xref: /openbmc/linux/drivers/i2c/busses/i2c-eg20t.c (revision 55fd7e02)
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 
184 static irqreturn_t pch_i2c_handler(int irq, void *pData);
185 
186 static inline void pch_setbit(void __iomem *addr, u32 offset, u32 bitmask)
187 {
188 	u32 val;
189 	val = ioread32(addr + offset);
190 	val |= bitmask;
191 	iowrite32(val, addr + offset);
192 }
193 
194 static inline void pch_clrbit(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 /**
203  * pch_i2c_init() - hardware initialization of I2C module
204  * @adap:	Pointer to struct i2c_algo_pch_data.
205  */
206 static void pch_i2c_init(struct i2c_algo_pch_data *adap)
207 {
208 	void __iomem *p = adap->pch_base_address;
209 	u32 pch_i2cbc;
210 	u32 pch_i2ctmr;
211 	u32 reg_value;
212 
213 	/* reset I2C controller */
214 	iowrite32(0x01, p + PCH_I2CSRST);
215 	msleep(20);
216 	iowrite32(0x0, p + PCH_I2CSRST);
217 
218 	/* Initialize I2C registers */
219 	iowrite32(0x21, p + PCH_I2CNF);
220 
221 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_I2CCTL_I2CMEN);
222 
223 	if (pch_i2c_speed != 400)
224 		pch_i2c_speed = 100;
225 
226 	reg_value = PCH_I2CCTL_I2CMEN;
227 	if (pch_i2c_speed == FAST_MODE_CLK) {
228 		reg_value |= FAST_MODE_EN;
229 		pch_dbg(adap, "Fast mode enabled\n");
230 	}
231 
232 	if (pch_clk > PCH_MAX_CLK)
233 		pch_clk = 62500;
234 
235 	pch_i2cbc = (pch_clk + (pch_i2c_speed * 4)) / (pch_i2c_speed * 8);
236 	/* Set transfer speed in I2CBC */
237 	iowrite32(pch_i2cbc, p + PCH_I2CBC);
238 
239 	pch_i2ctmr = (pch_clk) / 8;
240 	iowrite32(pch_i2ctmr, p + PCH_I2CTMR);
241 
242 	reg_value |= NORMAL_INTR_ENBL;	/* Enable interrupts in normal mode */
243 	iowrite32(reg_value, p + PCH_I2CCTL);
244 
245 	pch_dbg(adap,
246 		"I2CCTL=%x pch_i2cbc=%x pch_i2ctmr=%x Enable interrupts\n",
247 		ioread32(p + PCH_I2CCTL), pch_i2cbc, pch_i2ctmr);
248 
249 	init_waitqueue_head(&pch_event);
250 }
251 
252 /**
253  * pch_i2c_wait_for_bus_idle() - check the status of bus.
254  * @adap:	Pointer to struct i2c_algo_pch_data.
255  * @timeout:	waiting time counter (ms).
256  */
257 static s32 pch_i2c_wait_for_bus_idle(struct i2c_algo_pch_data *adap,
258 				     s32 timeout)
259 {
260 	void __iomem *p = adap->pch_base_address;
261 	int schedule = 0;
262 	unsigned long end = jiffies + msecs_to_jiffies(timeout);
263 
264 	while (ioread32(p + PCH_I2CSR) & I2CMBB_BIT) {
265 		if (time_after(jiffies, end)) {
266 			pch_dbg(adap, "I2CSR = %x\n", ioread32(p + PCH_I2CSR));
267 			pch_err(adap, "%s: Timeout Error.return%d\n",
268 					__func__, -ETIME);
269 			pch_i2c_init(adap);
270 
271 			return -ETIME;
272 		}
273 
274 		if (!schedule)
275 			/* Retry after some usecs */
276 			udelay(5);
277 		else
278 			/* Wait a bit more without consuming CPU */
279 			usleep_range(20, 1000);
280 
281 		schedule = 1;
282 	}
283 
284 	return 0;
285 }
286 
287 /**
288  * pch_i2c_start() - Generate I2C start condition in normal mode.
289  * @adap:	Pointer to struct i2c_algo_pch_data.
290  *
291  * Generate I2C start condition in normal mode by setting I2CCTL.I2CMSTA to 1.
292  */
293 static void pch_i2c_start(struct i2c_algo_pch_data *adap)
294 {
295 	void __iomem *p = adap->pch_base_address;
296 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
297 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_START);
298 }
299 
300 /**
301  * pch_i2c_stop() - generate stop condition in normal mode.
