xref: /openbmc/linux/drivers/i2c/busses/i2c-eg20t.c (revision 4c5a116a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2011 LAPIS Semiconductor Co., Ltd.
4  */
5 
6 #include <linux/module.h>
7 #include <linux/kernel.h>
8 #include <linux/delay.h>
9 #include <linux/errno.h>
10 #include <linux/i2c.h>
11 #include <linux/fs.h>
12 #include <linux/io.h>
13 #include <linux/types.h>
14 #include <linux/interrupt.h>
15 #include <linux/jiffies.h>
16 #include <linux/pci.h>
17 #include <linux/mutex.h>
18 #include <linux/ktime.h>
19 #include <linux/slab.h>
20 
21 #define PCH_EVENT_SET	0	/* I2C Interrupt Event Set Status */
22 #define PCH_EVENT_NONE	1	/* I2C Interrupt Event Clear Status */
23 #define PCH_MAX_CLK		100000	/* Maximum Clock speed in MHz */
24 #define PCH_BUFFER_MODE_ENABLE	0x0002	/* flag for Buffer mode enable */
25 #define PCH_EEPROM_SW_RST_MODE_ENABLE	0x0008	/* EEPROM SW RST enable flag */
26 
27 #define PCH_I2CSADR	0x00	/* I2C slave address register */
28 #define PCH_I2CCTL	0x04	/* I2C control register */
29 #define PCH_I2CSR	0x08	/* I2C status register */
30 #define PCH_I2CDR	0x0C	/* I2C data register */
31 #define PCH_I2CMON	0x10	/* I2C bus monitor register */
32 #define PCH_I2CBC	0x14	/* I2C bus transfer rate setup counter */
33 #define PCH_I2CMOD	0x18	/* I2C mode register */
34 #define PCH_I2CBUFSLV	0x1C	/* I2C buffer mode slave address register */
35 #define PCH_I2CBUFSUB	0x20	/* I2C buffer mode subaddress register */
36 #define PCH_I2CBUFFOR	0x24	/* I2C buffer mode format register */
37 #define PCH_I2CBUFCTL	0x28	/* I2C buffer mode control register */
38 #define PCH_I2CBUFMSK	0x2C	/* I2C buffer mode interrupt mask register */
39 #define PCH_I2CBUFSTA	0x30	/* I2C buffer mode status register */
40 #define PCH_I2CBUFLEV	0x34	/* I2C buffer mode level register */
41 #define PCH_I2CESRFOR	0x38	/* EEPROM software reset mode format register */
42 #define PCH_I2CESRCTL	0x3C	/* EEPROM software reset mode ctrl register */
43 #define PCH_I2CESRMSK	0x40	/* EEPROM software reset mode */
44 #define PCH_I2CESRSTA	0x44	/* EEPROM software reset mode status register */
45 #define PCH_I2CTMR	0x48	/* I2C timer register */
46 #define PCH_I2CSRST	0xFC	/* I2C reset register */
47 #define PCH_I2CNF	0xF8	/* I2C noise filter register */
48 
49 #define BUS_IDLE_TIMEOUT	20
50 #define PCH_I2CCTL_I2CMEN	0x0080
51 #define TEN_BIT_ADDR_DEFAULT	0xF000
52 #define TEN_BIT_ADDR_MASK	0xF0
53 #define PCH_START		0x0020
54 #define PCH_RESTART		0x0004
55 #define PCH_ESR_START		0x0001
56 #define PCH_BUFF_START		0x1
57 #define PCH_REPSTART		0x0004
58 #define PCH_ACK			0x0008
59 #define PCH_GETACK		0x0001
60 #define CLR_REG			0x0
61 #define I2C_RD			0x1
62 #define I2CMCF_BIT		0x0080
63 #define I2CMIF_BIT		0x0002
64 #define I2CMAL_BIT		0x0010
65 #define I2CBMFI_BIT		0x0001
66 #define I2CBMAL_BIT		0x0002
67 #define I2CBMNA_BIT		0x0004
68 #define I2CBMTO_BIT		0x0008
69 #define I2CBMIS_BIT		0x0010
70 #define I2CESRFI_BIT		0X0001
71 #define I2CESRTO_BIT		0x0002
72 #define I2CESRFIIE_BIT		0x1
