xref: /openbmc/linux/drivers/i2c/busses/i2c-ali1535.c (revision 9d633683)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) 2000  Frodo Looijaard <frodol@dds.nl>,
4  *                      Philip Edelbrock <phil@netroedge.com>,
5  *                      Mark D. Studebaker <mdsxyz123@yahoo.com>,
6  *                      Dan Eaton <dan.eaton@rocketlogix.com> and
7  *                      Stephen Rousset <stephen.rousset@rocketlogix.com>
8 */
9 
10 /*
11     This is the driver for the SMB Host controller on
12     Acer Labs Inc. (ALI) M1535 South Bridge.
13 
14     The M1535 is a South bridge for portable systems.
15     It is very similar to the M15x3 South bridges also produced
16     by Acer Labs Inc.  Some of the registers within the part
17     have moved and some have been redefined slightly. Additionally,
18     the sequencing of the SMBus transactions has been modified
19     to be more consistent with the sequencing recommended by
20     the manufacturer and observed through testing.  These
21     changes are reflected in this driver and can be identified
22     by comparing this driver to the i2c-ali15x3 driver.
23     For an overview of these chips see http://www.acerlabs.com
24 
25     The SMB controller is part of the 7101 device, which is an
26     ACPI-compliant Power Management Unit (PMU).
27 
28     The whole 7101 device has to be enabled for the SMB to work.
29     You can't just enable the SMB alone.
30     The SMB and the ACPI have separate I/O spaces.
31     We make sure that the SMB is enabled. We leave the ACPI alone.
32 
33     This driver controls the SMB Host only.
34 
35     This driver does not use interrupts.
36 */
37 
38 
39 /* Note: we assume there can only be one ALI1535, with one SMBus interface */
40 
41 #include <linux/module.h>
42 #include <linux/pci.h>
43 #include <linux/kernel.h>
44 #include <linux/stddef.h>
45 #include <linux/delay.h>
46 #include <linux/ioport.h>
47 #include <linux/i2c.h>
48 #include <linux/acpi.h>
49 #include <linux/io.h>
50 
51 
52 /* ALI1535 SMBus address offsets */
53 #define SMBHSTSTS	(0 + ali1535_smba)
54 #define SMBHSTTYP	(1 + ali1535_smba)
55 #define SMBHSTPORT	(2 + ali1535_smba)
56 #define SMBHSTCMD	(7 + ali1535_smba)
57 #define SMBHSTADD	(3 + ali1535_smba)
58 #define SMBHSTDAT0	(4 + ali1535_smba)
59 #define SMBHSTDAT1	(5 + ali1535_smba)
60 #define SMBBLKDAT	(6 + ali1535_smba)
61 
62 /* PCI Address Constants */
63 #define SMBCOM		0x004
64 #define SMBREV		0x008
65 #define SMBCFG		0x0D1
66 #define SMBBA		0x0E2
67 #define SMBHSTCFG	0x0F0
68 #define SMBCLK		0x0F2
69 
70 /* Other settings */
71 #define MAX_TIMEOUT		500	/* times 1/100 sec */
72 #define ALI1535_SMB_IOSIZE	32
73 
74 #define ALI1535_SMB_DEFAULTBASE	0x8040
75 
76 /* ALI1535 address lock bits */
77 #define ALI1535_LOCK		0x06	/* dwe */
78 
79 /* ALI1535 command constants */
80 #define ALI1535_QUICK		0x00
81 #define ALI1535_BYTE		0x10
82 #define ALI1535_BYTE_DATA	0x20
83 #define ALI1535_WORD_DATA	0x30
84 #define ALI1535_BLOCK_DATA	0x40
85 #define ALI1535_I2C_READ	0x60
86 
87 #define	ALI1535_DEV10B_EN	0x80	/* Enable 10-bit addressing in	*/
88 					/*  I2C read			*/
89 #define	ALI1535_T_OUT		0x08	/* Time-out Command (write)	*/
90 #define	ALI1535_A_HIGH_BIT9	0x08	/* Bit 9 of 10-bit address in	*/
91 					/* Alert-Response-Address	*/
92 					/* (read)			*/
93 #define	ALI1535_KILL		0x04	/* Kill Command (write)		*/
