The implementation makes use of the new fan control virtual registers exposed by the pmbus core. It mixes use of the default implementations with some overrides via the read/write handlers to handle FAN_COMMAND_1 on the MAX31785, whose definition breaks the value range into various control bands dependent on RPM or PWM mode. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
253 lines
5.9 KiB
C
253 lines
5.9 KiB
C
/*
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* Copyright (C) 2017 IBM Corp.
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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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#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/i2c.h>
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#include "pmbus.h"
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enum max31785_regs {
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MFR_REVISION = 0x9b,
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};
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#define MAX31785_NR_PAGES 23
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static int max31785_get_pwm(struct i2c_client *client, int page)
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{
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int rv;
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rv = pmbus_get_fan_rate_device(client, page, 0, percent);
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if (rv < 0)
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return rv;
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else if (rv >= 0x8000)
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return 0;
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else if (rv >= 0x2711)
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return 0x2710;
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return rv;
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}
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static int max31785_get_pwm_mode(struct i2c_client *client, int page)
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{
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int config;
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int command;
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config = pmbus_read_byte_data(client, page, PMBUS_FAN_CONFIG_12);
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if (config < 0)
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return config;
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command = pmbus_read_word_data(client, page, PMBUS_FAN_COMMAND_1);
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if (command < 0)
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return command;
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if (config & PB_FAN_1_RPM)
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return (command >= 0x8000) ? 3 : 2;
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if (command >= 0x8000)
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return 3;
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else if (command >= 0x2711)
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return 0;
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return 1;
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}
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static int max31785_read_word_data(struct i2c_client *client, int page,
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int reg)
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{
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int rv;
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switch (reg) {
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case PMBUS_VIRT_PWM_1:
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rv = max31785_get_pwm(client, page);
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break;
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case PMBUS_VIRT_PWM_ENABLE_1:
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rv = max31785_get_pwm_mode(client, page);
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break;
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default:
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rv = -ENODATA;
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break;
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}
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return rv;
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}
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static inline u32 max31785_scale_pwm(u32 sensor_val)
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{
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/*
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* The datasheet describes the accepted value range for manual PWM as
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* [0, 0x2710], while the hwmon pwmX sysfs interface accepts values in
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* [0, 255]. The MAX31785 uses DIRECT mode to scale the FAN_COMMAND
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* registers and in PWM mode the coefficients are m=1, b=0, R=2. The
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* important observation here is that 0x2710 == 10000 == 100 * 100.
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*
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* R=2 (== 10^2 == 100) accounts for scaling the value provided at the
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* sysfs interface into the required hardware resolution, but it does
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* not yet yield a value that we can write to the device (this initial
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* scaling is handled by pmbus_data2reg()). Multiplying by 100 below
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* translates the parameter value into the percentage units required by
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* PMBus, and then we scale back by 255 as required by the hwmon pwmX
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* interface to yield the percentage value at the appropriate
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* resolution for hardware.
