xref: /openbmc/linux/drivers/i2c/busses/i2c-eg20t.c (revision 9c1f8594)
1 /*
2  * Copyright (C) 2010 OKI SEMICONDUCTOR CO., LTD.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; version 2 of the License.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public License
14  * along with this program; if not, write to the Free Software
15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA.
16  */
17 
18 #include <linux/module.h>
19 #include <linux/kernel.h>
20 #include <linux/delay.h>
21 #include <linux/init.h>
22 #include <linux/errno.h>
23 #include <linux/i2c.h>
24 #include <linux/fs.h>
25 #include <linux/io.h>
26 #include <linux/types.h>
27 #include <linux/interrupt.h>
28 #include <linux/jiffies.h>
29 #include <linux/pci.h>
30 #include <linux/mutex.h>
31 #include <linux/ktime.h>
32 #include <linux/slab.h>
33 
34 #define PCH_EVENT_SET	0	/* I2C Interrupt Event Set Status */
35 #define PCH_EVENT_NONE	1	/* I2C Interrupt Event Clear Status */
36 #define PCH_MAX_CLK		100000	/* Maximum Clock speed in MHz */
37 #define PCH_BUFFER_MODE_ENABLE	0x0002	/* flag for Buffer mode enable */
38 #define PCH_EEPROM_SW_RST_MODE_ENABLE	0x0008	/* EEPROM SW RST enable flag */
39 
40 #define PCH_I2CSADR	0x00	/* I2C slave address register */
41 #define PCH_I2CCTL	0x04	/* I2C control register */
42 #define PCH_I2CSR	0x08	/* I2C status register */
43 #define PCH_I2CDR	0x0C	/* I2C data register */
44 #define PCH_I2CMON	0x10	/* I2C bus monitor register */
45 #define PCH_I2CBC	0x14	/* I2C bus transfer rate setup counter */
46 #define PCH_I2CMOD	0x18	/* I2C mode register */
47 #define PCH_I2CBUFSLV	0x1C	/* I2C buffer mode slave address register */
48 #define PCH_I2CBUFSUB	0x20	/* I2C buffer mode subaddress register */
49 #define PCH_I2CBUFFOR	0x24	/* I2C buffer mode format register */
50 #define PCH_I2CBUFCTL	0x28	/* I2C buffer mode control register */
51 #define PCH_I2CBUFMSK	0x2C	/* I2C buffer mode interrupt mask register */
52 #define PCH_I2CBUFSTA	0x30	/* I2C buffer mode status register */
53 #define PCH_I2CBUFLEV	0x34	/* I2C buffer mode level register */
54 #define PCH_I2CESRFOR	0x38	/* EEPROM software reset mode format register */
55 #define PCH_I2CESRCTL	0x3C	/* EEPROM software reset mode ctrl register */
56 #define PCH_I2CESRMSK	0x40	/* EEPROM software reset mode */
57 #define PCH_I2CESRSTA	0x44	/* EEPROM software reset mode status register */
58 #define PCH_I2CTMR	0x48	/* I2C timer register */
59 #define PCH_I2CSRST	0xFC	/* I2C reset register */
60 #define PCH_I2CNF	0xF8	/* I2C noise filter register */
61 
62 #define BUS_IDLE_TIMEOUT	20
63 #define PCH_I2CCTL_I2CMEN	0x0080
64 #define TEN_BIT_ADDR_DEFAULT	0xF000
65 #define TEN_BIT_ADDR_MASK	0xF0
66 #define PCH_START		0x0020
67 #define PCH_ESR_START		0x0001
68 #define PCH_BUFF_START		0x1
69 #define PCH_REPSTART		0x0004
70 #define PCH_ACK			0x0008
71 #define PCH_GETACK		0x0001
72 #define CLR_REG			0x0
73 #define I2C_RD			0x1
74 #define I2CMCF_BIT		0x0080
75 #define I2CMIF_BIT		0x0002
76 #define I2CMAL_BIT		0x0010
77 #define I2CBMFI_BIT		0x0001
78 #define I2CBMAL_BIT		0x0002
79 #define I2CBMNA_BIT		0x0004
80 #define I2CBMTO_BIT		0x0008