302  * @adap:	Pointer to struct i2c_algo_pch_data.
303  */
304 static void pch_i2c_stop(struct i2c_algo_pch_data *adap)
305 {
306 	void __iomem *p = adap->pch_base_address;
307 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
308 	/* clear the start bit */
309 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, PCH_START);
310 }
311 
312 static int pch_i2c_wait_for_check_xfer(struct i2c_algo_pch_data *adap)
313 {
314 	long ret;
315 	void __iomem *p = adap->pch_base_address;
316 
317 	ret = wait_event_timeout(pch_event,
318 			(adap->pch_event_flag != 0), msecs_to_jiffies(1000));
319 	if (!ret) {
320 		pch_err(adap, "%s:wait-event timeout\n", __func__);
321 		adap->pch_event_flag = 0;
322 		pch_i2c_stop(adap);
323 		pch_i2c_init(adap);
324 		return -ETIMEDOUT;
325 	}
326 
327 	if (adap->pch_event_flag & I2C_ERROR_MASK) {
328 		pch_err(adap, "Lost Arbitration\n");
329 		adap->pch_event_flag = 0;
330 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMAL_BIT);
331 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMIF_BIT);
332 		pch_i2c_init(adap);
333 		return -EAGAIN;
334 	}
335 
336 	adap->pch_event_flag = 0;
337 
338 	if (ioread32(p + PCH_I2CSR) & PCH_GETACK) {
339 		pch_dbg(adap, "Receive NACK for slave address setting\n");
340 		return -ENXIO;
341 	}
342 
343 	return 0;
344 }
345 
346 /**
347  * pch_i2c_repstart() - generate repeated start condition in normal mode
348  * @adap:	Pointer to struct i2c_algo_pch_data.
349  */
350 static void pch_i2c_repstart(struct i2c_algo_pch_data *adap)
351 {
352 	void __iomem *p = adap->pch_base_address;
353 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
354 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_REPSTART);
355 }
356 
357 /**
358  * pch_i2c_writebytes() - write data to I2C bus in normal mode
359  * @i2c_adap:	Pointer to the struct i2c_adapter.
360  * @last:	specifies whether last message or not.
361  *		In the case of compound mode it will be 1 for last message,
362  *		otherwise 0.
363  * @first:	specifies whether first message or not.
364  *		1 for first message otherwise 0.
365  */
366 static s32 pch_i2c_writebytes(struct i2c_adapter *i2c_adap,
367 			      struct i2c_msg *msgs, u32 last, u32 first)
368 {
369 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
370 	u8 *buf;
371 	u32 length;
372 	u32 addr;
373 	u32 addr_2_msb;
374 	u32 addr_8_lsb;
375 	s32 wrcount;
376 	s32 rtn;
377 	void __iomem *p = adap->pch_base_address;
378 
379 	length = msgs->len;
380 	buf = msgs->buf;
381 	addr = msgs->addr;
382 
383 	/* enable master tx */
384 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, I2C_TX_MODE);
385 
386 	pch_dbg(adap, "I2CCTL = %x msgs->len = %d\n", ioread32(p + PCH_I2CCTL),
387 		length);
388 
389 	if (first) {
390 		if (pch_i2c_wait_for_bus_idle(adap, BUS_IDLE_TIMEOUT) == -ETIME)
391 			return -ETIME;
392 	}
393 
394 	if (msgs->flags & I2C_M_TEN) {
395 		addr_2_msb = ((addr & I2C_MSB_2B_MSK) >> 7) & 0x06;
396 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
397 		if (first)
398 			pch_i2c_start(adap);
399 
400 		rtn = pch_i2c_wait_for_check_xfer(adap);
401 		if (rtn)
402 			return rtn;
403 
404 		addr_8_lsb = (addr & I2C_ADDR_MSK);
405 		iowrite32(addr_8_lsb, p + PCH_I2CDR);
406 	} else {
407 		/* set 7 bit slave address and R/W bit as 0 */
408 		iowrite32(i2c_8bit_addr_from_msg(msgs), p + PCH_I2CDR);
409 		if (first)
410 			pch_i2c_start(adap);
411 	}
412 
413 	rtn = pch_i2c_wait_for_check_xfer(adap);
414 	if (rtn)
415 		return rtn;
416 
417 	for (wrcount = 0; wrcount < length; ++wrcount) {
418 		/* write buffer value to I2C data register */
419 		iowrite32(buf[wrcount], p + PCH_I2CDR);
420 		pch_dbg(adap, "writing %x to Data register\n", buf[wrcount]);
421 
422 		rtn = pch_i2c_wait_for_check_xfer(adap);
423 		if (rtn)
424 			return rtn;
425 
426 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMCF_BIT);
427 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMIF_BIT);
428 	}
429 
430 	/* check if this is the last message */
431 	if (last)
432 		pch_i2c_stop(adap);
433 	else
434 		pch_i2c_repstart(adap);
435 
436 	pch_dbg(adap, "return=%d\n", wrcount);
437 
438 	return wrcount;
439 }
440 
441 /**
442  * pch_i2c_sendack() - send ACK
443  * @adap:	Pointer to struct i2c_algo_pch_data.