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*/
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return (sensor_val * 100) / 255;
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}
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static int max31785_pwm_enable(struct i2c_client *client, int page,
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u16 word)
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{
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int config = 0;
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int rate;
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switch (word) {
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case 0:
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rate = 0x7fff;
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break;
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case 1:
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rate = pmbus_get_fan_rate_cached(client, page, 0, percent);
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if (rate < 0)
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return rate;
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rate = max31785_scale_pwm(rate);
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break;
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case 2:
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config = PB_FAN_1_RPM;
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rate = pmbus_get_fan_rate_cached(client, page, 0, rpm);
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if (rate < 0)
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return rate;
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break;
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case 3:
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rate = 0xffff;
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break;
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default:
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return -EINVAL;
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}
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return pmbus_update_fan(client, page, 0, config, PB_FAN_1_RPM, rate);
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}
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static int max31785_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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switch (reg) {
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case PMBUS_VIRT_PWM_1:
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return pmbus_update_fan(client, page, 0, 0, PB_FAN_1_RPM,
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max31785_scale_pwm(word));
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case PMBUS_VIRT_PWM_ENABLE_1:
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return max31785_pwm_enable(client, page, word);
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default:
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break;
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}
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return -ENODATA;
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}
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#define MAX31785_FAN_FUNCS \
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(PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12 | PMBUS_HAVE_PWM12)
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#define MAX31785_TEMP_FUNCS \
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(PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP)
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#define MAX31785_VOUT_FUNCS \
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(PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT)
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static const struct pmbus_driver_info max31785_info = {
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.pages = MAX31785_NR_PAGES,
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.write_word_data = max31785_write_word_data,
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.read_word_data = max31785_read_word_data,
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/* RPM */
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.format[PSC_FAN] = direct,
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.m[PSC_FAN] = 1,
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.b[PSC_FAN] = 0,
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.R[PSC_FAN] = 0,
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/* PWM */
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.format[PSC_PWM] = direct,
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.m[PSC_PWM] = 1,
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.b[PSC_PWM] = 0,
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.R[PSC_PWM] = 2,
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.func[0] = MAX31785_FAN_FUNCS,
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.func[1] = MAX31785_FAN_FUNCS,
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.func[2] = MAX31785_FAN_FUNCS,
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.func[3] = MAX31785_FAN_FUNCS,
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.func[4] = MAX31785_FAN_FUNCS,
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.func[5] = MAX31785_FAN_FUNCS,
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.format[PSC_TEMPERATURE] = direct,
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.m[PSC_TEMPERATURE] = 1,
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.b[PSC_TEMPERATURE] = 0,
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.R[PSC_TEMPERATURE] = 2,
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.func[6] = MAX31785_TEMP_FUNCS,
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.func[7] = MAX31785_TEMP_FUNCS,
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.func[8] = MAX31785_TEMP_FUNCS,
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.func[9] = MAX31785_TEMP_FUNCS,
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.func[10] = MAX31785_TEMP_FUNCS,
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.func[11] = MAX31785_TEMP_FUNCS,
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.func[12] = MAX31785_TEMP_FUNCS,
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.func[13] = MAX31785_TEMP_FUNCS,
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.func[14] = MAX31785_TEMP_FUNCS,
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.func[15] = MAX31785_TEMP_FUNCS,
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.func[16] = MAX31785_TEMP_FUNCS,
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.format[PSC_VOLTAGE_OUT] = direct,
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.m[PSC_VOLTAGE_OUT] = 1,
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.b[PSC_VOLTAGE_OUT] = 0,
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.R[PSC_VOLTAGE_OUT] = 0,
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.func[17] = MAX31785_VOUT_FUNCS,
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.func[18] = MAX31785_VOUT_FUNCS,
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.func[19] = MAX31785_VOUT_FUNCS,
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.func[20] = MAX31785_VOUT_FUNCS,
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.func[21] = MAX31785_VOUT_FUNCS,
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.func[22] = MAX31785_VOUT_FUNCS,
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};
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static int max31785_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct device *dev = &client->dev;
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struct pmbus_driver_info *info;
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s64 ret;
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info = devm_kzalloc(dev, sizeof(struct pmbus_driver_info), GFP_KERNEL);
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if (!info)
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return -ENOMEM;
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*info = max31785_info;
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ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 255);
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if (ret < 0)
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return ret;
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return pmbus_do_probe(client, id, info);
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}
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static const struct i2c_device_id max31785_id[] = {
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{ "max31785", 0 },
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{ "max31785a", 0 },
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{ },
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};
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MODULE_DEVICE_TABLE(i2c, max31785_id);
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static struct i2c_driver max31785_driver = {
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.driver = {
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.name = "max31785",
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},
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.probe = max31785_probe,
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.remove = pmbus_do_remove,
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.id_table = max31785_id,
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};
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module_i2c_driver(max31785_driver);
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MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
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MODULE_DESCRIPTION("PMBus driver for the Maxim MAX31785");
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MODULE_LICENSE("GPL");
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