81 #define I2CBMIS_BIT		0x0010
82 #define I2CESRFI_BIT		0X0001
83 #define I2CESRTO_BIT		0x0002
84 #define I2CESRFIIE_BIT		0x1
85 #define I2CESRTOIE_BIT		0x2
86 #define I2CBMDZ_BIT		0x0040
87 #define I2CBMAG_BIT		0x0020
88 #define I2CMBB_BIT		0x0020
89 #define BUFFER_MODE_MASK	(I2CBMFI_BIT | I2CBMAL_BIT | I2CBMNA_BIT | \
90 				I2CBMTO_BIT | I2CBMIS_BIT)
91 #define I2C_ADDR_MSK		0xFF
92 #define I2C_MSB_2B_MSK		0x300
93 #define FAST_MODE_CLK		400
94 #define FAST_MODE_EN		0x0001
95 #define SUB_ADDR_LEN_MAX	4
96 #define BUF_LEN_MAX		32
97 #define PCH_BUFFER_MODE		0x1
98 #define EEPROM_SW_RST_MODE	0x0002
99 #define NORMAL_INTR_ENBL	0x0300
100 #define EEPROM_RST_INTR_ENBL	(I2CESRFIIE_BIT | I2CESRTOIE_BIT)
101 #define EEPROM_RST_INTR_DISBL	0x0
102 #define BUFFER_MODE_INTR_ENBL	0x001F
103 #define BUFFER_MODE_INTR_DISBL	0x0
104 #define NORMAL_MODE		0x0
105 #define BUFFER_MODE		0x1
106 #define EEPROM_SR_MODE		0x2
107 #define I2C_TX_MODE		0x0010
108 #define PCH_BUF_TX		0xFFF7
109 #define PCH_BUF_RD		0x0008
110 #define I2C_ERROR_MASK	(I2CESRTO_EVENT | I2CBMIS_EVENT | I2CBMTO_EVENT | \
111 			I2CBMNA_EVENT | I2CBMAL_EVENT | I2CMAL_EVENT)
112 #define I2CMAL_EVENT		0x0001
113 #define I2CMCF_EVENT		0x0002
114 #define I2CBMFI_EVENT		0x0004
115 #define I2CBMAL_EVENT		0x0008
116 #define I2CBMNA_EVENT		0x0010
117 #define I2CBMTO_EVENT		0x0020
118 #define I2CBMIS_EVENT		0x0040
119 #define I2CESRFI_EVENT		0x0080
120 #define I2CESRTO_EVENT		0x0100
121 #define PCI_DEVICE_ID_PCH_I2C	0x8817
122 
123 #define pch_dbg(adap, fmt, arg...)  \
124 	dev_dbg(adap->pch_adapter.dev.parent, "%s :" fmt, __func__, ##arg)
125 
126 #define pch_err(adap, fmt, arg...)  \
127 	dev_err(adap->pch_adapter.dev.parent, "%s :" fmt, __func__, ##arg)
128 
129 #define pch_pci_err(pdev, fmt, arg...)  \
130 	dev_err(&pdev->dev, "%s :" fmt, __func__, ##arg)
131 
132 #define pch_pci_dbg(pdev, fmt, arg...)  \
133 	dev_dbg(&pdev->dev, "%s :" fmt, __func__, ##arg)
134 
135 /*
136 Set the number of I2C instance max
137 Intel EG20T PCH :		1ch
138 OKI SEMICONDUCTOR ML7213 IOH :	2ch
139 */
140 #define PCH_I2C_MAX_DEV			2
141 
142 /**
143  * struct i2c_algo_pch_data - for I2C driver functionalities
144  * @pch_adapter:		stores the reference to i2c_adapter structure
145  * @p_adapter_info:		stores the reference to adapter_info structure
146  * @pch_base_address:		specifies the remapped base address
147  * @pch_buff_mode_en:		specifies if buffer mode is enabled
148  * @pch_event_flag:		specifies occurrence of interrupt events
149  * @pch_i2c_xfer_in_progress:	specifies whether the transfer is completed
150  */
151 struct i2c_algo_pch_data {
152 	struct i2c_adapter pch_adapter;
153 	struct adapter_info *p_adapter_info;
154 	void __iomem *pch_base_address;
155 	int pch_buff_mode_en;
156 	u32 pch_event_flag;
157 	bool pch_i2c_xfer_in_progress;
158 };
159 
160 /**
161  * struct adapter_info - This structure holds the adapter information for the
162 			 PCH i2c controller
163  * @pch_data:		stores a list of i2c_algo_pch_data
164  * @pch_i2c_suspended:	specifies whether the system is suspended or not
165  *			perhaps with more lines and words.