444  */
445 static void pch_i2c_sendack(struct i2c_algo_pch_data *adap)
446 {
447 	void __iomem *p = adap->pch_base_address;
448 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
449 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
450 }
451 
452 /**
453  * pch_i2c_sendnack() - send NACK
454  * @adap:	Pointer to struct i2c_algo_pch_data.
455  */
456 static void pch_i2c_sendnack(struct i2c_algo_pch_data *adap)
457 {
458 	void __iomem *p = adap->pch_base_address;
459 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
460 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
461 }
462 
463 /**
464  * pch_i2c_restart() - Generate I2C restart condition in normal mode.
465  * @adap:	Pointer to struct i2c_algo_pch_data.
466  *
467  * Generate I2C restart condition in normal mode by setting I2CCTL.I2CRSTA.
468  */
469 static void pch_i2c_restart(struct i2c_algo_pch_data *adap)
470 {
471 	void __iomem *p = adap->pch_base_address;
472 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
473 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_RESTART);
474 }
475 
476 /**
477  * pch_i2c_readbytes() - read data  from I2C bus in normal mode.
478  * @i2c_adap:	Pointer to the struct i2c_adapter.
479  * @msgs:	Pointer to i2c_msg structure.
480  * @last:	specifies whether last message or not.
481  * @first:	specifies whether first message or not.
482  */
483 static s32 pch_i2c_readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
484 			     u32 last, u32 first)
485 {
486 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
487 
488 	u8 *buf;
489 	u32 count;
490 	u32 length;
491 	u32 addr;
492 	u32 addr_2_msb;
493 	u32 addr_8_lsb;
494 	void __iomem *p = adap->pch_base_address;
495 	s32 rtn;
496 
497 	length = msgs->len;
498 	buf = msgs->buf;
499 	addr = msgs->addr;
500 
501 	/* enable master reception */
502 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, I2C_TX_MODE);
503 
504 	if (first) {
505 		if (pch_i2c_wait_for_bus_idle(adap, BUS_IDLE_TIMEOUT) == -ETIME)
506 			return -ETIME;
507 	}
508 
509 	if (msgs->flags & I2C_M_TEN) {
510 		addr_2_msb = ((addr & I2C_MSB_2B_MSK) >> 7);
511 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
512 		if (first)
513 			pch_i2c_start(adap);
514 
515 		rtn = pch_i2c_wait_for_check_xfer(adap);
516 		if (rtn)
517 			return rtn;
518 
519 		addr_8_lsb = (addr & I2C_ADDR_MSK);
520 		iowrite32(addr_8_lsb, p + PCH_I2CDR);
521 
522 		pch_i2c_restart(adap);
523 
524 		rtn = pch_i2c_wait_for_check_xfer(adap);
525 		if (rtn)
526 			return rtn;
527 
528 		addr_2_msb |= I2C_RD;
529 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
530 	} else {
531 		/* 7 address bits + R/W bit */
532 		iowrite32(i2c_8bit_addr_from_msg(msgs), p + PCH_I2CDR);
533 	}
534 
535 	/* check if it is the first message */
536 	if (first)
537 		pch_i2c_start(adap);
538 
539 	rtn = pch_i2c_wait_for_check_xfer(adap);
540 	if (rtn)
541 		return rtn;
542 
543 	if (length == 0) {
544 		pch_i2c_stop(adap);
545 		ioread32(p + PCH_I2CDR); /* Dummy read needs */
546 
547 		count = length;
548 	} else {
549 		int read_index;
550 		int loop;
551 		pch_i2c_sendack(adap);
552 
553 		/* Dummy read */
554 		for (loop = 1, read_index = 0; loop < length; loop++) {
555 			buf[read_index] = ioread32(p + PCH_I2CDR);
556 
557 			if (loop != 1)
558 				read_index++;
559 
560 			rtn = pch_i2c_wait_for_check_xfer(adap);
561 			if (rtn)
562 				return rtn;
563 		}	/* end for */
564 
565 		pch_i2c_sendnack(adap);
566 
567 		buf[read_index] = ioread32(p + PCH_I2CDR); /* Read final - 1 */
568 
569 		if (length != 1)
570 			read_index++;
571 
572 		rtn = pch_i2c_wait_for_check_xfer(adap);
573 		if (rtn)
574 			return rtn;
575 
576 		if (last)
577 			pch_i2c_stop(adap);
578 		else
579 			pch_i2c_repstart(adap);
580 
581 		buf[read_index++] = ioread32(p + PCH_I2CDR); /* Read Final */
582 		count = read_index;
583 	}
584 
585 	return count;
586 }
587 
588 /**
589  * pch_i2c_cb() - Interrupt handler Call back function
590  * @adap:	Pointer to struct i2c_algo_pch_data.
