440 lines
12 KiB
C
440 lines
12 KiB
C
/*
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* Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
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*
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* Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
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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; version 2 of the License.
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*
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* This driver is based on the ds1621 and ina209 drivers.
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*
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* Datasheet:
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* http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
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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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/* Here are names of the chip's registers (a.k.a. commands) */
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enum ltc4245_cmd {
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LTC4245_STATUS = 0x00, /* readonly */
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LTC4245_ALERT = 0x01,
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LTC4245_CONTROL = 0x02,
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LTC4245_ON = 0x03,
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LTC4245_FAULT1 = 0x04,
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LTC4245_FAULT2 = 0x05,
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LTC4245_GPIO = 0x06,
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LTC4245_ADCADR = 0x07,
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LTC4245_12VIN = 0x10,
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LTC4245_12VSENSE = 0x11,
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LTC4245_12VOUT = 0x12,
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LTC4245_5VIN = 0x13,
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LTC4245_5VSENSE = 0x14,
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LTC4245_5VOUT = 0x15,
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LTC4245_3VIN = 0x16,
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LTC4245_3VSENSE = 0x17,
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LTC4245_3VOUT = 0x18,
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LTC4245_VEEIN = 0x19,
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LTC4245_VEESENSE = 0x1a,
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LTC4245_VEEOUT = 0x1b,
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LTC4245_GPIOADC = 0x1c,
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};
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struct ltc4245_data {
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struct device *hwmon_dev;
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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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/* Control registers */
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u8 cregs[0x08];
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/* Voltage registers */
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u8 vregs[0x0d];
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};
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static struct ltc4245_data *ltc4245_update_device(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct ltc4245_data *data = i2c_get_clientdata(client);
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s32 val;
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int i;
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mutex_lock(&data->update_lock);
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if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
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dev_dbg(&client->dev, "Starting ltc4245 update\n");
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/* Read control registers -- 0x00 to 0x07 */
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for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
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val = i2c_smbus_read_byte_data(client, i);
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if (unlikely(val < 0))
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data->cregs[i] = 0;
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else
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data->cregs[i] = val;
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}
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/* Read voltage registers -- 0x10 to 0x1c */
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for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
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val = i2c_smbus_read_byte_data(client, i+0x10);
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if (unlikely(val < 0))
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data->vregs[i] = 0;
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else
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data->vregs[i] = val;
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}
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data->last_updated = jiffies;
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data->valid = 1;
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}
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mutex_unlock(&data->update_lock);
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return data;
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}
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/* Return the voltage from the given register in millivolts */
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static int ltc4245_get_voltage(struct device *dev, u8 reg)
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{
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struct ltc4245_data *data = ltc4245_update_device(dev);
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const u8 regval = data->vregs[reg - 0x10];
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u32 voltage = 0;
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switch (reg) {
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case LTC4245_12VIN:
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case LTC4245_12VOUT:
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voltage = regval * 55;
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break;
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case LTC4245_5VIN:
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case LTC4245_5VOUT:
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voltage = regval * 22;
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break;
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case LTC4245_3VIN:
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case LTC4245_3VOUT:
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voltage = regval * 15;
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break;
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case LTC4245_VEEIN:
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case LTC4245_VEEOUT:
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voltage = regval * -55;
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break;
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case LTC4245_GPIOADC:
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voltage = regval * 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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break;
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}
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return voltage;
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}
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/* Return the current in the given sense register in milliAmperes */
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static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
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{
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struct ltc4245_data *data = ltc4245_update_device(dev);
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const u8 regval = data->vregs[reg - 0x10];
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unsigned int voltage;
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unsigned int curr;
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/* The strange looking conversions that follow are fixed-point
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* math, since we cannot do floating point in the kernel.
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*
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* Step 1: convert sense register to microVolts
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* Step 2: convert voltage to milliAmperes
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*
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* If you play around with the V=IR equation, you come up with
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* the following: X uV / Y mOhm == Z mA
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*
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* With the resistors that are fractions of a milliOhm, we multiply
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* the voltage and resistance by 10, to shift the decimal point.
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* Now we can use the normal division operator again.