166  * @ch_num:		specifies the number of i2c instance
167  *
168  * pch_data has as many elements as maximum I2C channels
169  */
170 struct adapter_info {
171 	struct i2c_algo_pch_data pch_data[PCH_I2C_MAX_DEV];
172 	bool pch_i2c_suspended;
173 	int ch_num;
174 };
175 
176 
177 static int pch_i2c_speed = 100; /* I2C bus speed in Kbps */
178 static int pch_clk = 50000;	/* specifies I2C clock speed in KHz */
179 static wait_queue_head_t pch_event;
180 static DEFINE_MUTEX(pch_mutex);
181 
182 /* Definition for ML7213 by OKI SEMICONDUCTOR */
183 #define PCI_VENDOR_ID_ROHM		0x10DB
184 #define PCI_DEVICE_ID_ML7213_I2C	0x802D
185 #define PCI_DEVICE_ID_ML7223_I2C	0x8010
186 
187 static struct pci_device_id __devinitdata pch_pcidev_id[] = {
188 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_PCH_I2C),   1, },
189 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_I2C), 2, },
190 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_I2C), 1, },
191 	{0,}
192 };
193 
194 static irqreturn_t pch_i2c_handler(int irq, void *pData);
195 
196 static inline void pch_setbit(void __iomem *addr, u32 offset, u32 bitmask)
197 {
198 	u32 val;
199 	val = ioread32(addr + offset);
200 	val |= bitmask;
201 	iowrite32(val, addr + offset);
202 }
203 
204 static inline void pch_clrbit(void __iomem *addr, u32 offset, u32 bitmask)
205 {
206 	u32 val;
207 	val = ioread32(addr + offset);
208 	val &= (~bitmask);
209 	iowrite32(val, addr + offset);
210 }
211 
212 /**
213  * pch_i2c_init() - hardware initialization of I2C module
214  * @adap:	Pointer to struct i2c_algo_pch_data.
215  */
216 static void pch_i2c_init(struct i2c_algo_pch_data *adap)
217 {
218 	void __iomem *p = adap->pch_base_address;
219 	u32 pch_i2cbc;
220 	u32 pch_i2ctmr;
221 	u32 reg_value;
222 
223 	/* reset I2C controller */
224 	iowrite32(0x01, p + PCH_I2CSRST);
225 	msleep(20);
226 	iowrite32(0x0, p + PCH_I2CSRST);
227 
228 	/* Initialize I2C registers */
229 	iowrite32(0x21, p + PCH_I2CNF);
230 
231 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_I2CCTL_I2CMEN);
232 
233 	if (pch_i2c_speed != 400)
234 		pch_i2c_speed = 100;
235 
236 	reg_value = PCH_I2CCTL_I2CMEN;
237 	if (pch_i2c_speed == FAST_MODE_CLK) {
238 		reg_value |= FAST_MODE_EN;
239 		pch_dbg(adap, "Fast mode enabled\n");
240 	}
241 
242 	if (pch_clk > PCH_MAX_CLK)
243 		pch_clk = 62500;
244 
245 	pch_i2cbc = (pch_clk + (pch_i2c_speed * 4)) / pch_i2c_speed * 8;
246 	/* Set transfer speed in I2CBC */
247 	iowrite32(pch_i2cbc, p + PCH_I2CBC);
248 
249 	pch_i2ctmr = (pch_clk) / 8;
250 	iowrite32(pch_i2ctmr, p + PCH_I2CTMR);
251 
252 	reg_value |= NORMAL_INTR_ENBL;	/* Enable interrupts in normal mode */
253 	iowrite32(reg_value, p + PCH_I2CCTL);
254 
255 	pch_dbg(adap,
256 		"I2CCTL=%x pch_i2cbc=%x pch_i2ctmr=%x Enable interrupts\n",
257 		ioread32(p + PCH_I2CCTL), pch_i2cbc, pch_i2ctmr);
258 
259 	init_waitqueue_head(&pch_event);
260 }
261 
262 static inline bool ktime_lt(const ktime_t cmp1, const ktime_t cmp2)
263 {
264 	return cmp1.tv64 < cmp2.tv64;
265 }
266 
267 /**
268  * pch_i2c_wait_for_bus_idle() - check the status of bus.
269  * @adap:	Pointer to struct i2c_algo_pch_data.
270  * @timeout:	waiting time counter (us).
271  */
272 static s32 pch_i2c_wait_for_bus_idle(struct i2c_algo_pch_data *adap,
273 				     s32 timeout)
274 {
275 	void __iomem *p = adap->pch_base_address;
276 
277 	/* MAX timeout value is timeout*1000*1000nsec */
278 	ktime_t ns_val = ktime_add_ns(ktime_get(), timeout*1000*1000);
279 	do {
280 		if ((ioread32(p + PCH_I2CSR) & I2CMBB_BIT) == 0)
281 			break;
282 		msleep(20);
283 	} while (ktime_lt(ktime_get(), ns_val));
284 
285 	pch_dbg(adap, "I2CSR = %x\n", ioread32(p + PCH_I2CSR));
286 
287 	if (timeout == 0) {
288 		pch_err(adap, "%s: Timeout Error.return%d\n", __func__, -ETIME);
289 		return -ETIME;
290 	}
291 
292 	return 0;
293 }
294 
295 /**
296  * pch_i2c_start() - Generate I2C start condition in normal mode.
297  * @adap:	Pointer to struct i2c_algo_pch_data.
