xref: /linux/drivers/i2c/busses/i2c-eg20t.c (revision f2ee442115c9b6219083c019939a9cc0c9abb2f8)
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_RESTART		0x0004
68 #define PCH_ESR_START		0x0001
69 #define PCH_BUFF_START		0x1
70 #define PCH_REPSTART		0x0004
71 #define PCH_ACK			0x0008
72 #define PCH_GETACK		0x0001
73 #define CLR_REG			0x0
74 #define I2C_RD			0x1
75 #define I2CMCF_BIT		0x0080
76 #define I2CMIF_BIT		0x0002
77 #define I2CMAL_BIT		0x0010
78 #define I2CBMFI_BIT		0x0001
79 #define I2CBMAL_BIT		0x0002
80 #define I2CBMNA_BIT		0x0004
81 #define I2CBMTO_BIT		0x0008
82 #define I2CBMIS_BIT		0x0010
83 #define I2CESRFI_BIT		0X0001
84 #define I2CESRTO_BIT		0x0002
85 #define I2CESRFIIE_BIT		0x1
86 #define I2CESRTOIE_BIT		0x2
87 #define I2CBMDZ_BIT		0x0040
88 #define I2CBMAG_BIT		0x0020
89 #define I2CMBB_BIT		0x0020
90 #define BUFFER_MODE_MASK	(I2CBMFI_BIT | I2CBMAL_BIT | I2CBMNA_BIT | \
91 				I2CBMTO_BIT | I2CBMIS_BIT)
92 #define I2C_ADDR_MSK		0xFF
93 #define I2C_MSB_2B_MSK		0x300
94 #define FAST_MODE_CLK		400
95 #define FAST_MODE_EN		0x0001
96 #define SUB_ADDR_LEN_MAX	4
97 #define BUF_LEN_MAX		32
98 #define PCH_BUFFER_MODE		0x1
99 #define EEPROM_SW_RST_MODE	0x0002
100 #define NORMAL_INTR_ENBL	0x0300
101 #define EEPROM_RST_INTR_ENBL	(I2CESRFIIE_BIT | I2CESRTOIE_BIT)
102 #define EEPROM_RST_INTR_DISBL	0x0
103 #define BUFFER_MODE_INTR_ENBL	0x001F
104 #define BUFFER_MODE_INTR_DISBL	0x0
105 #define NORMAL_MODE		0x0
106 #define BUFFER_MODE		0x1
107 #define EEPROM_SR_MODE		0x2
108 #define I2C_TX_MODE		0x0010
109 #define PCH_BUF_TX		0xFFF7
110 #define PCH_BUF_RD		0x0008
111 #define I2C_ERROR_MASK	(I2CESRTO_EVENT | I2CBMIS_EVENT | I2CBMTO_EVENT | \
112 			I2CBMNA_EVENT | I2CBMAL_EVENT | I2CMAL_EVENT)
113 #define I2CMAL_EVENT		0x0001
114 #define I2CMCF_EVENT		0x0002
115 #define I2CBMFI_EVENT		0x0004
116 #define I2CBMAL_EVENT		0x0008
117 #define I2CBMNA_EVENT		0x0010
118 #define I2CBMTO_EVENT		0x0020
119 #define I2CBMIS_EVENT		0x0040
120 #define I2CESRFI_EVENT		0x0080
121 #define I2CESRTO_EVENT		0x0100
122 #define PCI_DEVICE_ID_PCH_I2C	0x8817
123 
124 #define pch_dbg(adap, fmt, arg...)  \
125 	dev_dbg(adap->pch_adapter.dev.parent, "%s :" fmt, __func__, ##arg)
126 
127 #define pch_err(adap, fmt, arg...)  \
128 	dev_err(adap->pch_adapter.dev.parent, "%s :" fmt, __func__, ##arg)
129 
130 #define pch_pci_err(pdev, fmt, arg...)  \
131 	dev_err(&pdev->dev, "%s :" fmt, __func__, ##arg)
132 
133 #define pch_pci_dbg(pdev, fmt, arg...)  \
134 	dev_dbg(&pdev->dev, "%s :" fmt, __func__, ##arg)
135 
136 /*
137 Set the number of I2C instance max
138 Intel EG20T PCH :		1ch
139 OKI SEMICONDUCTOR ML7213 IOH :	2ch
140 */
141 #define PCH_I2C_MAX_DEV			2
142 
143 /**
144  * struct i2c_algo_pch_data - for I2C driver functionalities
145  * @pch_adapter:		stores the reference to i2c_adapter structure
146  * @p_adapter_info:		stores the reference to adapter_info structure
147  * @pch_base_address:		specifies the remapped base address
148  * @pch_buff_mode_en:		specifies if buffer mode is enabled
149  * @pch_event_flag:		specifies occurrence of interrupt events
150  * @pch_i2c_xfer_in_progress:	specifies whether the transfer is completed
151  */
152 struct i2c_algo_pch_data {
153 	struct i2c_adapter pch_adapter;
154 	struct adapter_info *p_adapter_info;
155 	void __iomem *pch_base_address;
156 	int pch_buff_mode_en;
157 	u32 pch_event_flag;
158 	bool pch_i2c_xfer_in_progress;
159 };
160 
161 /**
162  * struct adapter_info - This structure holds the adapter information for the
163 			 PCH i2c controller
164  * @pch_data:		stores a list of i2c_algo_pch_data
165  * @pch_i2c_suspended:	specifies whether the system is suspended or not
166  *			perhaps with more lines and words.
