408 lines
11 KiB
C
408 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Hardware monitoring driver for MPS Multi-phase Digital VR Controllers
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*
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* Copyright (C) 2020 Nvidia Technologies Ltd.
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*/
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#include <linux/err.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include "pmbus.h"
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/* Vendor specific registers. */
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#define MP2888_MFR_SYS_CONFIG 0x44
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#define MP2888_MFR_READ_CS1_2 0x73
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#define MP2888_MFR_READ_CS3_4 0x74
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#define MP2888_MFR_READ_CS5_6 0x75
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#define MP2888_MFR_READ_CS7_8 0x76
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#define MP2888_MFR_READ_CS9_10 0x77
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#define MP2888_MFR_VR_CONFIG1 0xe1
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#define MP2888_TOTAL_CURRENT_RESOLUTION BIT(3)
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#define MP2888_PHASE_CURRENT_RESOLUTION BIT(4)
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#define MP2888_DRMOS_KCS GENMASK(2, 0)
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#define MP2888_TEMP_UNIT 10
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#define MP2888_MAX_PHASE 10
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struct mp2888_data {
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struct pmbus_driver_info info;
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int total_curr_resolution;
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int phase_curr_resolution;
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int curr_sense_gain;
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};
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#define to_mp2888_data(x) container_of(x, struct mp2888_data, info)
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static int mp2888_read_byte_data(struct i2c_client *client, int page, int reg)
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{
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switch (reg) {
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case PMBUS_VOUT_MODE:
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/* Enforce VOUT direct format. */
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return PB_VOUT_MODE_DIRECT;
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default:
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return -ENODATA;
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}
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}
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static int
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mp2888_current_sense_gain_and_resolution_get(struct i2c_client *client, struct mp2888_data *data)
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{
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int ret;
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/*
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* Obtain DrMOS current sense gain of power stage from the register
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* , bits 0-2. The value is selected as below:
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* 00b - 5µA/A, 01b - 8.5µA/A, 10b - 9.7µA/A, 11b - 10µA/A. Other
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* values are reserved.
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*/
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ret = i2c_smbus_read_word_data(client, MP2888_MFR_SYS_CONFIG);
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if (ret < 0)
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return ret;
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switch (ret & MP2888_DRMOS_KCS) {
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case 0:
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data->curr_sense_gain = 85;
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break;
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case 1:
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data->curr_sense_gain = 97;
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break;
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case 2:
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data->curr_sense_gain = 100;
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break;
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case 3:
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data->curr_sense_gain = 50;
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break;
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default:
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return -EINVAL;
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}
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/*
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* Obtain resolution selector for total and phase current report and protection.
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* 0: original resolution; 1: half resolution (in such case phase current value should
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* be doubled.
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*/
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data->total_curr_resolution = (ret & MP2888_TOTAL_CURRENT_RESOLUTION) >> 3;
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data->phase_curr_resolution = (ret & MP2888_PHASE_CURRENT_RESOLUTION) >> 4;
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return 0;
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}
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static int
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mp2888_read_phase(struct i2c_client *client, struct mp2888_data *data, int page, int phase, u8 reg)
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{
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int ret;
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ret = pmbus_read_word_data(client, page, phase, reg);
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if (ret < 0)
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return ret;
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if (!((phase + 1) % 2))
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ret >>= 8;
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ret &= 0xff;
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/*
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* Output value is calculated as: (READ_CSx / 80 – 1.23) / (Kcs * Rcs)
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* where:
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* - Kcs is the DrMOS current sense gain of power stage, which is obtained from the
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* register MP2888_MFR_VR_CONFIG1, bits 13-12 with the following selection of DrMOS
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* (data->curr_sense_gain):
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* 00b - 8.5µA/A, 01b - 9.7µA/A, 1b - 10µA/A, 11b - 5µA/A.
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* - Rcs is the internal phase current sense resistor. This parameter depends on hardware
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* assembly. By default it is set to 1kΩ. In case of different assembly, user should
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* scale this parameter by dividing it by Rcs.
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* If phase current resolution bit is set to 1, READ_CSx value should be doubled.
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* Note, that current phase sensing, providing by the device is not accurate. This is
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* because sampling of current occurrence of bit weight has a big deviation, especially for
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* light load.
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*/
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ret = DIV_ROUND_CLOSEST(ret * 200 - 19600, data->curr_sense_gain);
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/* Scale according to total current resolution. */
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ret = (data->total_curr_resolution) ? ret * 2 : ret;
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return ret;
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}
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static int
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mp2888_read_phases(struct i2c_client *client, struct mp2888_data *data, int page, int phase)
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{
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int ret;
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switch (phase) {
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case 0 ... 1:
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ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS1_2);
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break;
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case 2 ... 3:
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ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS3_4);
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break;
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case 4 ... 5:
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ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS5_6);
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break;
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case 6 ... 7:
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ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS7_8);
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break;
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case 8 ... 9:
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ret = mp2888_read_phase(client, data, page, phase, MP2888_MFR_READ_CS9_10);
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break;
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default:
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return -ENODATA;
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}
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return ret;
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}
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static int mp2888_read_word_data(struct i2c_client *client, int page, int phase, 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 mp2888_data *data = to_mp2888_data(info);
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int ret;
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switch (reg) {
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case PMBUS_READ_VIN:
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ret = pmbus_read_word_data(client, page, phase, reg);
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if (ret <= 0)
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return ret;
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/*
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* READ_VIN requires fixup to scale it to linear11 format. Register data format
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* provides 10 bits for mantissa and 6 bits for exponent. Bits 15:10 are set with
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* the fixed value 111011b.
