xref: /openbmc/linux/drivers/i2c/busses/i2c-eg20t.c (revision b11ed18e)
1 /*
2  * Copyright (C) 2011 LAPIS 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 
14 #include <linux/module.h>
15 #include <linux/kernel.h>
16 #include <linux/delay.h>
17 #include <linux/errno.h>
18 #include <linux/i2c.h>
19 #include <linux/fs.h>
20 #include <linux/io.h>
21 #include <linux/types.h>
22 #include <linux/interrupt.h>
23 #include <linux/jiffies.h>
24 #include <linux/pci.h>
25 #include <linux/mutex.h>
26 #include <linux/ktime.h>
27 #include <linux/slab.h>
28 
29 #define PCH_EVENT_SET	0	/* I2C Interrupt Event Set Status */
30 #define PCH_EVENT_NONE	1	/* I2C Interrupt Event Clear Status */
31 #define PCH_MAX_CLK		100000	/* Maximum Clock speed in MHz */
32 #define PCH_BUFFER_MODE_ENABLE	0x0002	/* flag for Buffer mode enable */
33 #define PCH_EEPROM_SW_RST_MODE_ENABLE	0x0008	/* EEPROM SW RST enable flag */
34 
35 #define PCH_I2CSADR	0x00	/* I2C slave address register */
36 #define PCH_I2CCTL	0x04	/* I2C control register */
37 #define PCH_I2CSR	0x08	/* I2C status register */
38 #define PCH_I2CDR	0x0C	/* I2C data register */
39 #define PCH_I2CMON	0x10	/* I2C bus monitor register */
40 #define PCH_I2CBC	0x14	/* I2C bus transfer rate setup counter */
41 #define PCH_I2CMOD	0x18	/* I2C mode register */
42 #define PCH_I2CBUFSLV	0x1C	/* I2C buffer mode slave address register */
43 #define PCH_I2CBUFSUB	0x20	/* I2C buffer mode subaddress register */
44 #define PCH_I2CBUFFOR	0x24	/* I2C buffer mode format register */
45 #define PCH_I2CBUFCTL	0x28	/* I2C buffer mode control register */
46 #define PCH_I2CBUFMSK	0x2C	/* I2C buffer mode interrupt mask register */
47 #define PCH_I2CBUFSTA	0x30	/* I2C buffer mode status register */
48 #define PCH_I2CBUFLEV	0x34	/* I2C buffer mode level register */
49 #define PCH_I2CESRFOR	0x38	/* EEPROM software reset mode format register */
50 #define PCH_I2CESRCTL	0x3C	/* EEPROM software reset mode ctrl register */
51 #define PCH_I2CESRMSK	0x40	/* EEPROM software reset mode */
52 #define PCH_I2CESRSTA	0x44	/* EEPROM software reset mode status register */
53 #define PCH_I2CTMR	0x48	/* I2C timer register */
54 #define PCH_I2CSRST	0xFC	/* I2C reset register */
55 #define PCH_I2CNF	0xF8	/* I2C noise filter register */
56 
57 #define BUS_IDLE_TIMEOUT	20
58 #define PCH_I2CCTL_I2CMEN	0x0080
59 #define TEN_BIT_ADDR_DEFAULT	0xF000
60 #define TEN_BIT_ADDR_MASK	0xF0
61 #define PCH_START		0x0020
62 #define PCH_RESTART		0x0004
63 #define PCH_ESR_START		0x0001
64 #define PCH_BUFF_START		0x1
65 #define PCH_REPSTART		0x0004
66 #define PCH_ACK			0x0008
67 #define PCH_GETACK		0x0001
68 #define CLR_REG			0x0
69 #define I2C_RD			0x1
70 #define I2CMCF_BIT		0x0080
71 #define I2CMIF_BIT		0x0002
72 #define I2CMAL_BIT		0x0010
73 #define I2CBMFI_BIT		0x0001
74 #define I2CBMAL_BIT		0x0002
75 #define I2CBMNA_BIT		0x0004
76 #define I2CBMTO_BIT		0x0008
77 #define I2CBMIS_BIT		0x0010
78 #define I2CESRFI_BIT		0X0001
79 #define I2CESRTO_BIT		0x0002
80 #define I2CESRFIIE_BIT		0x1
81 #define I2CESRTOIE_BIT		0x2
