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216 lines
4.9 KiB
216 lines
4.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Driver for Linear Technology LTC4151 High Voltage I2C Current |
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* and Voltage Monitor |
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* |
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* Copyright (C) 2011 AppearTV AS |
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* |
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* Derived from: |
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* |
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* Driver for Linear Technology LTC4261 I2C Negative Voltage Hot |
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* Swap Controller |
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* Copyright (C) 2010 Ericsson AB. |
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* |
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* Datasheet: http://www.linear.com/docs/Datasheet/4151fc.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/of.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 LTC4151_SENSE_H 0x00 |
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#define LTC4151_SENSE_L 0x01 |
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#define LTC4151_VIN_H 0x02 |
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#define LTC4151_VIN_L 0x03 |
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#define LTC4151_ADIN_H 0x04 |
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#define LTC4151_ADIN_L 0x05 |
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struct ltc4151_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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unsigned int shunt; /* in micro ohms */ |
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/* Registers */ |
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u8 regs[6]; |
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}; |
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static struct ltc4151_data *ltc4151_update_device(struct device *dev) |
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{ |
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struct ltc4151_data *data = dev_get_drvdata(dev); |
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struct i2c_client *client = data->client; |
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struct ltc4151_data *ret = data; |
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mutex_lock(&data->update_lock); |
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/* |
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* The chip's A/D updates 6 times per second |
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* (Conversion Rate 6 - 9 Hz) |
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*/ |
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if (time_after(jiffies, data->last_updated + HZ / 6) || !data->valid) { |
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int i; |
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dev_dbg(&client->dev, "Starting ltc4151 update\n"); |
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/* Read all registers */ |
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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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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 = 1; |
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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 */ |
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static int ltc4151_get_value(struct ltc4151_data *data, u8 reg) |
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{ |
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u32 val; |
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val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4); |
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switch (reg) { |
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case LTC4151_ADIN_H: |
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/* 500uV resolution. Convert to mV. */ |
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val = val * 500 / 1000; |
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break; |
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case LTC4151_SENSE_H: |
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/* |
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* 20uV resolution. Convert to current as measured with |
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* a given sense resistor, in mA. |
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*/ |
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val = val * 20 * 1000 / data->shunt; |
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break; |
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case LTC4151_VIN_H: |
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/* 25 mV per increment */ |
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val = val * 25; |
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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 ltc4151_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 ltc4151_data *data = ltc4151_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 = ltc4151_get_value(data, attr->index); |
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return sysfs_emit(buf, "%d\n", value); |
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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, ltc4151_value, LTC4151_VIN_H); |
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static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4151_value, LTC4151_ADIN_H); |
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/* Currents (via sense resistor) */ |
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static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4151_value, LTC4151_SENSE_H); |
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/* |
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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 *ltc4151_attrs[] = { |
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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_curr1_input.dev_attr.attr, |
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NULL, |
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}; |
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ATTRIBUTE_GROUPS(ltc4151); |
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static int ltc4151_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 ltc4151_data *data; |
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struct device *hwmon_dev; |
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u32 shunt; |
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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(dev, sizeof(*data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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if (of_property_read_u32(client->dev.of_node, |
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"shunt-resistor-micro-ohms", &shunt)) |
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shunt = 1000; /* 1 mOhm if not set via DT */ |
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if (shunt == 0) |
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return -EINVAL; |
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data->shunt = shunt; |
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data->client = client; |
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mutex_init(&data->update_lock); |
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hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
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data, |
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ltc4151_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 ltc4151_id[] = { |
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{ "ltc4151", 0 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, ltc4151_id); |
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static const struct of_device_id __maybe_unused ltc4151_match[] = { |
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{ .compatible = "lltc,ltc4151" }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, ltc4151_match); |
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/* This is the driver that will be inserted */ |
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static struct i2c_driver ltc4151_driver = { |
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.driver = { |
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.name = "ltc4151", |
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.of_match_table = of_match_ptr(ltc4151_match), |
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}, |
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.probe_new = ltc4151_probe, |
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.id_table = ltc4151_id, |
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}; |
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module_i2c_driver(ltc4151_driver); |
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MODULE_AUTHOR("Per Dalen <[email protected]>"); |
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MODULE_DESCRIPTION("LTC4151 driver"); |
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MODULE_LICENSE("GPL");
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