xref: /openbmc/linux/drivers/i2c/busses/i2c-viapro.c (revision 22246614)
1 /*
2     i2c-viapro.c - Part of lm_sensors, Linux kernel modules for hardware
3               monitoring
4     Copyright (c) 1998 - 2002  Frodo Looijaard <frodol@dds.nl>,
5     Philip Edelbrock <phil@netroedge.com>, Kyösti Mälkki <kmalkki@cc.hut.fi>,
6     Mark D. Studebaker <mdsxyz123@yahoo.com>
7     Copyright (C) 2005 - 2008  Jean Delvare <khali@linux-fr.org>
8 
9     This program is free software; you can redistribute it and/or modify
10     it under the terms of the GNU General Public License as published by
11     the Free Software Foundation; either version 2 of the License, or
12     (at your option) any later version.
13 
14     This program is distributed in the hope that it will be useful,
15     but WITHOUT ANY WARRANTY; without even the implied warranty of
16     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17     GNU General Public License for more details.
18 
19     You should have received a copy of the GNU General Public License
20     along with this program; if not, write to the Free Software
21     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 */
23 
24 /*
25    Supports the following VIA south bridges:
26 
27    Chip name          PCI ID  REV     I2C block
28    VT82C596A          0x3050             no
29    VT82C596B          0x3051             no
30    VT82C686A          0x3057  0x30       no
31    VT82C686B          0x3057  0x40       yes
32    VT8231             0x8235             no?
33    VT8233             0x3074             yes
34    VT8233A            0x3147             yes?
35    VT8235             0x3177             yes
36    VT8237R            0x3227             yes
37    VT8237A            0x3337             yes
38    VT8237S            0x3372             yes
39    VT8251             0x3287             yes
40    CX700              0x8324             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 <asm/io.h>
54 
55 static struct pci_dev *vt596_pdev;
56 
57 #define SMBBA1		0x90
58 #define SMBBA2		0x80
59 #define SMBBA3		0xD0
60 
61 /* SMBus address offsets */
62 static unsigned short vt596_smba;
63 #define SMBHSTSTS	(vt596_smba + 0)
64 #define SMBHSTCNT	(vt596_smba + 2)
65 #define SMBHSTCMD	(vt596_smba + 3)
66 #define SMBHSTADD	(vt596_smba + 4)
67 #define SMBHSTDAT0	(vt596_smba + 5)
68 #define SMBHSTDAT1	(vt596_smba + 6)
69 #define SMBBLKDAT	(vt596_smba + 7)
70 
71 /* PCI Address Constants */
72 
73 /* SMBus data in configuration space can be found in two places,
74    We try to select the better one */
75 
76 static unsigned short SMBHSTCFG = 0xD2;
77 
78 /* Other settings */
79 #define MAX_TIMEOUT	500
80 
81 /* VT82C596 constants */
82 #define VT596_QUICK		0x00
83 #define VT596_BYTE		0x04
84 #define VT596_BYTE_DATA		0x08
85 #define VT596_WORD_DATA		0x0C
86 #define VT596_BLOCK_DATA	0x14
87 #define VT596_I2C_BLOCK_DATA	0x34
88 
89 
90 /* If force is set to anything different from 0, we forcibly enable the