82 #define I2CBMDZ_BIT		0x0040
83 #define I2CBMAG_BIT		0x0020
84 #define I2CMBB_BIT		0x0020
85 #define BUFFER_MODE_MASK	(I2CBMFI_BIT | I2CBMAL_BIT | I2CBMNA_BIT | \
86 				I2CBMTO_BIT | I2CBMIS_BIT)
87 #define I2C_ADDR_MSK		0xFF
88 #define I2C_MSB_2B_MSK		0x300
89 #define FAST_MODE_CLK		400
90 #define FAST_MODE_EN		0x0001
91 #define SUB_ADDR_LEN_MAX	4
92 #define BUF_LEN_MAX		32
93 #define PCH_BUFFER_MODE		0x1
94 #define EEPROM_SW_RST_MODE	0x0002
95 #define NORMAL_INTR_ENBL	0x0300
96 #define EEPROM_RST_INTR_ENBL	(I2CESRFIIE_BIT | I2CESRTOIE_BIT)
97 #define EEPROM_RST_INTR_DISBL	0x0
98 #define BUFFER_MODE_INTR_ENBL	0x001F
99 #define BUFFER_MODE_INTR_DISBL	0x0
100 #define NORMAL_MODE		0x0
101 #define BUFFER_MODE		0x1
102 #define EEPROM_SR_MODE		0x2
103 #define I2C_TX_MODE		0x0010
104 #define PCH_BUF_TX		0xFFF7
105 #define PCH_BUF_RD		0x0008
106 #define I2C_ERROR_MASK	(I2CESRTO_EVENT | I2CBMIS_EVENT | I2CBMTO_EVENT | \
107 			I2CBMNA_EVENT | I2CBMAL_EVENT | I2CMAL_EVENT)
108 #define I2CMAL_EVENT		0x0001
109 #define I2CMCF_EVENT		0x0002
110 #define I2CBMFI_EVENT		0x0004
111 #define I2CBMAL_EVENT		0x0008
112 #define I2CBMNA_EVENT		0x0010
113 #define I2CBMTO_EVENT		0x0020
114 #define I2CBMIS_EVENT		0x0040
115 #define I2CESRFI_EVENT		0x0080
116 #define I2CESRTO_EVENT		0x0100
117 #define PCI_DEVICE_ID_PCH_I2C	0x8817
118 
119 #define pch_dbg(adap, fmt, arg...)  \
120 	dev_dbg(adap->pch_adapter.dev.parent, "%s :" fmt, __func__, ##arg)
121 
122 #define pch_err(adap, fmt, arg...)  \
123 	dev_err(adap->pch_adapter.dev.parent, "%s :" fmt, __func__, ##arg)
124 
125 #define pch_pci_err(pdev, fmt, arg...)  \
126 	dev_err(&pdev->dev, "%s :" fmt, __func__, ##arg)
127 
128 #define pch_pci_dbg(pdev, fmt, arg...)  \
129 	dev_dbg(&pdev->dev, "%s :" fmt, __func__, ##arg)
130 
131 /*
132 Set the number of I2C instance max
133 Intel EG20T PCH :		1ch
134 LAPIS Semiconductor ML7213 IOH :	2ch
135 LAPIS Semiconductor ML7831 IOH :	1ch
136 */
137 #define PCH_I2C_MAX_DEV			2
138 
139 /**
140  * struct i2c_algo_pch_data - for I2C driver functionalities
141  * @pch_adapter:		stores the reference to i2c_adapter structure
142  * @p_adapter_info:		stores the reference to adapter_info structure
143  * @pch_base_address:		specifies the remapped base address
144  * @pch_buff_mode_en:		specifies if buffer mode is enabled
145  * @pch_event_flag:		specifies occurrence of interrupt events
146  * @pch_i2c_xfer_in_progress:	specifies whether the transfer is completed
147  */
148 struct i2c_algo_pch_data {
149 	struct i2c_adapter pch_adapter;
150 	struct adapter_info *p_adapter_info;
151 	void __iomem *pch_base_address;
152 	int pch_buff_mode_en;
153 	u32 pch_event_flag;
154 	bool pch_i2c_xfer_in_progress;
155 };
156 
157 /**
158  * struct adapter_info - This structure holds the adapter information for the
159 			 PCH i2c controller
160  * @pch_data:		stores a list of i2c_algo_pch_data
161  * @pch_i2c_suspended:	specifies whether the system is suspended or not
162  *			perhaps with more lines and words.
