/*
* Hardware monitoring driver for LTC2978 and LTC3880
*
* Copyright (c) 2011 Ericsson AB.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include "pmbus.h"
enum chips { ltc2978, ltc3880 };
/* LTC2978 and LTC3880 */
#define LTC2978_MFR_VOUT_PEAK 0xdd
#define LTC2978_MFR_VIN_PEAK 0xde
#define LTC2978_MFR_TEMPERATURE_PEAK 0xdf
#define LTC2978_MFR_SPECIAL_ID 0xe7
/* LTC2978 only */
#define LTC2978_MFR_VOUT_MIN 0xfb
#define LTC2978_MFR_VIN_MIN 0xfc
#define LTC2978_MFR_TEMPERATURE_MIN 0xfd
/* LTC3880 only */
#define LTC3880_MFR_IOUT_PEAK 0xd7
#define LTC3880_MFR_CLEAR_PEAKS 0xe3
#define LTC3880_MFR_TEMPERATURE2_PEAK 0xf4
#define LTC2978_ID_REV1 0x0121
#define LTC2978_ID_REV2 0x0122
#define LTC3880_ID 0x4000
#define LTC3880_ID_MASK 0xff00
/*
* LTC2978 clears peak data whenever the CLEAR_FAULTS command is executed, which
* happens pretty much each time chip data is updated. Raw peak data therefore
* does not provide much value. To be able to provide useful peak data, keep an
* internal cache of measured peak data, which is only cleared if an explicit
* "clear peak" command is executed for the sensor in question.
*/
struct ltc2978_data {
enum chips id;
int vin_min, vin_max;
int temp_min, temp_max[2];
int vout_min[8], vout_max[8];
int iout_max[2];
int temp2_max;
struct pmbus_driver_info info;
};
#define to_ltc2978_data(x) container_of(x, struct ltc2978_data, info)
static inline int lin11_to_val(int data)
{
s16 e = ((s16)data) >> 11;
s32 m = (((s16)(data << 5)) >> 5);
/*
* mantissa is 10 bit + sign, exponent adds up to 15 bit.
* Add 6 bit to exponent for maximum accuracy (10 + 15 + 6 = 31).
*/
e += 6;
return (e < 0 ? m >> -e : m << e);
}
static int ltc2978_read_word_data_common(struct i2c_client *client, int page,
int reg)
{
const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
struct ltc2978_data *data = to_ltc2978_data(info);
int ret;
switch (reg) {
case PMBUS_VIRT_READ_VIN_MAX:
ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_PEAK);
if (ret >= 0) {
if (lin11_to_val(ret) > lin11_to_val(data->vin_max))
data->vin_max = ret;
ret = data->vin_max;
}
break;
case PMBUS_VIRT_READ_VOUT_MAX:
ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_PEAK);
if (ret >= 0) {
/*
* VOUT is 16 bit unsigned with fixed exponent,
* so we can compare it directly
*/
if (ret > data->vout_max[page])
data->vout_max[page] = ret;
ret = data->vout_max[page];
}
break;
case PMBUS_VIRT_READ_TEMP_MAX:
ret = pmbus_read_word_data(client, page,
LTC2978_MFR_TEMPERATURE_PEAK);
if (ret >= 0) {
if (lin11_to_val(ret)
> lin11_to_val(data->temp_max[page]))
data->temp_max[page] = ret;
ret = data->temp_max[page];
}
break;
case PMBUS_VIRT_RESET_VOUT_HISTORY:
case PMBUS_VIRT_RESET_VIN_HISTORY:
case PMBUS_VIRT_RESET_TEMP_HISTORY:
ret = 0;
break;
default:
ret = -ENODATA;
break;
}
return ret;
}
static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg)
{
const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
struct ltc2978_data *data = to_ltc2978_data(info);
int ret;
switch (reg) {
case PMBUS_VIRT_READ_VIN_MIN:
ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_MIN);
if (ret >= 0) {
if (lin11_to_val(ret) < lin11_to_val(data->vin_min))
data->vin_min = ret;
ret = data->vin_min;
}
break;
case PMBUS_VIRT_READ_VOUT_MIN:
ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_MIN);
if (ret >= 0) {
/*
* VOUT_MIN is known to not be supported on some lots
* of LTC2978 revision 1, and will return the maximum
* possible voltage if read. If VOUT_MAX is valid and
* lower than the reading of VOUT_MIN, use it instead.
