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244 lines
6.3 KiB
244 lines
6.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Driver for Linear Technology LTC4261 I2C Negative Voltage Hot Swap Controller |
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* |
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* Copyright (C) 2010 Ericsson AB. |
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* |
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* Derived from: |
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* |
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* Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller |
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* Copyright (C) 2008 Ira W. Snyder <[email protected]> |
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* |
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* Datasheet: http://cds.linear.com/docs/Datasheet/42612fb.pdf |
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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 <linux/hwmon.h> |
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#include <linux/hwmon-sysfs.h> |
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#include <linux/jiffies.h> |
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/* chip registers */ |
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#define LTC4261_STATUS 0x00 /* readonly */ |
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#define LTC4261_FAULT 0x01 |
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#define LTC4261_ALERT 0x02 |
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#define LTC4261_CONTROL 0x03 |
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#define LTC4261_SENSE_H 0x04 |
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#define LTC4261_SENSE_L 0x05 |
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#define LTC4261_ADIN2_H 0x06 |
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#define LTC4261_ADIN2_L 0x07 |
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#define LTC4261_ADIN_H 0x08 |
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#define LTC4261_ADIN_L 0x09 |
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/* |
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* Fault register bits |
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*/ |
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#define FAULT_OV (1<<0) |
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#define FAULT_UV (1<<1) |
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#define FAULT_OC (1<<2) |
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struct ltc4261_data { |
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struct i2c_client *client; |
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struct mutex update_lock; |
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bool valid; |
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unsigned long last_updated; /* in jiffies */ |
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/* Registers */ |
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u8 regs[10]; |
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}; |
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static struct ltc4261_data *ltc4261_update_device(struct device *dev) |
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{ |
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struct ltc4261_data *data = dev_get_drvdata(dev); |
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struct i2c_client *client = data->client; |
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struct ltc4261_data *ret = data; |
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mutex_lock(&data->update_lock); |
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if (time_after(jiffies, data->last_updated + HZ / 4) || !data->valid) { |
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int i; |
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/* Read registers -- 0x00 to 0x09 */ |
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for (i = 0; i < ARRAY_SIZE(data->regs); i++) { |
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int val; |
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val = i2c_smbus_read_byte_data(client, i); |
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if (unlikely(val < 0)) { |
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dev_dbg(dev, |
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"Failed to read ADC value: error %d\n", |
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val); |
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ret = ERR_PTR(val); |
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data->valid = false; |
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goto abort; |
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} |
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data->regs[i] = val; |
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} |
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data->last_updated = jiffies; |
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data->valid = true; |
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} |
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abort: |
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mutex_unlock(&data->update_lock); |
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return ret; |
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} |
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/* Return the voltage from the given register in mV or mA */ |
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static int ltc4261_get_value(struct ltc4261_data *data, u8 reg) |
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{ |
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u32 val; |
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val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6); |
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switch (reg) { |
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case LTC4261_ADIN_H: |
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case LTC4261_ADIN2_H: |
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/* 2.5mV resolution. Convert to mV. */ |
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val = val * 25 / 10; |
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break; |
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case LTC4261_SENSE_H: |
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/* |
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* 62.5uV 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 = val * 625 / 10; |
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break; |
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default: |
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/* If we get here, the developer messed up */ |
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WARN_ON_ONCE(1); |
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val = 0; |
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break; |
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} |
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return val; |
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} |
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static ssize_t ltc4261_value_show(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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struct ltc4261_data *data = ltc4261_update_device(dev); |
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int value; |
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if (IS_ERR(data)) |
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return PTR_ERR(data); |
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value = ltc4261_get_value(data, attr->index); |
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return sysfs_emit(buf, "%d\n", value); |
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} |
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static ssize_t ltc4261_bool_show(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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struct ltc4261_data *data = ltc4261_update_device(dev); |
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u8 fault; |
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if (IS_ERR(data)) |
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return PTR_ERR(data); |
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fault = data->regs[LTC4261_FAULT] & attr->index; |
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if (fault) /* Clear reported faults in chip register */ |
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i2c_smbus_write_byte_data(data->client, LTC4261_FAULT, ~fault); |
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return sysfs_emit(buf, "%d\n", fault ? 1 : 0); |
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} |
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/* |
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* Input voltages. |
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*/ |
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static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4261_value, LTC4261_ADIN_H); |
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static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4261_value, LTC4261_ADIN2_H); |
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/* |
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* Voltage alarms. The chip has only one set of voltage alarm status bits, |
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* triggered by input voltage alarms. In many designs, those alarms are |
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* associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin |
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* to the OV pin. ADIN2 is, however, not available on all chip variants. |
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* To ensure that the alarm condition is reported to the user, report it |
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* with both voltage sensors. |
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*/ |
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static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc4261_bool, FAULT_UV); |
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static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc4261_bool, FAULT_OV); |
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static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc4261_bool, FAULT_UV); |
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static SENSOR_DEVICE_ATTR_RO(in2_max_alarm, ltc4261_bool, FAULT_OV); |
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/* Currents (via sense resistor) */ |
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static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4261_value, LTC4261_SENSE_H); |
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/* Overcurrent alarm */ |
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static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc4261_bool, FAULT_OC); |
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static struct attribute *ltc4261_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_min_alarm.dev_attr.attr, |
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&sensor_dev_attr_in2_max_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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NULL, |
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}; |
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ATTRIBUTE_GROUPS(ltc4261); |
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static int ltc4261_probe(struct i2c_client *client) |
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{ |
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struct i2c_adapter *adapter = client->adapter; |
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struct device *dev = &client->dev; |
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struct ltc4261_data *data; |
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struct device *hwmon_dev; |
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) |
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return -ENODEV; |
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if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) { |
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dev_err(dev, "Failed to read status register\n"); |
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return -ENODEV; |
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} |
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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data->client = client; |
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mutex_init(&data->update_lock); |
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/* Clear faults */ |
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i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00); |
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hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
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data, |
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ltc4261_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 ltc4261_id[] = { |
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{"ltc4261", 0}, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(i2c, ltc4261_id); |
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/* This is the driver that will be inserted */ |
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static struct i2c_driver ltc4261_driver = { |
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.driver = { |
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.name = "ltc4261", |
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}, |
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.probe_new = ltc4261_probe, |
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.id_table = ltc4261_id, |
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}; |
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module_i2c_driver(ltc4261_driver); |
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MODULE_AUTHOR("Guenter Roeck <[email protected]>"); |
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MODULE_DESCRIPTION("LTC4261 driver"); |
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MODULE_LICENSE("GPL");
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