167  * @ch_num:		specifies the number of i2c instance
168  *
169  * pch_data has as many elements as maximum I2C channels
170  */
171 struct adapter_info {
172 	struct i2c_algo_pch_data pch_data[PCH_I2C_MAX_DEV];
173 	bool pch_i2c_suspended;
174 	int ch_num;
175 };
176 
177 
178 static int pch_i2c_speed = 100; /* I2C bus speed in Kbps */
179 static int pch_clk = 50000;	/* specifies I2C clock speed in KHz */
180 static wait_queue_head_t pch_event;
181 static DEFINE_MUTEX(pch_mutex);
182 
183 /* Definition for ML7213 by OKI SEMICONDUCTOR */
184 #define PCI_VENDOR_ID_ROHM		0x10DB
185 #define PCI_DEVICE_ID_ML7213_I2C	0x802D
186 #define PCI_DEVICE_ID_ML7223_I2C	0x8010
187 
188 static struct pci_device_id __devinitdata pch_pcidev_id[] = {
189 	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_PCH_I2C),   1, },
190 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7213_I2C), 2, },
191 	{ PCI_VDEVICE(ROHM, PCI_DEVICE_ID_ML7223_I2C), 1, },
192 	{0,}
193 };
194 
195 static irqreturn_t pch_i2c_handler(int irq, void *pData);
196 
197 static inline void pch_setbit(void __iomem *addr, u32 offset, u32 bitmask)
198 {
199 	u32 val;
200 	val = ioread32(addr + offset);
201 	val |= bitmask;
202 	iowrite32(val, addr + offset);
203 }
204 
205 static inline void pch_clrbit(void __iomem *addr, u32 offset, u32 bitmask)
206 {
207 	u32 val;
208 	val = ioread32(addr + offset);
209 	val &= (~bitmask);
210 	iowrite32(val, addr + offset);
211 }
212 
213 /**
214  * pch_i2c_init() - hardware initialization of I2C module
215  * @adap:	Pointer to struct i2c_algo_pch_data.
216  */
217 static void pch_i2c_init(struct i2c_algo_pch_data *adap)
218 {
219 	void __iomem *p = adap->pch_base_address;
220 	u32 pch_i2cbc;
221 	u32 pch_i2ctmr;
222 	u32 reg_value;
223 
224 	/* reset I2C controller */
225 	iowrite32(0x01, p + PCH_I2CSRST);
226 	msleep(20);
227 	iowrite32(0x0, p + PCH_I2CSRST);
228 
229 	/* Initialize I2C registers */
230 	iowrite32(0x21, p + PCH_I2CNF);
231 
232 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_I2CCTL_I2CMEN);
233 
234 	if (pch_i2c_speed != 400)
235 		pch_i2c_speed = 100;
236 
237 	reg_value = PCH_I2CCTL_I2CMEN;
238 	if (pch_i2c_speed == FAST_MODE_CLK) {
239 		reg_value |= FAST_MODE_EN;
240 		pch_dbg(adap, "Fast mode enabled\n");
241 	}
242 
243 	if (pch_clk > PCH_MAX_CLK)
244 		pch_clk = 62500;
245 
246 	pch_i2cbc = (pch_clk + (pch_i2c_speed * 4)) / pch_i2c_speed * 8;
247 	/* Set transfer speed in I2CBC */
248 	iowrite32(pch_i2cbc, p + PCH_I2CBC);
249 
250 	pch_i2ctmr = (pch_clk) / 8;
251 	iowrite32(pch_i2ctmr, p + PCH_I2CTMR);
252 
253 	reg_value |= NORMAL_INTR_ENBL;	/* Enable interrupts in normal mode */
254 	iowrite32(reg_value, p + PCH_I2CCTL);
255 
256 	pch_dbg(adap,
257 		"I2CCTL=%x pch_i2cbc=%x pch_i2ctmr=%x Enable interrupts\n",
258 		ioread32(p + PCH_I2CCTL), pch_i2cbc, pch_i2ctmr);
259 
260 	init_waitqueue_head(&pch_event);
261 }
262 
263 static inline bool ktime_lt(const ktime_t cmp1, const ktime_t cmp2)
264 {
265 	return cmp1.tv64 < cmp2.tv64;
266 }
267 
268 /**
269  * pch_i2c_wait_for_bus_idle() - check the status of bus.
