xref: /openbmc/linux/drivers/i2c/busses/i2c-ali1535.c (revision 9ac8d3fb)
1 /*
2     Copyright (c) 2000  Frodo Looijaard <frodol@dds.nl>,
3                         Philip Edelbrock <phil@netroedge.com>,
4                         Mark D. Studebaker <mdsxyz123@yahoo.com>,
5                         Dan Eaton <dan.eaton@rocketlogix.com> and
6                         Stephen Rousset<stephen.rousset@rocketlogix.com>
7 
8     This program is free software; you can redistribute it and/or modify
9     it under the terms of the GNU General Public License as published by
10     the Free Software Foundation; either version 2 of the License, or
11     (at your option) any later version.
12 
13     This program is distributed in the hope that it will be useful,
14     but WITHOUT ANY WARRANTY; without even the implied warranty of
15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16     GNU General Public License for more details.
17 
18     You should have received a copy of the GNU General Public License
19     along with this program; if not, write to the Free Software
20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22 
23 /*
24     This is the driver for the SMB Host controller on
25     Acer Labs Inc. (ALI) M1535 South Bridge.
26 
27     The M1535 is a South bridge for portable systems.
28     It is very similar to the M15x3 South bridges also produced
29     by Acer Labs Inc.  Some of the registers within the part
30     have moved and some have been redefined slightly. Additionally,
31     the sequencing of the SMBus transactions has been modified
32     to be more consistent with the sequencing recommended by
33     the manufacturer and observed through testing.  These
34     changes are reflected in this driver and can be identified
35     by comparing this driver to the i2c-ali15x3 driver.
36     For an overview of these chips see http://www.acerlabs.com
37 
38     The SMB controller is part of the 7101 device, which is an
39     ACPI-compliant Power Management Unit (PMU).
40 
41     The whole 7101 device has to be enabled for the SMB to work.
42     You can't just enable the SMB alone.
43     The SMB and the ACPI have separate I/O spaces.
44     We make sure that the SMB is enabled. We leave the ACPI alone.
45 
46     This driver controls the SMB Host only.
47 
48     This driver does not use interrupts.
49 */
50 
51 
52 /* Note: we assume there can only be one ALI1535, with one SMBus interface */
53 
54 #include <linux/module.h>
55 #include <linux/pci.h>
56 #include <linux/kernel.h>
57 #include <linux/stddef.h>
58 #include <linux/delay.h>
59 #include <linux/ioport.h>
60 #include <linux/i2c.h>
61 #include <linux/init.h>
62 #include <linux/acpi.h>
63 #include <asm/io.h>
64 
65 
66 /* ALI1535 SMBus address offsets */
67 #define SMBHSTSTS	(0 + ali1535_smba)
68 #define SMBHSTTYP	(1 + ali1535_smba)
69 #define SMBHSTPORT	(2 + ali1535_smba)
70 #define SMBHSTCMD	(7 + ali1535_smba)
71 #define SMBHSTADD	(3 + ali1535_smba)
72 #define SMBHSTDAT0	(4 + ali1535_smba)
73 #define SMBHSTDAT1	(5 + ali1535_smba)
74 #define SMBBLKDAT	(6 + ali1535_smba)
75 
76 /* PCI Address Constants */
77 #define SMBCOM		0x004
78 #define SMBREV		0x008
79 #define SMBCFG		0x0D1
80 #define SMBBA		0x0E2
81 #define SMBHSTCFG	0x0F0
82 #define SMBCLK		0x0F2
83 
84 /* Other settings */
85 #define MAX_TIMEOUT		500	/* times 1/100 sec */
86 #define ALI1535_SMB_IOSIZE	32
87 
88 #define ALI1535_SMB_DEFAULTBASE	0x8040
89 
90 /* ALI1535 address lock bits */
91 #define ALI1535_LOCK		0x06	/* dwe */
92 
93 /* ALI1535 command constants */
94 #define ALI1535_QUICK		0x00
