speed of bus in Khz */
186 	u16			cmd_err;
187 	u8			*buf;
188 	u8			*regs;
189 	size_t			buf_len;
190 	struct i2c_adapter	adapter;
191 	u8			fifo_size;	/* use as flag and value
192 						 * fifo_size==0 implies no fifo
193 						 * if set, should be trsh+1
194 						 */
195 	u8			rev;
196 	unsigned		b_hw:1;		/* bad h/w fixes */
197 	u16			iestate;	/* Saved interrupt register */
198 	u16			pscstate;
199 	u16			scllstate;
200 	u16			sclhstate;
201 	u16			bufstate;
202 	u16			syscstate;
203 	u16			westate;
204 	u16			errata;
205 };
206 
207 static const u8 reg_map_ip_v1[] = {
208 	[OMAP_I2C_REV_REG] = 0x00,
209 	[OMAP_I2C_IE_REG] = 0x01,
210 	[OMAP_I2C_STAT_REG] = 0x02,
211 	[OMAP_I2C_IV_REG] = 0x03,
212 	[OMAP_I2C_WE_REG] = 0x03,
213 	[OMAP_I2C_SYSS_REG] = 0x04,
214 	[OMAP_I2C_BUF_REG] = 0x05,
215 	[OMAP_I2C_CNT_REG] = 0x06,
216 	[OMAP_I2C_DATA_REG] = 0x07,
217 	[OMAP_I2C_SYSC_REG] = 0x08,
218 	[OMAP_I2C_CON_REG] = 0x09,
219 	[OMAP_I2C_OA_REG] = 0x0a,
220 	[OMAP_I2C_SA_REG] = 0x0b,
221 	[OMAP_I2C_PSC_REG] = 0x0c,
222 	[OMAP_I2C_SCLL_REG] = 0x0d,
223 	[OMAP_I2C_SCLH_REG] = 0x0e,
224 	[OMAP_I2C_SYSTEST_REG] = 0x0f,
225 	[OMAP_I2C_BUFSTAT_REG] = 0x10,
226 };
227 
228 static const u8 reg_map_ip_v2[] = {
229 	[OMAP_I2C_REV_REG] = 0x04,
230 	[OMAP_I2C_IE_REG] = 0x2c,
231 	[OMAP_I2C_STAT_REG] = 0x28,
232 	[OMAP_I2C_IV_REG] = 0x34,
233 	[OMAP_I2C_WE_REG] = 0x34,
234 	[OMAP_I2C_SYSS_REG] = 0x90,
235 	[OMAP_I2C_BUF_REG] = 0x94,
236 	[OMAP_I2C_CNT_REG] = 0x98,
237 	[OMAP_I2C_DATA_REG] = 0x9c,
238 	[OMAP_I2C_SYSC_REG] = 0x20,
239 	[OMAP_I2C_CON_REG] = 0xa4,
240 	[OMAP_I2C_OA_REG] = 0xa8,
241 	[OMAP_I2C_SA_REG] = 0xac,
242 	[OMAP_I2C_PSC_REG] = 0xb0,
243 	[OMAP_I2C_SCLL_REG] = 0xb4,
244 	[OMAP_I2C_SCLH_REG] = 0xb8,
245 	[OMAP_I2C_SYSTEST_REG] = 0xbC,
246 	[OMAP_I2C_BUFSTAT_REG] = 0xc0,
247 	[OMAP_I2C_IP_V2_REVNB_LO] = 0x00,
248 	[OMAP_I2C_IP_V2_REVNB_HI] = 0x04,
249 	[OMAP_I2C_IP_V2_IRQSTATUS_RAW] = 0x24,
250 	[OMAP_I2C_IP_V2_IRQENABLE_SET] = 0x2c,
251 	[OMAP_I2C_IP_V2_IRQENABLE_CLR] = 0x30,
252 };
253 
254 static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev,
255 				      int reg, u16 val)
256 {
257 	__raw_writew(val, i2c_dev->base +
258 			(i2c_dev->regs[reg] << i2c_dev->reg_shift));
259 }
260 
261 static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
262 {
263 	return __raw_readw(i2c_dev->base +
264 				(i2c_dev->regs[reg] << i2c_dev->reg_shift));
265 }
266 
267 static void omap_i2c_unidle(struct omap_i2c_dev *dev)
268 {
269 	struct omap_i2c_bus_platform_data *pdata;
270 
271 	pdata = dev->dev->platform_data;
272 
273 	if (pdata->flags & OMAP_I2C_FLAG_RESET_REGS_POSTIDLE) {
274 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
275 		omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, dev->pscstate);
276 		omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, dev->scllstate);
277 		omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, dev->sclhstate);
278 		omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, dev->bufstate);
279 		omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, dev->syscstate);
280 		omap_i2c_write_reg(dev, OMAP_I2C_WE_REG, dev->westate);
281 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
282 	}
283 
284 	/*
285 	 * Don't write to this register if the IE state is 0 as it can
286 	 * cause deadlock.