270  * @adap:	Pointer to struct i2c_algo_pch_data.
271  * @timeout:	waiting time counter (us).
272  */
273 static s32 pch_i2c_wait_for_bus_idle(struct i2c_algo_pch_data *adap,
274 				     s32 timeout)
275 {
276 	void __iomem *p = adap->pch_base_address;
277 	ktime_t ns_val;
278 
279 	if ((ioread32(p + PCH_I2CSR) & I2CMBB_BIT) == 0)
280 		return 0;
281 
282 	/* MAX timeout value is timeout*1000*1000nsec */
283 	ns_val = ktime_add_ns(ktime_get(), timeout*1000*1000);
284 	do {
285 		msleep(20);
286 		if ((ioread32(p + PCH_I2CSR) & I2CMBB_BIT) == 0)
287 			return 0;
288 	} while (ktime_lt(ktime_get(), ns_val));
289 
290 	pch_dbg(adap, "I2CSR = %x\n", ioread32(p + PCH_I2CSR));
291 	pch_err(adap, "%s: Timeout Error.return%d\n", __func__, -ETIME);
292 	pch_i2c_init(adap);
293 
294 	return -ETIME;
295 }
296 
297 /**
298  * pch_i2c_start() - Generate I2C start condition in normal mode.
299  * @adap:	Pointer to struct i2c_algo_pch_data.
300  *
301  * Generate I2C start condition in normal mode by setting I2CCTL.I2CMSTA to 1.
302  */
303 static void pch_i2c_start(struct i2c_algo_pch_data *adap)
304 {
305 	void __iomem *p = adap->pch_base_address;
306 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
307 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_START);
308 }
309 
310 /**
311  * pch_i2c_wait_for_xfer_complete() - initiates a wait for the tx complete event
312  * @adap:	Pointer to struct i2c_algo_pch_data.
313  */
314 static s32 pch_i2c_wait_for_xfer_complete(struct i2c_algo_pch_data *adap)
315 {
316 	long ret;
317 	ret = wait_event_timeout(pch_event,
318 			(adap->pch_event_flag != 0), msecs_to_jiffies(50));
319 
320 	if (ret == 0) {
321 		pch_err(adap, "timeout: %x\n", adap->pch_event_flag);
322 		adap->pch_event_flag = 0;
323 		return -ETIMEDOUT;
324 	}
325 
326 	if (adap->pch_event_flag & I2C_ERROR_MASK) {
327 		pch_err(adap, "error bits set: %x\n", adap->pch_event_flag);
328 		adap->pch_event_flag = 0;
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 	s32 rtn;
398 	void __iomem *p = adap->pch_base_address;
399 
400 	length = msgs->len;
401 	buf = msgs->buf;
402 	addr = msgs->addr;
403 
404 	/* enable master tx */
405 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, I2C_TX_MODE);
406 
407 	pch_dbg(adap, "I2CCTL = %x msgs->len = %d\n", ioread32(p + PCH_I2CCTL),
408 		length);
409 
410 	if (first) {
411 		if (pch_i2c_wait_for_bus_idle(adap, BUS_IDLE_TIMEOUT) == -ETIME)
412 			return -ETIME;
413 	}
414 
415 	if (msgs->flags & I2C_M_TEN) {
416 		addr_2_msb = ((addr & I2C_MSB_2B_MSK) >> 7) & 0x06;
417 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
418 		if (first)
419 			pch_i2c_start(adap);
420 
421 		rtn = pch_i2c_wait_for_xfer_complete(adap);
422 		if (rtn == 0) {
423 			if (pch_i2c_getack(adap)) {
424 				pch_dbg(adap, "Receive NACK for slave address"
425 					"setting\n");
426 				return -EIO;
427 			}
428 			addr_8_lsb = (addr & I2C_ADDR_MSK);
429 			iowrite32(addr_8_lsb, p + PCH_I2CDR);
430 		} else if (rtn == -EIO) { /* Arbitration Lost */
431 			pch_err(adap, "Lost Arbitration\n");
432 			pch_clrbit(adap->pch_base_address, PCH_I2CSR,
433 				   I2CMAL_BIT);
434 			pch_clrbit(adap->pch_base_address, PCH_I2CSR,
435 				   I2CMIF_BIT);
436 			pch_i2c_init(adap);
