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490 lines
12 KiB
490 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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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 <[email protected]> |
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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/bitops.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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#include <linux/platform_data/ltc4245.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 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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/* 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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/* GPIO ADC registers */ |
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bool use_extra_gpios; |
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int gpios[3]; |
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}; |
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/* |
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* Update the readings from the GPIO pins. If the driver has been configured to |
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* sample all GPIO's as analog voltages, a round-robin sampling method is used. |
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* Otherwise, only the configured GPIO pin is sampled. |
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* |
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* LOCKING: must hold data->update_lock |
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*/ |
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static void ltc4245_update_gpios(struct device *dev) |
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{ |
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struct ltc4245_data *data = dev_get_drvdata(dev); |
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struct i2c_client *client = data->client; |
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u8 gpio_curr, gpio_next, gpio_reg; |
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int i; |
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/* no extra gpio support, we're basically done */ |
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if (!data->use_extra_gpios) { |
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data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10]; |
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return; |
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} |
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/* |
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* If the last reading was too long ago, then we mark all old GPIO |
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* readings as stale by setting them to -EAGAIN |
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*/ |
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if (time_after(jiffies, data->last_updated + 5 * HZ)) { |
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for (i = 0; i < ARRAY_SIZE(data->gpios); i++) |
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data->gpios[i] = -EAGAIN; |
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} |
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/* |
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* Get the current GPIO pin |
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* |
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* The datasheet calls these GPIO[1-3], but we'll calculate the zero |
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* based array index instead, and call them GPIO[0-2]. This is much |
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* easier to think about. |
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*/ |
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gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6; |
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if (gpio_curr > 0) |
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gpio_curr -= 1; |
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/* Read the GPIO voltage from the GPIOADC register */ |
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data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10]; |
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/* Find the next GPIO pin to read */ |
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gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios); |
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/* |
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* Calculate the correct setting for the GPIO register so it will |
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* sample the next GPIO pin |
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*/ |
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gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6); |
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/* Update the GPIO register */ |
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i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg); |
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/* Update saved data */ |
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data->cregs[LTC4245_GPIO] = gpio_reg; |
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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 ltc4245_data *data = dev_get_drvdata(dev); |
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struct i2c_client *client = data->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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/* 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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/* Update GPIO readings */ |
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ltc4245_update_gpios(dev); |
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data->last_updated = jiffies; |
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data->valid = true; |
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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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/* |
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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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/* Map from voltage channel index to voltage register */ |
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static const s8 ltc4245_in_regs[] = { |
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LTC4245_12VIN, LTC4245_5VIN, LTC4245_3VIN, LTC4245_VEEIN, |
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LTC4245_12VOUT, LTC4245_5VOUT, LTC4245_3VOUT, LTC4245_VEEOUT, |
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}; |
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/* Map from current channel index to current register */ |
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static const s8 ltc4245_curr_regs[] = { |
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LTC4245_12VSENSE, LTC4245_5VSENSE, LTC4245_3VSENSE, LTC4245_VEESENSE, |
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}; |
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static int ltc4245_read_curr(struct device *dev, u32 attr, int channel, |
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long *val) |
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{ |
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struct ltc4245_data *data = ltc4245_update_device(dev); |
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switch (attr) { |
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case hwmon_curr_input: |
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*val = ltc4245_get_current(dev, ltc4245_curr_regs[channel]); |
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return 0; |
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case hwmon_curr_max_alarm: |
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*val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel + 4)); |
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return 0; |
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default: |
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return -EOPNOTSUPP; |
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} |
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} |
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static int ltc4245_read_in(struct device *dev, u32 attr, int channel, long *val) |
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{ |
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struct ltc4245_data *data = ltc4245_update_device(dev); |
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switch (attr) { |
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case hwmon_in_input: |
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if (channel < 8) { |
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*val = ltc4245_get_voltage(dev, |
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ltc4245_in_regs[channel]); |
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} else { |
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int regval = data->gpios[channel - 8]; |
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if (regval < 0) |
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return regval; |
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*val = regval * 10; |
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} |
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return 0; |
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case hwmon_in_min_alarm: |
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if (channel < 4) |
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*val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel)); |
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else |
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*val = !!(data->cregs[LTC4245_FAULT2] & |
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BIT(channel - 4)); |
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return 0; |
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default: |
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return -EOPNOTSUPP; |
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} |
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} |
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static int ltc4245_read_power(struct device *dev, u32 attr, int channel, |