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*/
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switch (reg) {
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case LTC4245_12VSENSE:
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voltage = regval * 250; /* voltage in uV */
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curr = voltage / 50; /* sense resistor 50 mOhm */
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break;
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case LTC4245_5VSENSE:
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voltage = regval * 125; /* voltage in uV */
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curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
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break;
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case LTC4245_3VSENSE:
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voltage = regval * 125; /* voltage in uV */
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curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
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break;
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case LTC4245_VEESENSE:
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voltage = regval * 250; /* voltage in uV */
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curr = voltage / 100; /* sense resistor 100 mOhm */
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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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curr = 0;
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break;
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}
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return curr;
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}
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static ssize_t ltc4245_show_voltage(struct device *dev,
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struct device_attribute *da,
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char *buf)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
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const int voltage = ltc4245_get_voltage(dev, attr->index);
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return snprintf(buf, PAGE_SIZE, "%d\n", voltage);
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}
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static ssize_t ltc4245_show_current(struct device *dev,
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struct device_attribute *da,
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char *buf)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
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const unsigned int curr = ltc4245_get_current(dev, attr->index);
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return snprintf(buf, PAGE_SIZE, "%u\n", curr);
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}
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static ssize_t ltc4245_show_power(struct device *dev,
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struct device_attribute *da,
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char *buf)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
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const unsigned int curr = ltc4245_get_current(dev, attr->index);
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const int output_voltage = ltc4245_get_voltage(dev, attr->index+1);
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/* current in mA * voltage in mV == power in uW */
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const unsigned int power = abs(output_voltage * curr);
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return snprintf(buf, PAGE_SIZE, "%u\n", power);
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}
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static ssize_t ltc4245_show_alarm(struct device *dev,
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struct device_attribute *da,
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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 ltc4245_data *data = ltc4245_update_device(dev);
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const u8 reg = data->cregs[attr->index];
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const u32 mask = attr->nr;
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return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0);
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}
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/* These macros are used below in constructing device attribute objects
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* for use with sysfs_create_group() to make a sysfs device file
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* for each register.
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*/
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#define LTC4245_VOLTAGE(name, ltc4245_cmd_idx) \
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static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
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ltc4245_show_voltage, NULL, ltc4245_cmd_idx)
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#define LTC4245_CURRENT(name, ltc4245_cmd_idx) \
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static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
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ltc4245_show_current, NULL, ltc4245_cmd_idx)
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#define LTC4245_POWER(name, ltc4245_cmd_idx) \
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static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
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ltc4245_show_power, NULL, ltc4245_cmd_idx)
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#define LTC4245_ALARM(name, mask, reg) \
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static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \
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ltc4245_show_alarm, NULL, (mask), reg)
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/* Construct a sensor_device_attribute structure for each register */
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/* Input voltages */
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LTC4245_VOLTAGE(in1_input, LTC4245_12VIN);
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LTC4245_VOLTAGE(in2_input, LTC4245_5VIN);
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LTC4245_VOLTAGE(in3_input, LTC4245_3VIN);
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LTC4245_VOLTAGE(in4_input, LTC4245_VEEIN);
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/* Input undervoltage alarms */
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LTC4245_ALARM(in1_min_alarm, (1 << 0), LTC4245_FAULT1);
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LTC4245_ALARM(in2_min_alarm, (1 << 1), LTC4245_FAULT1);
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LTC4245_ALARM(in3_min_alarm, (1 << 2), LTC4245_FAULT1);
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LTC4245_ALARM(in4_min_alarm, (1 << 3), LTC4245_FAULT1);
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/* Currents (via sense resistor) */
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LTC4245_CURRENT(curr1_input, LTC4245_12VSENSE);
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LTC4245_CURRENT(curr2_input, LTC4245_5VSENSE);
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LTC4245_CURRENT(curr3_input, LTC4245_3VSENSE);
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LTC4245_CURRENT(curr4_input, LTC4245_VEESENSE);
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/* Overcurrent alarms */
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LTC4245_ALARM(curr1_max_alarm, (1 << 4), LTC4245_FAULT1);
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LTC4245_ALARM(curr2_max_alarm, (1 << 5), LTC4245_FAULT1);
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LTC4245_ALARM(curr3_max_alarm, (1 << 6), LTC4245_FAULT1);
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LTC4245_ALARM(curr4_max_alarm, (1 << 7), LTC4245_FAULT1);
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/* Output voltages */
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LTC4245_VOLTAGE(in5_input, LTC4245_12VOUT);
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LTC4245_VOLTAGE(in6_input, LTC4245_5VOUT);
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LTC4245_VOLTAGE(in7_input, LTC4245_3VOUT);
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LTC4245_VOLTAGE(in8_input, LTC4245_VEEOUT);
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/* Power Bad alarms */
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LTC4245_ALARM(in5_min_alarm, (1 << 0), LTC4245_FAULT2);
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LTC4245_ALARM(in6_min_alarm, (1 << 1), LTC4245_FAULT2);
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LTC4245_ALARM(in7_min_alarm, (1 << 2), LTC4245_FAULT2);
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LTC4245_ALARM(in8_min_alarm, (1 << 3), LTC4245_FAULT2);