437 			return -EAGAIN;
438 		} else { /* wait-event timeout */
439 			pch_i2c_stop(adap);
440 			return -ETIME;
441 		}
442 	} else {
443 		/* set 7 bit slave address and R/W bit as 0 */
444 		iowrite32(addr << 1, p + PCH_I2CDR);
445 		if (first)
446 			pch_i2c_start(adap);
447 	}
448 
449 	rtn = pch_i2c_wait_for_xfer_complete(adap);
450 	if (rtn == 0) {
451 		if (pch_i2c_getack(adap)) {
452 			pch_dbg(adap, "Receive NACK for slave address"
453 				"setting\n");
454 			return -EIO;
455 		}
456 	} else if (rtn == -EIO) { /* Arbitration Lost */
457 		pch_err(adap, "Lost Arbitration\n");
458 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMAL_BIT);
459 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMIF_BIT);
460 		pch_i2c_init(adap);
461 		return -EAGAIN;
462 	} else { /* wait-event timeout */
463 		pch_i2c_stop(adap);
464 		return -ETIME;
465 	}
466 
467 	for (wrcount = 0; wrcount < length; ++wrcount) {
468 		/* write buffer value to I2C data register */
469 		iowrite32(buf[wrcount], p + PCH_I2CDR);
470 		pch_dbg(adap, "writing %x to Data register\n", buf[wrcount]);
471 
472 		rtn = pch_i2c_wait_for_xfer_complete(adap);
473 		if (rtn == 0) {
474 			if (pch_i2c_getack(adap)) {
475 				pch_dbg(adap, "Receive NACK for slave address"
476 					"setting\n");
477 				return -EIO;
478 			}
479 			pch_clrbit(adap->pch_base_address, PCH_I2CSR,
480 				   I2CMCF_BIT);
481 			pch_clrbit(adap->pch_base_address, PCH_I2CSR,
482 				   I2CMIF_BIT);
483 		} else { /* wait-event timeout */
484 			pch_i2c_stop(adap);
485 			return -ETIME;
486 		}
487 	}
488 
489 	/* check if this is the last message */
490 	if (last)
491 		pch_i2c_stop(adap);
492 	else
493 		pch_i2c_repstart(adap);
494 
495 	pch_dbg(adap, "return=%d\n", wrcount);
496 
497 	return wrcount;
498 }
499 
500 /**
501  * pch_i2c_sendack() - send ACK
502  * @adap:	Pointer to struct i2c_algo_pch_data.
503  */
504 static void pch_i2c_sendack(struct i2c_algo_pch_data *adap)
505 {
506 	void __iomem *p = adap->pch_base_address;
507 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
508 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
509 }
510 
511 /**
512  * pch_i2c_sendnack() - send NACK
513  * @adap:	Pointer to struct i2c_algo_pch_data.
514  */
515 static void pch_i2c_sendnack(struct i2c_algo_pch_data *adap)
516 {
517 	void __iomem *p = adap->pch_base_address;
518 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
519 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_ACK);
520 }
521 
522 /**
523  * pch_i2c_restart() - Generate I2C restart condition in normal mode.
524  * @adap:	Pointer to struct i2c_algo_pch_data.
525  *
526  * Generate I2C restart condition in normal mode by setting I2CCTL.I2CRSTA.
527  */
528 static void pch_i2c_restart(struct i2c_algo_pch_data *adap)
529 {
530 	void __iomem *p = adap->pch_base_address;
531 	pch_dbg(adap, "I2CCTL = %x\n", ioread32(p + PCH_I2CCTL));
532 	pch_setbit(adap->pch_base_address, PCH_I2CCTL, PCH_RESTART);
533 }
534 
535 /**
536  * pch_i2c_readbytes() - read data  from I2C bus in normal mode.
537  * @i2c_adap:	Pointer to the struct i2c_adapter.
538  * @msgs:	Pointer to i2c_msg structure.
539  * @last:	specifies whether last message or not.
540  * @first:	specifies whether first message or not.
