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1/*
2    Copyright (c) 1998 - 2002  Frodo Looijaard <frodol@dds.nl>,
3    Philip Edelbrock <phil@netroedge.com>, Ky��sti M��lkki <kmalkki@cc.hut.fi>,
4    Mark D. Studebaker <mdsxyz123@yahoo.com>
5    Copyright (C) 2005 - 2008  Jean Delvare <khali@linux-fr.org>
6
7    This program is free software; you can redistribute it and/or modify
8    it under the terms of the GNU General Public License as published by
9    the Free Software Foundation; either version 2 of the License, or
10    (at your option) any later version.
11
12    This program is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15    GNU General Public License for more details.
16
17    You should have received a copy of the GNU General Public License
18    along with this program; if not, write to the Free Software
19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20*/
21
22/*
23   Supports the following VIA south bridges:
24
25   Chip name          PCI ID  REV     I2C block
26   VT82C596A          0x3050             no
27   VT82C596B          0x3051             no
28   VT82C686A          0x3057  0x30       no
29   VT82C686B          0x3057  0x40       yes
30   VT8231             0x8235             no?
31   VT8233             0x3074             yes
32   VT8233A            0x3147             yes?
33   VT8235             0x3177             yes
34   VT8237R            0x3227             yes
35   VT8237A            0x3337             yes
36   VT8237S            0x3372             yes
37   VT8251             0x3287             yes
38   CX700              0x8324             yes
39   VX800/VX820        0x8353             yes
40   VX855/VX875        0x8409             yes
41
42   Note: we assume there can only be one device, with one SMBus interface.
43*/
44
45#include <linux/module.h>
46#include <linux/delay.h>
47#include <linux/pci.h>
48#include <linux/kernel.h>
49#include <linux/stddef.h>
50#include <linux/ioport.h>
51#include <linux/i2c.h>
52#include <linux/init.h>
53#include <linux/acpi.h>
54#include <linux/io.h>
55
56static struct pci_dev *vt596_pdev;
57
58#define SMBBA1		0x90
59#define SMBBA2		0x80
60#define SMBBA3		0xD0
61
62/* SMBus address offsets */
63static unsigned short vt596_smba;
64#define SMBHSTSTS	(vt596_smba + 0)
65#define SMBHSTCNT	(vt596_smba + 2)
66#define SMBHSTCMD	(vt596_smba + 3)
67#define SMBHSTADD	(vt596_smba + 4)
68#define SMBHSTDAT0	(vt596_smba + 5)
69#define SMBHSTDAT1	(vt596_smba + 6)
70#define SMBBLKDAT	(vt596_smba + 7)
71
72/* PCI Address Constants */
73
74/* SMBus data in configuration space can be found in two places,
75   We try to select the better one */
76
77static unsigned short SMBHSTCFG = 0xD2;
78
79/* Other settings */
80#define MAX_TIMEOUT	500
81
82/* VT82C596 constants */
83#define VT596_QUICK		0x00
84#define VT596_BYTE		0x04
85#define VT596_BYTE_DATA		0x08
86#define VT596_WORD_DATA		0x0C
87#define VT596_PROC_CALL		0x10
88#define VT596_BLOCK_DATA	0x14
89#define VT596_I2C_BLOCK_DATA	0x34
90
91