94 #define	ALI1535_A_HIGH_BIT8	0x04	/* Bit 8 of 10-bit address in	*/
95 					/*  Alert-Response-Address	*/
96 					/*  (read)			*/
97 
98 #define	ALI1535_D_HI_MASK	0x03	/* Mask for isolating bits 9-8	*/
99 					/*  of 10-bit address in I2C	*/
100 					/*  Read Command		*/
101 
102 /* ALI1535 status register bits */
103 #define ALI1535_STS_IDLE	0x04
104 #define ALI1535_STS_BUSY	0x08	/* host busy */
105 #define ALI1535_STS_DONE	0x10	/* transaction complete */
106 #define ALI1535_STS_DEV		0x20	/* device error */
107 #define ALI1535_STS_BUSERR	0x40	/* bus error    */
108 #define ALI1535_STS_FAIL	0x80	/* failed bus transaction */
109 #define ALI1535_STS_ERR		0xE0	/* all the bad error bits */
110 
111 #define ALI1535_BLOCK_CLR	0x04	/* reset block data index */
112 
113 /* ALI1535 device address register bits */
114 #define	ALI1535_RD_ADDR		0x01	/* Read/Write Bit in Device	*/
115 					/*  Address field		*/
116 					/*  -> Write = 0		*/
117 					/*  -> Read  = 1		*/
118 #define	ALI1535_SMBIO_EN	0x04	/* SMB I/O Space enable		*/
119 
120 static struct pci_driver ali1535_driver;
121 static unsigned long ali1535_smba;
122 static unsigned short ali1535_offset;
123 
124 /* Detect whether a ALI1535 can be found, and initialize it, where necessary.
125    Note the differences between kernels with the old PCI BIOS interface and
126    newer kernels with the real PCI interface. In compat.h some things are
127    defined to make the transition easier. */
ali1535_setup(struct pci_dev * dev)128 static int ali1535_setup(struct pci_dev *dev)
129 {
130 	int retval;
131 	unsigned char temp;
132 
133 	/* Check the following things:
134 		- SMB I/O address is initialized
135 		- Device is enabled
136 		- We can use the addresses
137 	*/
138 
139 	retval = pci_enable_device(dev);
140 	if (retval) {
141 		dev_err(&dev->dev, "ALI1535_smb can't enable device\n");
142 		goto exit;
143 	}
144 
145 	/* Determine the address of the SMBus area */
146 	pci_read_config_word(dev, SMBBA, &ali1535_offset);
147 	dev_dbg(&dev->dev, "ALI1535_smb is at offset 0x%04x\n", ali1535_offset);
148 	ali1535_offset &= (0xffff & ~(ALI1535_SMB_IOSIZE - 1));
149 	if (ali1535_offset == 0) {
150 		dev_warn(&dev->dev,
151 			"ALI1535_smb region uninitialized - upgrade BIOS?\n");
152 		retval = -ENODEV;
153 		goto exit;
154 	}
155 
156 	if (pci_resource_flags(dev, 0) & IORESOURCE_IO)
157 		ali1535_smba = pci_resource_start(dev, 0) + ali1535_offset;
158 	else
159 		ali1535_smba = ali1535_offset;
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%lx already in use!\n",
169 			ali1535_smba);
170 		retval = -EBUSY;
171 		goto exit;
172 	}
173 
174 	/* check if whole device is enabled */
175 	pci_read_config_byte(dev, SMBCFG, &temp);
176 	if ((temp & ALI1535_SMBIO_EN) == 0) {
177 		dev_err(&dev->dev, "SMB device not enabled - upgrade BIOS?\n");
178 		retval = -ENODEV;
179 		goto exit_free;
180 	}
181 
182 	/* Is SMB Host controller enabled? */
183 	pci_read_config_byte(dev, SMBHSTCFG, &temp);
184 	if ((temp & 1) == 0) {
185 		dev_err(&dev->dev, "SMBus controller not enabled - upgrade BIOS?\n");
186 		retval = -ENODEV;
187 		goto exit_free;
188 	}
189 
190 	/* set SMB clock to 74KHz as recommended in data sheet */
191 	pci_write_config_byte(dev, SMBCLK, 0x20);
192 
193 	/*
194 	  The interrupt routing for SMB is set up in register 0x77 in the
195 	  1533 ISA Bridge device, NOT in the 7101 device.