541  */
542 static s32 pch_i2c_readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
543 			     u32 last, u32 first)
544 {
545 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
546 
547 	u8 *buf;
548 	u32 count;
549 	u32 length;
550 	u32 addr;
551 	u32 addr_2_msb;
552 	u32 addr_8_lsb;
553 	void __iomem *p = adap->pch_base_address;
554 	s32 rtn;
555 
556 	length = msgs->len;
557 	buf = msgs->buf;
558 	addr = msgs->addr;
559 
560 	/* enable master reception */
561 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, I2C_TX_MODE);
562 
563 	if (first) {
564 		if (pch_i2c_wait_for_bus_idle(adap, BUS_IDLE_TIMEOUT) == -ETIME)
565 			return -ETIME;
566 	}
567 
568 	if (msgs->flags & I2C_M_TEN) {
569 		addr_2_msb = ((addr & I2C_MSB_2B_MSK) >> 7);
570 		iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK, p + PCH_I2CDR);
571 		if (first)
572 			pch_i2c_start(adap);
573 
574 		rtn = pch_i2c_wait_for_xfer_complete(adap);
575 		if (rtn == 0) {
576 			if (pch_i2c_getack(adap)) {
577 				pch_dbg(adap, "Receive NACK for slave address"
578 					"setting\n");
579 				return -EIO;
580 			}
581 			addr_8_lsb = (addr & I2C_ADDR_MSK);
582 			iowrite32(addr_8_lsb, p + PCH_I2CDR);
583 		} else if (rtn == -EIO) { /* Arbitration Lost */
584 			pch_err(adap, "Lost Arbitration\n");
585 			pch_clrbit(adap->pch_base_address, PCH_I2CSR,
586 				   I2CMAL_BIT);
587 			pch_clrbit(adap->pch_base_address, PCH_I2CSR,
588 				   I2CMIF_BIT);
589 			pch_i2c_init(adap);
590 			return -EAGAIN;
591 		} else { /* wait-event timeout */
592 			pch_i2c_stop(adap);
593 			return -ETIME;
594 		}
595 		pch_i2c_restart(adap);
596 		rtn = pch_i2c_wait_for_xfer_complete(adap);
597 		if (rtn == 0) {
598 			if (pch_i2c_getack(adap)) {
599 				pch_dbg(adap, "Receive NACK for slave address"
600 					"setting\n");
601 				return -EIO;
602 			}
603 			addr_2_msb |= I2C_RD;
604 			iowrite32(addr_2_msb | TEN_BIT_ADDR_MASK,
605 				  p + PCH_I2CDR);
606 		} else if (rtn == -EIO) { /* Arbitration Lost */
607 			pch_err(adap, "Lost Arbitration\n");
608 			pch_clrbit(adap->pch_base_address, PCH_I2CSR,
609 				   I2CMAL_BIT);
610 			pch_clrbit(adap->pch_base_address, PCH_I2CSR,
611 				   I2CMIF_BIT);
612 			pch_i2c_init(adap);
613 			return -EAGAIN;
614 		} else { /* wait-event timeout */
615 			pch_i2c_stop(adap);
616 			return -ETIME;
617 		}
618 	} else {
619 		/* 7 address bits + R/W bit */
620 		addr = (((addr) << 1) | (I2C_RD));
621 		iowrite32(addr, p + PCH_I2CDR);
622 	}
623 
624 	/* check if it is the first message */
625 	if (first)
626 		pch_i2c_start(adap);
627 
628 	rtn = pch_i2c_wait_for_xfer_complete(adap);
629 	if (rtn == 0) {
630 		if (pch_i2c_getack(adap)) {
631 			pch_dbg(adap, "Receive NACK for slave address"
632 				"setting\n");
633 			return -EIO;
634 		}
635 	} else if (rtn == -EIO) { /* Arbitration Lost */
636 		pch_err(adap, "Lost Arbitration\n");
637 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMAL_BIT);
638 		pch_clrbit(adap->pch_base_address, PCH_I2CSR, I2CMIF_BIT);
639 		pch_i2c_init(adap);
640 		return -EAGAIN;
641 	} else { /* wait-event timeout */
642 		pch_i2c_stop(adap);
643 		return -ETIME;
644 	}
645 
646 	if (length == 0) {
647 		pch_i2c_stop(adap);
648 		ioread32(p + PCH_I2CDR); /* Dummy read needs */
649 
650 		count = length;
651 	} else {
652 		int read_index;
653 		int loop;
654 		pch_i2c_sendack(adap);
655 
656 		/* Dummy read */
657 		for (loop = 1, read_index = 0; loop < length; loop++) {
658 			buf[read_index] = ioread32(p + PCH_I2CDR);
659 
660 			if (loop != 1)
661 				read_index++;
662 
663 			rtn = pch_i2c_wait_for_xfer_complete(adap);
664 			if (rtn == 0) {
665 				if (pch_i2c_getack(adap)) {
666 					pch_dbg(adap, "Receive NACK for slave"
667 						"address setting\n");
668 					return -EIO;
669 				}
670 			} else { /* wait-event timeout */
671 				pch_i2c_stop(adap);
672 				return -ETIME;
673 			}
674 
675 		}	/* end for */
676 
677 		pch_i2c_sendnack(adap);
678 
679 		buf[read_index] = ioread32(p + PCH_I2CDR); /* Read final - 1 */
680 
681 		if (length != 1)
682 			read_index++;
683 
684 		rtn = pch_i2c_wait_for_xfer_complete(adap);
685 		if (rtn == 0) {
686 			if (pch_i2c_getack(adap)) {
687 				pch_dbg(adap, "Receive NACK for slave"
688 					"address setting\n");
689 				return -EIO;
690 			}
691 		} else { /* wait-event timeout */
692 			pch_i2c_stop(adap);
693 			return -ETIME;
694 		}
695 
696 		if (last)
697 			pch_i2c_stop(adap);
698 		else
699 			pch_i2c_repstart(adap);
700 
701 		buf[read_index++] = ioread32(p + PCH_I2CDR); /* Read Final */
702 		count = read_index;
703 	}
704 
705 	return count;
706 }
707 
708 /**
709  * pch_i2c_cb() - Interrupt handler Call back function
710  * @adap:	Pointer to struct i2c_algo_pch_data.