163  * @ch_num:		specifies the number of i2c instance
164  *
165  * pch_data has as many elements as maximum I2C channels
166  */
167 struct adapter_info {
168 	struct i2c_algo_pch_data pch_data[PCH_I2C_MAX_DEV];
169 	bool pch_i2c_suspended;
170 	int ch_num;
171 };
172 
173 
174 static int pch_i2c_speed = 100; /* I2C bus speed in Kbps */
175 static int pch_clk = 50000;	/* specifies I2C clock speed in KHz */
176 static wait_queue_head_t pch_event;
177 static DEFINE_MUTEX(pch_mutex);
178 
179 /* Definition for ML7213 by LAPIS Semiconductor */
180 #define PCI_DEVICE_ID_ML7213_I2C	0x802D
181 #define PCI_DEVICE_ID_ML7223_I2C	0x8010
182 #define PCI_DEVICE_ID_ML7831_I2C	0x8817
183 
184 static const struct pci_device_id pch_pcidev_id[] = {
185 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_PCH_I2C),   1, },
186 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_I2C), 2, },
187 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_I2C), 1, },
188 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7831_I2C), 1, },
189 	{0,}
190 };
191 
192 static irqreturn_t pch_i2c_handler(int irq, void *pData);
193 
194 static inline void pch_setbit(void __iomem *addr, u32 offset, u32 bitmask)
195 {
196 	u32 val;
197 	val = ioread32(addr + offset);
198 	val |= bitmask;
199 	iowrite32(val, addr + offset);
200 }
201 
202 static inline void pch_clrbit(void __iomem *addr, u32 offset, u32 bitmask)
203 {
204 	u32 val;
205 	val = ioread32(addr + offset);
206 	val &= (~bitmask);
207 	iowrite32(val, addr + offset);
208 }
209 
210 /**
211  * pch_i2c_init() - hardware initialization of I2C module
212  * @adap:	Pointer to struct i2c_algo_pch_data.
213  */
214 static void pch_i2c_init(struct i2c_algo_pch_data *adap)
215 {
216 	void __iomem *p = adap->pch_base_address;
217 	u32 pch_i2cbc;
218 	u32 pch_i2ctmr;
219 	u32 reg_value;
220 
221 	/* reset I2C controller */
222 	iowrite32(0x01, p + PCH_I2CSRST);
223 	msleep(20);
224 	iowrite32(0x0, p + PCH_I2CSRST);
225 
226 	/* Initialize I2C registers */
227 	iowrite32(0x21, p + PCH_I2CNF);
228 
229 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_I2CCTL_I2CMEN);
230 
231 	if (pch_i2c_speed != 400)
232 		pch_i2c_speed = 100;
233 
234 	reg_value = PCH_I2CCTL_I2CMEN;
235 	if (pch_i2c_speed == FAST_MODE_CLK) {
236 		reg_value |= FAST_MODE_EN;
237 		pch_dbg(adap, "Fast mode enabled\n");
238 	}
239 
240 	if (pch_clk > PCH_MAX_CLK)
241 		pch_clk = 62500;
242 
243 	pch_i2cbc = (pch_clk + (pch_i2c_speed * 4)) / (pch_i2c_speed * 8);
244 	/* Set transfer speed in I2CBC */
245 	iowrite32(pch_i2cbc, p + PCH_I2CBC);
246 
247 	pch_i2ctmr = (pch_clk) / 8;
248 	iowrite32(pch_i2ctmr, p + PCH_I2CTMR);
249 
250 	reg_value |= NORMAL_INTR_ENBL;	/* Enable interrupts in normal mode */
251 	iowrite32(reg_value, p + PCH_I2CCTL);
252 
253 	pch_dbg(adap,
254 		"I2CCTL=%x pch_i2cbc=%x pch_i2ctmr=%x Enable interrupts\n",
255 		ioread32(p + PCH_I2CCTL), pch_i2cbc, pch_i2ctmr);
256 
257 	init_waitqueue_head(&pch_event);
258 }
259 
260 /**
261  * pch_i2c_wait_for_bus_idle() - check the status of bus.
262  * @adap:	Pointer to struct i2c_algo_pch_data.
263  * @timeout:	waiting time counter (ms).