*/
if (data->vout_max[page] && ret > data->vout_max[page])
ret = data->vout_max[page];
if (ret < data->vout_min[page])
data->vout_min[page] = ret;
ret = data->vout_min[page];
}
break;
case PMBUS_VIRT_READ_TEMP_MIN:
ret = pmbus_read_word_data(client, page,
LTC2978_MFR_TEMPERATURE_MIN);
if (ret >= 0) {
if (lin11_to_val(ret)
< lin11_to_val(data->temp_min))
data->temp_min = ret;
ret = data->temp_min;
}
break;
case PMBUS_VIRT_READ_IOUT_MAX:
case PMBUS_VIRT_RESET_IOUT_HISTORY:
case PMBUS_VIRT_READ_TEMP2_MAX:
case PMBUS_VIRT_RESET_TEMP2_HISTORY:
ret = -ENXIO;
break;
default:
ret = ltc2978_read_word_data_common(client, page, reg);
break;
}
return ret;
}
static int ltc3880_read_word_data(struct i2c_client *client, int page, int reg)
{
const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
struct ltc2978_data *data = to_ltc2978_data(info);
int ret;
switch (reg) {
case PMBUS_VIRT_READ_IOUT_MAX:
ret = pmbus_read_word_data(client, page, LTC3880_MFR_IOUT_PEAK);
if (ret >= 0) {
if (lin11_to_val(ret)
> lin11_to_val(data->iout_max[page]))
data->iout_max[page] = ret;
ret = data->iout_max[page];
}
break;
case PMBUS_VIRT_READ_TEMP2_MAX:
ret = pmbus_read_word_data(client, page,
LTC3880_MFR_TEMPERATURE2_PEAK);
if (ret >= 0) {
if (lin11_to_val(ret) > lin11_to_val(data->temp2_max))
data->temp2_max = ret;
ret = data->temp2_max;
}
break;
case PMBUS_VIRT_READ_VIN_MIN:
case PMBUS_VIRT_READ_VOUT_MIN:
case PMBUS_VIRT_READ_TEMP_MIN:
ret = -ENXIO;
break;
case PMBUS_VIRT_RESET_IOUT_HISTORY:
case PMBUS_VIRT_RESET_TEMP2_HISTORY:
ret = 0;
break;
default:
ret = ltc2978_read_word_data_common(client, page, reg);
break;
}
return ret;
}
static int ltc2978_clear_peaks(struct i2c_client *client, int page,
enum chips id)
{
int ret;
if (id == ltc2978)
ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
else
ret = pmbus_write_byte(client, 0, LTC3880_MFR_CLEAR_PEAKS);
return ret;
}
static int ltc2978_write_word_data(struct i2c_client *client, int page,
int reg, u16 word)
{
const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
struct ltc2978_data *data = to_ltc2978_data(info);
int ret;
switch (reg) {
case PMBUS_VIRT_RESET_IOUT_HISTORY:
data->iout_max[page] = 0x7c00;
ret = ltc2978_clear_peaks(client, page, data->id);
break;
case PMBUS_VIRT_RESET_TEMP2_HISTORY:
data->temp2_max = 0x7c00;
ret = ltc2978_clear_peaks(client, page, data->id);
break;
case PMBUS_VIRT_RESET_VOUT_HISTORY:
data->vout_min[page] = 0xffff;
data->vout_max[page] = 0;
ret = ltc2978_clear_peaks(client, page, data->id);
break;
case PMBUS_VIRT_RESET_VIN_HISTORY:
data->vin_min = 0x7bff;
data->vin_max = 0x7c00;
ret = ltc2978_clear_peaks(client, page, data->id);
break;
case PMBUS_VIRT_RESET_TEMP_HISTORY:
data->temp_min = 0x7bff;
data->temp_max[page] = 0x7c00;
ret = ltc2978_clear_peaks(client, page, data->id);
break;
default:
ret = -ENODATA;
break;
}
return ret;
}
static const struct i2c_device_id ltc2978_id[] = {
{"ltc2978", ltc2978},
{"ltc3880", ltc3880},
{}
};
MODULE_DEVICE_TABLE(i2c, ltc2978_id);
static int ltc2978_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int chip_id, i;
struct ltc2978_data *data;
struct pmbus_driver_info *info;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_WORD_DATA))
return -ENODEV;
data = devm_kzalloc(&client->dev, sizeof(struct ltc2978_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
chip_id = i2c_smbus_read_word_data(client, LTC2978_MFR_SPECIAL_ID);
if (chip_id < 0)
return chip_id;
if (chip_id == LTC2978_ID_REV1 || chip_id == LTC2978_ID_REV2) {
data->id = ltc2978;
} else if ((chip_id & LTC3880_ID_MASK) == LTC3880_ID) {
data->id = ltc3880;
} else {
dev_err(&client->dev, "Unsupported chip ID 0x%x\n", chip_id);
return -ENODEV;
}
if (data->id != id->driver_data)
dev_warn(&client->dev,
"Device mismatch: Configured %s, detected %s\n",
id->name,
ltc2978_id[data->id].name);
info = &data->info;
info->write_word_data = ltc2978_write_word_data;
data->vin_min = 0x7bff;
data->vin_max = 0x7c00;
data->temp_min = 0x7bff;
for (i = 0; i < ARRAY_SIZE(data->temp_max); i++)
data->temp_max[i] = 0x7c00;
data->temp2_max = 0x7c00;
switch (data->id) {
case ltc2978:
info->read_word_data = ltc2978_read_word_data;
info->pages = 8;
info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
| PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
| PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
for (i = 1; i < 8; i++) {
info->func[i] = PMBUS_HAVE_VOUT
| PMBUS_HAVE_STATUS_VOUT;
}
break;
case ltc3880:
info->read_word_data = ltc3880_read_word_data;
info->pages = 2;
info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
| PMBUS_HAVE_STATUS_INPUT
| PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
| PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
| PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
| PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
info->func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
| PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
| PMBUS_HAVE_POUT
| PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
data->iout_max[0] = 0x7c00;
data->iout_max[1] = 0x7c00;
break;
default:
return -ENODEV;
}
for (i = 0; i < info->pages; i++)
data->vout_min[i] = 0xffff;
return pmbus_do_probe(client, id, info);
}
/* This is the driver that will be inserted */
static struct i2c_driver ltc2978_driver = {
.driver = {
.name = "ltc2978",
},
.probe = ltc2978_probe,
.remove = pmbus_do_remove,
.id_table = ltc2978_id,
};
module_i2c_driver(ltc2978_driver);
MODULE_AUTHOR("Guenter Roeck");
MODULE_DESCRIPTION("PMBus driver for LTC2978 and LTC3880");
MODULE_LICENSE("GPL");