95 #define ALI1535_BYTE		0x10
96 #define ALI1535_BYTE_DATA	0x20
97 #define ALI1535_WORD_DATA	0x30
98 #define ALI1535_BLOCK_DATA	0x40
99 #define ALI1535_I2C_READ	0x60
100 
101 #define	ALI1535_DEV10B_EN	0x80	/* Enable 10-bit addressing in	*/
102 					/*  I2C read			*/
103 #define	ALI1535_T_OUT		0x08	/* Time-out Command (write)	*/
104 #define	ALI1535_A_HIGH_BIT9	0x08	/* Bit 9 of 10-bit address in	*/
105 					/* Alert-Response-Address	*/
106 					/* (read)			*/
107 #define	ALI1535_KILL		0x04	/* Kill Command (write)		*/
108 #define	ALI1535_A_HIGH_BIT8	0x04	/* Bit 8 of 10-bit address in	*/
109 					/*  Alert-Response-Address	*/
110 					/*  (read)			*/
111 
112 #define	ALI1535_D_HI_MASK	0x03	/* Mask for isolating bits 9-8	*/
113 					/*  of 10-bit address in I2C	*/
114 					/*  Read Command		*/
115 
116 /* ALI1535 status register bits */
117 #define ALI1535_STS_IDLE	0x04
118 #define ALI1535_STS_BUSY	0x08	/* host busy */
119 #define ALI1535_STS_DONE	0x10	/* transaction complete */
120 #define ALI1535_STS_DEV		0x20	/* device error */
121 #define ALI1535_STS_BUSERR	0x40	/* bus error    */
122 #define ALI1535_STS_FAIL	0x80	/* failed bus transaction */
123 #define ALI1535_STS_ERR		0xE0	/* all the bad error bits */
124 
125 #define ALI1535_BLOCK_CLR	0x04	/* reset block data index */
126 
127 /* ALI1535 device address register bits */
128 #define	ALI1535_RD_ADDR		0x01	/* Read/Write Bit in Device	*/
129 					/*  Address field		*/
130 					/*  -> Write = 0		*/
131 					/*  -> Read  = 1		*/
132 #define	ALI1535_SMBIO_EN	0x04	/* SMB I/O Space enable		*/
133 
134 static struct pci_driver ali1535_driver;
135 static unsigned short ali1535_smba;
136 
137 /* Detect whether a ALI1535 can be found, and initialize it, where necessary.
138    Note the differences between kernels with the old PCI BIOS interface and
139    newer kernels with the real PCI interface. In compat.h some things are
140    defined to make the transition easier. */
141 static int ali1535_setup(struct pci_dev *dev)
142 {
143 	int retval = -ENODEV;
144 	unsigned char temp;
145 
146 	/* Check the following things:
147 		- SMB I/O address is initialized
148 		- Device is enabled
149 		- We can use the addresses
150 	*/
151 
152 	/* Determine the address of the SMBus area */
153 	pci_read_config_word(dev, SMBBA, &ali1535_smba);
154 	ali1535_smba &= (0xffff & ~(ALI1535_SMB_IOSIZE - 1));
155 	if (ali1535_smba == 0) {
156 		dev_warn(&dev->dev,
157 			"ALI1535_smb region uninitialized - upgrade BIOS?\n");
158 		goto exit;
159 	}
160 
161 	retval = acpi_check_region(ali1535_smba, ALI1535_SMB_IOSIZE,
162 				   ali1535_driver.name);
163 	if (retval)
164 		goto exit;
165 
166 	if (!request_region(ali1535_smba, ALI1535_SMB_IOSIZE,
167 			    ali1535_driver.name)) {
168 		dev_err(&dev->dev, "ALI1535_smb region 0x%x already in use!\n",
169 			ali1535_smba);
170 		goto exit;
171 	}
172 
173 	/* check if whole device is enabled */
174 	pci_read_config_byte(dev, SMBCFG, &temp);
175 	if ((temp & ALI1535_SMBIO_EN) == 0) {
176 		dev_err(&dev->dev, "SMB device not enabled - upgrade BIOS?\n");
177 		goto exit_free;
178 	}
179 
180 	/* Is SMB Host controller enabled? */
181 	pci_read_config_byte(dev, SMBHSTCFG, &temp);
182 	if ((temp & 1) == 0) {
183 		dev_err(&dev->dev, "SMBus controller not enabled - upgrade BIOS?\n");
184 		goto exit_free;
185 	}
186 
187 	/* set SMB clock to 74KHz as recommended in data sheet */
188 	pci_write_config_byte(dev, SMBCLK, 0x20);
189 
190 	/*
191 	  The interrupt routing for SMB is set up in register 0x77 in the
192 	  1533 ISA Bridge device, NOT in the 7101 device.