264  */
265 static s32 pch_i2c_wait_for_bus_idle(struct i2c_algo_pch_data *adap,
266 				     s32 timeout)
267 {
268 	void __iomem *p = adap->pch_base_address;
269 	int schedule = 0;
270 	unsigned long end = jiffies + msecs_to_jiffies(timeout);
271 
272 	while (ioread32(p + PCH_I2CSR) & I2CMBB_BIT) {
273 		if (time_after(jiffies, end)) {
274 			pch_dbg(adap, "I2CSR = %x\n", ioread32(p + PCH_I2CSR));
275 			pch_err(adap, "%s: Timeout Error.return%d\n",
276 					__func__, -ETIME);
277 			pch_i2c_init(adap);
278 
279 			return -ETIME;
280 		}
281 
282 		if (!schedule)
283 			/* Retry after some usecs */
284 			udelay(5);
285 		else
286 			/* Wait a bit more without consuming CPU */
287 			usleep_range(20, 1000);
288 
289 		schedule = 1;
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_stop() - generate stop condition in normal mode.
310  * @adap:	Pointer to struct i2c_algo_pch_data.
311  */
312 static void pch_i2c_stop(struct i2c_algo_pch_data *adap)
313 {
314 	void __iomem *p = adap->pch_base_address;
315 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
316 	/* clear the start bit */
317 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, PCH_START);
318 }
319 
320 static int pch_i2c_wait_for_check_xfer(struct i2c_algo_pch_data *adap)
321 {
322 	long ret;
323 	void __iomem *p = adap->pch_base_address;
324 
325 	ret = wait_event_timeout(pch_event,
326 			(adap->pch_event_flag != 0), msecs_to_jiffies(1000));
327 	if (!ret) {
328 		pch_err(adap, "%s:wait-event timeout\n", __func__);
329 		adap->pch_event_flag = 0;
330 		pch_i2c_stop(adap);
331 		pch_i2c_init(adap);
332 		return -ETIMEDOUT;
333 	}
334 
335 	if (adap->pch_event_flag & I2C_ERROR_MASK) {
336 		pch_err(adap, "Lost Arbitration\n");
337 		adap->pch_event_flag = 0;
338 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMAL_BIT);
339 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMIF_BIT);
340 		pch_i2c_init(adap);
341 		return -EAGAIN;
342 	}
343 
344 	adap->pch_event_flag = 0;
345 
346 	if (ioread32(p + PCH_I2CSR) & PCH_GETACK) {
347 		pch_dbg(adap, "Receive NACK for slave address setting\n");
348 		return -ENXIO;
349 	}
350 
351 	return 0;
352 }
353 
354 /**
355  * pch_i2c_repstart() - generate repeated start condition in normal mode
356  * @adap:	Pointer to struct i2c_algo_pch_data.
357  */
358 static void pch_i2c_repstart(struct i2c_algo_pch_data *adap)
359 {
360 	void __iomem *p = adap->pch_base_address;
361 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
362 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_REPSTART);
363 }
364 
365 /**
366  * pch_i2c_writebytes() - write data to I2C bus in normal mode
367  * @i2c_adap:	Pointer to the struct i2c_adapter.
368  * @last:	specifies whether last message or not.
369  *		In the case of compound mode it will be 1 for last message,
370  *		otherwise 0.
371  * @first:	specifies whether first message or not.
372  *		1 for first message otherwise 0.