287 	 */
288 	if (dev->iestate)
289 		omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
290 }
291 
292 static void omap_i2c_idle(struct omap_i2c_dev *dev)
293 {
294 	struct omap_i2c_bus_platform_data *pdata;
295 	u16 iv;
296 
297 	pdata = dev->dev->platform_data;
298 
299 	dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
300 	if (pdata->rev == OMAP_I2C_IP_VERSION_2)
301 		omap_i2c_write_reg(dev, OMAP_I2C_IP_V2_IRQENABLE_CLR, 1);
302 	else
303 		omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0);
304 
305 	if (dev->rev < OMAP_I2C_OMAP1_REV_2) {
306 		iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG); /* Read clears */
307 	} else {
308 		omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate);
309 
310 		/* Flush posted write */
311 		omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
312 	}
313 }
314 
315 static int omap_i2c_init(struct omap_i2c_dev *dev)
316 {
317 	u16 psc = 0, scll = 0, sclh = 0, buf = 0;
318 	u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0;
319 	unsigned long fclk_rate = 12000000;
320 	unsigned long timeout;
321 	unsigned long internal_clk = 0;
322 	struct clk *fclk;
323 	struct omap_i2c_bus_platform_data *pdata;
324 
325 	pdata = dev->dev->platform_data;
326 
327 	if (dev->rev >= OMAP_I2C_OMAP1_REV_2) {
328 		/* Disable I2C controller before soft reset */
329 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
330 			omap_i2c_read_reg(dev, OMAP_I2C_CON_REG) &
331 				~(OMAP_I2C_CON_EN));
332 
333 		omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, SYSC_SOFTRESET_MASK);
334 		/* For some reason we need to set the EN bit before the
335 		 * reset done bit gets set. */
336 		timeout = jiffies + OMAP_I2C_TIMEOUT;
337 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
338 		while (!(omap_i2c_read_reg(dev, OMAP_I2C_SYSS_REG) &
339 			 SYSS_RESETDONE_MASK)) {
340 			if (time_after(jiffies, timeout)) {
341 				dev_warn(dev->dev, "timeout waiting "
342 						"for controller reset\n");
343 				return -ETIMEDOUT;
344 			}
345 			msleep(1);
346 		}
347 
348 		/* SYSC register is cleared by the reset; rewrite it */
349 		if (dev->rev == OMAP_I2C_REV_ON_2430) {
350 
351 			omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
352 					   SYSC_AUTOIDLE_MASK);
353 
354 		} else if (dev->rev >= OMAP_I2C_REV_ON_3430) {
355 			dev->syscstate = SYSC_AUTOIDLE_MASK;
356 			dev->syscstate |= SYSC_ENAWAKEUP_MASK;
357 			dev->syscstate |= (SYSC_IDLEMODE_SMART <<
358 			      __ffs(SYSC_SIDLEMODE_MASK));
359 			dev->syscstate |= (SYSC_CLOCKACTIVITY_FCLK <<
360 			      __ffs(SYSC_CLOCKACTIVITY_MASK));
361 
362 			omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
363 							dev->syscstate);
364 			/*
365 			 * Enabling all wakup sources to stop I2C freezing on
366 			 * WFI instruction.
367 			 * REVISIT: Some wkup sources might not be needed.
368 			 */
369 			dev->westate = OMAP_I2C_WE_ALL;
370 			omap_i2c_write_reg(dev, OMAP_I2C_WE_REG,
371 							dev->westate);
372 		}
373 	}
374 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
375 
376 	if (pdata->flags & OMAP_I2C_FLAG_ALWAYS_ARMXOR_CLK) {
377 		/*
378 		 * The I2C functional clock is the armxor_ck, so there's
379 		 * no need to get "armxor_ck" separately.  Now, if OMAP2420
380 		 * always returns 12MHz for the functional clock, we can
381 		 * do this bit unconditionally.
382 		 */
383 		fclk = clk_get(dev->dev, "fck");
384 		fclk_rate = clk_get_rate(fclk);
385 		clk_put(fclk);
386 
387 		/* TRM for 5912 says the I2C clock must be prescaled to be
388 		 * between 7 - 12 MHz. The XOR input clock is typically
389 		 * 12, 13 or 19.2 MHz. So we should have code that produces:
390 		 *
391 		 * XOR MHz	Divider		Prescaler
392 		 * 12		1		0
393 		 * 13		2		1
394 		 * 19.2		2		1
395 		 */
396 		if (fclk_rate > 12000000)
397 			psc = fclk_rate / 12000000;
398 	}
399 
400 	if (!(pdata->flags & OMAP_I2C_FLAG_SIMPLE_CLOCK)) {
401 
402 		/*
403 		 * HSI2C controller internal clk rate should be 19.2 Mhz for
404 		 * HS and for all modes on 2430. On 34xx we can use lower rate
405 		 * to get longer filter period for better noise suppression.