92/* If force is set to anything different from 0, we forcibly enable the
93   VT596. DANGEROUS! */
94static int force;
95module_param(force, bool, 0);
96MODULE_PARM_DESC(force, "Forcibly enable the SMBus. DANGEROUS!");
97
98/* If force_addr is set to anything different from 0, we forcibly enable
99   the VT596 at the given address. VERY DANGEROUS! */
100static u16 force_addr;
101module_param(force_addr, ushort, 0);
102MODULE_PARM_DESC(force_addr,
103		 "Forcibly enable the SMBus at the given address. "
104		 "EXTREMELY DANGEROUS!");
105
106
107static struct pci_driver vt596_driver;
108static struct i2c_adapter vt596_adapter;
109
110#define FEATURE_I2CBLOCK	(1<<0)
111static unsigned int vt596_features;
112
113#ifdef DEBUG
114static void vt596_dump_regs(const char *msg, u8 size)
115{
116	dev_dbg(&vt596_adapter.dev, "%s: STS=%02x CNT=%02x CMD=%02x ADD=%02x "
117		"DAT=%02x,%02x\n", msg, inb_p(SMBHSTSTS), inb_p(SMBHSTCNT),
118		inb_p(SMBHSTCMD), inb_p(SMBHSTADD), inb_p(SMBHSTDAT0),
119		inb_p(SMBHSTDAT1));
120
121	if (size == VT596_BLOCK_DATA
122	 || size == VT596_I2C_BLOCK_DATA) {
123		int i;
124
125		dev_dbg(&vt596_adapter.dev, "BLK=");
126		for (i = 0; i < I2C_SMBUS_BLOCK_MAX / 2; i++)
127			printk("%02x,", inb_p(SMBBLKDAT));
128		printk("\n");
129		dev_dbg(&vt596_adapter.dev, "    ");
130		for (; i < I2C_SMBUS_BLOCK_MAX - 1; i++)
131			printk("%02x,", inb_p(SMBBLKDAT));
132		printk("%02x\n", inb_p(SMBBLKDAT));
133	}
134}
135#else
136static inline void vt596_dump_regs(const char *msg, u8 size) { }
137#endif
138
139/* Return -1 on error, 0 on success */
140static int vt596_transaction(u8 size)
141{
142	int temp;
143	int result = 0;
144	int timeout = 0;
145
146	vt596_dump_regs("Transaction (pre)", size);
147
148	/* Make sure the SMBus host is ready to start transmitting */
149	if ((temp = inb_p(SMBHSTSTS)) & 0x1F) {
150		dev_dbg(&vt596_adapter.dev, "SMBus busy (0x%02x). "
151			"Resetting...\n", temp);
152
153		outb_p(temp, SMBHSTSTS);
154		if ((temp = inb_p(SMBHSTSTS)) & 0x1F) {
155			dev_err(&vt596_adapter.dev, "SMBus reset failed! "
156				"(0x%02x)\n", temp);
157			return -EBUSY;
158		}
159	}
160
161	/* Start the transaction by setting bit 6 */
162	outb_p(0x40 | size, SMBHSTCNT);
163
164	/* We will always wait for a fraction of a second */
165	do {
166		msleep(1);
167		temp = inb_p(SMBHSTSTS);
168	} while ((temp & 0x01) && (++timeout < MAX_TIMEOUT));
169
170	/* If the SMBus is still busy, we give up */
171	if (timeout == MAX_TIMEOUT) {
172		result = -ETIMEDOUT;
173		dev_err(&vt596_adapter.dev, "SMBus timeout!\n");
174	}
175
176	if (temp & 0x10) {
177		result = -EIO;
178		dev_err(&vt596_adapter.dev, "Transaction failed (0x%02x)\n",
179			size);
180	}
181
182	if (temp & 0x08) {
183		result = -EIO;
184		dev_err(&vt596_adapter.dev, "SMBus collision!\n");
185	}
186
187	if (temp & 0x04) {
188		int read = inb_p(SMBHSTADD) & 0x01;
189		result = -ENXIO;
190		/* The quick and receive byte commands are used to probe
191		   for chips, so errors are expected, and we don't want
