379 lines
10 KiB
C
379 lines
10 KiB
C
/*
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* Hardware monitoring driver for LTC2978 and LTC3880
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*
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* Copyright (c) 2011 Ericsson AB.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include "pmbus.h"
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enum chips { ltc2978, ltc3880 };
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/* LTC2978 and LTC3880 */
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#define LTC2978_MFR_VOUT_PEAK 0xdd
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#define LTC2978_MFR_VIN_PEAK 0xde
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#define LTC2978_MFR_TEMPERATURE_PEAK 0xdf
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#define LTC2978_MFR_SPECIAL_ID 0xe7
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/* LTC2978 only */
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#define LTC2978_MFR_VOUT_MIN 0xfb
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#define LTC2978_MFR_VIN_MIN 0xfc
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#define LTC2978_MFR_TEMPERATURE_MIN 0xfd
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/* LTC3880 only */
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#define LTC3880_MFR_IOUT_PEAK 0xd7
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#define LTC3880_MFR_CLEAR_PEAKS 0xe3
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#define LTC3880_MFR_TEMPERATURE2_PEAK 0xf4
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#define LTC2978_ID_REV1 0x0121
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#define LTC2978_ID_REV2 0x0122
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#define LTC3880_ID 0x4000
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#define LTC3880_ID_MASK 0xff00
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/*
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* LTC2978 clears peak data whenever the CLEAR_FAULTS command is executed, which
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* happens pretty much each time chip data is updated. Raw peak data therefore
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* does not provide much value. To be able to provide useful peak data, keep an
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* internal cache of measured peak data, which is only cleared if an explicit
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* "clear peak" command is executed for the sensor in question.
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*/
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struct ltc2978_data {
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enum chips id;
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int vin_min, vin_max;
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int temp_min, temp_max;
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int vout_min[8], vout_max[8];
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int iout_max[2];
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int temp2_max[2];
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struct pmbus_driver_info info;
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};
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#define to_ltc2978_data(x) container_of(x, struct ltc2978_data, info)
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static inline int lin11_to_val(int data)
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{
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s16 e = ((s16)data) >> 11;
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s32 m = (((s16)(data << 5)) >> 5);
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/*
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* mantissa is 10 bit + sign, exponent adds up to 15 bit.
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* Add 6 bit to exponent for maximum accuracy (10 + 15 + 6 = 31).
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*/
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e += 6;
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return (e < 0 ? m >> -e : m << e);
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}
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static int ltc2978_read_word_data_common(struct i2c_client *client, int page,
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int reg)
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{
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const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
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struct ltc2978_data *data = to_ltc2978_data(info);
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int ret;
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switch (reg) {
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case PMBUS_VIRT_READ_VIN_MAX:
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ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_PEAK);
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if (ret >= 0) {
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if (lin11_to_val(ret) > lin11_to_val(data->vin_max))
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data->vin_max = ret;
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ret = data->vin_max;
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}
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break;
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case PMBUS_VIRT_READ_VOUT_MAX:
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ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_PEAK);
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if (ret >= 0) {
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/*
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* VOUT is 16 bit unsigned with fixed exponent,
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* so we can compare it directly
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*/
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if (ret > data->vout_max[page])
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data->vout_max[page] = ret;
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ret = data->vout_max[page];
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}
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break;
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case PMBUS_VIRT_READ_TEMP_MAX:
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ret = pmbus_read_word_data(client, page,
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LTC2978_MFR_TEMPERATURE_PEAK);
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if (ret >= 0) {
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if (lin11_to_val(ret) > lin11_to_val(data->temp_max))
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data->temp_max = ret;
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ret = data->temp_max;
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}
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break;
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case PMBUS_VIRT_RESET_VOUT_HISTORY:
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case PMBUS_VIRT_RESET_VIN_HISTORY:
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case PMBUS_VIRT_RESET_TEMP_HISTORY:
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ret = 0;
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break;
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default:
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ret = -ENODATA;
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break;
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}
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return ret;
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}
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static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg)
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{
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const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
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struct ltc2978_data *data = to_ltc2978_data(info);
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int ret;
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switch (reg) {
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case PMBUS_VIRT_READ_VIN_MIN:
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ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_MIN);
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if (ret >= 0) {
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if (lin11_to_val(ret) < lin11_to_val(data->vin_min))
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data->vin_min = ret;
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ret = data->vin_min;
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}
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break;
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case PMBUS_VIRT_READ_VOUT_MIN:
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ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_MIN);
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if (ret >= 0) {
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/*
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* VOUT_MIN is known to not be supported on some lots
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* of LTC2978 revision 1, and will return the maximum
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* possible voltage if read. If VOUT_MAX is valid and
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* lower than the reading of VOUT_MIN, use it instead.