73 #define I2CESRTOIE_BIT		0x2
74 #define I2CBMDZ_BIT		0x0040
75 #define I2CBMAG_BIT		0x0020
76 #define I2CMBB_BIT		0x0020
77 #define BUFFER_MODE_MASK	(I2CBMFI_BIT | I2CBMAL_BIT | I2CBMNA_BIT | \
78 				I2CBMTO_BIT | I2CBMIS_BIT)
79 #define I2C_ADDR_MSK		0xFF
80 #define I2C_MSB_2B_MSK		0x300
81 #define FAST_MODE_CLK		400
82 #define FAST_MODE_EN		0x0001
83 #define SUB_ADDR_LEN_MAX	4
84 #define BUF_LEN_MAX		32
85 #define PCH_BUFFER_MODE		0x1
86 #define EEPROM_SW_RST_MODE	0x0002
87 #define NORMAL_INTR_ENBL	0x0300
88 #define EEPROM_RST_INTR_ENBL	(I2CESRFIIE_BIT | I2CESRTOIE_BIT)
89 #define EEPROM_RST_INTR_DISBL	0x0
90 #define BUFFER_MODE_INTR_ENBL	0x001F
91 #define BUFFER_MODE_INTR_DISBL	0x0
92 #define NORMAL_MODE		0x0
93 #define BUFFER_MODE		0x1
94 #define EEPROM_SR_MODE		0x2
95 #define I2C_TX_MODE		0x0010
96 #define PCH_BUF_TX		0xFFF7
97 #define PCH_BUF_RD		0x0008
98 #define I2C_ERROR_MASK	(I2CESRTO_EVENT | I2CBMIS_EVENT | I2CBMTO_EVENT | \
99 			I2CBMNA_EVENT | I2CBMAL_EVENT | I2CMAL_EVENT)
100 #define I2CMAL_EVENT		0x0001
101 #define I2CMCF_EVENT		0x0002
102 #define I2CBMFI_EVENT		0x0004
103 #define I2CBMAL_EVENT		0x0008
104 #define I2CBMNA_EVENT		0x0010
105 #define I2CBMTO_EVENT		0x0020
106 #define I2CBMIS_EVENT		0x0040
107 #define I2CESRFI_EVENT		0x0080
108 #define I2CESRTO_EVENT		0x0100
109 #define PCI_DEVICE_ID_PCH_I2C	0x8817
110 
111 #define pch_dbg(adap, fmt, arg...)  \
112 	dev_dbg(adap->pch_adapter.dev.parent, "%s :" fmt, __func__, ##arg)
113 
114 #define pch_err(adap, fmt, arg...)  \
115 	dev_err(adap->pch_adapter.dev.parent, "%s :" fmt, __func__, ##arg)
116 
117 #define pch_pci_err(pdev, fmt, arg...)  \
118 	dev_err(&pdev->dev, "%s :" fmt, __func__, ##arg)
119 
120 #define pch_pci_dbg(pdev, fmt, arg...)  \
121 	dev_dbg(&pdev->dev, "%s :" fmt, __func__, ##arg)
122 
123 /*
124 Set the number of I2C instance max
125 Intel EG20T PCH :		1ch
126 LAPIS Semiconductor ML7213 IOH :	2ch
127 LAPIS Semiconductor ML7831 IOH :	1ch
128 */
129 #define PCH_I2C_MAX_DEV			2
130 
131 /**
132  * struct i2c_algo_pch_data - for I2C driver functionalities
133  * @pch_adapter:		stores the reference to i2c_adapter structure
134  * @p_adapter_info:		stores the reference to adapter_info structure
135  * @pch_base_address:		specifies the remapped base address
136  * @pch_buff_mode_en:		specifies if buffer mode is enabled
137  * @pch_event_flag:		specifies occurrence of interrupt events
138  * @pch_i2c_xfer_in_progress:	specifies whether the transfer is completed
139  */
140 struct i2c_algo_pch_data {
141 	struct i2c_adapter pch_adapter;
142 	struct adapter_info *p_adapter_info;
143 	void __iomem *pch_base_address;
144 	int pch_buff_mode_en;
145 	u32 pch_event_flag;
146 	bool pch_i2c_xfer_in_progress;
147 };
148 
149 /**
150  * struct adapter_info - This structure holds the adapter information for the
151 			 PCH i2c controller
152  * @pch_data:		stores a list of i2c_algo_pch_data
153  * @pch_i2c_suspended:	specifies whether the system is suspended or not
154  *			perhaps with more lines and words.