196 	  Don't bother with finding the 1533 device and reading the register.
197 	if ((....... & 0x0F) == 1)
198 		dev_dbg(&dev->dev, "ALI1535 using Interrupt 9 for SMBus.\n");
199 	*/
200 	pci_read_config_byte(dev, SMBREV, &temp);
201 	dev_dbg(&dev->dev, "SMBREV = 0x%X\n", temp);
202 	dev_dbg(&dev->dev, "ALI1535_smba = 0x%lx\n", ali1535_smba);
203 
204 	return 0;
205 
206 exit_free:
207 	release_region(ali1535_smba, ALI1535_SMB_IOSIZE);
208 exit:
209 	return retval;
210 }
211 
ali1535_transaction(struct i2c_adapter * adap)212 static int ali1535_transaction(struct i2c_adapter *adap)
213 {
214 	int temp;
215 	int result = 0;
216 	int timeout = 0;
217 
218 	dev_dbg(&adap->dev, "Transaction (pre): STS=%02x, TYP=%02x, "
219 		"CMD=%02x, ADD=%02x, DAT0=%02x, DAT1=%02x\n",
220 		inb_p(SMBHSTSTS), inb_p(SMBHSTTYP), inb_p(SMBHSTCMD),
221 		inb_p(SMBHSTADD), inb_p(SMBHSTDAT0), inb_p(SMBHSTDAT1));
222 
223 	/* get status */
224 	temp = inb_p(SMBHSTSTS);
225 
226 	/* Make sure the SMBus host is ready to start transmitting */
227 	/* Check the busy bit first */
228 	if (temp & ALI1535_STS_BUSY) {
229 		/* If the host controller is still busy, it may have timed out
230 		 * in the previous transaction, resulting in a "SMBus Timeout"
231 		 * printk.  I've tried the following to reset a stuck busy bit.
232 		 *   1. Reset the controller with an KILL command. (this
233 		 *      doesn't seem to clear the controller if an external
234 		 *      device is hung)
235 		 *   2. Reset the controller and the other SMBus devices with a
236 		 *      T_OUT command. (this clears the host busy bit if an
237 		 *      external device is hung, but it comes back upon a new
238 		 *      access to a device)
239 		 *   3. Disable and reenable the controller in SMBHSTCFG. Worst
240 		 *      case, nothing seems to work except power reset.
241 		 */
242 
243 		/* Try resetting entire SMB bus, including other devices - This
244 		 * may not work either - it clears the BUSY bit but then the
245 		 * BUSY bit may come back on when you try and use the chip
246 		 * again.  If that's the case you are stuck.
247 		 */
248 		dev_info(&adap->dev,
249 			"Resetting entire SMB Bus to clear busy condition (%02x)\n",
250 			temp);
251 		outb_p(ALI1535_T_OUT, SMBHSTTYP);
252 		temp = inb_p(SMBHSTSTS);
253 	}
254 
255 	/* now check the error bits and the busy bit */
256 	if (temp & (ALI1535_STS_ERR | ALI1535_STS_BUSY)) {
257 		/* do a clear-on-write */
258 		outb_p(0xFF, SMBHSTSTS);
259 		temp = inb_p(SMBHSTSTS);
260 		if (temp & (ALI1535_STS_ERR | ALI1535_STS_BUSY)) {
261 			/* This is probably going to be correctable only by a
262 			 * power reset as one of the bits now appears to be
263 			 * stuck */
264 			/* This may be a bus or device with electrical problems. */
265 			dev_err(&adap->dev,
266 				"SMBus reset failed! (0x%02x) - controller or "
267 				"device on bus is probably hung\n", temp);
268 			return -EBUSY;
269 		}
270 	} else {
271 		/* check and clear done bit */
272 		if (temp & ALI1535_STS_DONE)
273 			outb_p(temp, SMBHSTSTS);
274 	}
275 
276 	/* start the transaction by writing anything to the start register */
277 	outb_p(0xFF, SMBHSTPORT);
278 
279 	/* We will always wait for a fraction of a second! */
280 	timeout = 0;
281 	do {
282 		usleep_range(1000, 2000);
283 		temp = inb_p(SMBHSTSTS);
284 	} while (((temp & ALI1535_STS_BUSY) && !(temp & ALI1535_STS_IDLE))
285 		 && (timeout++ < MAX_TIMEOUT));
286 
287 	/* If the SMBus is still busy, we give up */
288 	if (timeout > MAX_TIMEOUT) {
289 		result = -ETIMEDOUT;
290 		dev_err(&adap->dev, "SMBus Timeout!\n");
291 	}
292 
293 	if (temp & ALI1535_STS_FAIL) {
294 		result = -EIO;
295 		dev_dbg(&adap->dev, "Error: Failed bus transaction\n");
296 	}
297 
298 	/* Unfortunately the ALI SMB controller maps "no response" and "bus
299 	 * collision" into a single bit. No response is the usual case so don't
300 	 * do a printk.  This means that bus collisions go unreported.