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long *val) |
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{ |
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unsigned long curr; |
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long voltage; |
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switch (attr) { |
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case hwmon_power_input: |
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(void)ltc4245_update_device(dev); |
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curr = ltc4245_get_current(dev, ltc4245_curr_regs[channel]); |
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voltage = ltc4245_get_voltage(dev, ltc4245_in_regs[channel]); |
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*val = abs(curr * voltage); |
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return 0; |
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default: |
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return -EOPNOTSUPP; |
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} |
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} |
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static int ltc4245_read(struct device *dev, enum hwmon_sensor_types type, |
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u32 attr, int channel, long *val) |
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{ |
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switch (type) { |
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case hwmon_curr: |
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return ltc4245_read_curr(dev, attr, channel, val); |
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case hwmon_power: |
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return ltc4245_read_power(dev, attr, channel, val); |
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case hwmon_in: |
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return ltc4245_read_in(dev, attr, channel - 1, val); |
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default: |
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return -EOPNOTSUPP; |
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} |
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} |
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static umode_t ltc4245_is_visible(const void *_data, |
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enum hwmon_sensor_types type, |
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u32 attr, int channel) |
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{ |
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const struct ltc4245_data *data = _data; |
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switch (type) { |
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case hwmon_in: |
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if (channel == 0) |
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return 0; |
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switch (attr) { |
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case hwmon_in_input: |
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if (channel > 9 && !data->use_extra_gpios) |
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return 0; |
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return 0444; |
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case hwmon_in_min_alarm: |
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if (channel > 8) |
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return 0; |
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return 0444; |
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default: |
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return 0; |
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} |
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case hwmon_curr: |
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switch (attr) { |
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case hwmon_curr_input: |
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case hwmon_curr_max_alarm: |
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return 0444; |
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default: |
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return 0; |
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} |
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case hwmon_power: |
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switch (attr) { |
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case hwmon_power_input: |
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return 0444; |
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default: |
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return 0; |
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} |
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default: |
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return 0; |
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} |
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} |
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static const struct hwmon_channel_info *ltc4245_info[] = { |
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HWMON_CHANNEL_INFO(in, |
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HWMON_I_INPUT, |
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HWMON_I_INPUT | HWMON_I_MIN_ALARM, |
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HWMON_I_INPUT | HWMON_I_MIN_ALARM, |
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HWMON_I_INPUT | HWMON_I_MIN_ALARM, |
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HWMON_I_INPUT | HWMON_I_MIN_ALARM, |
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HWMON_I_INPUT | HWMON_I_MIN_ALARM, |
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HWMON_I_INPUT | HWMON_I_MIN_ALARM, |
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HWMON_I_INPUT | HWMON_I_MIN_ALARM, |
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HWMON_I_INPUT | HWMON_I_MIN_ALARM, |
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HWMON_I_INPUT, |
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HWMON_I_INPUT, |
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HWMON_I_INPUT), |
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HWMON_CHANNEL_INFO(curr, |
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HWMON_C_INPUT | HWMON_C_MAX_ALARM, |
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HWMON_C_INPUT | HWMON_C_MAX_ALARM, |
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HWMON_C_INPUT | HWMON_C_MAX_ALARM, |
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HWMON_C_INPUT | HWMON_C_MAX_ALARM), |
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HWMON_CHANNEL_INFO(power, |
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HWMON_P_INPUT, |
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HWMON_P_INPUT, |
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HWMON_P_INPUT, |
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HWMON_P_INPUT), |
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NULL |
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}; |
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static const struct hwmon_ops ltc4245_hwmon_ops = { |
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.is_visible = ltc4245_is_visible, |
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.read = ltc4245_read, |
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}; |
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static const struct hwmon_chip_info ltc4245_chip_info = { |
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.ops = <c4245_hwmon_ops, |
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.info = ltc4245_info, |
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}; |
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static bool ltc4245_use_extra_gpios(struct i2c_client *client) |
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{ |
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struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev); |
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struct device_node *np = client->dev.of_node; |
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/* prefer platform data */ |
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if (pdata) |
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return pdata->use_extra_gpios; |
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/* fallback on OF */ |
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if (of_find_property(np, "ltc4245,use-extra-gpios", NULL)) |
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return true; |
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return false; |
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} |
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static int ltc4245_probe(struct i2c_client *client) |
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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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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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data = devm_kzalloc(&client->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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data->use_extra_gpios = ltc4245_use_extra_gpios(client); |
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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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hwmon_dev = devm_hwmon_device_register_with_info(&client->dev, |
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client->name, data, |
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<c4245_chip_info, |
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NULL); |
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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 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_new = ltc4245_probe, |
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.id_table = ltc4245_id, |
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}; |
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module_i2c_driver(ltc4245_driver); |
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MODULE_AUTHOR("Ira W. Snyder <[email protected]>"); |
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MODULE_DESCRIPTION("LTC4245 driver"); |
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MODULE_LICENSE("GPL");
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