193 	  Don't bother with finding the 1533 device and reading the register.
194 	if ((....... & 0x0F) == 1)
195 		dev_dbg(&dev->dev, "ALI1535 using Interrupt 9 for SMBus.\n");
196 	*/
197 	pci_read_config_byte(dev, SMBREV, &temp);
198 	dev_dbg(&dev->dev, "SMBREV = 0x%X\n", temp);
199 	dev_dbg(&dev->dev, "ALI1535_smba = 0x%X\n", ali1535_smba);
200 
201 	retval = 0;
202 exit:
203 	return retval;
204 
205 exit_free:
206 	release_region(ali1535_smba, ALI1535_SMB_IOSIZE);
207 	return retval;
208 }
209 
210 static int ali1535_transaction(struct i2c_adapter *adap)
211 {
212 	int temp;
213 	int result = 0;
214 	int timeout = 0;
215 
216 	dev_dbg(&adap->dev, "Transaction (pre): STS=%02x, TYP=%02x, "
217 		"CMD=%02x, ADD=%02x, DAT0=%02x, DAT1=%02x\n",
218 		inb_p(SMBHSTSTS), inb_p(SMBHSTTYP), inb_p(SMBHSTCMD),
219 		inb_p(SMBHSTADD), inb_p(SMBHSTDAT0), inb_p(SMBHSTDAT1));
220 
221 	/* get status */
222 	temp = inb_p(SMBHSTSTS);
223 
224 	/* Make sure the SMBus host is ready to start transmitting */
225 	/* Check the busy bit first */
226 	if (temp & ALI1535_STS_BUSY) {
227 		/* If the host controller is still busy, it may have timed out
228 		 * in the previous transaction, resulting in a "SMBus Timeout"
229 		 * printk.  I've tried the following to reset a stuck busy bit.
230 		 *   1. Reset the controller with an KILL command. (this
231 		 *      doesn't seem to clear the controller if an external
232 		 *      device is hung)
233 		 *   2. Reset the controller and the other SMBus devices with a
234 		 *      T_OUT command. (this clears the host busy bit if an
235 		 *      external device is hung, but it comes back upon a new
236 		 *      access to a device)
237 		 *   3. Disable and reenable the controller in SMBHSTCFG. Worst
238 		 *      case, nothing seems to work except power reset.
239 		 */
240 
241 		/* Try resetting entire SMB bus, including other devices - This
242 		 * may not work either - it clears the BUSY bit but then the
243 		 * BUSY bit may come back on when you try and use the chip
244 		 * again.  If that's the case you are stuck.