711  */
712 static void pch_i2c_cb(struct i2c_algo_pch_data *adap)
713 {
714 	u32 sts;
715 	void __iomem *p = adap->pch_base_address;
716 
717 	sts = ioread32(p + PCH_I2CSR);
718 	sts &= (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT);
719 	if (sts & I2CMAL_BIT)
720 		adap->pch_event_flag |= I2CMAL_EVENT;
721 
722 	if (sts & I2CMCF_BIT)
723 		adap->pch_event_flag |= I2CMCF_EVENT;
724 
725 	/* clear the applicable bits */
726 	pch_clrbit(adap->pch_base_address, PCH_I2CSR, sts);
727 
728 	pch_dbg(adap, "PCH_I2CSR = %x\n", ioread32(p + PCH_I2CSR));
729 
730 	wake_up(&pch_event);
731 }
732 
733 /**
734  * pch_i2c_handler() - interrupt handler for the PCH I2C controller
735  * @irq:	irq number.
736  * @pData:	cookie passed back to the handler function.
737  */
738 static irqreturn_t pch_i2c_handler(int irq, void *pData)
739 {
740 	u32 reg_val;
741 	int flag;
742 	int i;
743 	struct adapter_info *adap_info = pData;
744 	void __iomem *p;
745 	u32 mode;
746 
747 	for (i = 0, flag = 0; i < adap_info->ch_num; i++) {
748 		p = adap_info->pch_data[i].pch_base_address;
749 		mode = ioread32(p + PCH_I2CMOD);
750 		mode &= BUFFER_MODE | EEPROM_SR_MODE;
751 		if (mode != NORMAL_MODE) {
752 			pch_err(adap_info->pch_data,
753 				"I2C-%d mode(%d) is not supported\n", mode, i);
754 			continue;
755 		}
756 		reg_val = ioread32(p + PCH_I2CSR);
757 		if (reg_val & (I2CMAL_BIT | I2CMCF_BIT | I2CMIF_BIT)) {
758 			pch_i2c_cb(&adap_info->pch_data[i]);
759 			flag = 1;
760 		}
761 	}
762 
763 	return flag ? IRQ_HANDLED : IRQ_NONE;
764 }
765 
766 /**
767  * pch_i2c_xfer() - Reading adnd writing data through I2C bus
768  * @i2c_adap:	Pointer to the struct i2c_adapter.
769  * @msgs:	Pointer to i2c_msg structure.
770  * @num:	number of messages.
771  */
772 static s32 pch_i2c_xfer(struct i2c_adapter *i2c_adap,
773 			struct i2c_msg *msgs, s32 num)
774 {
775 	struct i2c_msg *pmsg;
776 	u32 i = 0;
777 	u32 status;
778 	u32 msglen;
779 	u32 subaddrlen;
780 	s32 ret;
781 
782 	struct i2c_algo_pch_data *adap = i2c_adap->algo_data;
783 
784 	ret = mutex_lock_interruptible(&pch_mutex);
785 	if (ret)
786 		return -ERESTARTSYS;
787 
788 	if (adap->p_adapter_info->pch_i2c_suspended) {
789 		mutex_unlock(&pch_mutex);
790 		return -EBUSY;
791 	}
792 
793 	pch_dbg(adap, "adap->p_adapter_info->pch_i2c_suspended is %d\n",
794 		adap->p_adapter_info->pch_i2c_suspended);
795 	/* transfer not completed */
796 	adap->pch_i2c_xfer_in_progress = true;
797 
798 	for (i = 0; i < num && ret >= 0; i++) {
799 		pmsg = &msgs[i];
800 		pmsg->flags |= adap->pch_buff_mode_en;
801 		status = pmsg->flags;
802 		pch_dbg(adap,
803 			"After invoking I2C_MODE_SEL :flag= 0x%x\n", status);
804 		/* calculate sub address length and message length */
805 		/* these are applicable only for buffer mode */
806 		subaddrlen = pmsg->buf[0];
807 		/* calculate actual message length excluding
808 		 * the sub address fields */
809 		msglen = (pmsg->len) - (subaddrlen + 1);
810 
811 		if ((status & (I2C_M_RD)) != false) {
812 			ret = pch_i2c_readbytes(i2c_adap, pmsg, (i + 1 == num),
813 						(i == 0));
814 		} else {
815 			ret = pch_i2c_writebytes(i2c_adap, pmsg, (i + 1 == num),
816 						 (i == 0));
817 		}
818 	}
819 
820 	adap->pch_i2c_xfer_in_progress = false;	/* transfer completed */
821 
822 	mutex_unlock(&pch_mutex);
823 
824 	return (ret < 0) ? ret : num;
825 }
826 
827 /**
828  * pch_i2c_func() - return the functionality of the I2C driver
829  * @adap:	Pointer to struct i2c_algo_pch_data.