155  * @ch_num:		specifies the number of i2c instance
156  *
157  * pch_data has as many elements as maximum I2C channels
158  */
159 struct adapter_info {
160 	struct i2c_algo_pch_data pch_data[PCH_I2C_MAX_DEV];
161 	bool pch_i2c_suspended;
162 	int ch_num;
163 };
164 
165 
166 static int pch_i2c_speed = 100; /* I2C bus speed in Kbps */
167 static int pch_clk = 50000;	/* specifies I2C clock speed in KHz */
168 static wait_queue_head_t pch_event;
169 static DEFINE_MUTEX(pch_mutex);
170 
171 /* Definition for ML7213 by LAPIS Semiconductor */
172 #define PCI_DEVICE_ID_ML7213_I2C	0x802D
173 #define PCI_DEVICE_ID_ML7223_I2C	0x8010
174 #define PCI_DEVICE_ID_ML7831_I2C	0x8817
175 
176 static const struct pci_device_id pch_pcidev_id[] = {
177 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_PCH_I2C),   1, },
178 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_I2C), 2, },
179 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_I2C), 1, },
180 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7831_I2C), 1, },
181 	{0,}
182 };
183 MODULE_DEVICE_TABLE(pci, pch_pcidev_id);
184 
185 static irqreturn_t pch_i2c_handler(int irq, void *pData);
186 
187 static inline void pch_setbit(void __iomem *addr, u32 offset, u32 bitmask)
188 {
189 	u32 val;
190 	val = ioread32(addr + offset);
191 	val |= bitmask;
192 	iowrite32(val, addr + offset);
193 }
194 
195 static inline void pch_clrbit(void __iomem *addr, u32 offset, u32 bitmask)
196 {
197 	u32 val;
198 	val = ioread32(addr + offset);
199 	val &= (~bitmask);
200 	iowrite32(val, addr + offset);
201 }
202 
203 /**
204  * pch_i2c_init() - hardware initialization of I2C module
205  * @adap:	Pointer to struct i2c_algo_pch_data.
206  */
207 static void pch_i2c_init(struct i2c_algo_pch_data *adap)
208 {
209 	void __iomem *p = adap->pch_base_address;
210 	u32 pch_i2cbc;
211 	u32 pch_i2ctmr;
212 	u32 reg_value;
213 
214 	/* reset I2C controller */
215 	iowrite32(0x01, p + PCH_I2CSRST);
216 	msleep(20);
217 	iowrite32(0x0, p + PCH_I2CSRST);
218 
219 	/* Initialize I2C registers */
220 	iowrite32(0x21, p + PCH_I2CNF);
221 
222 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_I2CCTL_I2CMEN);
223 
224 	if (pch_i2c_speed != 400)
225 		pch_i2c_speed = 100;
226 
227 	reg_value = PCH_I2CCTL_I2CMEN;
228 	if (pch_i2c_speed == FAST_MODE_CLK) {
229 		reg_value |= FAST_MODE_EN;
230 		pch_dbg(adap, "Fast mode enabled\n");
231 	}
232 
233 	if (pch_clk > PCH_MAX_CLK)
234 		pch_clk = 62500;
235 
236 	pch_i2cbc = (pch_clk + (pch_i2c_speed * 4)) / (pch_i2c_speed * 8);
237 	/* Set transfer speed in I2CBC */
238 	iowrite32(pch_i2cbc, p + PCH_I2CBC);
239 
240 	pch_i2ctmr = (pch_clk) / 8;
241 	iowrite32(pch_i2ctmr, p + PCH_I2CTMR);
242 
243 	reg_value |= NORMAL_INTR_ENBL;	/* Enable interrupts in normal mode */
244 	iowrite32(reg_value, p + PCH_I2CCTL);
245 
246 	pch_dbg(adap,
247 		"I2CCTL=%x pch_i2cbc=%x pch_i2ctmr=%x Enable interrupts\n",
248 		ioread32(p + PCH_I2CCTL), pch_i2cbc, pch_i2ctmr);
249 
250 	init_waitqueue_head(&pch_event);
251 }
252 
253 /**
254  * pch_i2c_wait_for_bus_idle() - check the status of bus.
255  * @adap:	Pointer to struct i2c_algo_pch_data.
256  * @timeout:	waiting time counter (ms).