591  */
592 static void pch_i2c_cb(struct i2c_algo_pch_data *adap)
593 {
594 	u32 sts;
595 	void __iomem *p = adap->pch_base_address;
596 
597 	sts = ioread32(p + PCH_I2CSR);
598 	sts &= (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT);
599 	if (sts & I2CMAL_BIT)
600 		adap->pch_event_flag |= I2CMAL_EVENT;
601 
602 	if (sts & I2CMCF_BIT)
603 		adap->pch_event_flag |= I2CMCF_EVENT;
604 
605 	/* clear the applicable bits */
606 	pch_clrbit(adap->pch_base_address, PCH_I2CSR, sts);
607 
608 	pch_dbg(adap, "PCH_I2CSR = %x\n", ioread32(p + PCH_I2CSR));
609 
610 	wake_up(&pch_event);
611 }
612 
613 /**
614  * pch_i2c_handler() - interrupt handler for the PCH I2C controller
615  * @irq:	irq number.
616  * @pData:	cookie passed back to the handler function.
617  */
618 static irqreturn_t pch_i2c_handler(int irq, void *pData)
619 {
620 	u32 reg_val;
621 	int flag;
622 	int i;
623 	struct adapter_info *adap_info = pData;
624 	void __iomem *p;
625 	u32 mode;
626 
627 	for (i = 0, flag = 0; i < adap_info->ch_num; i++) {
628 		p = adap_info->pch_data[i].pch_base_address;
629 		mode = ioread32(p + PCH_I2CMOD);
630 		mode &= BUFFER_MODE | EEPROM_SR_MODE;
631 		if (mode != NORMAL_MODE) {
632 			pch_err(adap_info->pch_data,
633 				"I2C-%d mode(%d) is not supported\n", mode, i);
634 			continue;
635 		}
636 		reg_val = ioread32(p + PCH_I2CSR);
637 		if (reg_val & (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT)) {
638 			pch_i2c_cb(&adap_info->pch_data[i]);
639 			flag = 1;
640 		}
641 	}
642 
643 	return flag ? IRQ_HANDLED : IRQ_NONE;
644 }
645 
646 /**
647  * pch_i2c_xfer() - Reading adnd writing data through I2C bus
648  * @i2c_adap:	Pointer to the struct i2c_adapter.
649  * @msgs:	Pointer to i2c_msg structure.
650  * @num:	number of messages.
651  */
652 static s32 pch_i2c_xfer(struct i2c_adapter *i2c_adap,
653 			struct i2c_msg *msgs, s32 num)
654 {
655 	struct i2c_msg *pmsg;
656 	u32 i = 0;
657 	u32 status;
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 ret;
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 
683 		if ((status & (I2C_M_RD)) != false) {
684 			ret = pch_i2c_readbytes(i2c_adap, pmsg, (i + 1 == num),
685 						(i == 0));
686 		} else {
687 			ret = pch_i2c_writebytes(i2c_adap, pmsg, (i + 1 == num),
688 						 (i == 0));
689 		}
690 	}
691 
692 	adap->pch_i2c_xfer_in_progress = false;	/* transfer completed */
693 
694 	mutex_unlock(&pch_mutex);
695 
696 	return (ret < 0) ? ret : num;
697 }
698 
699 /**
700  * pch_i2c_func() - return the functionality of the I2C driver
701  * @adap:	Pointer to struct i2c_algo_pch_data.