91    VT596. DANGEROUS! */
92 static int force;
93 module_param(force, bool, 0);
94 MODULE_PARM_DESC(force, "Forcibly enable the SMBus. DANGEROUS!");
95 
96 /* If force_addr is set to anything different from 0, we forcibly enable
97    the VT596 at the given address. VERY DANGEROUS! */
98 static u16 force_addr;
99 module_param(force_addr, ushort, 0);
100 MODULE_PARM_DESC(force_addr,
101 		 "Forcibly enable the SMBus at the given address. "
102 		 "EXTREMELY DANGEROUS!");
103 
104 
105 static struct pci_driver vt596_driver;
106 static struct i2c_adapter vt596_adapter;
107 
108 #define FEATURE_I2CBLOCK	(1<<0)
109 static unsigned int vt596_features;
110 
111 #ifdef DEBUG
112 static void vt596_dump_regs(const char *msg, u8 size)
113 {
114 	dev_dbg(&vt596_adapter.dev, "%s: STS=%02x CNT=%02x CMD=%02x ADD=%02x "
115 		"DAT=%02x,%02x\n", msg, inb_p(SMBHSTSTS), inb_p(SMBHSTCNT),
116 		inb_p(SMBHSTCMD), inb_p(SMBHSTADD), inb_p(SMBHSTDAT0),
117 		inb_p(SMBHSTDAT1));
118 
119 	if (size == VT596_BLOCK_DATA
120 	 || size == VT596_I2C_BLOCK_DATA) {
121 		int i;
122 
123 		dev_dbg(&vt596_adapter.dev, "BLK=");
124 		for (i = 0; i < I2C_SMBUS_BLOCK_MAX / 2; i++)
125 			printk("%02x,", inb_p(SMBBLKDAT));
126 		printk("\n");
127 		dev_dbg(&vt596_adapter.dev, "    ");
128 		for (; i < I2C_SMBUS_BLOCK_MAX - 1; i++)
129 			printk("%02x,", inb_p(SMBBLKDAT));
130 		printk("%02x\n", inb_p(SMBBLKDAT));
131 	}
132 }
133 #else
134 static inline void vt596_dump_regs(const char *msg, u8 size) { }
135 #endif
136 
137 /* Return -1 on error, 0 on success */
138 static int vt596_transaction(u8 size)
139 {
140 	int temp;
141 	int result = 0;
142 	int timeout = 0;
143 
144 	vt596_dump_regs("Transaction (pre)", size);
145 
146 	/* Make sure the SMBus host is ready to start transmitting */
147 	if ((temp = inb_p(SMBHSTSTS)) & 0x1F) {
148 		dev_dbg(&vt596_adapter.dev, "SMBus busy (0x%02x). "
149 			"Resetting...\n", temp);
150 
151 		outb_p(temp, SMBHSTSTS);
152 		if ((temp = inb_p(SMBHSTSTS)) & 0x1F) {
153 			dev_err(&vt596_adapter.dev, "SMBus reset failed! "
154 				"(0x%02x)\n", temp);
155 			return -1;
156 		}
157 	}
158 
159 	/* Start the transaction by setting bit 6 */
160 	outb_p(0x40 | size, SMBHSTCNT);
161 
162 	/* We will always wait for a fraction of a second */
163 	do {
164 		msleep(1);
165 		temp = inb_p(SMBHSTSTS);
166 	} while ((temp & 0x01) && (timeout++ < MAX_TIMEOUT));
167 
168 	/* If the SMBus is still busy, we give up */
169 	if (timeout >= MAX_TIMEOUT) {
170 		result = -1;
171 		dev_err(&vt596_adapter.dev, "SMBus timeout!\n");
172 	}
173 
174 	if (temp & 0x10) {
175 		result = -1;
176 		dev_err(&vt596_adapter.dev, "Transaction failed (0x%02x)\n",
177 			size);
178 	}
179 
180 	if (temp & 0x08) {
181 		result = -1;
182 		dev_err(&vt596_adapter.dev, "SMBus collision!\n");
183 	}
184 
185 	if (temp & 0x04) {
186 		int read = inb_p(SMBHSTADD) & 0x01;
187 		result = -1;
188 		/* The quick and receive byte commands are used to probe