830  */
831 static u32 pch_i2c_func(struct i2c_adapter *adap)
832 {
833 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
834 }
835 
836 static struct i2c_algorithm pch_algorithm = {
837 	.master_xfer = pch_i2c_xfer,
838 	.functionality = pch_i2c_func
839 };
840 
841 /**
842  * pch_i2c_disbl_int() - Disable PCH I2C interrupts
843  * @adap:	Pointer to struct i2c_algo_pch_data.
844  */
845 static void pch_i2c_disbl_int(struct i2c_algo_pch_data *adap)
846 {
847 	void __iomem *p = adap->pch_base_address;
848 
849 	pch_clrbit(adap->pch_base_address, PCH_I2CCTL, NORMAL_INTR_ENBL);
850 
851 	iowrite32(EEPROM_RST_INTR_DISBL, p + PCH_I2CESRMSK);
852 
853 	iowrite32(BUFFER_MODE_INTR_DISBL, p + PCH_I2CBUFMSK);
854 }
855 
856 static int __devinit pch_i2c_probe(struct pci_dev *pdev,
857 				   const struct pci_device_id *id)
858 {
859 	void __iomem *base_addr;
860 	int ret;
861 	int i, j;
862 	struct adapter_info *adap_info;
863 	struct i2c_adapter *pch_adap;
864 
865 	pch_pci_dbg(pdev, "Entered.\n");
866 
867 	adap_info = kzalloc((sizeof(struct adapter_info)), GFP_KERNEL);
868 	if (adap_info == NULL) {
869 		pch_pci_err(pdev, "Memory allocation FAILED\n");
870 		return -ENOMEM;
871 	}
872 
873 	ret = pci_enable_device(pdev);
874 	if (ret) {
875 		pch_pci_err(pdev, "pci_enable_device FAILED\n");
876 		goto err_pci_enable;
877 	}
878 
879 	ret = pci_request_regions(pdev, KBUILD_MODNAME);
880 	if (ret) {
881 		pch_pci_err(pdev, "pci_request_regions FAILED\n");
882 		goto err_pci_req;
883 	}
884 
885 	base_addr = pci_iomap(pdev, 1, 0);
886 
887 	if (base_addr == NULL) {
888 		pch_pci_err(pdev, "pci_iomap FAILED\n");
889 		ret = -ENOMEM;
890 		goto err_pci_iomap;
891 	}
892 
893 	/* Set the number of I2C channel instance */
894 	adap_info->ch_num = id->driver_data;
895 
896 	for (i = 0; i < adap_info->ch_num; i++) {
897 		pch_adap = &adap_info->pch_data[i].pch_adapter;
898 		adap_info->pch_i2c_suspended = false;
899 
900 		adap_info->pch_data[i].p_adapter_info = adap_info;
901 
902 		pch_adap->owner = THIS_MODULE;
903 		pch_adap->class = I2C_CLASS_HWMON;
904 		strcpy(pch_adap->name, KBUILD_MODNAME);
905 		pch_adap->algo = &pch_algorithm;
906 		pch_adap->algo_data = &adap_info->pch_data[i];
907 
908 		/* base_addr + offset; */
909 		adap_info->pch_data[i].pch_base_address = base_addr + 0x100 * i;
910 
911 		pch_adap->dev.parent = &pdev->dev;
912 
913 		ret = i2c_add_adapter(pch_adap);
914 		if (ret) {
915 			pch_pci_err(pdev, "i2c_add_adapter[ch:%d] FAILED\n", i);
916 			goto err_i2c_add_adapter;
917 		}
918 
919 		pch_i2c_init(&adap_info->pch_data[i]);
920 	}
921 	ret = request_irq(pdev->irq, pch_i2c_handler, IRQF_SHARED,
922 		  KBUILD_MODNAME, adap_info);
923 	if (ret) {
924 		pch_pci_err(pdev, "request_irq FAILED\n");
925 		goto err_i2c_add_adapter;
926 	}
927 
928 	pci_set_drvdata(pdev, adap_info);
929 	pch_pci_dbg(pdev, "returns %d.\n", ret);
930 	return 0;
931 
932 err_i2c_add_adapter:
933 	for (j = 0; j < i; j++)
934 		i2c_del_adapter(&adap_info->pch_data[j].pch_adapter);
935 	pci_iounmap(pdev, base_addr);
936 err_pci_iomap:
937 	pci_release_regions(pdev);
938 err_pci_req:
939 	pci_disable_device(pdev);
940 err_pci_enable:
941 	kfree(adap_info);
942 	return ret;
943 }
944 
945 static void __devexit pch_i2c_remove(struct pci_dev *pdev)
946 {
947 	int i;