702  */
703 static u32 pch_i2c_func(struct i2c_adapter *adap)
704 {
705 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
706 }
707 
708 static const struct i2c_algorithm pch_algorithm = {
709 	.master_xfer = pch_i2c_xfer,
710 	.functionality = pch_i2c_func
711 };
712 
713 /**
714  * pch_i2c_disbl_int() - Disable PCH I2C interrupts
715  * @adap:	Pointer to struct i2c_algo_pch_data.
716  */
717 static void pch_i2c_disbl_int(struct i2c_algo_pch_data *adap)
718 {
719 	void __iomem *p = adap->pch_base_address;
720 
721 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, NORMAL_INTR_ENBL);
722 
723 	iowrite32(EEPROM_RST_INTR_DISBL, p + PCH_I2CESRMSK);
724 
725 	iowrite32(BUFFER_MODE_INTR_DISBL, p + PCH_I2CBUFMSK);
726 }
727 
728 static int pch_i2c_probe(struct pci_dev *pdev,
729 				   const struct pci_device_id *id)
730 {
731 	void __iomem *base_addr;
732 	int ret;
733 	int i, j;
734 	struct adapter_info *adap_info;
735 	struct i2c_adapter *pch_adap;
736 
737 	pch_pci_dbg(pdev, "Entered.\n");
738 
739 	adap_info = kzalloc((sizeof(struct adapter_info)), GFP_KERNEL);
740 	if (adap_info == NULL)
741 		return -ENOMEM;
742 
743 	ret = pci_enable_device(pdev);
744 	if (ret) {
745 		pch_pci_err(pdev, "pci_enable_device FAILED\n");
746 		goto err_pci_enable;
747 	}
748 
749 	ret = pci_request_regions(pdev, KBUILD_MODNAME);
750 	if (ret) {
751 		pch_pci_err(pdev, "pci_request_regions FAILED\n");
752 		goto err_pci_req;
753 	}
754 
755 	base_addr = pci_iomap(pdev, 1, 0);
756 
757 	if (base_addr == NULL) {
758 		pch_pci_err(pdev, "pci_iomap FAILED\n");
759 		ret = -ENOMEM;
760 		goto err_pci_iomap;
761 	}
762 
763 	/* Set the number of I2C channel instance */
764 	adap_info->ch_num = id->driver_data;
765 
766 	for (i = 0; i < adap_info->ch_num; i++) {
767 		pch_adap = &adap_info->pch_data[i].pch_adapter;
768 		adap_info->pch_i2c_suspended = false;
769 
770 		adap_info->pch_data[i].p_adapter_info = adap_info;
771 
772 		pch_adap->owner = THIS_MODULE;
773 		pch_adap->class = I2C_CLASS_HWMON;
774 		strlcpy(pch_adap->name, KBUILD_MODNAME, sizeof(pch_adap->name));
775 		pch_adap->algo = &pch_algorithm;
776 		pch_adap->algo_data = &adap_info->pch_data[i];
777 
778 		/* base_addr + offset; */
779 		adap_info->pch_data[i].pch_base_address = base_addr + 0x100 * i;
780 
781 		pch_adap->dev.of_node = pdev->dev.of_node;
782 		pch_adap->dev.parent = &pdev->dev;
783 	}
784 
785 	ret = request_irq(pdev->irq, pch_i2c_handler, IRQF_SHARED,
786 		  KBUILD_MODNAME, adap_info);
787 	if (ret) {
788 		pch_pci_err(pdev, "request_irq FAILED\n");
789 		goto err_request_irq;
790 	}
791 
792 	for (i = 0; i < adap_info->ch_num; i++) {
793 		pch_adap = &adap_info->pch_data[i].pch_adapter;
794 
795 		pch_i2c_init(&adap_info->pch_data[i]);
796 
797 		pch_adap->nr = i;
798 		ret = i2c_add_numbered_adapter(pch_adap);
799 		if (ret) {
800 			pch_pci_err(pdev, "i2c_add_adapter[ch:%d] FAILED\n", i);
801 			goto err_add_adapter;
802 		}
803 	}
804 
805 	pci_set_drvdata(pdev, adap_info);
806 	pch_pci_dbg(pdev, "returns %d.\n", ret);
807 	return 0;
808 
809 err_add_adapter:
810 	for (j = 0; j < i; j++)
811 		i2c_del_adapter(&adap_info->pch_data[j].pch_adapter);
812 	free_irq(pdev->irq, adap_info);
813 err_request_irq:
814 	pci_iounmap(pdev, base_addr);