301 	 */
302 	if (temp & ALI1535_STS_BUSERR) {
303 		result = -ENXIO;
304 		dev_dbg(&adap->dev,
305 			"Error: no response or bus collision ADD=%02x\n",
306 			inb_p(SMBHSTADD));
307 	}
308 
309 	/* haven't ever seen this */
310 	if (temp & ALI1535_STS_DEV) {
311 		result = -EIO;
312 		dev_err(&adap->dev, "Error: device error\n");
313 	}
314 
315 	/* check to see if the "command complete" indication is set */
316 	if (!(temp & ALI1535_STS_DONE)) {
317 		result = -ETIMEDOUT;
318 		dev_err(&adap->dev, "Error: command never completed\n");
319 	}
320 
321 	dev_dbg(&adap->dev, "Transaction (post): STS=%02x, TYP=%02x, "
322 		"CMD=%02x, ADD=%02x, DAT0=%02x, DAT1=%02x\n",
323 		inb_p(SMBHSTSTS), inb_p(SMBHSTTYP), inb_p(SMBHSTCMD),
324 		inb_p(SMBHSTADD), inb_p(SMBHSTDAT0), inb_p(SMBHSTDAT1));
325 
326 	/* take consequent actions for error conditions */
327 	if (!(temp & ALI1535_STS_DONE)) {
328 		/* issue "kill" to reset host controller */
329 		outb_p(ALI1535_KILL, SMBHSTTYP);
330 		outb_p(0xFF, SMBHSTSTS);
331 	} else if (temp & ALI1535_STS_ERR) {
332 		/* issue "timeout" to reset all devices on bus */
333 		outb_p(ALI1535_T_OUT, SMBHSTTYP);
334 		outb_p(0xFF, SMBHSTSTS);
335 	}
336 
337 	return result;
338 }
339 
340 /* Return negative errno on error. */
ali1535_access(struct i2c_adapter * adap,u16 addr,unsigned short flags,char read_write,u8 command,int size,union i2c_smbus_data * data)341 static s32 ali1535_access(struct i2c_adapter *adap, u16 addr,
342 			  unsigned short flags, char read_write, u8 command,
343 			  int size, union i2c_smbus_data *data)
344 {
345 	int i, len;
346 	int temp;
347 	int timeout;
348 	s32 result = 0;
349 
350 	/* make sure SMBus is idle */
351 	temp = inb_p(SMBHSTSTS);
352 	for (timeout = 0;
353 	     (timeout < MAX_TIMEOUT) && !(temp & ALI1535_STS_IDLE);
354 	     timeout++) {
355 		usleep_range(1000, 2000);
356 		temp = inb_p(SMBHSTSTS);
357 	}
358 	if (timeout >= MAX_TIMEOUT)
359 		dev_warn(&adap->dev, "Idle wait Timeout! STS=0x%02x\n", temp);
360 
361 	/* clear status register (clear-on-write) */
362 	outb_p(0xFF, SMBHSTSTS);
363 
364 	switch (size) {
365 	case I2C_SMBUS_QUICK:
366 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
367 		       SMBHSTADD);
368 		size = ALI1535_QUICK;
369 		outb_p(size, SMBHSTTYP);	/* output command */
370 		break;
371 	case I2C_SMBUS_BYTE:
372 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
373 		       SMBHSTADD);
374 		size = ALI1535_BYTE;
375 		outb_p(size, SMBHSTTYP);	/* output command */
376 		if (read_write == I2C_SMBUS_WRITE)
377 			outb_p(command, SMBHSTCMD);
378 		break;
379 	case I2C_SMBUS_BYTE_DATA:
380 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
381 		       SMBHSTADD);
382 		size = ALI1535_BYTE_DATA;
383 		outb_p(size, SMBHSTTYP);	/* output command */
384 		outb_p(command, SMBHSTCMD);
385 		if (read_write == I2C_SMBUS_WRITE)
386 			outb_p(data->byte, SMBHSTDAT0);
387 		break;
388 	case I2C_SMBUS_WORD_DATA:
389 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
390 		       SMBHSTADD);
391 		size = ALI1535_WORD_DATA;
392 		outb_p(size, SMBHSTTYP);	/* output command */
393 		outb_p(command, SMBHSTCMD);
394 		if (read_write == I2C_SMBUS_WRITE) {
395 			outb_p(data->word & 0xff, SMBHSTDAT0);
396 			outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
397 		}
398 		break;
399 	case I2C_SMBUS_BLOCK_DATA:
400 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
401 		       SMBHSTADD);