189 		   for chips, so errors are expected, and we don't want
190 		   to frighten the user. */
191 		if (!((size == VT596_QUICK && !read) ||
192 		      (size == VT596_BYTE && read)))
193 			dev_err(&vt596_adapter.dev, "Transaction error!\n");
194 	}
195 
196 	/* Resetting status register */
197 	if (temp & 0x1F)
198 		outb_p(temp, SMBHSTSTS);
199 
200 	vt596_dump_regs("Transaction (post)", size);
201 
202 	return result;
203 }
204 
205 /* Return -1 on error, 0 on success */
206 static s32 vt596_access(struct i2c_adapter *adap, u16 addr,
207 		unsigned short flags, char read_write, u8 command,
208 		int size, union i2c_smbus_data *data)
209 {
210 	int i;
211 
212 	switch (size) {
213 	case I2C_SMBUS_QUICK:
214 		size = VT596_QUICK;
215 		break;
216 	case I2C_SMBUS_BYTE:
217 		if (read_write == I2C_SMBUS_WRITE)
218 			outb_p(command, SMBHSTCMD);
219 		size = VT596_BYTE;
220 		break;
221 	case I2C_SMBUS_BYTE_DATA:
222 		outb_p(command, SMBHSTCMD);
223 		if (read_write == I2C_SMBUS_WRITE)
224 			outb_p(data->byte, SMBHSTDAT0);
225 		size = VT596_BYTE_DATA;
226 		break;
227 	case I2C_SMBUS_WORD_DATA:
228 		outb_p(command, SMBHSTCMD);
229 		if (read_write == I2C_SMBUS_WRITE) {
230 			outb_p(data->word & 0xff, SMBHSTDAT0);
231 			outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
232 		}
233 		size = VT596_WORD_DATA;
234 		break;
235 	case I2C_SMBUS_I2C_BLOCK_DATA:
236 		if (!(vt596_features & FEATURE_I2CBLOCK))
237 			goto exit_unsupported;
238 		if (read_write == I2C_SMBUS_READ)
239 			outb_p(data->block[0], SMBHSTDAT0);
240 		/* Fall through */
241 	case I2C_SMBUS_BLOCK_DATA:
242 		outb_p(command, SMBHSTCMD);
243 		if (read_write == I2C_SMBUS_WRITE) {
244 			u8 len = data->block[0];
245 			if (len > I2C_SMBUS_BLOCK_MAX)
246 				len = I2C_SMBUS_BLOCK_MAX;
247 			outb_p(len, SMBHSTDAT0);
248 			inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
249 			for (i = 1; i <= len; i++)
250 				outb_p(data->block[i], SMBBLKDAT);
251 		}
252 		size = (size == I2C_SMBUS_I2C_BLOCK_DATA) ?
253 		       VT596_I2C_BLOCK_DATA : VT596_BLOCK_DATA;
254 		break;
255 	default:
256 		goto exit_unsupported;
257 	}
258 
259 	outb_p(((addr & 0x7f) << 1) | read_write, SMBHSTADD);
260 
261 	if (vt596_transaction(size)) /* Error in transaction */
262 		return -1;
263 
264 	if ((read_write == I2C_SMBUS_WRITE) || (size == VT596_QUICK))
265 		return 0;
266 
267 	switch (size) {
268 	case VT596_BYTE:
269 	case VT596_BYTE_DATA:
270 		data->byte = inb_p(SMBHSTDAT0);
271 		break;
272 	case VT596_WORD_DATA:
273 		data->word = inb_p(SMBHSTDAT0) + (inb_p(SMBHSTDAT1) << 8);
274 		break;
275 	case VT596_I2C_BLOCK_DATA:
276 	case VT596_BLOCK_DATA:
277 		data->block[0] = inb_p(SMBHSTDAT0);
278 		if (data->block[0] > I2C_SMBUS_BLOCK_MAX)
279 			data->block[0] = I2C_SMBUS_BLOCK_MAX;
280 		inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
281 		for (i = 1; i <= data->block[0]; i++)
282 			data->block[i] = inb_p(SMBBLKDAT);
283 		break;
284 	}
285 	return 0;
286 