815 err_pci_iomap:
816 	pci_release_regions(pdev);
817 err_pci_req:
818 	pci_disable_device(pdev);
819 err_pci_enable:
820 	kfree(adap_info);
821 	return ret;
822 }
823 
824 static void pch_i2c_remove(struct pci_dev *pdev)
825 {
826 	int i;
827 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
828 
829 	free_irq(pdev->irq, adap_info);
830 
831 	for (i = 0; i < adap_info->ch_num; i++) {
832 		pch_i2c_disbl_int(&adap_info->pch_data[i]);
833 		i2c_del_adapter(&adap_info->pch_data[i].pch_adapter);
834 	}
835 
836 	if (adap_info->pch_data[0].pch_base_address)
837 		pci_iounmap(pdev, adap_info->pch_data[0].pch_base_address);
838 
839 	for (i = 0; i < adap_info->ch_num; i++)
840 		adap_info->pch_data[i].pch_base_address = NULL;
841 
842 	pci_release_regions(pdev);
843 
844 	pci_disable_device(pdev);
845 	kfree(adap_info);
846 }
847 
848 #ifdef CONFIG_PM
849 static int pch_i2c_suspend(struct pci_dev *pdev, pm_message_t state)
850 {
851 	int ret;
852 	int i;
853 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
854 	void __iomem *p = adap_info->pch_data[0].pch_base_address;
855 
856 	adap_info->pch_i2c_suspended = true;
857 
858 	for (i = 0; i < adap_info->ch_num; i++) {
859 		while ((adap_info->pch_data[i].pch_i2c_xfer_in_progress)) {
860 			/* Wait until all channel transfers are completed */
861 			msleep(20);
862 		}
863 	}
864 
865 	/* Disable the i2c interrupts */
866 	for (i = 0; i < adap_info->ch_num; i++)
867 		pch_i2c_disbl_int(&adap_info->pch_data[i]);
868 
869 	pch_pci_dbg(pdev, "I2CSR = %x I2CBUFSTA = %x I2CESRSTA = %x "
870 		"invoked function pch_i2c_disbl_int successfully\n",
871 		ioread32(p + PCH_I2CSR), ioread32(p + PCH_I2CBUFSTA),
872 		ioread32(p + PCH_I2CESRSTA));
873 
874 	ret = pci_save_state(pdev);
875 
876 	if (ret) {
877 		pch_pci_err(pdev, "pci_save_state\n");
878 		return ret;
879 	}
880 
881 	pci_enable_wake(pdev, PCI_D3hot, 0);
882 	pci_disable_device(pdev);
883 	pci_set_power_state(pdev, pci_choose_state(pdev, state));
884 
885 	return 0;
886 }
887 
888 static int pch_i2c_resume(struct pci_dev *pdev)
889 {
890 	int i;
891 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
892 
893 	pci_set_power_state(pdev, PCI_D0);
894 	pci_restore_state(pdev);
895 
896 	if (pci_enable_device(pdev) < 0) {
897 		pch_pci_err(pdev, "pch_i2c_resume:pci_enable_device FAILED\n");
898 		return -EIO;
899 	}
900 
901 	pci_enable_wake(pdev, PCI_D3hot, 0);
902 
903 	for (i = 0; i < adap_info->ch_num; i++)
904 		pch_i2c_init(&adap_info->pch_data[i]);
905 
906 	adap_info->pch_i2c_suspended = false;
907 
908 	return 0;
909 }
910 #else
911 #define pch_i2c_suspend NULL
912 #define pch_i2c_resume NULL
913 #endif
914 
915 static struct pci_driver pch_pcidriver = {
916 	.name = KBUILD_MODNAME,
917 	.id_table = pch_pcidev_id,
918 	.probe = pch_i2c_probe,
919 	.remove = pch_i2c_remove,
920 	.suspend = pch_i2c_suspend,
921 	.resume = pch_i2c_resume
922 };
923 
924 module_pci_driver(pch_pcidriver);
925 
926 MODULE_DESCRIPTION("Intel EG20T PCH/LAPIS Semico ML7213/ML7223/ML7831 IOH I2C");
927 MODULE_LICENSE("GPL");
928 MODULE_AUTHOR("Tomoya MORINAGA. <tomoya.rohm@gmail.com>");
929 module_param(pch_i2c_speed, int, (S_IRUSR | S_IWUSR));
930 module_param(pch_clk, int, (S_IRUSR | S_IWUSR));
931