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path: root/drivers/hwmon/ltc4245.c
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Diffstat (limited to 'drivers/hwmon/ltc4245.c')
-rw-r--r--drivers/hwmon/ltc4245.c131
1 files changed, 5 insertions, 126 deletions
diff --git a/drivers/hwmon/ltc4245.c b/drivers/hwmon/ltc4245.c
index e38964333612..65c232a9d0c5 100644
--- a/drivers/hwmon/ltc4245.c
+++ b/drivers/hwmon/ltc4245.c
@@ -22,15 +22,6 @@
22#include <linux/hwmon.h> 22#include <linux/hwmon.h>
23#include <linux/hwmon-sysfs.h> 23#include <linux/hwmon-sysfs.h>
24 24
25/* Valid addresses are 0x20 - 0x3f
26 *
27 * For now, we do not probe, since some of these addresses
28 * are known to be unfriendly to probing */
29static const unsigned short normal_i2c[] = { I2C_CLIENT_END };
30
31/* Insmod parameters */
32I2C_CLIENT_INSMOD_1(ltc4245);
33
34/* Here are names of the chip's registers (a.k.a. commands) */ 25/* Here are names of the chip's registers (a.k.a. commands) */
35enum ltc4245_cmd { 26enum ltc4245_cmd {
36 LTC4245_STATUS = 0x00, /* readonly */ 27 LTC4245_STATUS = 0x00, /* readonly */
@@ -369,9 +360,13 @@ static const struct attribute_group ltc4245_group = {
369static int ltc4245_probe(struct i2c_client *client, 360static int ltc4245_probe(struct i2c_client *client,
370 const struct i2c_device_id *id) 361 const struct i2c_device_id *id)
371{ 362{
363 struct i2c_adapter *adapter = client->adapter;
372 struct ltc4245_data *data; 364 struct ltc4245_data *data;
373 int ret; 365 int ret;
374 366
367 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
368 return -ENODEV;
369
375 data = kzalloc(sizeof(*data), GFP_KERNEL); 370 data = kzalloc(sizeof(*data), GFP_KERNEL);
376 if (!data) { 371 if (!data) {
377 ret = -ENOMEM; 372 ret = -ENOMEM;
@@ -418,136 +413,20 @@ static int ltc4245_remove(struct i2c_client *client)
418 return 0; 413 return 0;
419} 414}
420 415
421/* Check that some bits in a control register appear at all possible
422 * locations without changing value
423 *
424 * @client: the i2c client to use
425 * @reg: the register to read
426 * @bits: the bits to check (0xff checks all bits,
427 * 0x03 checks only the last two bits)
428 *
429 * return -ERRNO if the register read failed
430 * return -ENODEV if the register value doesn't stay constant at all
431 * possible addresses
432 *
433 * return 0 for success
434 */
435static int ltc4245_check_control_reg(struct i2c_client *client, u8 reg, u8 bits)
436{
437 int i;
438 s32 v, voff1, voff2;
439
440 /* Read register and check for error */
441 v = i2c_smbus_read_byte_data(client, reg);
442 if (v < 0)
443 return v;
444
445 v &= bits;
446
447 for (i = 0x00; i < 0xff; i += 0x20) {
448
449 voff1 = i2c_smbus_read_byte_data(client, reg + i);
450 if (voff1 < 0)
451 return voff1;
452
453 voff2 = i2c_smbus_read_byte_data(client, reg + i + 0x08);
454 if (voff2 < 0)
455 return voff2;
456
457 voff1 &= bits;
458 voff2 &= bits;
459
460 if (v != voff1 || v != voff2)
461 return -ENODEV;
462 }
463
464 return 0;
465}
466
467static int ltc4245_detect(struct i2c_client *client,
468 int kind,
469 struct i2c_board_info *info)
470{
471 struct i2c_adapter *adapter = client->adapter;
472
473 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
474 return -ENODEV;
475
476 if (kind < 0) { /* probed detection - check the chip type */
477 s32 v; /* 8 bits from the chip, or -ERRNO */
478
479 /* Chip registers 0x00-0x07 are control registers
480 * Chip registers 0x10-0x1f are data registers
481 *
482 * Address bits b7-b5 are ignored. This makes the chip "repeat"
483 * in steps of 0x20. Any control registers should appear with
484 * the same values across all duplicated addresses.
485 *
486 * Register 0x02 bit b2 is reserved, expect 0
487 * Register 0x07 bits b7 to b4 are reserved, expect 0
488 *
489 * Registers 0x01, 0x02 are control registers and should not
490 * change on their own.
491 *
492 * Register 0x06 bits b6 and b7 are control bits, and should
493 * not change on their own.
494 *
495 * Register 0x07 bits b3 to b0 are control bits, and should
496 * not change on their own.
497 */
498
499 /* read register 0x02 reserved bit, expect 0 */
500 v = i2c_smbus_read_byte_data(client, LTC4245_CONTROL);
501 if (v < 0 || (v & 0x04) != 0)
502 return -ENODEV;
503
504 /* read register 0x07 reserved bits, expect 0 */
505 v = i2c_smbus_read_byte_data(client, LTC4245_ADCADR);
506 if (v < 0 || (v & 0xf0) != 0)
507 return -ENODEV;
508
509 /* check that the alert register appears at all locations */
510 if (ltc4245_check_control_reg(client, LTC4245_ALERT, 0xff))
511 return -ENODEV;
512
513 /* check that the control register appears at all locations */
514 if (ltc4245_check_control_reg(client, LTC4245_CONTROL, 0xff))
515 return -ENODEV;
516
517 /* check that register 0x06 bits b6 and b7 stay constant */
518 if (ltc4245_check_control_reg(client, LTC4245_GPIO, 0xc0))
519 return -ENODEV;
520
521 /* check that register 0x07 bits b3-b0 stay constant */
522 if (ltc4245_check_control_reg(client, LTC4245_ADCADR, 0x0f))
523 return -ENODEV;
524 }
525
526 strlcpy(info->type, "ltc4245", I2C_NAME_SIZE);
527 dev_info(&adapter->dev, "ltc4245 %s at address 0x%02x\n",
528 kind < 0 ? "probed" : "forced",
529 client->addr);
530
531 return 0;
532}
533
534static const struct i2c_device_id ltc4245_id[] = { 416static const struct i2c_device_id ltc4245_id[] = {
535 { "ltc4245", ltc4245 }, 417 { "ltc4245", 0 },
536 { } 418 { }
537}; 419};
538MODULE_DEVICE_TABLE(i2c, ltc4245_id); 420MODULE_DEVICE_TABLE(i2c, ltc4245_id);
539 421
540/* This is the driver that will be inserted */ 422/* This is the driver that will be inserted */
541static struct i2c_driver ltc4245_driver = { 423static struct i2c_driver ltc4245_driver = {
542 .class = I2C_CLASS_HWMON,
543 .driver = { 424 .driver = {
544 .name = "ltc4245", 425 .name = "ltc4245",
545 }, 426 },
546 .probe = ltc4245_probe, 427 .probe = ltc4245_probe,
547 .remove = ltc4245_remove, 428 .remove = ltc4245_remove,
548 .id_table = ltc4245_id, 429 .id_table = ltc4245_id,
549 .detect = ltc4245_detect,
550 .address_data = &addr_data,
551}; 430};
552 431
553static int __init ltc4245_init(void) 432static int __init ltc4245_init(void)