298  *
299  * Generate I2C start condition in normal mode by setting I2CCTL.I2CMSTA to 1.
300  */
301 static void pch_i2c_start(struct i2c_algo_pch_data *adap)
302 {
303 	void __iomem *p = adap->pch_base_address;
304 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
305 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_START);
306 }
307 
308 /**
309  * pch_i2c_wait_for_xfer_complete() - initiates a wait for the tx complete event
310  * @adap:	Pointer to struct i2c_algo_pch_data.
311  */
312 static s32 pch_i2c_wait_for_xfer_complete(struct i2c_algo_pch_data *adap)
313 {
314 	s32 ret;
315 	ret = wait_event_timeout(pch_event,
316 			(adap->pch_event_flag != 0), msecs_to_jiffies(50));
317 	if (ret < 0) {
318 		pch_err(adap, "timeout: %x\n", adap->pch_event_flag);
319 		return ret;
320 	}
321 
322 	if (ret == 0) {
323 		pch_err(adap, "timeout: %x\n", adap->pch_event_flag);
324 		return -ETIMEDOUT;
325 	}
326 
327 	if (adap->pch_event_flag & I2C_ERROR_MASK) {
328 		pch_err(adap, "error bits set: %x\n", adap->pch_event_flag);
329 		return -EIO;
330 	}
331 
332 	adap->pch_event_flag = 0;
333 
334 	return 0;
335 }
336 
337 /**
338  * pch_i2c_getack() - to confirm ACK/NACK
339  * @adap:	Pointer to struct i2c_algo_pch_data.
340  */
341 static s32 pch_i2c_getack(struct i2c_algo_pch_data *adap)
342 {
343 	u32 reg_val;
344 	void __iomem *p = adap->pch_base_address;
345 	reg_val = ioread32(p + PCH_I2CSR) & PCH_GETACK;
346 
347 	if (reg_val != 0) {
348 		pch_err(adap, "return%d\n", -EPROTO);
349 		return -EPROTO;
350 	}
351 
352 	return 0;
353 }
354 
355 /**
356  * pch_i2c_stop() - generate stop condition in normal mode.
357  * @adap:	Pointer to struct i2c_algo_pch_data.
358  */
359 static void pch_i2c_stop(struct i2c_algo_pch_data *adap)
360 {
361 	void __iomem *p = adap->pch_base_address;
362 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
363 	/* clear the start bit */
364 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, PCH_START);
365 }
366 
367 /**
368  * pch_i2c_repstart() - generate repeated start condition in normal mode
369  * @adap:	Pointer to struct i2c_algo_pch_data.
370  */
371 static void pch_i2c_repstart(struct i2c_algo_pch_data *adap)
372 {
373 	void __iomem *p = adap->pch_base_address;
374 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
375 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_REPSTART);
376 }
377 
378 /**
379  * pch_i2c_writebytes() - write data to I2C bus in normal mode
380  * @i2c_adap:	Pointer to the struct i2c_adapter.
381  * @last:	specifies whether last message or not.
382  *		In the case of compound mode it will be 1 for last message,
383  *		otherwise 0.
384  * @first:	specifies whether first message or not.
385  *		1 for first message otherwise 0.
386  */
387 static s32 pch_i2c_writebytes(struct i2c_adapter *i2c_adap,
388 			      struct i2c_msg *msgs, u32 last, u32 first)
389 {
390 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
391 	u8 *buf;
392 	u32 length;
393 	u32 addr;
394 	u32 addr_2_msb;
395 	u32 addr_8_lsb;
396 	s32 wrcount;
397 	void __iomem *p = adap->pch_base_address;
398 
399 	length = msgs->len;
400 	buf = msgs->buf;
401 	addr = msgs->addr;
402 
403 	/* enable master tx */
404 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, I2C_TX_MODE);
405 
406 	pch_dbg(adap, "I2CCTL = %x msgs->len = %d\n", ioread32(p + PCH_I2CCTL),
407 		length);
408 
409 	if (first) {
410 		if (pch_i2c_wait_for_bus_idle(adap, BUS_IDLE_TIMEOUT) == -ETIME)
411 			return -ETIME;
412 	}
413 
414 	if (msgs->flags & I2C_M_TEN) {
415 		addr_2_msb = ((addr & I2C_MSB_2B_MSK) >> 7);
416 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
417 		if (first)
418 			pch_i2c_start(adap);
419 		if (pch_i2c_wait_for_xfer_complete(adap) == 0 &&
420 		    pch_i2c_getack(adap) == 0) {
421 			addr_8_lsb = (addr & I2C_ADDR_MSK);
422 			iowrite32(addr_8_lsb, p + PCH_I2CDR);
423 		} else {
424 			pch_i2c_stop(adap);
425 			return -ETIME;
426 		}
427 	} else {
428 		/* set 7 bit slave address and R/W bit as 0 */
429 		iowrite32(addr << 1, p + PCH_I2CDR);
430 		if (first)
431 			pch_i2c_start(adap);
432 	}
433 
434 	if ((pch_i2c_wait_for_xfer_complete(adap) == 0) &&
435 	    (pch_i2c_getack(adap) == 0)) {
436 		for (wrcount = 0; wrcount < length; ++wrcount) {
437 			/* write buffer value to I2C data register */
438 			iowrite32(buf[wrcount], p + PCH_I2CDR);
439 			pch_dbg(adap, "writing %x to Data register\n",
440 				buf[wrcount]);
441 
442 			if (pch_i2c_wait_for_xfer_complete(adap) != 0)
443 				return -ETIME;
444 
445 			if (pch_i2c_getack(adap))
446 				return -EIO;
447 		}
448 
449 		/* check if this is the last message */
450 		if (last)
451 			pch_i2c_stop(adap);
452 		else
453 			pch_i2c_repstart(adap);
454 	} else {
455 		pch_i2c_stop(adap);
456 		return -EIO;
457 	}
458 
459 	pch_dbg(adap, "return=%d\n", wrcount);
460 
461 	return wrcount;
462 }
463 
464 /**
465  * pch_i2c_sendack() - send ACK
466  * @adap:	Pointer to struct i2c_algo_pch_data.