406 		 * The filter is iclk (fclk for HS) period.
407 		 */
408 		if (dev->speed > 400 ||
409 			       pdata->flags & OMAP_I2C_FLAG_FORCE_19200_INT_CLK)
410 			internal_clk = 19200;
411 		else if (dev->speed > 100)
412 			internal_clk = 9600;
413 		else
414 			internal_clk = 4000;
415 		fclk = clk_get(dev->dev, "fck");
416 		fclk_rate = clk_get_rate(fclk) / 1000;
417 		clk_put(fclk);
418 
419 		/* Compute prescaler divisor */
420 		psc = fclk_rate / internal_clk;
421 		psc = psc - 1;
422 
423 		/* If configured for High Speed */
424 		if (dev->speed > 400) {
425 			unsigned long scl;
426 
427 			/* For first phase of HS mode */
428 			scl = internal_clk / 400;
429 			fsscll = scl - (scl / 3) - 7;
430 			fssclh = (scl / 3) - 5;
431 
432 			/* For second phase of HS mode */
433 			scl = fclk_rate / dev->speed;
434 			hsscll = scl - (scl / 3) - 7;
435 			hssclh = (scl / 3) - 5;
436 		} else if (dev->speed > 100) {
437 			unsigned long scl;
438 
439 			/* Fast mode */
440 			scl = internal_clk / dev->speed;
441 			fsscll = scl - (scl / 3) - 7;
442 			fssclh = (scl / 3) - 5;
443 		} else {
444 			/* Standard mode */
445 			fsscll = internal_clk / (dev->speed * 2) - 7;
446 			fssclh = internal_clk / (dev->speed * 2) - 5;
447 		}
448 		scll = (hsscll << OMAP_I2C_SCLL_HSSCLL) | fsscll;
449 		sclh = (hssclh << OMAP_I2C_SCLH_HSSCLH) | fssclh;
450 	} else {
451 		/* Program desired operating rate */
452 		fclk_rate /= (psc + 1) * 1000;
453 		if (psc > 2)
454 			psc = 2;
455 		scll = fclk_rate / (dev->speed * 2) - 7 + psc;
456 		sclh = fclk_rate / (dev->speed * 2) - 7 + psc;
457 	}
458 
459 	/* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
460 	omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, psc);
461 
462 	/* SCL low and high time values */
463 	omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll);
464 	omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh);
465 
466 	if (dev->fifo_size) {
467 		/* Note: setup required fifo size - 1. RTRSH and XTRSH */
468 		buf = (dev->fifo_size - 1) << 8 | OMAP_I2C_BUF_RXFIF_CLR |
469 			(dev->fifo_size - 1) | OMAP_I2C_BUF_TXFIF_CLR;
470 		omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, buf);
471 	}
472 
473 	/* Take the I2C module out of reset: */
474 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
475 
476 	dev->errata = 0;
477 
478 	if (pdata->flags & OMAP_I2C_FLAG_APPLY_ERRATA_I207)
479 		dev->errata |= I2C_OMAP_ERRATA_I207;
480 
481 	/* Enable interrupts */
482 	dev->iestate = (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
483 			OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK |
484 			OMAP_I2C_IE_AL)  | ((dev->fifo_size) ?
485 				(OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0);
486 	omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
487 	if (pdata->flags & OMAP_I2C_FLAG_RESET_REGS_POSTIDLE) {
488 		dev->pscstate = psc;
489 		dev->scllstate = scll;
490 		dev->sclhstate = sclh;
491 		dev->bufstate = buf;
492 	}
493 	return 0;
494 }
495 
496 /*
497  * Waiting on Bus Busy
498  */
499 static int omap_i2c_wait_for_bb(struct omap_i2c_dev *dev)
500 {
501 	unsigned long timeout;
502 
503 	timeout = jiffies + OMAP_I2C_TIMEOUT;
504 	while (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_BB) {
505 		if (time_after(jiffies, timeout)) {
506 			dev_warn(dev->dev, "timeout waiting for bus ready\n");
507 			return -ETIMEDOUT;
508 		}
509 		msleep(1);
510 	}
511 
512 	return 0;
513 }
514 
515 /*
516  * Low level master read/write transaction.