948 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
949 
950 	free_irq(pdev->irq, adap_info);
951 
952 	for (i = 0; i < adap_info->ch_num; i++) {
953 		pch_i2c_disbl_int(&adap_info->pch_data[i]);
954 		i2c_del_adapter(&adap_info->pch_data[i].pch_adapter);
955 	}
956 
957 	if (adap_info->pch_data[0].pch_base_address)
958 		pci_iounmap(pdev, adap_info->pch_data[0].pch_base_address);
959 
960 	for (i = 0; i < adap_info->ch_num; i++)
961 		adap_info->pch_data[i].pch_base_address = 0;
962 
963 	pci_set_drvdata(pdev, NULL);
964 
965 	pci_release_regions(pdev);
966 
967 	pci_disable_device(pdev);
968 	kfree(adap_info);
969 }
970 
971 #ifdef CONFIG_PM
972 static int pch_i2c_suspend(struct pci_dev *pdev, pm_message_t state)
973 {
974 	int ret;
975 	int i;
976 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
977 	void __iomem *p = adap_info->pch_data[0].pch_base_address;
978 
979 	adap_info->pch_i2c_suspended = true;
980 
981 	for (i = 0; i < adap_info->ch_num; i++) {
982 		while ((adap_info->pch_data[i].pch_i2c_xfer_in_progress)) {
983 			/* Wait until all channel transfers are completed */
984 			msleep(20);
985 		}
986 	}
987 
988 	/* Disable the i2c interrupts */
989 	for (i = 0; i < adap_info->ch_num; i++)
990 		pch_i2c_disbl_int(&adap_info->pch_data[i]);
991 
992 	pch_pci_dbg(pdev, "I2CSR = %x I2CBUFSTA = %x I2CESRSTA = %x "
993 		"invoked function pch_i2c_disbl_int successfully\n",
994 		ioread32(p + PCH_I2CSR), ioread32(p + PCH_I2CBUFSTA),
995 		ioread32(p + PCH_I2CESRSTA));
996 
997 	ret = pci_save_state(pdev);
998 
999 	if (ret) {
1000 		pch_pci_err(pdev, "pci_save_state\n");
1001 		return ret;
1002 	}
1003 
1004 	pci_enable_wake(pdev, PCI_D3hot, 0);
1005 	pci_disable_device(pdev);
1006 	pci_set_power_state(pdev, pci_choose_state(pdev, state));
1007 
1008 	return 0;
1009 }
1010 
1011 static int pch_i2c_resume(struct pci_dev *pdev)
1012 {
1013 	int i;
1014 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
1015 
1016 	pci_set_power_state(pdev, PCI_D0);
1017 	pci_restore_state(pdev);
1018 
1019 	if (pci_enable_device(pdev) < 0) {
1020 		pch_pci_err(pdev, "pch_i2c_resume:pci_enable_device FAILED\n");
1021 		return -EIO;
1022 	}
1023 
1024 	pci_enable_wake(pdev, PCI_D3hot, 0);
1025 
1026 	for (i = 0; i < adap_info->ch_num; i++)
1027 		pch_i2c_init(&adap_info->pch_data[i]);
1028 
1029 	adap_info->pch_i2c_suspended = false;
1030 
1031 	return 0;
1032 }
1033 #else
1034 #define pch_i2c_suspend NULL
1035 #define pch_i2c_resume NULL
1036 #endif
1037 
1038 static struct pci_driver pch_pcidriver = {
1039 	.name = KBUILD_MODNAME,
1040 	.id_table = pch_pcidev_id,
1041 	.probe = pch_i2c_probe,
1042 	.remove = __devexit_p(pch_i2c_remove),
1043 	.suspend = pch_i2c_suspend,
1044 	.resume = pch_i2c_resume
1045 };
1046 
1047 static int __init pch_pci_init(void)
1048 {
1049 	return pci_register_driver(&pch_pcidriver);
1050 }
1051 module_init(pch_pci_init);
1052 
1053 static void __exit pch_pci_exit(void)
1054 {
1055 	pci_unregister_driver(&pch_pcidriver);
1056 }
1057 module_exit(pch_pci_exit);
1058 
1059 MODULE_DESCRIPTION("Intel EG20T PCH/OKI SEMICONDUCTOR ML7213 IOH I2C Driver");
1060 MODULE_LICENSE("GPL");
1061 MODULE_AUTHOR("Tomoya MORINAGA. <tomoya-linux@dsn.okisemi.com>");
1062 module_param(pch_i2c_speed, int, (S_IRUSR | S_IWUSR));
1063 module_param(pch_clk, int, (S_IRUSR | S_IWUSR));
1064