467  */
468 static void pch_i2c_sendack(struct i2c_algo_pch_data *adap)
469 {
470 	void __iomem *p = adap->pch_base_address;
471 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
472 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
473 }
474 
475 /**
476  * pch_i2c_sendnack() - send NACK
477  * @adap:	Pointer to struct i2c_algo_pch_data.
478  */
479 static void pch_i2c_sendnack(struct i2c_algo_pch_data *adap)
480 {
481 	void __iomem *p = adap->pch_base_address;
482 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
483 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
484 }
485 
486 /**
487  * pch_i2c_readbytes() - read data  from I2C bus in normal mode.
488  * @i2c_adap:	Pointer to the struct i2c_adapter.
489  * @msgs:	Pointer to i2c_msg structure.
490  * @last:	specifies whether last message or not.
491  * @first:	specifies whether first message or not.
492  */
493 static s32 pch_i2c_readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
494 			     u32 last, u32 first)
495 {
496 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
497 
498 	u8 *buf;
499 	u32 count;
500 	u32 length;
501 	u32 addr;
502 	u32 addr_2_msb;
503 	void __iomem *p = adap->pch_base_address;
504 
505 	length = msgs->len;
506 	buf = msgs->buf;
507 	addr = msgs->addr;
508 
509 	/* enable master reception */
510 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, I2C_TX_MODE);
511 
512 	if (first) {
513 		if (pch_i2c_wait_for_bus_idle(adap, BUS_IDLE_TIMEOUT) == -ETIME)
514 			return -ETIME;
515 	}
516 
517 	if (msgs->flags & I2C_M_TEN) {
518 		addr_2_msb = (((addr & I2C_MSB_2B_MSK) >> 7) | (I2C_RD));
519 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
520 
521 	} else {
522 		/* 7 address bits + R/W bit */
523 		addr = (((addr) << 1) | (I2C_RD));
524 		iowrite32(addr, p + PCH_I2CDR);
525 	}
526 
527 	/* check if it is the first message */
528 	if (first)
529 		pch_i2c_start(adap);
530 
531 	if ((pch_i2c_wait_for_xfer_complete(adap) == 0) &&
532 	    (pch_i2c_getack(adap) == 0)) {
533 		pch_dbg(adap, "return %d\n", 0);
534 
535 		if (length == 0) {
536 			pch_i2c_stop(adap);
537 			ioread32(p + PCH_I2CDR); /* Dummy read needs */
538 
539 			count = length;
540 		} else {
541 			int read_index;
542 			int loop;
543 			pch_i2c_sendack(adap);
544 
545 			/* Dummy read */
546 			for (loop = 1, read_index = 0; loop < length; loop++) {
547 				buf[read_index] = ioread32(p + PCH_I2CDR);
548 
549 				if (loop != 1)
550 					read_index++;
551 
552 				if (pch_i2c_wait_for_xfer_complete(adap) != 0) {
553 					pch_i2c_stop(adap);
554 					return -ETIME;
555 				}
556 			}	/* end for */
557 
558 			pch_i2c_sendnack(adap);
559 
560 			buf[read_index] = ioread32(p + PCH_I2CDR);
561 
562 			if (length != 1)
563 				read_index++;
564 
565 			if (pch_i2c_wait_for_xfer_complete(adap) == 0) {
566 				if (last)
567 					pch_i2c_stop(adap);
568 				else
569 					pch_i2c_repstart(adap);
570 
571 				buf[read_index++] = ioread32(p + PCH_I2CDR);
572 				count = read_index;
573 			} else {
574 				count = -ETIME;
575 			}
576 
577 		}
578 	} else {
579 		count = -ETIME;
580 		pch_i2c_stop(adap);
581 	}
582 
583 	return count;
584 }
585 
586 /**
587  * pch_i2c_cb() - Interrupt handler Call back function
588  * @adap:	Pointer to struct i2c_algo_pch_data.