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*/
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ret = (ret & GENMASK(9, 0)) | ((ret & GENMASK(31, 10)) << 1);
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break;
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case PMBUS_OT_WARN_LIMIT:
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ret = pmbus_read_word_data(client, page, phase, reg);
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if (ret < 0)
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return ret;
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/*
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* Chip reports limits in degrees C, but the actual temperature in 10th of
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* degrees C - scaling is needed to match both.
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*/
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ret *= MP2888_TEMP_UNIT;
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break;
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case PMBUS_READ_IOUT:
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if (phase != 0xff)
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return mp2888_read_phases(client, data, page, phase);
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ret = pmbus_read_word_data(client, page, phase, reg);
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if (ret < 0)
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return ret;
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/*
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* READ_IOUT register has unused bits 15:12 with fixed value 1110b. Clear these
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* bits and scale with total current resolution. Data is provided in direct format.
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*/
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ret &= GENMASK(11, 0);
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ret = data->total_curr_resolution ? ret * 2 : ret;
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break;
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case PMBUS_IOUT_OC_WARN_LIMIT:
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ret = pmbus_read_word_data(client, page, phase, reg);
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if (ret < 0)
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return ret;
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ret &= GENMASK(9, 0);
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/*
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* Chip reports limits with resolution 1A or 2A, if total current resolution bit is
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* set 1. Actual current is reported with 0.25A or respectively 0.5A resolution.
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* Scaling is needed to match both.
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*/
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ret = data->total_curr_resolution ? ret * 8 : ret * 4;
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break;
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case PMBUS_READ_POUT:
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case PMBUS_READ_PIN:
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ret = pmbus_read_word_data(client, page, phase, reg);
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if (ret < 0)
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return ret;
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ret = data->total_curr_resolution ? ret : DIV_ROUND_CLOSEST(ret, 2);
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break;
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case PMBUS_POUT_OP_WARN_LIMIT:
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ret = pmbus_read_word_data(client, page, phase, reg);
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if (ret < 0)
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return ret;
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/*
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* Chip reports limits with resolution 1W or 2W, if total current resolution bit is
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* set 1. Actual power is reported with 0.5W or 1W respectively resolution. Scaling
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* is needed to match both.
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*/
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ret = data->total_curr_resolution ? ret * 2 : ret;
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break;
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/*
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* The below registers are not implemented by device or implemented not according to the
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* spec. Skip all of them to avoid exposing non-relevant inputs to sysfs.
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*/
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case PMBUS_OT_FAULT_LIMIT:
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case PMBUS_UT_WARN_LIMIT:
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case PMBUS_UT_FAULT_LIMIT:
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case PMBUS_VIN_UV_FAULT_LIMIT:
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case PMBUS_VOUT_UV_WARN_LIMIT:
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case PMBUS_VOUT_OV_WARN_LIMIT:
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case PMBUS_VOUT_UV_FAULT_LIMIT:
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case PMBUS_VOUT_OV_FAULT_LIMIT:
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case PMBUS_VIN_OV_WARN_LIMIT:
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case PMBUS_IOUT_OC_LV_FAULT_LIMIT:
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case PMBUS_IOUT_OC_FAULT_LIMIT:
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case PMBUS_POUT_MAX:
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case PMBUS_IOUT_UC_FAULT_LIMIT:
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case PMBUS_POUT_OP_FAULT_LIMIT:
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case PMBUS_PIN_OP_WARN_LIMIT:
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case PMBUS_MFR_VIN_MIN:
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case PMBUS_MFR_VOUT_MIN:
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case PMBUS_MFR_VIN_MAX:
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case PMBUS_MFR_VOUT_MAX:
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case PMBUS_MFR_IIN_MAX:
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case PMBUS_MFR_IOUT_MAX:
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case PMBUS_MFR_PIN_MAX:
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case PMBUS_MFR_POUT_MAX:
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case PMBUS_MFR_MAX_TEMP_1:
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return -ENXIO;
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default:
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return -ENODATA;
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}
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return ret;
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}
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static int mp2888_write_word_data(struct i2c_client *client, int page, 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 mp2888_data *data = to_mp2888_data(info);
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switch (reg) {
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case PMBUS_OT_WARN_LIMIT:
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word = DIV_ROUND_CLOSEST(word, MP2888_TEMP_UNIT);
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/* Drop unused bits 15:8. */
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word = clamp_val(word, 0, GENMASK(7, 0));
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break;
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case PMBUS_IOUT_OC_WARN_LIMIT:
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/* Fix limit according to total curent resolution. */
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word = data->total_curr_resolution ? DIV_ROUND_CLOSEST(word, 8) :
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DIV_ROUND_CLOSEST(word, 4);
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/* Drop unused bits 15:10. */
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word = clamp_val(word, 0, GENMASK(9, 0));
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break;
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case PMBUS_POUT_OP_WARN_LIMIT:
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/* Fix limit according to total curent resolution. */
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word = data->total_curr_resolution ? DIV_ROUND_CLOSEST(word, 4) :
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DIV_ROUND_CLOSEST(word, 2);
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/* Drop unused bits 15:10. */
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word = clamp_val(word, 0, GENMASK(9, 0));
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break;
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default:
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return -ENODATA;
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}
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return pmbus_write_word_data(client, page, reg, word);
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}
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static int
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mp2888_identify_multiphase(struct i2c_client *client, struct mp2888_data *data,
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struct pmbus_driver_info *info)
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{
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int ret;
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ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
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if (ret < 0)
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return ret;
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/* Identify multiphase number - could be from 1 to 10. */
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ret = i2c_smbus_read_word_data(client, MP2888_MFR_VR_CONFIG1);
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if (ret <= 0)
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return ret;
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info->phases[0] = ret & GENMASK(3, 0);
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/*
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* The device provides a total of 10 PWM pins, and can be configured to different phase
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* count applications for rail.