257  */
258 static s32 pch_i2c_wait_for_bus_idle(struct i2c_algo_pch_data *adap,
259 				     s32 timeout)
260 {
261 	void __iomem *p = adap->pch_base_address;
262 	int schedule = 0;
263 	unsigned long end = jiffies + msecs_to_jiffies(timeout);
264 
265 	while (ioread32(p + PCH_I2CSR) & I2CMBB_BIT) {
266 		if (time_after(jiffies, end)) {
267 			pch_dbg(adap, "I2CSR = %x\n", ioread32(p + PCH_I2CSR));
268 			pch_err(adap, "%s: Timeout Error.return%d\n",
269 					__func__, -ETIME);
270 			pch_i2c_init(adap);
271 
272 			return -ETIME;
273 		}
274 
275 		if (!schedule)
276 			/* Retry after some usecs */
277 			udelay(5);
278 		else
279 			/* Wait a bit more without consuming CPU */
280 			usleep_range(20, 1000);
281 
282 		schedule = 1;
283 	}
284 
285 	return 0;
286 }
287 
288 /**
289  * pch_i2c_start() - Generate I2C start condition in normal mode.
290  * @adap:	Pointer to struct i2c_algo_pch_data.
291  *
292  * Generate I2C start condition in normal mode by setting I2CCTL.I2CMSTA to 1.
293  */
294 static void pch_i2c_start(struct i2c_algo_pch_data *adap)
295 {
296 	void __iomem *p = adap->pch_base_address;
297 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
298 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_START);
299 }
300 
301 /**
302  * pch_i2c_stop() - generate stop condition in normal mode.
303  * @adap:	Pointer to struct i2c_algo_pch_data.
304  */
305 static void pch_i2c_stop(struct i2c_algo_pch_data *adap)
306 {
307 	void __iomem *p = adap->pch_base_address;
308 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
309 	/* clear the start bit */
310 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, PCH_START);
311 }
312 
313 static int pch_i2c_wait_for_check_xfer(struct i2c_algo_pch_data *adap)
314 {
315 	long ret;
316 	void __iomem *p = adap->pch_base_address;
317 
318 	ret = wait_event_timeout(pch_event,
319 			(adap->pch_event_flag != 0), msecs_to_jiffies(1000));
320 	if (!ret) {
321 		pch_err(adap, "%s:wait-event timeout\n", __func__);
322 		adap->pch_event_flag = 0;
323 		pch_i2c_stop(adap);
324 		pch_i2c_init(adap);
325 		return -ETIMEDOUT;
326 	}
327 
328 	if (adap->pch_event_flag & I2C_ERROR_MASK) {
329 		pch_err(adap, "Lost Arbitration\n");
330 		adap->pch_event_flag = 0;
331 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMAL_BIT);
332 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMIF_BIT);
333 		pch_i2c_init(adap);
334 		return -EAGAIN;
335 	}
336 
337 	adap->pch_event_flag = 0;
338 
339 	if (ioread32(p + PCH_I2CSR) & PCH_GETACK) {
340 		pch_dbg(adap, "Receive NACK for slave address setting\n");
341 		return -ENXIO;
342 	}
343 
344 	return 0;
345 }
346 
347 /**
348  * pch_i2c_repstart() - generate repeated start condition in normal mode
349  * @adap:	Pointer to struct i2c_algo_pch_data.
350  */
351 static void pch_i2c_repstart(struct i2c_algo_pch_data *adap)
352 {
353 	void __iomem *p = adap->pch_base_address;
354 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
355 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_REPSTART);
356 }
357 
358 /**
359  * pch_i2c_writebytes() - write data to I2C bus in normal mode
360  * @i2c_adap:	Pointer to the struct i2c_adapter.
361  * @last:	specifies whether last message or not.
362  *		In the case of compound mode it will be 1 for last message,
363  *		otherwise 0.
364  * @first:	specifies whether first message or not.
365  *		1 for first message otherwise 0.
