1/*
2    Copyright (c) 1998 - 2002  Frodo Looijaard <frodol@dds.nl>,
3    Philip Edelbrock <phil@netroedge.com>, Kyösti Mälkki <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 bool 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		result = -ENXIO;
189		dev_dbg(&vt596_adapter.dev, "No response\n");
190	}
191
192	/* Resetting status register */
193	if (temp & 0x1F)
194		outb_p(temp, SMBHSTSTS);
195
196	vt596_dump_regs("Transaction (post)", size);
197
198	return result;
199}
200
201/* Return negative errno on error, 0 on success */
202static s32 vt596_access(struct i2c_adapter *adap, u16 addr,
203		unsigned short flags, char read_write, u8 command,
204		int size, union i2c_smbus_data *data)
205{
206	int i;
207	int status;
208
209	switch (size) {
210	case I2C_SMBUS_QUICK:
211		size = VT596_QUICK;
212		break;
213	case I2C_SMBUS_BYTE:
214		if (read_write == I2C_SMBUS_WRITE)
215			outb_p(command, SMBHSTCMD);
216		size = VT596_BYTE;
217		break;
218	case I2C_SMBUS_BYTE_DATA:
219		outb_p(command, SMBHSTCMD);
220		if (read_write == I2C_SMBUS_WRITE)
221			outb_p(data->byte, SMBHSTDAT0);
222		size = VT596_BYTE_DATA;
223		break;
224	case I2C_SMBUS_WORD_DATA:
225		outb_p(command, SMBHSTCMD);
226		if (read_write == I2C_SMBUS_WRITE) {
227			outb_p(data->word & 0xff, SMBHSTDAT0);
228			outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
229		}
230		size = VT596_WORD_DATA;
231		break;
232	case I2C_SMBUS_PROC_CALL:
233		outb_p(command, SMBHSTCMD);
234		outb_p(data->word & 0xff, SMBHSTDAT0);
235		outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
236		size = VT596_PROC_CALL;
237		break;
238	case I2C_SMBUS_I2C_BLOCK_DATA:
239		if (!(vt596_features & FEATURE_I2CBLOCK))
240			goto exit_unsupported;
241		if (read_write == I2C_SMBUS_READ)
242			outb_p(data->block[0], SMBHSTDAT0);
243		/* Fall through */
244	case I2C_SMBUS_BLOCK_DATA:
245		outb_p(command, SMBHSTCMD);
246		if (read_write == I2C_SMBUS_WRITE) {
247			u8 len = data->block[0];
248			if (len > I2C_SMBUS_BLOCK_MAX)
249				len = I2C_SMBUS_BLOCK_MAX;
250			outb_p(len, SMBHSTDAT0);
251			inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
252			for (i = 1; i <= len; i++)
253				outb_p(data->block[i], SMBBLKDAT);
254		}
255		size = (size == I2C_SMBUS_I2C_BLOCK_DATA) ?
256		       VT596_I2C_BLOCK_DATA : VT596_BLOCK_DATA;
257		break;
258	default:
259		goto exit_unsupported;
260	}
261
262	outb_p(((addr & 0x7f) << 1) | read_write, SMBHSTADD);
263
264	status = vt596_transaction(size);
265	if (status)
266		return status;
267
268	if (size == VT596_PROC_CALL)
269		read_write = I2C_SMBUS_READ;
270
271	if ((read_write == I2C_SMBUS_WRITE) || (size == VT596_QUICK))
272		return 0;
273
274	switch (size) {
275	case VT596_BYTE:
276	case VT596_BYTE_DATA:
277		data->byte = inb_p(SMBHSTDAT0);
278		break;
279	case VT596_WORD_DATA:
280	case VT596_PROC_CALL:
281		data->word = inb_p(SMBHSTDAT0) + (inb_p(SMBHSTDAT1) << 8);
282		break;
283	case VT596_I2C_BLOCK_DATA:
284	case VT596_BLOCK_DATA:
285		data->block[0] = inb_p(SMBHSTDAT0);
286		if (data->block[0] > I2C_SMBUS_BLOCK_MAX)