192		   to frighten the user. */
193		if (!((size == VT596_QUICK && !read) ||
194		      (size == VT596_BYTE && read)))
195			dev_err(&vt596_adapter.dev, "Transaction error!\n");
196	}
197
198	/* Resetting status register */
199	if (temp & 0x1F)
200		outb_p(temp, SMBHSTSTS);
201
202	vt596_dump_regs("Transaction (post)", size);
203
204	return result;
205}
206
207/* Return negative errno on error, 0 on success */
208static s32 vt596_access(struct i2c_adapter *adap, u16 addr,
209		unsigned short flags, char read_write, u8 command,
210		int size, union i2c_smbus_data *data)
211{
212	int i;
213	int status;
214
215	switch (size) {
216	case I2C_SMBUS_QUICK:
217		size = VT596_QUICK;
218		break;
219	case I2C_SMBUS_BYTE:
220		if (read_write == I2C_SMBUS_WRITE)
221			outb_p(command, SMBHSTCMD);
222		size = VT596_BYTE;
223		break;
224	case I2C_SMBUS_BYTE_DATA:
225		outb_p(command, SMBHSTCMD);
226		if (read_write == I2C_SMBUS_WRITE)
227			outb_p(data->byte, SMBHSTDAT0);
228		size = VT596_BYTE_DATA;
229		break;
230	case I2C_SMBUS_WORD_DATA:
231		outb_p(command, SMBHSTCMD);
232		if (read_write == I2C_SMBUS_WRITE) {
233			outb_p(data->word & 0xff, SMBHSTDAT0);
234			outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
235		}
236		size = VT596_WORD_DATA;
237		break;
238	case I2C_SMBUS_PROC_CALL:
239		outb_p(command, SMBHSTCMD);
240		outb_p(data->word & 0xff, SMBHSTDAT0);
241		outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
242		size = VT596_PROC_CALL;
243		break;
244	case I2C_SMBUS_I2C_BLOCK_DATA:
245		if (!(vt596_features & FEATURE_I2CBLOCK))
246			goto exit_unsupported;
247		if (read_write == I2C_SMBUS_READ)
248			outb_p(data->block[0], SMBHSTDAT0);
249		/* Fall through */
250	case I2C_SMBUS_BLOCK_DATA:
251		outb_p(command, SMBHSTCMD);
252		if (read_write == I2C_SMBUS_WRITE) {
253			u8 len = data->block[0];
254			if (len > I2C_SMBUS_BLOCK_MAX)
255				len = I2C_SMBUS_BLOCK_MAX;
256			outb_p(len, SMBHSTDAT0);
257			inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
258			for (i = 1; i <= len; i++)
259				outb_p(data->block[i], SMBBLKDAT);
260		}
261		size = (size == I2C_SMBUS_I2C_BLOCK_DATA) ?
262		       VT596_I2C_BLOCK_DATA : VT596_BLOCK_DATA;
263		break;
264	default:
265		goto exit_unsupported;
266	}
267
268	outb_p(((addr & 0x7f) << 1) | read_write, SMBHSTADD);
269
270	status = vt596_transaction(size);
271	if (status)
272		return status;
273
274	if (size == VT596_PROC_CALL)
275		read_write = I2C_SMBUS_READ;
276
277	if ((read_write == I2C_SMBUS_WRITE) || (size == VT596_QUICK))
278		return 0;
279
280	switch (size) {
281	case VT596_BYTE:
282	case VT596_BYTE_DATA:
283		data->byte = inb_p(SMBHSTDAT0);
284		break;
285	case VT596_WORD_DATA:
286	case VT596_PROC_CALL:
287		data->word = inb_p(SMBHSTDAT0) + (inb_p(SMBHSTDAT1) << 8);
288		break;
289	case VT596_I2C_BLOCK_DATA:
290	case VT596_BLOCK_DATA:
291		data->block[0] = inb_p(SMBHSTDAT0);
292		if (data->block[0] > I2C_SMBUS_BLOCK_MAX)
293			data->block[0] = I2C_SMBUS_BLOCK_MAX;
294		inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