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/* GPIO voltages */
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LTC4245_VOLTAGE(in9_input, LTC4245_GPIOADC);
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/* Power Consumption (virtual) */
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LTC4245_POWER(power1_input, LTC4245_12VSENSE);
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LTC4245_POWER(power2_input, LTC4245_5VSENSE);
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LTC4245_POWER(power3_input, LTC4245_3VSENSE);
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LTC4245_POWER(power4_input, LTC4245_VEESENSE);
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/* Finally, construct an array of pointers to members of the above objects,
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* as required for sysfs_create_group()
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*/
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static struct attribute *ltc4245_attributes[] = {
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&sensor_dev_attr_in1_input.dev_attr.attr,
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&sensor_dev_attr_in2_input.dev_attr.attr,
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&sensor_dev_attr_in3_input.dev_attr.attr,
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&sensor_dev_attr_in4_input.dev_attr.attr,
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&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
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&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
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&sensor_dev_attr_in3_min_alarm.dev_attr.attr,
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&sensor_dev_attr_in4_min_alarm.dev_attr.attr,
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&sensor_dev_attr_curr1_input.dev_attr.attr,
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&sensor_dev_attr_curr2_input.dev_attr.attr,
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&sensor_dev_attr_curr3_input.dev_attr.attr,
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&sensor_dev_attr_curr4_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_max_alarm.dev_attr.attr,
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&sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
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&sensor_dev_attr_curr4_max_alarm.dev_attr.attr,
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&sensor_dev_attr_in5_input.dev_attr.attr,
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&sensor_dev_attr_in6_input.dev_attr.attr,
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&sensor_dev_attr_in7_input.dev_attr.attr,
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&sensor_dev_attr_in8_input.dev_attr.attr,
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&sensor_dev_attr_in5_min_alarm.dev_attr.attr,
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&sensor_dev_attr_in6_min_alarm.dev_attr.attr,
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&sensor_dev_attr_in7_min_alarm.dev_attr.attr,
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&sensor_dev_attr_in8_min_alarm.dev_attr.attr,
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&sensor_dev_attr_in9_input.dev_attr.attr,
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&sensor_dev_attr_power1_input.dev_attr.attr,
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&sensor_dev_attr_power2_input.dev_attr.attr,
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&sensor_dev_attr_power3_input.dev_attr.attr,
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&sensor_dev_attr_power4_input.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group ltc4245_group = {
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.attrs = ltc4245_attributes,
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};
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static int ltc4245_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct i2c_adapter *adapter = client->adapter;
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struct ltc4245_data *data;
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int ret;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
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return -ENODEV;
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data = kzalloc(sizeof(*data), GFP_KERNEL);
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if (!data) {
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ret = -ENOMEM;
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goto out_kzalloc;
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}
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i2c_set_clientdata(client, data);
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mutex_init(&data->update_lock);
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/* Initialize the LTC4245 chip */
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i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
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i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
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/* Register sysfs hooks */
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ret = sysfs_create_group(&client->dev.kobj, <c4245_group);
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if (ret)
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goto out_sysfs_create_group;
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data->hwmon_dev = hwmon_device_register(&client->dev);
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if (IS_ERR(data->hwmon_dev)) {
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ret = PTR_ERR(data->hwmon_dev);
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goto out_hwmon_device_register;
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}
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return 0;
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out_hwmon_device_register:
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sysfs_remove_group(&client->dev.kobj, <c4245_group);
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out_sysfs_create_group:
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kfree(data);
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out_kzalloc:
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return ret;
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}
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static int ltc4245_remove(struct i2c_client *client)
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{
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struct ltc4245_data *data = i2c_get_clientdata(client);
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hwmon_device_unregister(data->hwmon_dev);
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sysfs_remove_group(&client->dev.kobj, <c4245_group);
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kfree(data);
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return 0;
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}
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static const struct i2c_device_id ltc4245_id[] = {
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{ "ltc4245", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ltc4245_id);
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/* This is the driver that will be inserted */
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static struct i2c_driver ltc4245_driver = {
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.driver = {
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.name = "ltc4245",
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},
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.probe = ltc4245_probe,
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.remove = ltc4245_remove,
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.id_table = ltc4245_id,
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};
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static int __init ltc4245_init(void)
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{
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return i2c_add_driver(<c4245_driver);
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}
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static void __exit ltc4245_exit(void)
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{
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i2c_del_driver(<c4245_driver);
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}
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MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
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MODULE_DESCRIPTION("LTC4245 driver");
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MODULE_LICENSE("GPL");
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module_init(ltc4245_init);
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module_exit(ltc4245_exit);
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