402 		size = ALI1535_BLOCK_DATA;
403 		outb_p(size, SMBHSTTYP);	/* output command */
404 		outb_p(command, SMBHSTCMD);
405 		if (read_write == I2C_SMBUS_WRITE) {
406 			len = data->block[0];
407 			if (len < 0) {
408 				len = 0;
409 				data->block[0] = len;
410 			}
411 			if (len > 32) {
412 				len = 32;
413 				data->block[0] = len;
414 			}
415 			outb_p(len, SMBHSTDAT0);
416 			/* Reset SMBBLKDAT */
417 			outb_p(inb_p(SMBHSTTYP) | ALI1535_BLOCK_CLR, SMBHSTTYP);
418 			for (i = 1; i <= len; i++)
419 				outb_p(data->block[i], SMBBLKDAT);
420 		}
421 		break;
422 	default:
423 		dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
424 		result = -EOPNOTSUPP;
425 		goto EXIT;
426 	}
427 
428 	result = ali1535_transaction(adap);
429 	if (result)
430 		goto EXIT;
431 
432 	if ((read_write == I2C_SMBUS_WRITE) || (size == ALI1535_QUICK)) {
433 		result = 0;
434 		goto EXIT;
435 	}
436 
437 	switch (size) {
438 	case ALI1535_BYTE:	/* Result put in SMBHSTDAT0 */
439 		data->byte = inb_p(SMBHSTDAT0);
440 		break;
441 	case ALI1535_BYTE_DATA:
442 		data->byte = inb_p(SMBHSTDAT0);
443 		break;
444 	case ALI1535_WORD_DATA:
445 		data->word = inb_p(SMBHSTDAT0) + (inb_p(SMBHSTDAT1) << 8);
446 		break;
447 	case ALI1535_BLOCK_DATA:
448 		len = inb_p(SMBHSTDAT0);
449 		if (len > 32)
450 			len = 32;
451 		data->block[0] = len;
452 		/* Reset SMBBLKDAT */
453 		outb_p(inb_p(SMBHSTTYP) | ALI1535_BLOCK_CLR, SMBHSTTYP);
454 		for (i = 1; i <= data->block[0]; i++) {
455 			data->block[i] = inb_p(SMBBLKDAT);
456 			dev_dbg(&adap->dev, "Blk: len=%d, i=%d, data=%02x\n",
457 				len, i, data->block[i]);
458 		}
459 		break;
460 	}
461 EXIT:
462 	return result;
463 }
464 
465 
ali1535_func(struct i2c_adapter * adapter)466 static u32 ali1535_func(struct i2c_adapter *adapter)
467 {
468 	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
469 	    I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
470 	    I2C_FUNC_SMBUS_BLOCK_DATA;
471 }
472 
473 static const struct i2c_algorithm smbus_algorithm = {
474 	.smbus_xfer	= ali1535_access,
475 	.functionality	= ali1535_func,
476 };
477 
478 static struct i2c_adapter ali1535_adapter = {
479 	.owner		= THIS_MODULE,
480 	.class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
481 	.algo		= &smbus_algorithm,
482 };
483 
484 static const 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 
ali1535_probe(struct pci_dev * dev,const struct pci_device_id * id)491 static int 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_offset);
504 	return i2c_add_adapter(&ali1535_adapter);
505 }
506 
ali1535_remove(struct pci_dev * dev)507 static void ali1535_remove(struct pci_dev *dev)
508 {
509 	i2c_del_adapter(&ali1535_adapter);
510 	release_region(ali1535_smba, ALI1535_SMB_IOSIZE);
511 
512 	/*
513 	 * do not call pci_disable_device(dev) since it can cause hard hangs on
514 	 * some systems during power-off
515 	 */
516 }
517 
518 static struct pci_driver ali1535_driver = {
519 	.name		= "ali1535_smbus",
520 	.id_table	= ali1535_ids,
521 	.probe		= ali1535_probe,
522 	.remove		= ali1535_remove,
523 };
524 
525 module_pci_driver(ali1535_driver);
526 
527 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
528 MODULE_AUTHOR("Philip Edelbrock <phil@netroedge.com>");
529 MODULE_AUTHOR("Mark D. Studebaker <mdsxyz123@yahoo.com>");
530 MODULE_AUTHOR("Dan Eaton <dan.eaton@rocketlogix.com>");
531 MODULE_DESCRIPTION("ALI1535 SMBus driver");
532 MODULE_LICENSE("GPL");
533