517  */
518 static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
519 			     struct i2c_msg *msg, int stop)
520 {
521 	struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
522 	int r;
523 	u16 w;
524 
525 	dev_dbg(dev->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
526 		msg->addr, msg->len, msg->flags, stop);
527 
528 	if (msg->len == 0)
529 		return -EINVAL;
530 
531 	omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr);
532 
533 	/* REVISIT: Could the STB bit of I2C_CON be used with probing? */
534 	dev->buf = msg->buf;
535 	dev->buf_len = msg->len;
536 
537 	omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len);
538 
539 	/* Clear the FIFO Buffers */
540 	w = omap_i2c_read_reg(dev, OMAP_I2C_BUF_REG);
541 	w |= OMAP_I2C_BUF_RXFIF_CLR | OMAP_I2C_BUF_TXFIF_CLR;
542 	omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, w);
543 
544 	init_completion(&dev->cmd_complete);
545 	dev->cmd_err = 0;
546 
547 	w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;
548 
549 	/* High speed configuration */
550 	if (dev->speed > 400)
551 		w |= OMAP_I2C_CON_OPMODE_HS;
552 
553 	if (msg->flags & I2C_M_TEN)
554 		w |= OMAP_I2C_CON_XA;
555 	if (!(msg->flags & I2C_M_RD))
556 		w |= OMAP_I2C_CON_TRX;
557 
558 	if (!dev->b_hw && stop)
559 		w |= OMAP_I2C_CON_STP;
560 
561 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
562 
563 	/*
564 	 * Don't write stt and stp together on some hardware.
565 	 */
566 	if (dev->b_hw && stop) {
567 		unsigned long delay = jiffies + OMAP_I2C_TIMEOUT;
568 		u16 con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
569 		while (con & OMAP_I2C_CON_STT) {
570 			con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
571 
572 			/* Let the user know if i2c is in a bad state */
573 			if (time_after(jiffies, delay)) {
574 				dev_err(dev->dev, "controller timed out "
575 				"waiting for start condition to finish\n");
576 				return -ETIMEDOUT;
577 			}
578 			cpu_relax();
579 		}
580 
581 		w |= OMAP_I2C_CON_STP;
582 		w &= ~OMAP_I2C_CON_STT;
583 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
584 	}
585 
586 	/*
587 	 * REVISIT: We should abort the transfer on signals, but the bus goes
588 	 * into arbitration and we're currently unable to recover from it.
589 	 */
590 	r = wait_for_completion_timeout(&dev->cmd_complete,
591 					OMAP_I2C_TIMEOUT);
592 	dev->buf_len = 0;
593 	if (r < 0)
594 		return r;
595 	if (r == 0) {
596 		dev_err(dev->dev, "controller timed out\n");
597 		omap_i2c_init(dev);
598 		return -ETIMEDOUT;
599 	}
600 
601 	if (likely(!dev->cmd_err))
602 		return 0;
603 
604 	/* We have an error */
605 	if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR |
606 			    OMAP_I2C_STAT_XUDF)) {
607 		omap_i2c_init(dev);
608 		return -EIO;
609 	}
610 
611 	if (dev->cmd_err & OMAP_I2C_STAT_NACK) {
612 		if (msg->flags & I2C_M_IGNORE_NAK)
613 			return 0;
614 		if (stop) {
615 			w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
616 			w |= OMAP_I2C_CON_STP;
617 			omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
618 		}
619 		return -EREMOTEIO;
620 	}
621 	return -EIO;
622 }
623 
624 
625 /*
626  * Prepare controller for a transaction and call omap_i2c_xfer_msg
627  * to do the work during IRQ processing.
628  */
629 static int
630 omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
631 {
632 	struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
633 	int i;
634 	int r;
635 
636 	pm_runtime_get_sync(dev->dev);
637 
638 	r = omap_i2c_wait_for_bb(dev);
639 	if (r < 0)
640 		goto out;
641 
642 	if (dev->set_mpu_wkup_lat != NULL)
643 		dev->set_mpu_wkup_lat(dev->dev, dev->latency);
644 
645 	for (i = 0; i < num; i++) {
646 		r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
647 		if (r != 0)
648 			break;
649 	}
650 
651 	if (dev->set_mpu_wkup_lat != NULL)
652 		dev->set_mpu_wkup_lat(dev->dev, -1);
653 
654 	if (r == 0)
655 		r = num;
656 
657 	omap_i2c_wait_for_bb(dev);
658 out:
659 	pm_runtime_put(dev->dev);
660 	return r;
661 }
662 
663 static u32
664 omap_i2c_func(struct i2c_adapter *adap)
665 {
666 	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
667 }
668 
669 static inline void
670 omap_i2c_complete_cmd(struct omap_i2c_dev *dev, u16 err)
671 {
672 	dev->cmd_err |= err;
673 	complete(&dev->cmd_complete);
674 }
675 
676 static inline void
677 omap_i2c_ack_stat(struct omap_i2c_dev *dev, u16 stat)
678 {
679 	omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
680 }
681 
682 static inline void i2c_omap_errata_i207(struct omap_i2c_dev *dev, u16 stat)
683 {
684 	/*
685 	 * I2C Errata(Errata Nos. OMAP2: 1.67, OMAP3: 1.8)
686 	 * Not applicable for OMAP4.