366  */
367 static s32 pch_i2c_writebytes(struct i2c_adapter *i2c_adap,
368 			      struct i2c_msg *msgs, u32 last, u32 first)
369 {
370 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
371 	u8 *buf;
372 	u32 length;
373 	u32 addr;
374 	u32 addr_2_msb;
375 	u32 addr_8_lsb;
376 	s32 wrcount;
377 	s32 rtn;
378 	void __iomem *p = adap->pch_base_address;
379 
380 	length = msgs->len;
381 	buf = msgs->buf;
382 	addr = msgs->addr;
383 
384 	/* enable master tx */
385 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, I2C_TX_MODE);
386 
387 	pch_dbg(adap, "I2CCTL = %x msgs->len = %d\n", ioread32(p + PCH_I2CCTL),
388 		length);
389 
390 	if (first) {
391 		if (pch_i2c_wait_for_bus_idle(adap, BUS_IDLE_TIMEOUT) == -ETIME)
392 			return -ETIME;
393 	}
394 
395 	if (msgs->flags & I2C_M_TEN) {
396 		addr_2_msb = ((addr & I2C_MSB_2B_MSK) >> 7) & 0x06;
397 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
398 		if (first)
399 			pch_i2c_start(adap);
400 
401 		rtn = pch_i2c_wait_for_check_xfer(adap);
402 		if (rtn)
403 			return rtn;
404 
405 		addr_8_lsb = (addr & I2C_ADDR_MSK);
406 		iowrite32(addr_8_lsb, p + PCH_I2CDR);
407 	} else {
408 		/* set 7 bit slave address and R/W bit as 0 */
409 		iowrite32(i2c_8bit_addr_from_msg(msgs), p + PCH_I2CDR);
410 		if (first)
411 			pch_i2c_start(adap);
412 	}
413 
414 	rtn = pch_i2c_wait_for_check_xfer(adap);
415 	if (rtn)
416 		return rtn;
417 
418 	for (wrcount = 0; wrcount < length; ++wrcount) {
419 		/* write buffer value to I2C data register */
420 		iowrite32(buf[wrcount], p + PCH_I2CDR);
421 		pch_dbg(adap, "writing %x to Data register\n", buf[wrcount]);
422 
423 		rtn = pch_i2c_wait_for_check_xfer(adap);
424 		if (rtn)
425 			return rtn;
426 
427 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMCF_BIT);
428 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMIF_BIT);
429 	}
430 
431 	/* check if this is the last message */
432 	if (last)
433 		pch_i2c_stop(adap);
434 	else
435 		pch_i2c_repstart(adap);
436 
437 	pch_dbg(adap, "return=%d\n", wrcount);
438 
439 	return wrcount;
440 }
441 
442 /**
443  * pch_i2c_sendack() - send ACK
444  * @adap:	Pointer to struct i2c_algo_pch_data.
445  */
446 static void pch_i2c_sendack(struct i2c_algo_pch_data *adap)
447 {
448 	void __iomem *p = adap->pch_base_address;
449 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
450 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
451 }
452 
453 /**
454  * pch_i2c_sendnack() - send NACK
455  * @adap:	Pointer to struct i2c_algo_pch_data.
456  */
457 static void pch_i2c_sendnack(struct i2c_algo_pch_data *adap)
458 {
459 	void __iomem *p = adap->pch_base_address;
460 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
461 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
462 }
463 
464 /**
465  * pch_i2c_restart() - Generate I2C restart condition in normal mode.
466  * @adap:	Pointer to struct i2c_algo_pch_data.
467  *
468  * Generate I2C restart condition in normal mode by setting I2CCTL.I2CRSTA.
469  */
470 static void pch_i2c_restart(struct i2c_algo_pch_data *adap)
471 {
472 	void __iomem *p = adap->pch_base_address;
473 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
474 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_RESTART);
475 }
476 
477 /**
478  * pch_i2c_readbytes() - read data  from I2C bus in normal mode.
479  * @i2c_adap:	Pointer to the struct i2c_adapter.
480  * @msgs:	Pointer to i2c_msg structure.
481  * @last:	specifies whether last message or not.
482  * @first:	specifies whether first message or not.