287 exit_unsupported:
288 	dev_warn(&vt596_adapter.dev, "Unsupported command invoked! (0x%02x)\n",
289 		 size);
290 	return -1;
291 }
292 
293 static u32 vt596_func(struct i2c_adapter *adapter)
294 {
295 	u32 func = I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
296 	    I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
297 	    I2C_FUNC_SMBUS_BLOCK_DATA;
298 
299 	if (vt596_features & FEATURE_I2CBLOCK)
300 		func |= I2C_FUNC_SMBUS_I2C_BLOCK;
301 	return func;
302 }
303 
304 static const struct i2c_algorithm smbus_algorithm = {
305 	.smbus_xfer	= vt596_access,
306 	.functionality	= vt596_func,
307 };
308 
309 static struct i2c_adapter vt596_adapter = {
310 	.owner		= THIS_MODULE,
311 	.id		= I2C_HW_SMBUS_VIA2,
312 	.class		= I2C_CLASS_HWMON,
313 	.algo		= &smbus_algorithm,
314 };
315 
316 static int __devinit vt596_probe(struct pci_dev *pdev,
317 				 const struct pci_device_id *id)
318 {
319 	unsigned char temp;
320 	int error = -ENODEV;
321 
322 	/* driver_data might come from user-space, so check it */
323 	if (id->driver_data & 1 || id->driver_data > 0xff)
324 		return -EINVAL;
325 
326 	/* Determine the address of the SMBus areas */
327 	if (force_addr) {
328 		vt596_smba = force_addr & 0xfff0;
329 		force = 0;
330 		goto found;
331 	}
332 
333 	if ((pci_read_config_word(pdev, id->driver_data, &vt596_smba)) ||
334 	    !(vt596_smba & 0x0001)) {
335 		/* try 2nd address and config reg. for 596 */
336 		if (id->device == PCI_DEVICE_ID_VIA_82C596_3 &&
337 		    !pci_read_config_word(pdev, SMBBA2, &vt596_smba) &&
338 		    (vt596_smba & 0x0001)) {
339 			SMBHSTCFG = 0x84;
340 		} else {
341 			/* no matches at all */
342 			dev_err(&pdev->dev, "Cannot configure "
343 				"SMBus I/O Base address\n");
344 			return -ENODEV;
345 		}
346 	}
347 
348 	vt596_smba &= 0xfff0;
349 	if (vt596_smba == 0) {
350 		dev_err(&pdev->dev, "SMBus base address "
351 			"uninitialized - upgrade BIOS or use "
352 			"force_addr=0xaddr\n");
353 		return -ENODEV;
354 	}
355 
356 found:
357 	if (!request_region(vt596_smba, 8, vt596_driver.name)) {
358 		dev_err(&pdev->dev, "SMBus region 0x%x already in use!\n",
359 			vt596_smba);
360 		return -ENODEV;
361 	}
362 
363 	pci_read_config_byte(pdev, SMBHSTCFG, &temp);
364 	/* If force_addr is set, we program the new address here. Just to make
365 	   sure, we disable the VT596 first. */
366 	if (force_addr) {
367 		pci_write_config_byte(pdev, SMBHSTCFG, temp & 0xfe);
368 		pci_write_config_word(pdev, id->driver_data, vt596_smba);
369 		pci_write_config_byte(pdev, SMBHSTCFG, temp | 0x01);
370 		dev_warn(&pdev->dev, "WARNING: SMBus interface set to new "
371 			 "address 0x%04x!\n", vt596_smba);
372 	} else if (!(temp & 0x01)) {
373 		if (force) {
374 			/* NOTE: This assumes I/O space and other allocations
375 			 * WERE done by the Bios!  Don't complain if your
376 			 * hardware does weird things after enabling this.
377 			 * :') Check for Bios updates before resorting to
378 			 * this.