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*/
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if (data->vout_max[page] && ret > data->vout_max[page])
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ret = data->vout_max[page];
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if (ret < data->vout_min[page])
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data->vout_min[page] = ret;
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ret = data->vout_min[page];
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}
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break;
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case PMBUS_VIRT_READ_TEMP_MIN:
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ret = pmbus_read_word_data(client, page,
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LTC2978_MFR_TEMPERATURE_MIN);
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if (ret >= 0) {
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if (lin11_to_val(ret)
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< lin11_to_val(data->temp_min))
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data->temp_min = ret;
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ret = data->temp_min;
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}
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break;
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case PMBUS_VIRT_READ_IOUT_MAX:
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case PMBUS_VIRT_RESET_IOUT_HISTORY:
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case PMBUS_VIRT_READ_TEMP2_MAX:
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case PMBUS_VIRT_RESET_TEMP2_HISTORY:
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ret = -ENXIO;
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break;
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default:
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ret = ltc2978_read_word_data_common(client, page, reg);
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break;
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}
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return ret;
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}
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static int ltc3880_read_word_data(struct i2c_client *client, int page, int reg)
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{
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const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
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struct ltc2978_data *data = to_ltc2978_data(info);
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int ret;
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switch (reg) {
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case PMBUS_VIRT_READ_IOUT_MAX:
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ret = pmbus_read_word_data(client, page, LTC3880_MFR_IOUT_PEAK);
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if (ret >= 0) {
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if (lin11_to_val(ret)
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> lin11_to_val(data->iout_max[page]))
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data->iout_max[page] = ret;
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ret = data->iout_max[page];
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}
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break;
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case PMBUS_VIRT_READ_TEMP2_MAX:
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ret = pmbus_read_word_data(client, page,
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LTC3880_MFR_TEMPERATURE2_PEAK);
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if (ret >= 0) {
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if (lin11_to_val(ret)
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> lin11_to_val(data->temp2_max[page]))
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data->temp2_max[page] = ret;
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ret = data->temp2_max[page];
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}
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break;
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case PMBUS_VIRT_READ_VIN_MIN:
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case PMBUS_VIRT_READ_VOUT_MIN:
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case PMBUS_VIRT_READ_TEMP_MIN:
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ret = -ENXIO;
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break;
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case PMBUS_VIRT_RESET_IOUT_HISTORY:
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case PMBUS_VIRT_RESET_TEMP2_HISTORY:
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ret = 0;
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break;
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default:
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ret = ltc2978_read_word_data_common(client, page, reg);
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break;
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}
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return ret;
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}
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static int ltc2978_clear_peaks(struct i2c_client *client, int page,
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enum chips id)
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{
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int ret;
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if (id == ltc2978)
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ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
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else
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ret = pmbus_write_byte(client, 0, LTC3880_MFR_CLEAR_PEAKS);
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return ret;
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}
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static int ltc2978_write_word_data(struct i2c_client *client, int page,
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int reg, u16 word)
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{
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const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
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struct ltc2978_data *data = to_ltc2978_data(info);
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int ret;
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switch (reg) {
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case PMBUS_VIRT_RESET_IOUT_HISTORY:
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data->iout_max[page] = 0x7fff;
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ret = ltc2978_clear_peaks(client, page, data->id);
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break;
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case PMBUS_VIRT_RESET_TEMP2_HISTORY:
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data->temp2_max[page] = 0x7fff;
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ret = ltc2978_clear_peaks(client, page, data->id);
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break;
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case PMBUS_VIRT_RESET_VOUT_HISTORY:
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data->vout_min[page] = 0xffff;
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data->vout_max[page] = 0;
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ret = ltc2978_clear_peaks(client, page, data->id);
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break;
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case PMBUS_VIRT_RESET_VIN_HISTORY:
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data->vin_min = 0x7bff;
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data->vin_max = 0;