373  */
374 static s32 pch_i2c_writebytes(struct i2c_adapter *i2c_adap,
375 			      struct i2c_msg *msgs, u32 last, u32 first)
376 {
377 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
378 	u8 *buf;
379 	u32 length;
380 	u32 addr;
381 	u32 addr_2_msb;
382 	u32 addr_8_lsb;
383 	s32 wrcount;
384 	s32 rtn;
385 	void __iomem *p = adap->pch_base_address;
386 
387 	length = msgs->len;
388 	buf = msgs->buf;
389 	addr = msgs->addr;
390 
391 	/* enable master tx */
392 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, I2C_TX_MODE);
393 
394 	pch_dbg(adap, "I2CCTL = %x msgs->len = %d\n", ioread32(p + PCH_I2CCTL),
395 		length);
396 
397 	if (first) {
398 		if (pch_i2c_wait_for_bus_idle(adap, BUS_IDLE_TIMEOUT) == -ETIME)
399 			return -ETIME;
400 	}
401 
402 	if (msgs->flags & I2C_M_TEN) {
403 		addr_2_msb = ((addr & I2C_MSB_2B_MSK) >> 7) & 0x06;
404 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
405 		if (first)
406 			pch_i2c_start(adap);
407 
408 		rtn = pch_i2c_wait_for_check_xfer(adap);
409 		if (rtn)
410 			return rtn;
411 
412 		addr_8_lsb = (addr & I2C_ADDR_MSK);
413 		iowrite32(addr_8_lsb, p + PCH_I2CDR);
414 	} else {
415 		/* set 7 bit slave address and R/W bit as 0 */
416 		iowrite32(i2c_8bit_addr_from_msg(msgs), p + PCH_I2CDR);
417 		if (first)
418 			pch_i2c_start(adap);
419 	}
420 
421 	rtn = pch_i2c_wait_for_check_xfer(adap);
422 	if (rtn)
423 		return rtn;
424 
425 	for (wrcount = 0; wrcount < length; ++wrcount) {
426 		/* write buffer value to I2C data register */
427 		iowrite32(buf[wrcount], p + PCH_I2CDR);
428 		pch_dbg(adap, "writing %x to Data register\n", buf[wrcount]);
429 
430 		rtn = pch_i2c_wait_for_check_xfer(adap);
431 		if (rtn)
432 			return rtn;
433 
434 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMCF_BIT);
435 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMIF_BIT);
436 	}
437 
438 	/* check if this is the last message */
439 	if (last)
440 		pch_i2c_stop(adap);
441 	else
442 		pch_i2c_repstart(adap);
443 
444 	pch_dbg(adap, "return=%d\n", wrcount);
445 
446 	return wrcount;
447 }
448 
449 /**
450  * pch_i2c_sendack() - send ACK
451  * @adap:	Pointer to struct i2c_algo_pch_data.
452  */
453 static void pch_i2c_sendack(struct i2c_algo_pch_data *adap)
454 {
455 	void __iomem *p = adap->pch_base_address;
456 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
457 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
458 }
459 
460 /**
461  * pch_i2c_sendnack() - send NACK
462  * @adap:	Pointer to struct i2c_algo_pch_data.
463  */
464 static void pch_i2c_sendnack(struct i2c_algo_pch_data *adap)
465 {
466 	void __iomem *p = adap->pch_base_address;
467 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
468 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
469 }
470 
471 /**
472  * pch_i2c_restart() - Generate I2C restart condition in normal mode.
473  * @adap:	Pointer to struct i2c_algo_pch_data.
474  *
475  * Generate I2C restart condition in normal mode by setting I2CCTL.I2CRSTA.
476  */
477 static void pch_i2c_restart(struct i2c_algo_pch_data *adap)
478 {
479 	void __iomem *p = adap->pch_base_address;
480 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
481 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_RESTART);
482 }
483 
484 /**
485  * pch_i2c_readbytes() - read data  from I2C bus in normal mode.
486  * @i2c_adap:	Pointer to the struct i2c_adapter.
487  * @msgs:	Pointer to i2c_msg structure.
488  * @last:	specifies whether last message or not.
489  * @first:	specifies whether first message or not.
490  */
491 static s32 pch_i2c_readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
492 			     u32 last, u32 first)
493 {
494 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
495 
496 	u8 *buf;
497 	u32 count;
498 	u32 length;
499 	u32 addr;
500 	u32 addr_2_msb;