245 		 */
246 		dev_info(&adap->dev,
247 			"Resetting entire SMB Bus to clear busy condition (%02x)\n",
248 			temp);
249 		outb_p(ALI1535_T_OUT, SMBHSTTYP);
250 		temp = inb_p(SMBHSTSTS);
251 	}
252 
253 	/* now check the error bits and the busy bit */
254 	if (temp & (ALI1535_STS_ERR | ALI1535_STS_BUSY)) {
255 		/* do a clear-on-write */
256 		outb_p(0xFF, SMBHSTSTS);
257 		if ((temp = inb_p(SMBHSTSTS)) &
258 		    (ALI1535_STS_ERR | ALI1535_STS_BUSY)) {
259 			/* This is probably going to be correctable only by a
260 			 * power reset as one of the bits now appears to be
261 			 * stuck */
262 			/* This may be a bus or device with electrical problems. */
263 			dev_err(&adap->dev,
264 				"SMBus reset failed! (0x%02x) - controller or "
265 				"device on bus is probably hung\n", temp);
266 			return -EBUSY;
267 		}
268 	} else {
269 		/* check and clear done bit */
270 		if (temp & ALI1535_STS_DONE) {
271 			outb_p(temp, SMBHSTSTS);
272 		}
273 	}
274 
275 	/* start the transaction by writing anything to the start register */
276 	outb_p(0xFF, SMBHSTPORT);
277 
278 	/* We will always wait for a fraction of a second! */
279 	timeout = 0;
280 	do {
281 		msleep(1);
282 		temp = inb_p(SMBHSTSTS);
283 	} while (((temp & ALI1535_STS_BUSY) && !(temp & ALI1535_STS_IDLE))
284 		 && (timeout++ < MAX_TIMEOUT));
285 
286 	/* If the SMBus is still busy, we give up */
287 	if (timeout >= MAX_TIMEOUT) {
288 		result = -ETIMEDOUT;
289 		dev_err(&adap->dev, "SMBus Timeout!\n");
290 	}
291 
292 	if (temp & ALI1535_STS_FAIL) {
293 		result = -EIO;
294 		dev_dbg(&adap->dev, "Error: Failed bus transaction\n");
295 	}
296 
297 	/* Unfortunately the ALI SMB controller maps "no response" and "bus
298 	 * collision" into a single bit. No reponse is the usual case so don't
299 	 * do a printk.  This means that bus collisions go unreported.
300 	 */
301 	if (temp & ALI1535_STS_BUSERR) {
302 		result = -ENXIO;
303 		dev_dbg(&adap->dev,
304 			"Error: no response or bus collision ADD=%02x\n",
305 			inb_p(SMBHSTADD));
306 	}
307 
308 	/* haven't ever seen this */
309 	if (temp & ALI1535_STS_DEV) {
310 		result = -EIO;
311 		dev_err(&adap->dev, "Error: device error\n");
312 	}
313 
314 	/* check to see if the "command complete" indication is set */
315 	if (!(temp & ALI1535_STS_DONE)) {
316 		result = -ETIMEDOUT;
317 		dev_err(&adap->dev, "Error: command never completed\n");
318 	}
319 
320 	dev_dbg(&adap->dev, "Transaction (post): STS=%02x, TYP=%02x, "
321 		"CMD=%02x, ADD=%02x, DAT0=%02x, DAT1=%02x\n",
322 		inb_p(SMBHSTSTS), inb_p(SMBHSTTYP), inb_p(SMBHSTCMD),
323 		inb_p(SMBHSTADD), inb_p(SMBHSTDAT0), inb_p(SMBHSTDAT1));
324 
325 	/* take consequent actions for error conditions */
326 	if (!(temp & ALI1535_STS_DONE)) {
327 		/* issue "kill" to reset host controller */
328 		outb_p(ALI1535_KILL,SMBHSTTYP);
329 		outb_p(0xFF,SMBHSTSTS);
330 	} else if (temp & ALI1535_STS_ERR) {
331 		/* issue "timeout" to reset all devices on bus */
332 		outb_p(ALI1535_T_OUT,SMBHSTTYP);
333 		outb_p(0xFF,SMBHSTSTS);