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ret = ltc2978_clear_peaks(client, page, data->id);
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break;
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case PMBUS_VIRT_RESET_TEMP_HISTORY:
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data->temp_min = 0x7bff;
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data->temp_max = 0x7fff;
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ret = ltc2978_clear_peaks(client, page, data->id);
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break;
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default:
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ret = -ENODATA;
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break;
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}
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return ret;
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}
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static const struct i2c_device_id ltc2978_id[] = {
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{"ltc2978", ltc2978},
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{"ltc3880", ltc3880},
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{}
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};
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MODULE_DEVICE_TABLE(i2c, ltc2978_id);
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static int ltc2978_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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int chip_id, i;
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struct ltc2978_data *data;
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struct pmbus_driver_info *info;
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if (!i2c_check_functionality(client->adapter,
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I2C_FUNC_SMBUS_READ_WORD_DATA))
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return -ENODEV;
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data = devm_kzalloc(&client->dev, sizeof(struct ltc2978_data),
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GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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chip_id = i2c_smbus_read_word_data(client, LTC2978_MFR_SPECIAL_ID);
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if (chip_id < 0)
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return chip_id;
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if (chip_id == LTC2978_ID_REV1 || chip_id == LTC2978_ID_REV2) {
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data->id = ltc2978;
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} else if ((chip_id & LTC3880_ID_MASK) == LTC3880_ID) {
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data->id = ltc3880;
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} else {
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dev_err(&client->dev, "Unsupported chip ID 0x%x\n", chip_id);
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return -ENODEV;
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}
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if (data->id != id->driver_data)
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dev_warn(&client->dev,
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"Device mismatch: Configured %s, detected %s\n",
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id->name,
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ltc2978_id[data->id].name);
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info = &data->info;
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info->write_word_data = ltc2978_write_word_data;
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data->vout_min[0] = 0xffff;
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data->vin_min = 0x7bff;
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data->temp_min = 0x7bff;
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data->temp_max = 0x7fff;
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switch (id->driver_data) {
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case ltc2978:
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info->read_word_data = ltc2978_read_word_data;
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info->pages = 8;
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info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
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| PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
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| PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
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for (i = 1; i < 8; i++) {
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info->func[i] = PMBUS_HAVE_VOUT
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| PMBUS_HAVE_STATUS_VOUT;
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data->vout_min[i] = 0xffff;
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}
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break;
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case ltc3880:
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info->read_word_data = ltc3880_read_word_data;
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info->pages = 2;
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info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
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| PMBUS_HAVE_STATUS_INPUT
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| PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
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| PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
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| PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
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| PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
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info->func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
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| PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
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| PMBUS_HAVE_POUT
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| PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
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data->vout_min[1] = 0xffff;
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break;
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default:
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return -ENODEV;
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}
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return pmbus_do_probe(client, id, info);
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}
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/* This is the driver that will be inserted */
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static struct i2c_driver ltc2978_driver = {
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.driver = {
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.name = "ltc2978",
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},
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.probe = ltc2978_probe,
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.remove = pmbus_do_remove,
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.id_table = ltc2978_id,
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};
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module_i2c_driver(ltc2978_driver);
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MODULE_AUTHOR("Guenter Roeck");
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MODULE_DESCRIPTION("PMBus driver for LTC2978 and LTC3880");
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MODULE_LICENSE("GPL");
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