295		for (i = 1; i <= data->block[0]; i++)
296			data->block[i] = inb_p(SMBBLKDAT);
297		break;
298	}
299	return 0;
300
301exit_unsupported:
302	dev_warn(&vt596_adapter.dev, "Unsupported transaction %d\n",
303		 size);
304	return -EOPNOTSUPP;
305}
306
307static u32 vt596_func(struct i2c_adapter *adapter)
308{
309	u32 func = I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
310	    I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
311	    I2C_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_BLOCK_DATA;
312
313	if (vt596_features & FEATURE_I2CBLOCK)
314		func |= I2C_FUNC_SMBUS_I2C_BLOCK;
315	return func;
316}
317
318static const struct i2c_algorithm smbus_algorithm = {
319	.smbus_xfer	= vt596_access,
320	.functionality	= vt596_func,
321};
322
323static struct i2c_adapter vt596_adapter = {
324	.owner		= THIS_MODULE,
325	.class		= I2C_CLASS_HWMON | I2C_CLASS_SPD,
326	.algo		= &smbus_algorithm,
327};
328
329static int __devinit vt596_probe(struct pci_dev *pdev,
330				 const struct pci_device_id *id)
331{
332	unsigned char temp;
333	int error = -ENODEV;
334
335	/* Determine the address of the SMBus areas */
336	if (force_addr) {
337		vt596_smba = force_addr & 0xfff0;
338		force = 0;
339		goto found;
340	}
341
342	if ((pci_read_config_word(pdev, id->driver_data, &vt596_smba)) ||
343	    !(vt596_smba & 0x0001)) {
344		/* try 2nd address and config reg. for 596 */
345		if (id->device == PCI_DEVICE_ID_VIA_82C596_3 &&
346		    !pci_read_config_word(pdev, SMBBA2, &vt596_smba) &&
347		    (vt596_smba & 0x0001)) {
348			SMBHSTCFG = 0x84;
349		} else {
350			/* no matches at all */
351			dev_err(&pdev->dev, "Cannot configure "
352				"SMBus I/O Base address\n");
353			return -ENODEV;
354		}
355	}
356
357	vt596_smba &= 0xfff0;
358	if (vt596_smba == 0) {
359		dev_err(&pdev->dev, "SMBus base address "
360			"uninitialized - upgrade BIOS or use "
361			"force_addr=0xaddr\n");
362		return -ENODEV;
363	}
364
365found:
366	error = acpi_check_region(vt596_smba, 8, vt596_driver.name);
367	if (error)
368		return -ENODEV;
369
370	if (!request_region(vt596_smba, 8, vt596_driver.name)) {
371		dev_err(&pdev->dev, "SMBus region 0x%x already in use!\n",
372			vt596_smba);
373		return -ENODEV;
374	}
375
376	pci_read_config_byte(pdev, SMBHSTCFG, &temp);
377	/* If force_addr is set, we program the new address here. Just to make
378	   sure, we disable the VT596 first. */
379	if (force_addr) {
380		pci_write_config_byte(pdev, SMBHSTCFG, temp & 0xfe);
381		pci_write_config_word(pdev, id->driver_data, vt596_smba);
382		pci_write_config_byte(pdev, SMBHSTCFG, temp | 0x01);
383		dev_warn(&pdev->dev, "WARNING: SMBus interface set to new "
384			 "address 0x%04x!\n", vt596_smba);
385	} else if (!(temp & 0x01)) {
386		if (force) {
387			/* NOTE: This assumes I/O space and other allocations
388			 * WERE done by the Bios!  Don't complain if your
389			 * hardware does weird things after enabling this.
390			 * :') Check for Bios updates before resorting to
391			 * this.
