238 lines
6.8 KiB
C
238 lines
6.8 KiB
C
/*
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* Driver for Linear Technology LTC4222 Dual Hot Swap controller
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*
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* Copyright (c) 2014 Guenter Roeck
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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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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/bitops.h>
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#include <linux/i2c.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/jiffies.h>
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#include <linux/regmap.h>
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/* chip registers */
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#define LTC4222_CONTROL1 0xd0
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#define LTC4222_ALERT1 0xd1
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#define LTC4222_STATUS1 0xd2
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#define LTC4222_FAULT1 0xd3
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#define LTC4222_CONTROL2 0xd4
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#define LTC4222_ALERT2 0xd5
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#define LTC4222_STATUS2 0xd6
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#define LTC4222_FAULT2 0xd7
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#define LTC4222_SOURCE1 0xd8
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#define LTC4222_SOURCE2 0xda
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#define LTC4222_ADIN1 0xdc
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#define LTC4222_ADIN2 0xde
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#define LTC4222_SENSE1 0xe0
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#define LTC4222_SENSE2 0xe2
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#define LTC4222_ADC_CONTROL 0xe4
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/*
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* Fault register bits
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*/
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#define FAULT_OV BIT(0)
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#define FAULT_UV BIT(1)
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#define FAULT_OC BIT(2)
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#define FAULT_POWER_BAD BIT(3)
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#define FAULT_FET_BAD BIT(5)
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/* Return the voltage from the given register in mV or mA */
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static int ltc4222_get_value(struct device *dev, u8 reg)
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{
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struct regmap *regmap = dev_get_drvdata(dev);
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unsigned int val;
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u8 buf[2];
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int ret;
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ret = regmap_bulk_read(regmap, reg, buf, 2);
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if (ret < 0)
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return ret;
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val = ((buf[0] << 8) + buf[1]) >> 6;
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switch (reg) {
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case LTC4222_ADIN1:
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case LTC4222_ADIN2:
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/* 1.25 mV resolution. Convert to mV. */
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val = DIV_ROUND_CLOSEST(val * 5, 4);
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break;
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case LTC4222_SOURCE1:
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case LTC4222_SOURCE2:
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/* 31.25 mV resolution. Convert to mV. */
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val = DIV_ROUND_CLOSEST(val * 125, 4);
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break;
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case LTC4222_SENSE1:
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case LTC4222_SENSE2:
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/*
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* 62.5 uV resolution. Convert to current as measured with
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* an 1 mOhm sense resistor, in mA. If a different sense
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* resistor is installed, calculate the actual current by
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* dividing the reported current by the sense resistor value
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* in mOhm.
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*/
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val = DIV_ROUND_CLOSEST(val * 125, 2);
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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 val;
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}
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static ssize_t ltc4222_show_value(struct device *dev,
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struct device_attribute *da, char *buf)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
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int value;
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value = ltc4222_get_value(dev, attr->index);
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if (value < 0)
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return value;
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return snprintf(buf, PAGE_SIZE, "%d\n", value);
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}
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static ssize_t ltc4222_show_bool(struct device *dev,
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struct device_attribute *da, char *buf)
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{
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struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
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struct regmap *regmap = dev_get_drvdata(dev);
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unsigned int fault;
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int ret;
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ret = regmap_read(regmap, attr->nr, &fault);
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if (ret < 0)
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return ret;
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fault &= attr->index;
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if (fault) /* Clear reported faults in chip register */
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regmap_update_bits(regmap, attr->nr, attr->index, 0);
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return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
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}
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/* Voltages */
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static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4222_show_value, NULL,
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LTC4222_SOURCE1);
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static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4222_show_value, NULL,
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LTC4222_ADIN1);
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static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4222_show_value, NULL,
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LTC4222_SOURCE2);
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static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4222_show_value, NULL,
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LTC4222_ADIN2);
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/*
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* Voltage alarms
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* UV/OV faults are associated with the input voltage, and power bad and fet
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* faults are associated with the output voltage.
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*/
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static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
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LTC4222_FAULT1, FAULT_UV);
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static SENSOR_DEVICE_ATTR_2(in1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
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LTC4222_FAULT1, FAULT_OV);
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static SENSOR_DEVICE_ATTR_2(in2_alarm, S_IRUGO, ltc4222_show_bool, NULL,
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LTC4222_FAULT1, FAULT_POWER_BAD | FAULT_FET_BAD);
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static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
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LTC4222_FAULT2, FAULT_UV);
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static SENSOR_DEVICE_ATTR_2(in3_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
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LTC4222_FAULT2, FAULT_OV);
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static SENSOR_DEVICE_ATTR_2(in4_alarm, S_IRUGO, ltc4222_show_bool, NULL,
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LTC4222_FAULT2, FAULT_POWER_BAD | FAULT_FET_BAD);
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/* Current (via sense resistor) */
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static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4222_show_value, NULL,
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LTC4222_SENSE1);
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static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4222_show_value, NULL,
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LTC4222_SENSE2);
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/* Overcurrent alarm */
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static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
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LTC4222_FAULT1, FAULT_OC);
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static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
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LTC4222_FAULT2, FAULT_OC);
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static struct attribute *ltc4222_attrs[] = {
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&sensor_dev_attr_in1_input.dev_attr.attr,
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&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
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&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
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&sensor_dev_attr_in2_input.dev_attr.attr,
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&sensor_dev_attr_in2_alarm.dev_attr.attr,
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&sensor_dev_attr_in3_input.dev_attr.attr,
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&sensor_dev_attr_in3_min_alarm.dev_attr.attr,
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&sensor_dev_attr_in3_max_alarm.dev_attr.attr,
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&sensor_dev_attr_in4_input.dev_attr.attr,
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&sensor_dev_attr_in4_alarm.dev_attr.attr,
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&sensor_dev_attr_curr1_input.dev_attr.attr,
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&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
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&sensor_dev_attr_curr2_input.dev_attr.attr,
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&sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(ltc4222);
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static const struct regmap_config ltc4222_regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.max_register = LTC4222_ADC_CONTROL,
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};
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static int ltc4222_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 device *hwmon_dev;
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struct regmap *regmap;
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regmap = devm_regmap_init_i2c(client, <c4222_regmap_config);
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if (IS_ERR(regmap)) {
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dev_err(dev, "failed to allocate register map\n");
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return PTR_ERR(regmap);
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}
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/* Clear faults */
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regmap_write(regmap, LTC4222_FAULT1, 0x00);
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regmap_write(regmap, LTC4222_FAULT2, 0x00);
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hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
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regmap,
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ltc4222_groups);
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return PTR_ERR_OR_ZERO(hwmon_dev);
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}
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static const struct i2c_device_id ltc4222_id[] = {
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{"ltc4222", 0},
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ltc4222_id);
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static struct i2c_driver ltc4222_driver = {
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.driver = {
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.name = "ltc4222",
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},
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.probe = ltc4222_probe,
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.id_table = ltc4222_id,
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};
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module_i2c_driver(ltc4222_driver);
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MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
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MODULE_DESCRIPTION("LTC4222 driver");
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MODULE_LICENSE("GPL");
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