334 	}
335 
336 	return result;
337 }
338 
339 /* Return negative errno on error. */
340 static s32 ali1535_access(struct i2c_adapter *adap, u16 addr,
341 			  unsigned short flags, char read_write, u8 command,
342 			  int size, union i2c_smbus_data *data)
343 {
344 	int i, len;
345 	int temp;
346 	int timeout;
347 	s32 result = 0;
348 
349 	/* make sure SMBus is idle */
350 	temp = inb_p(SMBHSTSTS);
351 	for (timeout = 0;
352 	     (timeout < MAX_TIMEOUT) && !(temp & ALI1535_STS_IDLE);
353 	     timeout++) {
354 		msleep(1);
355 		temp = inb_p(SMBHSTSTS);
356 	}
357 	if (timeout >= MAX_TIMEOUT)
358 		dev_warn(&adap->dev, "Idle wait Timeout! STS=0x%02x\n", temp);
359 
360 	/* clear status register (clear-on-write) */
361 	outb_p(0xFF, SMBHSTSTS);
362 
363 	switch (size) {
364 	case I2C_SMBUS_QUICK:
365 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
366 		       SMBHSTADD);
367 		size = ALI1535_QUICK;
368 		outb_p(size, SMBHSTTYP);	/* output command */
369 		break;
370 	case I2C_SMBUS_BYTE:
371 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
372 		       SMBHSTADD);
373 		size = ALI1535_BYTE;
374 		outb_p(size, SMBHSTTYP);	/* output command */
375 		if (read_write == I2C_SMBUS_WRITE)
376 			outb_p(command, SMBHSTCMD);
377 		break;
378 	case I2C_SMBUS_BYTE_DATA:
379 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
380 		       SMBHSTADD);
381 		size = ALI1535_BYTE_DATA;
382 		outb_p(size, SMBHSTTYP);	/* output command */
383 		outb_p(command, SMBHSTCMD);
384 		if (read_write == I2C_SMBUS_WRITE)
385 			outb_p(data->byte, SMBHSTDAT0);
386 		break;
387 	case I2C_SMBUS_WORD_DATA:
388 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
389 		       SMBHSTADD);
390 		size = ALI1535_WORD_DATA;
391 		outb_p(size, SMBHSTTYP);	/* output command */
392 		outb_p(command, SMBHSTCMD);
393 		if (read_write == I2C_SMBUS_WRITE) {
394 			outb_p(data->word & 0xff, SMBHSTDAT0);
395 			outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
396 		}
397 		break;
398 	case I2C_SMBUS_BLOCK_DATA:
399 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
400 		       SMBHSTADD);
401 		size = ALI1535_BLOCK_DATA;
402 		outb_p(size, SMBHSTTYP);	/* output command */
403 		outb_p(command, SMBHSTCMD);
404 		if (read_write == I2C_SMBUS_WRITE) {
405 			len = data->block[0];
406 			if (len < 0) {
407 				len = 0;
408 				data->block[0] = len;
409 			}
410 			if (len > 32) {
411 				len = 32;
412 				data->block[0] = len;
413 			}
414 			outb_p(len, SMBHSTDAT0);
415 			/* Reset SMBBLKDAT */
416 			outb_p(inb_p(SMBHSTTYP) | ALI1535_BLOCK_CLR, SMBHSTTYP);
417 			for (i = 1; i <= len; i++)
418 				outb_p(data->block[i], SMBBLKDAT);
419 		}
420 		break;
421 	default:
422 		dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
423 		result = -EOPNOTSUPP;
424 		goto EXIT;
425 	}
426 
427 	result = ali1535_transaction(adap);
428 	if (result)
429 		goto EXIT;
430 
431 	if ((read_write == I2C_SMBUS_WRITE) || (size == ALI1535_QUICK)) {
432 		result = 0;
433 		goto EXIT;
434 	}
435 
436 	switch (size) {
