diff options
Diffstat (limited to 'drivers/hwmon/pmbus/ltc2978.c')
| -rw-r--r-- | drivers/hwmon/pmbus/ltc2978.c | 408 |
1 files changed, 408 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/ltc2978.c b/drivers/hwmon/pmbus/ltc2978.c new file mode 100644 index 000000000000..820fff48910b --- /dev/null +++ b/drivers/hwmon/pmbus/ltc2978.c @@ -0,0 +1,408 @@ +/* + * 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; + int vout_min[8], vout_max[8]; + int iout_max[2]; + int temp2_max[2]; + 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)) + data->temp_max = ret; + ret = data->temp_max; + } + 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[page])) + data->temp2_max[page] = ret; + ret = data->temp2_max[page]; + } + 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] = 0x7fff; + ret = ltc2978_clear_peaks(client, page, data->id); + break; + case PMBUS_VIRT_RESET_TEMP2_HISTORY: + data->temp2_max[page] = 0x7fff; + 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 = 0; + ret = ltc2978_clear_peaks(client, page, data->id); + break; + case PMBUS_VIRT_RESET_TEMP_HISTORY: + data->temp_min = 0x7bff; + data->temp_max = 0x7fff; + 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, ret, 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 = kzalloc(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) { + ret = chip_id; + goto err_mem; + } + + 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); + ret = -ENODEV; + goto err_mem; + } + 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->vout_min[0] = 0xffff; + data->vin_min = 0x7bff; + data->temp_min = 0x7bff; + data->temp_max = 0x7fff; + + switch (id->driver_data) { + 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; + data->vout_min[i] = 0xffff; + } + 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->vout_min[1] = 0xffff; + break; + default: + ret = -ENODEV; + goto err_mem; + } + + ret = pmbus_do_probe(client, id, info); + if (ret) + goto err_mem; + return 0; + +err_mem: + kfree(data); + return ret; +} + +static int ltc2978_remove(struct i2c_client *client) +{ + const struct pmbus_driver_info *info = pmbus_get_driver_info(client); + const struct ltc2978_data *data = to_ltc2978_data(info); + + pmbus_do_remove(client); + kfree(data); + return 0; +} + +/* This is the driver that will be inserted */ +static struct i2c_driver ltc2978_driver = { + .driver = { + .name = "ltc2978", + }, + .probe = ltc2978_probe, + .remove = ltc2978_remove, + .id_table = ltc2978_id, +}; + +static int __init ltc2978_init(void) +{ + return i2c_add_driver(<c2978_driver); +} + +static void __exit ltc2978_exit(void) +{ + i2c_del_driver(<c2978_driver); +} + +MODULE_AUTHOR("Guenter Roeck"); +MODULE_DESCRIPTION("PMBus driver for LTC2978 and LTC3880"); +MODULE_LICENSE("GPL"); +module_init(ltc2978_init); +module_exit(ltc2978_exit); |