501 	u32 addr_8_lsb;
502 	void __iomem *p = adap->pch_base_address;
503 	s32 rtn;
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);
519 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
520 		if (first)
521 			pch_i2c_start(adap);
522 
523 		rtn = pch_i2c_wait_for_check_xfer(adap);
524 		if (rtn)
525 			return rtn;
526 
527 		addr_8_lsb = (addr & I2C_ADDR_MSK);
528 		iowrite32(addr_8_lsb, p + PCH_I2CDR);
529 
530 		pch_i2c_restart(adap);
531 
532 		rtn = pch_i2c_wait_for_check_xfer(adap);
533 		if (rtn)
534 			return rtn;
535 
536 		addr_2_msb |= I2C_RD;
537 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
538 	} else {
539 		/* 7 address bits + R/W bit */
540 		iowrite32(i2c_8bit_addr_from_msg(msgs), p + PCH_I2CDR);
541 	}
542 
543 	/* check if it is the first message */
544 	if (first)
545 		pch_i2c_start(adap);
546 
547 	rtn = pch_i2c_wait_for_check_xfer(adap);
548 	if (rtn)
549 		return rtn;
550 
551 	if (length == 0) {
552 		pch_i2c_stop(adap);
553 		ioread32(p + PCH_I2CDR); /* Dummy read needs */
554 
555 		count = length;
556 	} else {
557 		int read_index;
558 		int loop;
559 		pch_i2c_sendack(adap);
560 
561 		/* Dummy read */
562 		for (loop = 1, read_index = 0; loop < length; loop++) {
563 			buf[read_index] = ioread32(p + PCH_I2CDR);
564 
565 			if (loop != 1)
566 				read_index++;
567 
568 			rtn = pch_i2c_wait_for_check_xfer(adap);
569 			if (rtn)
570 				return rtn;
571 		}	/* end for */
572 
573 		pch_i2c_sendnack(adap);
574 
575 		buf[read_index] = ioread32(p + PCH_I2CDR); /* Read final - 1 */
576 
577 		if (length != 1)
578 			read_index++;
579 
580 		rtn = pch_i2c_wait_for_check_xfer(adap);
581 		if (rtn)
582 			return rtn;
583 
584 		if (last)
585 			pch_i2c_stop(adap);
586 		else
587 			pch_i2c_repstart(adap);
588 
589 		buf[read_index++] = ioread32(p + PCH_I2CDR); /* Read Final */
590 		count = read_index;
591 	}
592 
593 	return count;
594 }
595 
596 /**
597  * pch_i2c_cb() - Interrupt handler Call back function
598  * @adap:	Pointer to struct i2c_algo_pch_data.
599  */
600 static void pch_i2c_cb(struct i2c_algo_pch_data *adap)
601 {
602 	u32 sts;
603 	void __iomem *p = adap->pch_base_address;
604 
605 	sts = ioread32(p + PCH_I2CSR);
606 	sts &= (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT);
607 	if (sts & I2CMAL_BIT)
608 		adap->pch_event_flag |= I2CMAL_EVENT;
609 
610 	if (sts & I2CMCF_BIT)
611 		adap->pch_event_flag |= I2CMCF_EVENT;
612 
613 	/* clear the applicable bits */
614 	pch_clrbit(adap->pch_base_address, PCH_I2CSR, sts);
615 
616 	pch_dbg(adap, "PCH_I2CSR = %x\n", ioread32(p + PCH_I2CSR));
617 
618 	wake_up(&pch_event);
619 }
620 
621 /**
622  * pch_i2c_handler() - interrupt handler for the PCH I2C controller
623  * @irq:	irq number.
624  * @pData:	cookie passed back to the handler function.
625  */
626 static irqreturn_t pch_i2c_handler(int irq, void *pData)
627 {
628 	u32 reg_val;
629 	int flag;
630 	int i;
631 	struct adapter_info *adap_info = pData;
632 	void __iomem *p;
633 	u32 mode;
634 
635 	for (i = 0, flag = 0; i < adap_info->ch_num; i++) {
636 		p = adap_info->pch_data[i].pch_base_address;
637 		mode = ioread32(p + PCH_I2CMOD);
638 		mode &= BUFFER_MODE | EEPROM_SR_MODE;
639 		if (mode != NORMAL_MODE) {
640 			pch_err(adap_info->pch_data,
641 				"I2C-%d mode(%d) is not supported\n", mode, i);
642 			continue;
643 		}
644 		reg_val = ioread32(p + PCH_I2CSR);
645 		if (reg_val & (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT)) {
646 			pch_i2c_cb(&adap_info->pch_data[i]);
647 			flag = 1;
648 		}
649 	}
650 
651 	return flag ? IRQ_HANDLED : IRQ_NONE;
652 }
653 
654 /**
655  * pch_i2c_xfer() - Reading adnd writing data through I2C bus
656  * @i2c_adap:	Pointer to the struct i2c_adapter.
657  * @msgs:	Pointer to i2c_msg structure.
658  * @num:	number of messages.