687 	 * Under certain rare conditions, RDR could be set again
688 	 * when the bus is busy, then ignore the interrupt and
689 	 * clear the interrupt.
690 	 */
691 	if (stat & OMAP_I2C_STAT_RDR) {
692 		/* Step 1: If RDR is set, clear it */
693 		omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RDR);
694 
695 		/* Step 2: */
696 		if (!(omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG)
697 						& OMAP_I2C_STAT_BB)) {
698 
699 			/* Step 3: */
700 			if (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG)
701 						& OMAP_I2C_STAT_RDR) {
702 				omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RDR);
703 				dev_dbg(dev->dev, "RDR when bus is busy.\n");
704 			}
705 
706 		}
707 	}
708 }
709 
710 /* rev1 devices are apparently only on some 15xx */
711 #ifdef CONFIG_ARCH_OMAP15XX
712 
713 static irqreturn_t
714 omap_i2c_omap1_isr(int this_irq, void *dev_id)
715 {
716 	struct omap_i2c_dev *dev = dev_id;
717 	u16 iv, w;
718 
719 	if (pm_runtime_suspended(dev->dev))
720 		return IRQ_NONE;
721 
722 	iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
723 	switch (iv) {
724 	case 0x00:	/* None */
725 		break;
726 	case 0x01:	/* Arbitration lost */
727 		dev_err(dev->dev, "Arbitration lost\n");
728 		omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
729 		break;
730 	case 0x02:	/* No acknowledgement */
731 		omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
732 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_STP);
733 		break;
734 	case 0x03:	/* Register access ready */
735 		omap_i2c_complete_cmd(dev, 0);
736 		break;
737 	case 0x04:	/* Receive data ready */
738 		if (dev->buf_len) {
739 			w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
740 			*dev->buf++ = w;
741 			dev->buf_len--;
742 			if (dev->buf_len) {
743 				*dev->buf++ = w >> 8;
744 				dev->buf_len--;
745 			}
746 		} else
747 			dev_err(dev->dev, "RRDY IRQ while no data requested\n");
748 		break;
749 	case 0x05:	/* Transmit data ready */
750 		if (dev->buf_len) {
751 			w = *dev->buf++;
752 			dev->buf_len--;
753 			if (dev->buf_len) {
754 				w |= *dev->buf++ << 8;
755 				dev->buf_len--;
756 			}
757 			omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
758 		} else
759 			dev_err(dev->dev, "XRDY IRQ while no data to send\n");
760 		break;
761 	default:
762 		return IRQ_NONE;
763 	}
764 
765 	return IRQ_HANDLED;
766 }
767 #else
768 #define omap_i2c_omap1_isr		NULL
769 #endif
770 
771 /*
772  * OMAP3430 Errata 1.153: When an XRDY/XDR is hit, wait for XUDF before writing
773  * data to DATA_REG. Otherwise some data bytes can be lost while transferring
774  * them from the memory to the I2C interface.
775  */
776 static int errata_omap3_1p153(struct omap_i2c_dev *dev, u16 *stat, int *err)
777 {
778 	unsigned long timeout = 10000;
779 
780 	while (--timeout && !(*stat & OMAP_I2C_STAT_XUDF)) {
781 		if (*stat & (OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) {
782 			omap_i2c_ack_stat(dev, *stat & (OMAP_I2C_STAT_XRDY |
783 							OMAP_I2C_STAT_XDR));
784 			*err |= OMAP_I2C_STAT_XUDF;
785 			return -ETIMEDOUT;
786 		}
787 
788 		cpu_relax();
789 		*stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
790 	}
791 
792 	if (!timeout) {
793 		dev_err(dev->dev, "timeout waiting on XUDF bit\n");
794 		return 0;
795 	}
796 
797 	return 0;
798 }
799 
800 static irqreturn_t
801 omap_i2c_isr(int this_irq, void *dev_id)
802 {
803 	struct omap_i2c_dev *dev = dev_id;
804 	u16 bits;
805 	u16 stat, w;
806 	int err, count = 0;
807 	struct omap_i2c_bus_platform_data *pdata;
808 
809 	pdata = dev->dev->platform_data;
810 
811 	if (pm_runtime_suspended(dev->dev))
812 		return IRQ_NONE;
813 
814 	bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
815 	while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) {
816 		dev_dbg(dev->dev, "IRQ (ISR = 0x%04x)\n", stat);
817 		if (count++ == 100) {
818 			dev_warn(dev->dev, "Too much work in one IRQ\n");
819 			break;
820 		}
821 
822 		err = 0;
823 complete:
824 		/*
825 		 * Ack the stat in one go, but [R/X]DR and [R/X]RDY should be
826 		 * acked after the data operation is complete.