483  */
484 static s32 pch_i2c_readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
485 			     u32 last, u32 first)
486 {
487 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
488 
489 	u8 *buf;
490 	u32 count;
491 	u32 length;
492 	u32 addr;
493 	u32 addr_2_msb;
494 	u32 addr_8_lsb;
495 	void __iomem *p = adap->pch_base_address;
496 	s32 rtn;
497 
498 	length = msgs->len;
499 	buf = msgs->buf;
500 	addr = msgs->addr;
501 
502 	/* enable master reception */
503 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, I2C_TX_MODE);
504 
505 	if (first) {
506 		if (pch_i2c_wait_for_bus_idle(adap, BUS_IDLE_TIMEOUT) == -ETIME)
507 			return -ETIME;
508 	}
509 
510 	if (msgs->flags & I2C_M_TEN) {
511 		addr_2_msb = ((addr & I2C_MSB_2B_MSK) >> 7);
512 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
513 		if (first)
514 			pch_i2c_start(adap);
515 
516 		rtn = pch_i2c_wait_for_check_xfer(adap);
517 		if (rtn)
518 			return rtn;
519 
520 		addr_8_lsb = (addr & I2C_ADDR_MSK);
521 		iowrite32(addr_8_lsb, p + PCH_I2CDR);
522 
523 		pch_i2c_restart(adap);
524 
525 		rtn = pch_i2c_wait_for_check_xfer(adap);
526 		if (rtn)
527 			return rtn;
528 
529 		addr_2_msb |= I2C_RD;
530 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
531 	} else {
532 		/* 7 address bits + R/W bit */
533 		iowrite32(i2c_8bit_addr_from_msg(msgs), p + PCH_I2CDR);
534 	}
535 
536 	/* check if it is the first message */
537 	if (first)
538 		pch_i2c_start(adap);
539 
540 	rtn = pch_i2c_wait_for_check_xfer(adap);
541 	if (rtn)
542 		return rtn;
543 
544 	if (length == 0) {
545 		pch_i2c_stop(adap);
546 		ioread32(p + PCH_I2CDR); /* Dummy read needs */
547 
548 		count = length;
549 	} else {
550 		int read_index;
551 		int loop;
552 		pch_i2c_sendack(adap);
553 
554 		/* Dummy read */
555 		for (loop = 1, read_index = 0; loop < length; loop++) {
556 			buf[read_index] = ioread32(p + PCH_I2CDR);
557 
558 			if (loop != 1)
559 				read_index++;
560 
561 			rtn = pch_i2c_wait_for_check_xfer(adap);
562 			if (rtn)
563 				return rtn;
564 		}	/* end for */
565 
566 		pch_i2c_sendnack(adap);
567 
568 		buf[read_index] = ioread32(p + PCH_I2CDR); /* Read final - 1 */
569 
570 		if (length != 1)
571 			read_index++;
572 
573 		rtn = pch_i2c_wait_for_check_xfer(adap);
574 		if (rtn)
575 			return rtn;
576 
577 		if (last)
578 			pch_i2c_stop(adap);
579 		else
580 			pch_i2c_repstart(adap);
581 
582 		buf[read_index++] = ioread32(p + PCH_I2CDR); /* Read Final */
583 		count = read_index;
584 	}
585 
586 	return count;
587 }
588 
589 /**
590  * pch_i2c_cb() - Interrupt handler Call back function
591  * @adap:	Pointer to struct i2c_algo_pch_data.
592  */
593 static void pch_i2c_cb(struct i2c_algo_pch_data *adap)
594 {
595 	u32 sts;
596 	void __iomem *p = adap->pch_base_address;
597 
598 	sts = ioread32(p + PCH_I2CSR);
599 	sts &= (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT);
600 	if (sts & I2CMAL_BIT)
601 		adap->pch_event_flag |= I2CMAL_EVENT;
602 
603 	if (sts & I2CMCF_BIT)
604 		adap->pch_event_flag |= I2CMCF_EVENT;
605 
606 	/* clear the applicable bits */
607 	pch_clrbit(adap->pch_base_address, PCH_I2CSR, sts);
608 
609 	pch_dbg(adap, "PCH_I2CSR = %x\n", ioread32(p + PCH_I2CSR));
610 
611 	wake_up(&pch_event);
612 }
613 
614 /**
615  * pch_i2c_handler() - interrupt handler for the PCH I2C controller
616  * @irq:	irq number.
617  * @pData:	cookie passed back to the handler function.
618  */
619 static irqreturn_t pch_i2c_handler(int irq, void *pData)
620 {
621 	u32 reg_val;
622 	int flag;
623 	int i;
624 	struct adapter_info *adap_info = pData;
625 	void __iomem *p;
626 	u32 mode;
627 
628 	for (i = 0, flag = 0; i < adap_info->ch_num; i++) {
629 		p = adap_info->pch_data[i].pch_base_address;
630 		mode = ioread32(p + PCH_I2CMOD);
631 		mode &= BUFFER_MODE | EEPROM_SR_MODE;
632 		if (mode != NORMAL_MODE) {
633 			pch_err(adap_info->pch_data,
634 				"I2C-%d mode(%d) is not supported\n", mode, i);
635 			continue;
636 		}
637 		reg_val = ioread32(p + PCH_I2CSR);
638 		if (reg_val & (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT)) {
639 			pch_i2c_cb(&adap_info->pch_data[i]);
640 			flag = 1;
641 		}
642 	}
643 
644 	return flag ? IRQ_HANDLED : IRQ_NONE;
645 }
646 
647 /**
648  * pch_i2c_xfer() - Reading adnd writing data through I2C bus
649  * @i2c_adap:	Pointer to the struct i2c_adapter.