287			data->block[0] = I2C_SMBUS_BLOCK_MAX;
288		inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
289		for (i = 1; i <= data->block[0]; i++)
290			data->block[i] = inb_p(SMBBLKDAT);
291		break;
292	}
293	return 0;
294
295exit_unsupported:
296	dev_warn(&vt596_adapter.dev, "Unsupported transaction %d\n",
297		 size);
298	return -EOPNOTSUPP;
299}
300
301static u32 vt596_func(struct i2c_adapter *adapter)
302{
303	u32 func = I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
304	    I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
305	    I2C_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_BLOCK_DATA;
306
307	if (vt596_features & FEATURE_I2CBLOCK)
308		func |= I2C_FUNC_SMBUS_I2C_BLOCK;
309	return func;
310}
311
312static const struct i2c_algorithm smbus_algorithm = {
313	.smbus_xfer	= vt596_access,
314	.functionality	= vt596_func,
315};
316
317static struct i2c_adapter vt596_adapter = {
318	.owner		= THIS_MODULE,
319	.class		= I2C_CLASS_HWMON | I2C_CLASS_SPD,
320	.algo		= &smbus_algorithm,
321};
322
323static int __devinit vt596_probe(struct pci_dev *pdev,
324				 const struct pci_device_id *id)
325{
326	unsigned char temp;
327	int error;
328
329	/* Determine the address of the SMBus areas */
330	if (force_addr) {
331		vt596_smba = force_addr & 0xfff0;
332		force = 0;
333		goto found;
334	}
335
336	if ((pci_read_config_word(pdev, id->driver_data, &vt596_smba)) ||
337	    !(vt596_smba & 0x0001)) {
338		/* try 2nd address and config reg. for 596 */
339		if (id->device == PCI_DEVICE_ID_VIA_82C596_3 &&
340		    !pci_read_config_word(pdev, SMBBA2, &vt596_smba) &&
341		    (vt596_smba & 0x0001)) {
342			SMBHSTCFG = 0x84;
343		} else {
344			/* no matches at all */
345			dev_err(&pdev->dev, "Cannot configure "
346				"SMBus I/O Base address\n");
347			return -ENODEV;
348		}
349	}
350
351	vt596_smba &= 0xfff0;
352	if (vt596_smba == 0) {
353		dev_err(&pdev->dev, "SMBus base address "
354			"uninitialized - upgrade BIOS or use "
355			"force_addr=0xaddr\n");
356		return -ENODEV;
357	}
358
359found:
360	error = acpi_check_region(vt596_smba, 8, vt596_driver.name);
361	if (error)
362		return -ENODEV;
363
364	if (!request_region(vt596_smba, 8, vt596_driver.name)) {
365		dev_err(&pdev->dev, "SMBus region 0x%x already in use!\n",
366			vt596_smba);
367		return -ENODEV;
368	}
369
370	pci_read_config_byte(pdev, SMBHSTCFG, &temp);
371	/* If force_addr is set, we program the new address here. Just to make
372	   sure, we disable the VT596 first. */
373	if (force_addr) {
374		pci_write_config_byte(pdev, SMBHSTCFG, temp & 0xfe);
375		pci_write_config_word(pdev, id->driver_data, vt596_smba);
376		pci_write_config_byte(pdev, SMBHSTCFG, temp | 0x01);
377		dev_warn(&pdev->dev, "WARNING: SMBus interface set to new "
378			 "address 0x%04x!\n", vt596_smba);
379	} else if (!(temp & 0x01)) {
380		if (force) {
381			/* NOTE: This assumes I/O space and other allocations
382			 * WERE done by the Bios!  Don't complain if your
383			 * hardware does weird things after enabling this.
384			 * :') Check for Bios updates before resorting to
385			 * this.