827 		 * Ref: TRM SWPU114Q Figure 18-31
828 		 */
829 		omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat &
830 				~(OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
831 				OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
832 
833 		if (stat & OMAP_I2C_STAT_NACK) {
834 			err |= OMAP_I2C_STAT_NACK;
835 			omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
836 					   OMAP_I2C_CON_STP);
837 		}
838 		if (stat & OMAP_I2C_STAT_AL) {
839 			dev_err(dev->dev, "Arbitration lost\n");
840 			err |= OMAP_I2C_STAT_AL;
841 		}
842 		/*
843 		 * ProDB0017052: Clear ARDY bit twice
844 		 */
845 		if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK |
846 					OMAP_I2C_STAT_AL)) {
847 			omap_i2c_ack_stat(dev, stat &
848 				(OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
849 				OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR |
850 				OMAP_I2C_STAT_ARDY));
851 			omap_i2c_complete_cmd(dev, err);
852 			return IRQ_HANDLED;
853 		}
854 		if (stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR)) {
855 			u8 num_bytes = 1;
856 
857 			if (dev->errata & I2C_OMAP_ERRATA_I207)
858 				i2c_omap_errata_i207(dev, stat);
859 
860 			if (dev->fifo_size) {
861 				if (stat & OMAP_I2C_STAT_RRDY)
862 					num_bytes = dev->fifo_size;
863 				else    /* read RXSTAT on RDR interrupt */
864 					num_bytes = (omap_i2c_read_reg(dev,
865 							OMAP_I2C_BUFSTAT_REG)
866 							>> 8) & 0x3F;
867 			}
868 			while (num_bytes) {
869 				num_bytes--;
870 				w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
871 				if (dev->buf_len) {
872 					*dev->buf++ = w;
873 					dev->buf_len--;
874 					/*
875 					 * Data reg in 2430, omap3 and
876 					 * omap4 is 8 bit wide
877 					 */
878 					if (pdata->flags &
879 						 OMAP_I2C_FLAG_16BIT_DATA_REG) {
880 						if (dev->buf_len) {
881 							*dev->buf++ = w >> 8;
882 							dev->buf_len--;
883 						}
884 					}
885 				} else {
886 					if (stat & OMAP_I2C_STAT_RRDY)
887 						dev_err(dev->dev,
888 							"RRDY IRQ while no data"
889 								" requested\n");
890 					if (stat & OMAP_I2C_STAT_RDR)
891 						dev_err(dev->dev,
892 							"RDR IRQ while no data"
893 								" requested\n");
894 					break;
895 				}
896 			}
897 			omap_i2c_ack_stat(dev,
898 				stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR));
899 			continue;
900 		}
901 		if (stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR)) {
902 			u8 num_bytes = 1;
903 			if (dev->fifo_size) {
904 				if (stat & OMAP_I2C_STAT_XRDY)
905 					num_bytes = dev->fifo_size;
906 				else    /* read TXSTAT on XDR interrupt */
907 					num_bytes = omap_i2c_read_reg(dev,
908 							OMAP_I2C_BUFSTAT_REG)
909 							& 0x3F;
910 			}
911 			while (num_bytes) {
912 				num_bytes--;
913 				w = 0;
914 				if (dev->buf_len) {
915 					w = *dev->buf++;
916 					dev->buf_len--;
917 					/*
918 					 * Data reg in 2430, omap3 and
919 					 * omap4 is 8 bit wide
920 					 */
921 					if (pdata->flags &
922 						 OMAP_I2C_FLAG_16BIT_DATA_REG) {
923 						if (dev->buf_len) {
924 							w |= *dev->buf++ << 8;
925 							dev->buf_len--;
926 						}
927 					}
928 				} else {
929 					if (stat & OMAP_I2C_STAT_XRDY)
930 						dev_err(dev->dev,
931 							"XRDY IRQ while no "
932 							"data to send\n");
933 					if (stat & OMAP_I2C_STAT_XDR)