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*/
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if (info->phases[0] > MP2888_MAX_PHASE)
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return -EINVAL;
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return 0;
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}
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static struct pmbus_driver_info mp2888_info = {
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.pages = 1,
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.format[PSC_VOLTAGE_IN] = linear,
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.format[PSC_VOLTAGE_OUT] = direct,
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.format[PSC_TEMPERATURE] = direct,
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.format[PSC_CURRENT_IN] = linear,
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.format[PSC_CURRENT_OUT] = direct,
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.format[PSC_POWER] = direct,
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.m[PSC_TEMPERATURE] = 1,
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.R[PSC_TEMPERATURE] = 1,
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.m[PSC_VOLTAGE_OUT] = 1,
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.R[PSC_VOLTAGE_OUT] = 3,
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.m[PSC_CURRENT_OUT] = 4,
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.m[PSC_POWER] = 1,
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.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_IOUT |
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PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP |
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PMBUS_HAVE_POUT | PMBUS_HAVE_PIN | PMBUS_HAVE_STATUS_INPUT |
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PMBUS_PHASE_VIRTUAL,
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.pfunc[0] = PMBUS_HAVE_IOUT,
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.pfunc[1] = PMBUS_HAVE_IOUT,
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.pfunc[2] = PMBUS_HAVE_IOUT,
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.pfunc[3] = PMBUS_HAVE_IOUT,
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.pfunc[4] = PMBUS_HAVE_IOUT,
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.pfunc[5] = PMBUS_HAVE_IOUT,
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.pfunc[6] = PMBUS_HAVE_IOUT,
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.pfunc[7] = PMBUS_HAVE_IOUT,
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.pfunc[8] = PMBUS_HAVE_IOUT,
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.pfunc[9] = PMBUS_HAVE_IOUT,
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.read_byte_data = mp2888_read_byte_data,
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.read_word_data = mp2888_read_word_data,
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.write_word_data = mp2888_write_word_data,
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};
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static int mp2888_probe(struct i2c_client *client)
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{
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struct pmbus_driver_info *info;
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struct mp2888_data *data;
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int ret;
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data = devm_kzalloc(&client->dev, sizeof(struct mp2888_data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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memcpy(&data->info, &mp2888_info, sizeof(*info));
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info = &data->info;
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/* Identify multiphase configuration. */
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ret = mp2888_identify_multiphase(client, data, info);
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if (ret)
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return ret;
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/* Obtain current sense gain of power stage and current resolution. */
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ret = mp2888_current_sense_gain_and_resolution_get(client, data);
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if (ret)
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return ret;
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return pmbus_do_probe(client, info);
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}
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static const struct i2c_device_id mp2888_id[] = {
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{"mp2888", 0},
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{}
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};
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MODULE_DEVICE_TABLE(i2c, mp2888_id);
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static const struct of_device_id __maybe_unused mp2888_of_match[] = {
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{.compatible = "mps,mp2888"},
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{}
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};
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MODULE_DEVICE_TABLE(of, mp2888_of_match);
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static struct i2c_driver mp2888_driver = {
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.driver = {
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.name = "mp2888",
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.of_match_table = of_match_ptr(mp2888_of_match),
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},
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.probe = mp2888_probe,
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.id_table = mp2888_id,
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};
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module_i2c_driver(mp2888_driver);
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MODULE_AUTHOR("Vadim Pasternak <vadimp@nvidia.com>");
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MODULE_DESCRIPTION("PMBus driver for MPS MP2888 device");
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MODULE_LICENSE("GPL");
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MODULE_IMPORT_NS(PMBUS);
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