392			 */
393			pci_write_config_byte(pdev, SMBHSTCFG, temp | 0x01);
394			dev_info(&pdev->dev, "Enabling SMBus device\n");
395		} else {
396			dev_err(&pdev->dev, "SMBUS: Error: Host SMBus "
397				"controller not enabled! - upgrade BIOS or "
398				"use force=1\n");
399			goto release_region;
400		}
401	}
402
403	dev_dbg(&pdev->dev, "VT596_smba = 0x%X\n", vt596_smba);
404
405	switch (pdev->device) {
406	case PCI_DEVICE_ID_VIA_CX700:
407	case PCI_DEVICE_ID_VIA_VX800:
408	case PCI_DEVICE_ID_VIA_VX855:
409	case PCI_DEVICE_ID_VIA_8251:
410	case PCI_DEVICE_ID_VIA_8237:
411	case PCI_DEVICE_ID_VIA_8237A:
412	case PCI_DEVICE_ID_VIA_8237S:
413	case PCI_DEVICE_ID_VIA_8235:
414	case PCI_DEVICE_ID_VIA_8233A:
415	case PCI_DEVICE_ID_VIA_8233_0:
416		vt596_features |= FEATURE_I2CBLOCK;
417		break;
418	case PCI_DEVICE_ID_VIA_82C686_4:
419		/* The VT82C686B (rev 0x40) does support I2C block
420		   transactions, but the VT82C686A (rev 0x30) doesn't */
421		if (pdev->revision >= 0x40)
422			vt596_features |= FEATURE_I2CBLOCK;
423		break;
424	}
425
426	vt596_adapter.dev.parent = &pdev->dev;
427	snprintf(vt596_adapter.name, sizeof(vt596_adapter.name),
428		 "SMBus Via Pro adapter at %04x", vt596_smba);
429
430	vt596_pdev = pci_dev_get(pdev);
431	if (i2c_add_adapter(&vt596_adapter)) {
432		pci_dev_put(vt596_pdev);
433		vt596_pdev = NULL;
434	}
435
436	/* Always return failure here.  This is to allow other drivers to bind
437	 * to this pci device.  We don't really want to have control over the
438	 * pci device, we only wanted to read as few register values from it.
439	 */
440	return -ENODEV;
441
442release_region:
443	release_region(vt596_smba, 8);
444	return error;
445}
446
447static const struct pci_device_id vt596_ids[] = {
448	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C596_3),
449	  .driver_data = SMBBA1 },
450	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C596B_3),
451	  .driver_data = SMBBA1 },
452	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C686_4),
453	  .driver_data = SMBBA1 },
454	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8233_0),
455	  .driver_data = SMBBA3 },
456	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8233A),
457	  .driver_data = SMBBA3 },
458	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8235),
459	  .driver_data = SMBBA3 },
460	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237),
461	  .driver_data = SMBBA3 },
462	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237A),
463	  .driver_data = SMBBA3 },
464	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237S),
465	  .driver_data = SMBBA3 },
466	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8231_4),
467	  .driver_data = SMBBA1 },
468	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8251),
469	  .driver_data = SMBBA3 },
470	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_CX700),
471	  .driver_data = SMBBA3 },
472	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX800),
473	  .driver_data = SMBBA3 },
474	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX855),
475	  .driver_data = SMBBA3 },
476	{ 0, }
477};
478
479MODULE_DEVICE_TABLE(pci, vt596_ids);
480
481static struct pci_driver vt596_driver = {
482	.name		= "vt596_smbus",
483	.id_table	= vt596_ids,
484	.probe		= vt596_probe,
485};
486
487static int __init i2c_vt596_init(void)
488{
489	return pci_register_driver(&vt596_driver);
490}
491
492
493static void __exit i2c_vt596_exit(void)
494{
495	pci_unregister_driver(&vt596_driver);
496	if (vt596_pdev != NULL) {
497		i2c_del_adapter(&vt596_adapter);
498		release_region(vt596_smba, 8);
499		pci_dev_put(vt596_pdev);
500		vt596_pdev = NULL;
501	}
502}
503
504MODULE_AUTHOR("Kyosti Malkki <kmalkki@cc.hut.fi>, "
505	      "Mark D. Studebaker <mdsxyz123@yahoo.com> and "
506	      "Jean Delvare <khali@linux-fr.org>");
507MODULE_DESCRIPTION("vt82c596 SMBus driver");
508MODULE_LICENSE("GPL");
509
510module_init(i2c_vt596_init);
511module_exit(i2c_vt596_exit);
512