437 	case ALI1535_BYTE:	/* Result put in SMBHSTDAT0 */
438 		data->byte = inb_p(SMBHSTDAT0);
439 		break;
440 	case ALI1535_BYTE_DATA:
441 		data->byte = inb_p(SMBHSTDAT0);
442 		break;
443 	case ALI1535_WORD_DATA:
444 		data->word = inb_p(SMBHSTDAT0) + (inb_p(SMBHSTDAT1) << 8);
445 		break;
446 	case ALI1535_BLOCK_DATA:
447 		len = inb_p(SMBHSTDAT0);
448 		if (len > 32)
449 			len = 32;
450 		data->block[0] = len;
451 		/* Reset SMBBLKDAT */
452 		outb_p(inb_p(SMBHSTTYP) | ALI1535_BLOCK_CLR, SMBHSTTYP);
453 		for (i = 1; i <= data->block[0]; i++) {
454 			data->block[i] = inb_p(SMBBLKDAT);
455 			dev_dbg(&adap->dev, "Blk: len=%d, i=%d, data=%02x\n",
456 				len, i, data->block[i]);
457 		}
458 		break;
459 	}
460 EXIT:
461 	return result;
462 }
463 
464 
465 static u32 ali1535_func(struct i2c_adapter *adapter)
466 {
467 	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
468 	    I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
469 	    I2C_FUNC_SMBUS_BLOCK_DATA;
470 }
471 
472 static const struct i2c_algorithm smbus_algorithm = {
473 	.smbus_xfer	= ali1535_access,
474 	.functionality	= ali1535_func,
475 };
476 
477 static struct i2c_adapter ali1535_adapter = {
478 	.owner		= THIS_MODULE,
479 	.id		= I2C_HW_SMBUS_ALI1535,
480 	.class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
481 	.algo		= &smbus_algorithm,
482 };
483 
484 static struct pci_device_id ali1535_ids[] = {
485 	{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
486 	{ },
487 };
488 
489 MODULE_DEVICE_TABLE (pci, ali1535_ids);
490 
491 static int __devinit ali1535_probe(struct pci_dev *dev, const struct pci_device_id *id)
492 {
493 	if (ali1535_setup(dev)) {
494 		dev_warn(&dev->dev,
495 			"ALI1535 not detected, module not inserted.\n");
496 		return -ENODEV;
497 	}
498 
499 	/* set up the sysfs linkage to our parent device */
500 	ali1535_adapter.dev.parent = &dev->dev;
501 
502 	snprintf(ali1535_adapter.name, sizeof(ali1535_adapter.name),
503 		"SMBus ALI1535 adapter at %04x", ali1535_smba);
504 	return i2c_add_adapter(&ali1535_adapter);
505 }
506 
507 static void __devexit ali1535_remove(struct pci_dev *dev)
508 {
509 	i2c_del_adapter(&ali1535_adapter);
510 	release_region(ali1535_smba, ALI1535_SMB_IOSIZE);
511 }
512 
513 static struct pci_driver ali1535_driver = {
514 	.name		= "ali1535_smbus",
515 	.id_table	= ali1535_ids,
516 	.probe		= ali1535_probe,
517 	.remove		= __devexit_p(ali1535_remove),
518 };
519 
520 static int __init i2c_ali1535_init(void)
521 {
522 	return pci_register_driver(&ali1535_driver);
523 }
524 
525 static void __exit i2c_ali1535_exit(void)
526 {
527 	pci_unregister_driver(&ali1535_driver);
528 }
529 
530 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>, "
531 	      "Philip Edelbrock <phil@netroedge.com>, "
532 	      "Mark D. Studebaker <mdsxyz123@yahoo.com> "
533 	      "and Dan Eaton <dan.eaton@rocketlogix.com>");
534 MODULE_DESCRIPTION("ALI1535 SMBus driver");
535 MODULE_LICENSE("GPL");
536 
537 module_init(i2c_ali1535_init);
538 module_exit(i2c_ali1535_exit);
539