934 						dev_err(dev->dev,
935 							"XDR IRQ while no "
936 							"data to send\n");
937 					break;
938 				}
939 
940 				if ((dev->errata & I2C_OMAP3_1P153) &&
941 				    errata_omap3_1p153(dev, &stat, &err))
942 					goto complete;
943 
944 				omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
945 			}
946 			omap_i2c_ack_stat(dev,
947 				stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
948 			continue;
949 		}
950 		if (stat & OMAP_I2C_STAT_ROVR) {
951 			dev_err(dev->dev, "Receive overrun\n");
952 			dev->cmd_err |= OMAP_I2C_STAT_ROVR;
953 		}
954 		if (stat & OMAP_I2C_STAT_XUDF) {
955 			dev_err(dev->dev, "Transmit underflow\n");
956 			dev->cmd_err |= OMAP_I2C_STAT_XUDF;
957 		}
958 	}
959 
960 	return count ? IRQ_HANDLED : IRQ_NONE;
961 }
962 
963 static const struct i2c_algorithm omap_i2c_algo = {
964 	.master_xfer	= omap_i2c_xfer,
965 	.functionality	= omap_i2c_func,
966 };
967 
968 static int __devinit
969 omap_i2c_probe(struct platform_device *pdev)
970 {
971 	struct omap_i2c_dev	*dev;
972 	struct i2c_adapter	*adap;
973 	struct resource		*mem, *irq, *ioarea;
974 	struct omap_i2c_bus_platform_data *pdata = pdev->dev.platform_data;
975 	irq_handler_t isr;
976 	int r;
977 	u32 speed = 0;
978 
979 	/* NOTE: driver uses the static register mapping */
980 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
981 	if (!mem) {
982 		dev_err(&pdev->dev, "no mem resource?\n");
983 		return -ENODEV;
984 	}
985 	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
986 	if (!irq) {
987 		dev_err(&pdev->dev, "no irq resource?\n");
988 		return -ENODEV;
989 	}
990 
991 	ioarea = request_mem_region(mem->start, resource_size(mem),
992 			pdev->name);
993 	if (!ioarea) {
994 		dev_err(&pdev->dev, "I2C region already claimed\n");
995 		return -EBUSY;
996 	}
997 
998 	dev = kzalloc(sizeof(struct omap_i2c_dev), GFP_KERNEL);
999 	if (!dev) {
1000 		r = -ENOMEM;
1001 		goto err_release_region;
1002 	}
1003 
1004 	if (pdata != NULL) {
1005 		speed = pdata->clkrate;
1006 		dev->set_mpu_wkup_lat = pdata->set_mpu_wkup_lat;
1007 	} else {
1008 		speed = 100;	/* Default speed */
1009 		dev->set_mpu_wkup_lat = NULL;
1010 	}
1011 
1012 	dev->speed = speed;
1013 	dev->dev = &pdev->dev;
1014 	dev->irq = irq->start;
1015 	dev->base = ioremap(mem->start, resource_size(mem));
1016 	if (!dev->base) {
1017 		r = -ENOMEM;
1018 		goto err_free_mem;
1019 	}
1020 
1021 	platform_set_drvdata(pdev, dev);
1022 
1023 	dev->reg_shift = (pdata->flags >> OMAP_I2C_FLAG_BUS_SHIFT__SHIFT) & 3;
1024 
1025 	if (pdata->rev == OMAP_I2C_IP_VERSION_2)
1026 		dev->regs = (u8 *)reg_map_ip_v2;
1027 	else
1028 		dev->regs = (u8 *)reg_map_ip_v1;
1029 
1030 	pm_runtime_enable(dev->dev);
1031 	pm_runtime_get_sync(dev->dev);
1032 
1033 	dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
1034 
1035 	if (dev->rev <= OMAP_I2C_REV_ON_3430)
1036 		dev->errata |= I2C_OMAP3_1P153;
1037 
1038 	if (!(pdata->flags & OMAP_I2C_FLAG_NO_FIFO)) {
1039 		u16 s;
1040 
1041 		/* Set up the fifo size - Get total size */
1042 		s = (omap_i2c_read_reg(dev, OMAP_I2C_BUFSTAT_REG) >> 14) & 0x3;
1043 		dev->fifo_size = 0x8 << s;
1044 
1045 		/*
1046 		 * Set up notification threshold as half the total available
1047 		 * size. This is to ensure that we can handle the status on int
1048 		 * call back latencies.