650  * @msgs:	Pointer to i2c_msg structure.
651  * @num:	number of messages.
652  */
653 static s32 pch_i2c_xfer(struct i2c_adapter *i2c_adap,
654 			struct i2c_msg *msgs, s32 num)
655 {
656 	struct i2c_msg *pmsg;
657 	u32 i = 0;
658 	u32 status;
659 	s32 ret;
660 
661 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
662 
663 	ret = mutex_lock_interruptible(&pch_mutex);
664 	if (ret)
665 		return ret;
666 
667 	if (adap->p_adapter_info->pch_i2c_suspended) {
668 		mutex_unlock(&pch_mutex);
669 		return -EBUSY;
670 	}
671 
672 	pch_dbg(adap, "adap->p_adapter_info->pch_i2c_suspended is %d\n",
673 		adap->p_adapter_info->pch_i2c_suspended);
674 	/* transfer not completed */
675 	adap->pch_i2c_xfer_in_progress = true;
676 
677 	for (i = 0; i < num && ret >= 0; i++) {
678 		pmsg = &msgs[i];
679 		pmsg->flags |= adap->pch_buff_mode_en;
680 		status = pmsg->flags;
681 		pch_dbg(adap,
682 			"After invoking I2C_MODE_SEL :flag= 0x%x\n", status);
683 
684 		if ((status & (I2C_M_RD)) != false) {
685 			ret = pch_i2c_readbytes(i2c_adap, pmsg, (i + 1 == num),
686 						(i == 0));
687 		} else {
688 			ret = pch_i2c_writebytes(i2c_adap, pmsg, (i + 1 == num),
689 						 (i == 0));
690 		}
691 	}
692 
693 	adap->pch_i2c_xfer_in_progress = false;	/* transfer completed */
694 
695 	mutex_unlock(&pch_mutex);
696 
697 	return (ret < 0) ? ret : num;
698 }
699 
700 /**
701  * pch_i2c_func() - return the functionality of the I2C driver
702  * @adap:	Pointer to struct i2c_algo_pch_data.
703  */
704 static u32 pch_i2c_func(struct i2c_adapter *adap)
705 {
706 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
707 }
708 
709 static const struct i2c_algorithm pch_algorithm = {
710 	.master_xfer = pch_i2c_xfer,
711 	.functionality = pch_i2c_func
712 };
713 
714 /**
715  * pch_i2c_disbl_int() - Disable PCH I2C interrupts
716  * @adap:	Pointer to struct i2c_algo_pch_data.