589  */
590 static void pch_i2c_cb(struct i2c_algo_pch_data *adap)
591 {
592 	u32 sts;
593 	void __iomem *p = adap->pch_base_address;
594 
595 	sts = ioread32(p + PCH_I2CSR);
596 	sts &= (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT);
597 	if (sts & I2CMAL_BIT)
598 		adap->pch_event_flag |= I2CMAL_EVENT;
599 
600 	if (sts & I2CMCF_BIT)
601 		adap->pch_event_flag |= I2CMCF_EVENT;
602 
603 	/* clear the applicable bits */
604 	pch_clrbit(adap->pch_base_address, PCH_I2CSR, sts);
605 
606 	pch_dbg(adap, "PCH_I2CSR = %x\n", ioread32(p + PCH_I2CSR));
607 
608 	wake_up(&pch_event);
609 }
610 
611 /**
612  * pch_i2c_handler() - interrupt handler for the PCH I2C controller
613  * @irq:	irq number.
614  * @pData:	cookie passed back to the handler function.
615  */
616 static irqreturn_t pch_i2c_handler(int irq, void *pData)
617 {
618 	u32 reg_val;
619 	int flag;
620 	int i;
621 	struct adapter_info *adap_info = pData;
622 	void __iomem *p;
623 	u32 mode;
624 
625 	for (i = 0, flag = 0; i < adap_info->ch_num; i++) {
626 		p = adap_info->pch_data[i].pch_base_address;
627 		mode = ioread32(p + PCH_I2CMOD);
628 		mode &= BUFFER_MODE | EEPROM_SR_MODE;
629 		if (mode != NORMAL_MODE) {
630 			pch_err(adap_info->pch_data,
631 				"I2C-%d mode(%d) is not supported\n", mode, i);
632 			continue;
633 		}
634 		reg_val = ioread32(p + PCH_I2CSR);
635 		if (reg_val & (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT)) {
636 			pch_i2c_cb(&adap_info->pch_data[i]);
637 			flag = 1;
638 		}
639 	}
640 
641 	return flag ? IRQ_HANDLED : IRQ_NONE;
642 }
643 
644 /**
645  * pch_i2c_xfer() - Reading adnd writing data through I2C bus
646  * @i2c_adap:	Pointer to the struct i2c_adapter.
647  * @msgs:	Pointer to i2c_msg structure.
648  * @num:	number of messages.
649  */
650 static s32 pch_i2c_xfer(struct i2c_adapter *i2c_adap,
651 			struct i2c_msg *msgs, s32 num)
652 {
653 	struct i2c_msg *pmsg;
654 	u32 i = 0;
655 	u32 status;
656 	u32 msglen;
657 	u32 subaddrlen;
658 	s32 ret;
659 
660 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
661 
662 	ret = mutex_lock_interruptible(&pch_mutex);
663 	if (ret)
664 		return -ERESTARTSYS;
665 
666 	if (adap->p_adapter_info->pch_i2c_suspended) {
667 		mutex_unlock(&pch_mutex);
668 		return -EBUSY;
669 	}
670 
671 	pch_dbg(adap, "adap->p_adapter_info->pch_i2c_suspended is %d\n",
672 		adap->p_adapter_info->pch_i2c_suspended);
673 	/* transfer not completed */
674 	adap->pch_i2c_xfer_in_progress = true;
675 
676 	for (i = 0; i < num && ret >= 0; i++) {
677 		pmsg = &msgs[i];
678 		pmsg->flags |= adap->pch_buff_mode_en;
679 		status = pmsg->flags;
680 		pch_dbg(adap,
681 			"After invoking I2C_MODE_SEL :flag= 0x%x\n", status);
682 		/* calculate sub address length and message length */
683 		/* these are applicable only for buffer mode */
684 		subaddrlen = pmsg->buf[0];
685 		/* calculate actual message length excluding
686 		 * the sub address fields */
687 		msglen = (pmsg->len) - (subaddrlen + 1);
688 
689 		if ((status & (I2C_M_RD)) != false) {
690 			ret = pch_i2c_readbytes(i2c_adap, pmsg, (i + 1 == num),
691 						(i == 0));
692 		} else {
693 			ret = pch_i2c_writebytes(i2c_adap, pmsg, (i + 1 == num),
694 						 (i == 0));
695 		}
696 	}
697 
698 	adap->pch_i2c_xfer_in_progress = false;	/* transfer completed */
699 
700 	mutex_unlock(&pch_mutex);
701 
702 	return (ret < 0) ? ret : num;
703 }
704 
705 /**
706  * pch_i2c_func() - return the functionality of the I2C driver
707  * @adap:	Pointer to struct i2c_algo_pch_data.