1049 		 */
1050 		if (dev->rev >= OMAP_I2C_REV_ON_3530_4430) {
1051 			dev->fifo_size = 0;
1052 			dev->b_hw = 0; /* Disable hardware fixes */
1053 		} else {
1054 			dev->fifo_size = (dev->fifo_size / 2);
1055 			dev->b_hw = 1; /* Enable hardware fixes */
1056 		}
1057 		/* calculate wakeup latency constraint for MPU */
1058 		if (dev->set_mpu_wkup_lat != NULL)
1059 			dev->latency = (1000000 * dev->fifo_size) /
1060 				       (1000 * speed / 8);
1061 	}
1062 
1063 	/* reset ASAP, clearing any IRQs */
1064 	omap_i2c_init(dev);
1065 
1066 	isr = (dev->rev < OMAP_I2C_OMAP1_REV_2) ? omap_i2c_omap1_isr :
1067 								   omap_i2c_isr;
1068 	r = request_irq(dev->irq, isr, 0, pdev->name, dev);
1069 
1070 	if (r) {
1071 		dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
1072 		goto err_unuse_clocks;
1073 	}
1074 
1075 	dev_info(dev->dev, "bus %d rev%d.%d.%d at %d kHz\n", pdev->id,
1076 		 pdata->rev, dev->rev >> 4, dev->rev & 0xf, dev->speed);
1077 
1078 	pm_runtime_put(dev->dev);
1079 
1080 	adap = &dev->adapter;
1081 	i2c_set_adapdata(adap, dev);
1082 	adap->owner = THIS_MODULE;
1083 	adap->class = I2C_CLASS_HWMON;
1084 	strlcpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
1085 	adap->algo = &omap_i2c_algo;
1086 	adap->dev.parent = &pdev->dev;
1087 
1088 	/* i2c device drivers may be active on return from add_adapter() */
1089 	adap->nr = pdev->id;
1090 	r = i2c_add_numbered_adapter(adap);
1091 	if (r) {
1092 		dev_err(dev->dev, "failure adding adapter\n");
1093 		goto err_free_irq;
1094 	}
1095 
1096 	return 0;
1097 
1098 err_free_irq:
1099 	free_irq(dev->irq, dev);
1100 err_unuse_clocks:
1101 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
1102 	pm_runtime_put(dev->dev);
1103 	iounmap(dev->base);
1104 err_free_mem:
1105 	platform_set_drvdata(pdev, NULL);
1106 	kfree(dev);
1107 err_release_region:
1108 	release_mem_region(mem->start, resource_size(mem));
1109 
1110 	return r;
1111 }
1112 
1113 static int
1114 omap_i2c_remove(struct platform_device *pdev)
1115 {
1116 	struct omap_i2c_dev	*dev = platform_get_drvdata(pdev);
1117 	struct resource		*mem;
1118 
1119 	platform_set_drvdata(pdev, NULL);
1120 
1121 	free_irq(dev->irq, dev);
1122 	i2c_del_adapter(&dev->adapter);
1123 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
1124 	iounmap(dev->base);
1125 	kfree(dev);
1126 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1127 	release_mem_region(mem->start, resource_size(mem));
1128 	return 0;
1129 }
1130 
1131 #ifdef CONFIG_PM_RUNTIME
1132 static int omap_i2c_runtime_suspend(struct device *dev)
1133 {
1134 	struct platform_device *pdev = to_platform_device(dev);
1135 	struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);
1136 
1137 	omap_i2c_idle(_dev);
1138 
1139 	return 0;
1140 }
1141 
1142 static int omap_i2c_runtime_resume(struct device *dev)
1143 {
1144 	struct platform_device *pdev = to_platform_device(dev);
1145 	struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);
1146 
1147 	omap_i2c_unidle(_dev);
1148 
1149 	return 0;
1150 }
1151 
1152 static struct dev_pm_ops omap_i2c_pm_ops = {
1153 	.runtime_suspend = omap_i2c_runtime_suspend,
1154 	.runtime_resume = omap_i2c_runtime_resume,
1155 };
1156 #define OMAP_I2C_PM_OPS (&omap_i2c_pm_ops)
1157 #else
1158 #define OMAP_I2C_PM_OPS NULL
1159 #endif
1160 
1161 static struct platform_driver omap_i2c_driver = {
1162 	.probe		= omap_i2c_probe,
1163 	.remove		= omap_i2c_remove,
1164 	.driver		= {
1165 		.name	= "omap_i2c",
1166 		.owner	= THIS_MODULE,
1167 		.pm	= OMAP_I2C_PM_OPS,
1168 	},
1169 };
1170 
1171 /* I2C may be needed to bring up other drivers */
1172 static int __init
1173 omap_i2c_init_driver(void)
1174 {
1175 	return platform_driver_register(&omap_i2c_driver);
1176 }
1177 subsys_initcall(omap_i2c_init_driver);
1178 
1179 static void __exit omap_i2c_exit_driver(void)
1180 {
1181 	platform_driver_unregister(&omap_i2c_driver);
1182 }
1183 module_exit(omap_i2c_exit_driver);
1184 
1185 MODULE_AUTHOR("MontaVista Software, Inc. (and others)");
1186 MODULE_DESCRIPTION("TI OMAP I2C bus adapter");
1187 MODULE_LICENSE("GPL");
1188 MODULE_ALIAS("platform:omap_i2c");
1189