659  */
660 static s32 pch_i2c_xfer(struct i2c_adapter *i2c_adap,
661 			struct i2c_msg *msgs, s32 num)
662 {
663 	struct i2c_msg *pmsg;
664 	u32 i = 0;
665 	u32 status;
666 	s32 ret;
667 
668 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
669 
670 	ret = mutex_lock_interruptible(&pch_mutex);
671 	if (ret)
672 		return ret;
673 
674 	if (adap->p_adapter_info->pch_i2c_suspended) {
675 		mutex_unlock(&pch_mutex);
676 		return -EBUSY;
677 	}
678 
679 	pch_dbg(adap, "adap->p_adapter_info->pch_i2c_suspended is %d\n",
680 		adap->p_adapter_info->pch_i2c_suspended);
681 	/* transfer not completed */
682 	adap->pch_i2c_xfer_in_progress = true;
683 
684 	for (i = 0; i < num && ret >= 0; i++) {
685 		pmsg = &msgs[i];
686 		pmsg->flags |= adap->pch_buff_mode_en;
687 		status = pmsg->flags;
688 		pch_dbg(adap,
689 			"After invoking I2C_MODE_SEL :flag= 0x%x\n", status);
690 
691 		if ((status & (I2C_M_RD)) != false) {
692 			ret = pch_i2c_readbytes(i2c_adap, pmsg, (i + 1 == num),
693 						(i == 0));
694 		} else {
695 			ret = pch_i2c_writebytes(i2c_adap, pmsg, (i + 1 == num),
696 						 (i == 0));
697 		}
698 	}
699 
700 	adap->pch_i2c_xfer_in_progress = false;	/* transfer completed */
701 
702 	mutex_unlock(&pch_mutex);
703 
704 	return (ret < 0) ? ret : num;
705 }
706 
707 /**
708  * pch_i2c_func() - return the functionality of the I2C driver
709  * @adap:	Pointer to struct i2c_algo_pch_data.
710  */
711 static u32 pch_i2c_func(struct i2c_adapter *adap)
712 {
713 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
714 }
715 
716 static const struct i2c_algorithm pch_algorithm = {
717 	.master_xfer = pch_i2c_xfer,
718 	.functionality = pch_i2c_func
719 };
720 
721 /**
722  * pch_i2c_disbl_int() - Disable PCH I2C interrupts
723  * @adap:	Pointer to struct i2c_algo_pch_data.
724  */
725 static void pch_i2c_disbl_int(struct i2c_algo_pch_data *adap)
726 {
727 	void __iomem *p = adap->pch_base_address;
728 
729 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, NORMAL_INTR_ENBL);
730 
731 	iowrite32(EEPROM_RST_INTR_DISBL, p + PCH_I2CESRMSK);
732 
733 	iowrite32(BUFFER_MODE_INTR_DISBL, p + PCH_I2CBUFMSK);
734 }
735 
736 static int pch_i2c_probe(struct pci_dev *pdev,
737 				   const struct pci_device_id *id)
738 {
739 	void __iomem *base_addr;
740 	int ret;
741 	int i, j;
742 	struct adapter_info *adap_info;
743 	struct i2c_adapter *pch_adap;
744 
745 	pch_pci_dbg(pdev, "Entered.\n");
746 
747 	adap_info = kzalloc((sizeof(struct adapter_info)), GFP_KERNEL);
748 	if (adap_info == NULL)
749 		return -ENOMEM;
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 		strlcpy(pch_adap->name, KBUILD_MODNAME, sizeof(pch_adap->name));
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.of_node = pdev->dev.of_node;
790 		pch_adap->dev.parent = &pdev->dev;
791 	}
792 
793 	ret = request_irq(pdev->irq, pch_i2c_handler, IRQF_SHARED,
794 		  KBUILD_MODNAME, adap_info);
795 	if (ret) {
796 		pch_pci_err(pdev, "request_irq FAILED\n");
797 		goto err_request_irq;
798 	}
799 
800 	for (i = 0; i < adap_info->ch_num; i++) {
801 		pch_adap = &adap_info->pch_data[i].pch_adapter;
802 
803 		pch_i2c_init(&adap_info->pch_data[i]);
804 
805 		pch_adap->nr = i;
806 		ret = i2c_add_numbered_adapter(pch_adap);
807 		if (ret) {
808 			pch_pci_err(pdev, "i2c_add_adapter[ch:%d] FAILED\n", i);
809 			goto err_add_adapter;
810 		}
811 	}
812 
813 	pci_set_drvdata(pdev, adap_info);
814 	pch_pci_dbg(pdev, "returns %d.\n", ret);