708  */
709 static u32 pch_i2c_func(struct i2c_adapter *adap)
710 {
711 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
712 }
713 
714 static struct i2c_algorithm pch_algorithm = {
715 	.master_xfer = pch_i2c_xfer,
716 	.functionality = pch_i2c_func
717 };
718 
719 /**
720  * pch_i2c_disbl_int() - Disable PCH I2C interrupts
721  * @adap:	Pointer to struct i2c_algo_pch_data.
722  */
723 static void pch_i2c_disbl_int(struct i2c_algo_pch_data *adap)
724 {
725 	void __iomem *p = adap->pch_base_address;
726 
727 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, NORMAL_INTR_ENBL);
728 
729 	iowrite32(EEPROM_RST_INTR_DISBL, p + PCH_I2CESRMSK);
730 
731 	iowrite32(BUFFER_MODE_INTR_DISBL, p + PCH_I2CBUFMSK);
732 }
733 
734 static int __devinit pch_i2c_probe(struct pci_dev *pdev,
735 				   const struct pci_device_id *id)
736 {
737 	void __iomem *base_addr;
738 	int ret;
739 	int i, j;
740 	struct adapter_info *adap_info;
741 	struct i2c_adapter *pch_adap;
742 
743 	pch_pci_dbg(pdev, "Entered.\n");
744 
745 	adap_info = kzalloc((sizeof(struct adapter_info)), GFP_KERNEL);
746 	if (adap_info == NULL) {
747 		pch_pci_err(pdev, "Memory allocation FAILED\n");
748 		return -ENOMEM;
749 	}
750 
751 	ret = pci_enable_device(pdev);
752 	if (ret) {
753 		pch_pci_err(pdev, "pci_enable_device FAILED\n");
754 		goto err_pci_enable;
755 	}
756 
757 	ret = pci_request_regions(pdev, KBUILD_MODNAME);
758 	if (ret) {
759 		pch_pci_err(pdev, "pci_request_regions FAILED\n");
760 		goto err_pci_req;
761 	}
762 
763 	base_addr = pci_iomap(pdev, 1, 0);
764 
765 	if (base_addr == NULL) {
766 		pch_pci_err(pdev, "pci_iomap FAILED\n");
767 		ret = -ENOMEM;
768 		goto err_pci_iomap;
769 	}
770 
771 	/* Set the number of I2C channel instance */
772 	adap_info->ch_num = id->driver_data;
773 
774 	for (i = 0; i < adap_info->ch_num; i++) {
775 		pch_adap = &adap_info->pch_data[i].pch_adapter;
776 		adap_info->pch_i2c_suspended = false;
777 
778 		adap_info->pch_data[i].p_adapter_info = adap_info;
779 
780 		pch_adap->owner = THIS_MODULE;
781 		pch_adap->class = I2C_CLASS_HWMON;
782 		strcpy(pch_adap->name, KBUILD_MODNAME);
783 		pch_adap->algo = &pch_algorithm;
784 		pch_adap->algo_data = &adap_info->pch_data[i];
785 
786 		/* base_addr + offset; */
787 		adap_info->pch_data[i].pch_base_address = base_addr + 0x100 * i;
788 
789 		pch_adap->dev.parent = &pdev->dev;
790 
791 		ret = i2c_add_adapter(pch_adap);
792 		if (ret) {
793 			pch_pci_err(pdev, "i2c_add_adapter[ch:%d] FAILED\n", i);
794 			goto err_i2c_add_adapter;
795 		}
796 
797 		pch_i2c_init(&adap_info->pch_data[i]);
798 	}
799 	ret = request_irq(pdev->irq, pch_i2c_handler, IRQF_SHARED,
800 		  KBUILD_MODNAME, adap_info);
801 	if (ret) {
802 		pch_pci_err(pdev, "request_irq FAILED\n");
803 		goto err_i2c_add_adapter;
804 	}
805 
806 	pci_set_drvdata(pdev, adap_info);
807 	pch_pci_dbg(pdev, "returns %d.\n", ret);
808 	return 0;
809 
810 err_i2c_add_adapter:
811 	for (j = 0; j < i; j++)
812 		i2c_del_adapter(&adap_info->pch_data[j].pch_adapter);
813 	pci_iounmap(pdev, base_addr);
814 err_pci_iomap:
815 	pci_release_regions(pdev);
816 err_pci_req:
817 	pci_disable_device(pdev);
818 err_pci_enable:
819 	kfree(adap_info);
820 	return ret;
821 }
822 
823 static void __devexit pch_i2c_remove(struct pci_dev *pdev)