379 			 */
380 			pci_write_config_byte(pdev, SMBHSTCFG, temp | 0x01);
381 			dev_info(&pdev->dev, "Enabling SMBus device\n");
382 		} else {
383 			dev_err(&pdev->dev, "SMBUS: Error: Host SMBus "
384 				"controller not enabled! - upgrade BIOS or "
385 				"use force=1\n");
386 			goto release_region;
387 		}
388 	}
389 
390 	dev_dbg(&pdev->dev, "VT596_smba = 0x%X\n", vt596_smba);
391 
392 	switch (pdev->device) {
393 	case PCI_DEVICE_ID_VIA_CX700:
394 	case PCI_DEVICE_ID_VIA_8251:
395 	case PCI_DEVICE_ID_VIA_8237:
396 	case PCI_DEVICE_ID_VIA_8237A:
397 	case PCI_DEVICE_ID_VIA_8237S:
398 	case PCI_DEVICE_ID_VIA_8235:
399 	case PCI_DEVICE_ID_VIA_8233A:
400 	case PCI_DEVICE_ID_VIA_8233_0:
401 		vt596_features |= FEATURE_I2CBLOCK;
402 		break;
403 	case PCI_DEVICE_ID_VIA_82C686_4:
404 		/* The VT82C686B (rev 0x40) does support I2C block
405 		   transactions, but the VT82C686A (rev 0x30) doesn't */
406 		if (pdev->revision >= 0x40)
407 			vt596_features |= FEATURE_I2CBLOCK;
408 		break;
409 	}
410 
411 	vt596_adapter.dev.parent = &pdev->dev;
412 	snprintf(vt596_adapter.name, sizeof(vt596_adapter.name),
413 		 "SMBus Via Pro adapter at %04x", vt596_smba);
414 
415 	vt596_pdev = pci_dev_get(pdev);
416 	if (i2c_add_adapter(&vt596_adapter)) {
417 		pci_dev_put(vt596_pdev);
418 		vt596_pdev = NULL;
419 	}
420 
421 	/* Always return failure here.  This is to allow other drivers to bind
422 	 * to this pci device.  We don't really want to have control over the
423 	 * pci device, we only wanted to read as few register values from it.
424 	 */
425 	return -ENODEV;
426 
427 release_region:
428 	release_region(vt596_smba, 8);
429 	return error;
430 }
431 
432 static struct pci_device_id vt596_ids[] = {
433 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C596_3),
434 	  .driver_data = SMBBA1 },
435 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C596B_3),
436 	  .driver_data = SMBBA1 },
437 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C686_4),
438 	  .driver_data = SMBBA1 },
439 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8233_0),
440 	  .driver_data = SMBBA3 },
441 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8233A),
442 	  .driver_data = SMBBA3 },
443 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8235),
444 	  .driver_data = SMBBA3 },
445 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237),
446 	  .driver_data = SMBBA3 },
447 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237A),
448 	  .driver_data = SMBBA3 },
449 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237S),
450 	  .driver_data = SMBBA3 },
451 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8231_4),
452 	  .driver_data = SMBBA1 },
453 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8251),
454 	  .driver_data = SMBBA3 },
455 	{ PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_CX700),
456 	  .driver_data = SMBBA3 },
457 	{ 0, }
458 };
459 
460 MODULE_DEVICE_TABLE(pci, vt596_ids);
461 
462 static struct pci_driver vt596_driver = {
463 	.name		= "vt596_smbus",
464 	.id_table	= vt596_ids,
465 	.probe		= vt596_probe,
466 	.dynids.use_driver_data = 1,
467 };
468 
469 static int __init i2c_vt596_init(void)
470 {
471 	return pci_register_driver(&vt596_driver);
472 }
473 
474 
475 static void __exit i2c_vt596_exit(void)
476 {
477 	pci_unregister_driver(&vt596_driver);
478 	if (vt596_pdev != NULL) {
479 		i2c_del_adapter(&vt596_adapter);
480 		release_region(vt596_smba, 8);
481 		pci_dev_put(vt596_pdev);
482 		vt596_pdev = NULL;
483 	}
484 }
485 
486 MODULE_AUTHOR("Kyosti Malkki <kmalkki@cc.hut.fi>, "
487 	      "Mark D. Studebaker <mdsxyz123@yahoo.com> and "
488 	      "Jean Delvare <khali@linux-fr.org>");
489 MODULE_DESCRIPTION("vt82c596 SMBus driver");
490 MODULE_LICENSE("GPL");
491 
492 module_init(i2c_vt596_init);
493 module_exit(i2c_vt596_exit);
494