386			 */
387			pci_write_config_byte(pdev, SMBHSTCFG, temp | 0x01);
388			dev_info(&pdev->dev, "Enabling SMBus device\n");
389		} else {
390			dev_err(&pdev->dev, "SMBUS: Error: Host SMBus "
391				"controller not enabled! - upgrade BIOS or "
392				"use force=1\n");
393			error = -ENODEV;
394			goto release_region;
395		}
396	}
397
398	dev_dbg(&pdev->dev, "VT596_smba = 0x%X\n", vt596_smba);
399
400	switch (pdev->device) {
401	case PCI_DEVICE_ID_VIA_CX700:
402	case PCI_DEVICE_ID_VIA_VX800:
403	case PCI_DEVICE_ID_VIA_VX855:
404	case PCI_DEVICE_ID_VIA_8251:
405	case PCI_DEVICE_ID_VIA_8237:
406	case PCI_DEVICE_ID_VIA_8237A:
407	case PCI_DEVICE_ID_VIA_8237S:
408	case PCI_DEVICE_ID_VIA_8235:
409	case PCI_DEVICE_ID_VIA_8233A:
410	case PCI_DEVICE_ID_VIA_8233_0:
411		vt596_features |= FEATURE_I2CBLOCK;
412		break;
413	case PCI_DEVICE_ID_VIA_82C686_4:
414		/* The VT82C686B (rev 0x40) does support I2C block
415		   transactions, but the VT82C686A (rev 0x30) doesn't */
416		if (pdev->revision >= 0x40)
417			vt596_features |= FEATURE_I2CBLOCK;
418		break;
419	}
420
421	vt596_adapter.dev.parent = &pdev->dev;
422	snprintf(vt596_adapter.name, sizeof(vt596_adapter.name),
423		 "SMBus Via Pro adapter at %04x", vt596_smba);
424
425	vt596_pdev = pci_dev_get(pdev);
426	error = i2c_add_adapter(&vt596_adapter);
427	if (error) {
428		pci_dev_put(vt596_pdev);
429		vt596_pdev = NULL;
430		goto release_region;
431	}
432
433	/* Always return failure here.  This is to allow other drivers to bind
434	 * to this pci device.  We don't really want to have control over the
435	 * pci device, we only wanted to read as few register values from it.
436	 */
437	return -ENODEV;
438
439release_region:
440	release_region(vt596_smba, 8);
441	return error;
442}
443
444static DEFINE_PCI_DEVICE_TABLE(vt596_ids) = {
445	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C596_3),
446	  .driver_data = SMBBA1 },
447	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C596B_3),
448	  .driver_data = SMBBA1 },
449	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C686_4),
450	  .driver_data = SMBBA1 },
451	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8233_0),
452	  .driver_data = SMBBA3 },
453	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8233A),
454	  .driver_data = SMBBA3 },
455	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8235),
456	  .driver_data = SMBBA3 },
457	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237),
458	  .driver_data = SMBBA3 },
459	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237A),
460	  .driver_data = SMBBA3 },
461	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237S),
462	  .driver_data = SMBBA3 },
463	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8231_4),
464	  .driver_data = SMBBA1 },
465	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8251),
466	  .driver_data = SMBBA3 },
467	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_CX700),
468	  .driver_data = SMBBA3 },
469	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX800),
470	  .driver_data = SMBBA3 },
471	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_VX855),
472	  .driver_data = SMBBA3 },
473	{ 0, }
474};
475
476MODULE_DEVICE_TABLE(pci, vt596_ids);
477
478static struct pci_driver vt596_driver = {
479	.name		= "vt596_smbus",
480	.id_table	= vt596_ids,
481	.probe		= vt596_probe,
482};
483
484static int __init i2c_vt596_init(void)
485{
486	return pci_register_driver(&vt596_driver);
487}
488
489
490static void __exit i2c_vt596_exit(void)
491{
492	pci_unregister_driver(&vt596_driver);
493	if (vt596_pdev != NULL) {
494		i2c_del_adapter(&vt596_adapter);
495		release_region(vt596_smba, 8);
496		pci_dev_put(vt596_pdev);
497		vt596_pdev = NULL;
498	}
499}
500
501MODULE_AUTHOR("Kyosti Malkki <kmalkki@cc.hut.fi>, "
502	      "Mark D. Studebaker <mdsxyz123@yahoo.com> and "
503	      "Jean Delvare <khali@linux-fr.org>");
504MODULE_DESCRIPTION("vt82c596 SMBus driver");
505MODULE_LICENSE("GPL");
506
507module_init(i2c_vt596_init);
508module_exit(i2c_vt596_exit);
509