815 	return 0;
816 
817 err_add_adapter:
818 	for (j = 0; j < i; j++)
819 		i2c_del_adapter(&adap_info->pch_data[j].pch_adapter);
820 	free_irq(pdev->irq, adap_info);
821 err_request_irq:
822 	pci_iounmap(pdev, base_addr);
823 err_pci_iomap:
824 	pci_release_regions(pdev);
825 err_pci_req:
826 	pci_disable_device(pdev);
827 err_pci_enable:
828 	kfree(adap_info);
829 	return ret;
830 }
831 
832 static void pch_i2c_remove(struct pci_dev *pdev)
833 {
834 	int i;
835 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
836 
837 	free_irq(pdev->irq, adap_info);
838 
839 	for (i = 0; i < adap_info->ch_num; i++) {
840 		pch_i2c_disbl_int(&adap_info->pch_data[i]);
841 		i2c_del_adapter(&adap_info->pch_data[i].pch_adapter);
842 	}
843 
844 	if (adap_info->pch_data[0].pch_base_address)
845 		pci_iounmap(pdev, adap_info->pch_data[0].pch_base_address);
846 
847 	for (i = 0; i < adap_info->ch_num; i++)
848 		adap_info->pch_data[i].pch_base_address = NULL;
849 
850 	pci_release_regions(pdev);
851 
852 	pci_disable_device(pdev);
853 	kfree(adap_info);
854 }
855 
856 #ifdef CONFIG_PM
857 static int pch_i2c_suspend(struct pci_dev *pdev, pm_message_t state)
858 {
859 	int ret;
860 	int i;
861 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
862 	void __iomem *p = adap_info->pch_data[0].pch_base_address;
863 
864 	adap_info->pch_i2c_suspended = true;
865 
866 	for (i = 0; i < adap_info->ch_num; i++) {
867 		while ((adap_info->pch_data[i].pch_i2c_xfer_in_progress)) {
868 			/* Wait until all channel transfers are completed */
869 			msleep(20);
870 		}
871 	}
872 
873 	/* Disable the i2c interrupts */
874 	for (i = 0; i < adap_info->ch_num; i++)
875 		pch_i2c_disbl_int(&adap_info->pch_data[i]);
876 
877 	pch_pci_dbg(pdev, "I2CSR = %x I2CBUFSTA = %x I2CESRSTA = %x "
878 		"invoked function pch_i2c_disbl_int successfully\n",
879 		ioread32(p + PCH_I2CSR), ioread32(p + PCH_I2CBUFSTA),
880 		ioread32(p + PCH_I2CESRSTA));
881 
882 	ret = pci_save_state(pdev);
883 
884 	if (ret) {
885 		pch_pci_err(pdev, "pci_save_state\n");
886 		return ret;
887 	}
888 
889 	pci_enable_wake(pdev, PCI_D3hot, 0);
890 	pci_disable_device(pdev);
891 	pci_set_power_state(pdev, pci_choose_state(pdev, state));
892 
893 	return 0;
894 }
895 
896 static int pch_i2c_resume(struct pci_dev *pdev)
897 {
898 	int i;
899 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
900 
901 	pci_set_power_state(pdev, PCI_D0);
902 	pci_restore_state(pdev);
903 
904 	if (pci_enable_device(pdev) < 0) {
905 		pch_pci_err(pdev, "pch_i2c_resume:pci_enable_device FAILED\n");
906 		return -EIO;
907 	}
908 
909 	pci_enable_wake(pdev, PCI_D3hot, 0);
910 
911 	for (i = 0; i < adap_info->ch_num; i++)
912 		pch_i2c_init(&adap_info->pch_data[i]);
913 
914 	adap_info->pch_i2c_suspended = false;
915 
916 	return 0;
917 }
918 #else
919 #define pch_i2c_suspend NULL
920 #define pch_i2c_resume NULL
921 #endif
922 
923 static struct pci_driver pch_pcidriver = {
924 	.name = KBUILD_MODNAME,
925 	.id_table = pch_pcidev_id,
926 	.probe = pch_i2c_probe,
927 	.remove = pch_i2c_remove,
928 	.suspend = pch_i2c_suspend,
929 	.resume = pch_i2c_resume
930 };
931 
932 module_pci_driver(pch_pcidriver);
933 
934 MODULE_DESCRIPTION("Intel EG20T PCH/LAPIS Semico ML7213/ML7223/ML7831 IOH I2C");
935 MODULE_LICENSE("GPL");
936 MODULE_AUTHOR("Tomoya MORINAGA. <tomoya.rohm@gmail.com>");
937 module_param(pch_i2c_speed, int, (S_IRUSR | S_IWUSR));
938 module_param(pch_clk, int, (S_IRUSR | S_IWUSR));
939