717  */
718 static void pch_i2c_disbl_int(struct i2c_algo_pch_data *adap)
719 {
720 	void __iomem *p = adap->pch_base_address;
721 
722 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, NORMAL_INTR_ENBL);
723 
724 	iowrite32(EEPROM_RST_INTR_DISBL, p + PCH_I2CESRMSK);
725 
726 	iowrite32(BUFFER_MODE_INTR_DISBL, p + PCH_I2CBUFMSK);
727 }
728 
729 static int pch_i2c_probe(struct pci_dev *pdev,
730 				   const struct pci_device_id *id)
731 {
732 	void __iomem *base_addr;
733 	int ret;
734 	int i, j;
735 	struct adapter_info *adap_info;
736 	struct i2c_adapter *pch_adap;
737 
738 	pch_pci_dbg(pdev, "Entered.\n");
739 
740 	adap_info = kzalloc((sizeof(struct adapter_info)), GFP_KERNEL);
741 	if (adap_info == NULL)
742 		return -ENOMEM;
743 
744 	ret = pci_enable_device(pdev);
745 	if (ret) {
746 		pch_pci_err(pdev, "pci_enable_device FAILED\n");
747 		goto err_pci_enable;
748 	}
749 
750 	ret = pci_request_regions(pdev, KBUILD_MODNAME);
751 	if (ret) {
752 		pch_pci_err(pdev, "pci_request_regions FAILED\n");
753 		goto err_pci_req;
754 	}
755 
756 	base_addr = pci_iomap(pdev, 1, 0);
757 
758 	if (base_addr == NULL) {
759 		pch_pci_err(pdev, "pci_iomap FAILED\n");
760 		ret = -ENOMEM;
761 		goto err_pci_iomap;
762 	}
763 
764 	/* Set the number of I2C channel instance */
765 	adap_info->ch_num = id->driver_data;
766 
767 	for (i = 0; i < adap_info->ch_num; i++) {
768 		pch_adap = &adap_info->pch_data[i].pch_adapter;
769 		adap_info->pch_i2c_suspended = false;
770 
771 		adap_info->pch_data[i].p_adapter_info = adap_info;
772 
773 		pch_adap->owner = THIS_MODULE;
774 		pch_adap->class = I2C_CLASS_HWMON;
775 		strlcpy(pch_adap->name, KBUILD_MODNAME, sizeof(pch_adap->name));
776 		pch_adap->algo = &pch_algorithm;
777 		pch_adap->algo_data = &adap_info->pch_data[i];
778 
779 		/* base_addr + offset; */
780 		adap_info->pch_data[i].pch_base_address = base_addr + 0x100 * i;
781 
782 		pch_adap->dev.of_node = pdev->dev.of_node;
783 		pch_adap->dev.parent = &pdev->dev;
784 	}
785 
786 	ret = request_irq(pdev->irq, pch_i2c_handler, IRQF_SHARED,
787 		  KBUILD_MODNAME, adap_info);
788 	if (ret) {
789 		pch_pci_err(pdev, "request_irq FAILED\n");
790 		goto err_request_irq;
791 	}
792 
793 	for (i = 0; i < adap_info->ch_num; i++) {
794 		pch_adap = &adap_info->pch_data[i].pch_adapter;
795 
796 		pch_i2c_init(&adap_info->pch_data[i]);
797 
798 		pch_adap->nr = i;
799 		ret = i2c_add_numbered_adapter(pch_adap);
800 		if (ret) {
801 			pch_pci_err(pdev, "i2c_add_adapter[ch:%d] FAILED\n", i);
802 			goto err_add_adapter;
803 		}
804 	}
805 
806 	pci_set_drvdata(pdev, adap_info);
807 	pch_pci_dbg(pdev, "returns %d.\n", ret);
808 	return 0;
809 
810 err_add_adapter:
811 	for (j = 0; j < i; j++)
812 		i2c_del_adapter(&adap_info->pch_data[j].pch_adapter);
813 	free_irq(pdev->irq, adap_info);
814 err_request_irq:
815 	pci_iounmap(pdev, base_addr);
816 err_pci_iomap:
817 	pci_release_regions(pdev);
818 err_pci_req:
819 	pci_disable_device(pdev);
820 err_pci_enable:
821 	kfree(adap_info);
822 	return ret;
823 }
824 
825 static void pch_i2c_remove(struct pci_dev *pdev)
826 {
827 	int i;
828 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
829 
830 	free_irq(pdev->irq, adap_info);
831 
832 	for (i = 0; i < adap_info->ch_num; i++) {
833 		pch_i2c_disbl_int(&adap_info->pch_data[i]);
834 		i2c_del_adapter(&adap_info->pch_data[i].pch_adapter);
835 	}
836 
837 	if (adap_info->pch_data[0].pch_base_address)
838 		pci_iounmap(pdev, adap_info->pch_data[0].pch_base_address);
839 
840 	for (i = 0; i < adap_info->ch_num; i++)
841 		adap_info->pch_data[i].pch_base_address = 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 = pch_i2c_remove,
921 	.suspend = pch_i2c_suspend,
922 	.resume = pch_i2c_resume
923 };
924 
925 module_pci_driver(pch_pcidriver);
926 
927 MODULE_DESCRIPTION("Intel EG20T PCH/LAPIS Semico ML7213/ML7223/ML7831 IOH I2C");
928 MODULE_LICENSE("GPL");
929 MODULE_AUTHOR("Tomoya MORINAGA. <tomoya.rohm@gmail.com>");
930 module_param(pch_i2c_speed, int, (S_IRUSR | S_IWUSR));
931 module_param(pch_clk, int, (S_IRUSR | S_IWUSR));
932