824 {
825 	int i;
826 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
827 
828 	free_irq(pdev->irq, adap_info);
829 
830 	for (i = 0; i < adap_info->ch_num; i++) {
831 		pch_i2c_disbl_int(&adap_info->pch_data[i]);
832 		i2c_del_adapter(&adap_info->pch_data[i].pch_adapter);
833 	}
834 
835 	if (adap_info->pch_data[0].pch_base_address)
836 		pci_iounmap(pdev, adap_info->pch_data[0].pch_base_address);
837 
838 	for (i = 0; i < adap_info->ch_num; i++)
839 		adap_info->pch_data[i].pch_base_address = 0;
840 
841 	pci_set_drvdata(pdev, NULL);
842 
843 	pci_release_regions(pdev);
844 
845 	pci_disable_device(pdev);
846 	kfree(adap_info);
847 }
848 
849 #ifdef CONFIG_PM
850 static int pch_i2c_suspend(struct pci_dev *pdev, pm_message_t state)
851 {
852 	int ret;
853 	int i;
854 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
855 	void __iomem *p = adap_info->pch_data[0].pch_base_address;
856 
857 	adap_info->pch_i2c_suspended = true;
858 
859 	for (i = 0; i < adap_info->ch_num; i++) {
860 		while ((adap_info->pch_data[i].pch_i2c_xfer_in_progress)) {
861 			/* Wait until all channel transfers are completed */
862 			msleep(20);
863 		}
864 	}
865 
866 	/* Disable the i2c interrupts */
867 	for (i = 0; i < adap_info->ch_num; i++)
868 		pch_i2c_disbl_int(&adap_info->pch_data[i]);
869 
870 	pch_pci_dbg(pdev, "I2CSR = %x I2CBUFSTA = %x I2CESRSTA = %x "
871 		"invoked function pch_i2c_disbl_int successfully\n",
872 		ioread32(p + PCH_I2CSR), ioread32(p + PCH_I2CBUFSTA),
873 		ioread32(p + PCH_I2CESRSTA));
874 
875 	ret = pci_save_state(pdev);
876 
877 	if (ret) {
878 		pch_pci_err(pdev, "pci_save_state\n");
879 		return ret;
880 	}
881 
882 	pci_enable_wake(pdev, PCI_D3hot, 0);
883 	pci_disable_device(pdev);
884 	pci_set_power_state(pdev, pci_choose_state(pdev, state));
885 
886 	return 0;
887 }
888 
889 static int pch_i2c_resume(struct pci_dev *pdev)
890 {
891 	int i;
892 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
893 
894 	pci_set_power_state(pdev, PCI_D0);
895 	pci_restore_state(pdev);
896 
897 	if (pci_enable_device(pdev) < 0) {
898 		pch_pci_err(pdev, "pch_i2c_resume:pci_enable_device FAILED\n");
899 		return -EIO;
900 	}
901 
902 	pci_enable_wake(pdev, PCI_D3hot, 0);
903 
904 	for (i = 0; i < adap_info->ch_num; i++)
905 		pch_i2c_init(&adap_info->pch_data[i]);
906 
907 	adap_info->pch_i2c_suspended = false;
908 
909 	return 0;
910 }
911 #else
912 #define pch_i2c_suspend NULL
913 #define pch_i2c_resume NULL
914 #endif
915 
916 static struct pci_driver pch_pcidriver = {
917 	.name = KBUILD_MODNAME,
918 	.id_table = pch_pcidev_id,
919 	.probe = pch_i2c_probe,
920 	.remove = __devexit_p(pch_i2c_remove),
921 	.suspend = pch_i2c_suspend,
922 	.resume = pch_i2c_resume
923 };
924 
925 static int __init pch_pci_init(void)
926 {
927 	return pci_register_driver(&pch_pcidriver);
928 }
929 module_init(pch_pci_init);
930 
931 static void __exit pch_pci_exit(void)
932 {
933 	pci_unregister_driver(&pch_pcidriver);
934 }
935 module_exit(pch_pci_exit);
936 
937 MODULE_DESCRIPTION("Intel EG20T PCH/OKI SEMICONDUCTOR ML7213 IOH I2C Driver");
938 MODULE_LICENSE("GPL");
939 MODULE_AUTHOR("Tomoya MORINAGA. <tomoya-linux@dsn.okisemi.com>");
940 module_param(pch_i2c_speed, int, (S_IRUSR | S_IWUSR));
941 module_param(pch_clk, int, (S_IRUSR | S_IWUSR));
942