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217 lines
5.3 KiB
217 lines
5.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* g760a - Driver for the Global Mixed-mode Technology Inc. G760A |
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* fan speed PWM controller chip |
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* |
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* Copyright (C) 2007 Herbert Valerio Riedel <[email protected]> |
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* |
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* Complete datasheet is available at GMT's website: |
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* http://www.gmt.com.tw/product/datasheet/EDS-760A.pdf |
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*/ |
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/slab.h> |
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#include <linux/jiffies.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/err.h> |
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#include <linux/mutex.h> |
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#include <linux/sysfs.h> |
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enum g760a_regs { |
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G760A_REG_SET_CNT = 0x00, |
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G760A_REG_ACT_CNT = 0x01, |
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G760A_REG_FAN_STA = 0x02 |
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}; |
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#define G760A_REG_FAN_STA_RPM_OFF 0x1 /* +/-20% off */ |
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#define G760A_REG_FAN_STA_RPM_LOW 0x2 /* below 1920rpm */ |
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/* register data is read (and cached) at most once per second */ |
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#define G760A_UPDATE_INTERVAL (HZ) |
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struct g760a_data { |
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struct i2c_client *client; |
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struct mutex update_lock; |
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/* board specific parameters */ |
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u32 clk; /* default 32kHz */ |
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u16 fan_div; /* default P=2 */ |
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/* g760a register cache */ |
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unsigned int valid:1; |
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unsigned long last_updated; /* In jiffies */ |
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u8 set_cnt; /* PWM (period) count number; 0xff stops fan */ |
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u8 act_cnt; /* formula: cnt = (CLK * 30)/(rpm * P) */ |
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u8 fan_sta; /* bit 0: set when actual fan speed more than 20% |
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* outside requested fan speed |
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* bit 1: set when fan speed below 1920 rpm |
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*/ |
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}; |
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#define G760A_DEFAULT_CLK 32768 |
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#define G760A_DEFAULT_FAN_DIV 2 |
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#define PWM_FROM_CNT(cnt) (0xff-(cnt)) |
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#define PWM_TO_CNT(pwm) (0xff-(pwm)) |
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static inline unsigned int rpm_from_cnt(u8 val, u32 clk, u16 div) |
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{ |
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return ((val == 0x00) ? 0 : ((clk*30)/(val*div))); |
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} |
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/* read/write wrappers */ |
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static int g760a_read_value(struct i2c_client *client, enum g760a_regs reg) |
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{ |
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return i2c_smbus_read_byte_data(client, reg); |
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} |
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static int g760a_write_value(struct i2c_client *client, enum g760a_regs reg, |
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u16 value) |
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{ |
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return i2c_smbus_write_byte_data(client, reg, value); |
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} |
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/* |
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* sysfs attributes |
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*/ |
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static struct g760a_data *g760a_update_client(struct device *dev) |
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{ |
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struct g760a_data *data = dev_get_drvdata(dev); |
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struct i2c_client *client = data->client; |
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mutex_lock(&data->update_lock); |
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if (time_after(jiffies, data->last_updated + G760A_UPDATE_INTERVAL) |
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|| !data->valid) { |
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dev_dbg(&client->dev, "Starting g760a update\n"); |
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data->set_cnt = g760a_read_value(client, G760A_REG_SET_CNT); |
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data->act_cnt = g760a_read_value(client, G760A_REG_ACT_CNT); |
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data->fan_sta = g760a_read_value(client, G760A_REG_FAN_STA); |
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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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static ssize_t fan1_input_show(struct device *dev, |
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struct device_attribute *da, char *buf) |
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{ |
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struct g760a_data *data = g760a_update_client(dev); |
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unsigned int rpm = 0; |
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mutex_lock(&data->update_lock); |
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if (!(data->fan_sta & G760A_REG_FAN_STA_RPM_LOW)) |
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rpm = rpm_from_cnt(data->act_cnt, data->clk, data->fan_div); |
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mutex_unlock(&data->update_lock); |
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return sprintf(buf, "%d\n", rpm); |
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} |
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static ssize_t fan1_alarm_show(struct device *dev, |
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struct device_attribute *da, char *buf) |
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{ |
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struct g760a_data *data = g760a_update_client(dev); |
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int fan_alarm = (data->fan_sta & G760A_REG_FAN_STA_RPM_OFF) ? 1 : 0; |
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return sprintf(buf, "%d\n", fan_alarm); |
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} |
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static ssize_t pwm1_show(struct device *dev, struct device_attribute *da, |
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char *buf) |
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{ |
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struct g760a_data *data = g760a_update_client(dev); |
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return sprintf(buf, "%d\n", PWM_FROM_CNT(data->set_cnt)); |
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} |
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static ssize_t pwm1_store(struct device *dev, struct device_attribute *da, |
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const char *buf, size_t count) |
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{ |
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struct g760a_data *data = g760a_update_client(dev); |
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struct i2c_client *client = data->client; |
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unsigned long val; |
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if (kstrtoul(buf, 10, &val)) |
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return -EINVAL; |
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mutex_lock(&data->update_lock); |
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data->set_cnt = PWM_TO_CNT(clamp_val(val, 0, 255)); |
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g760a_write_value(client, G760A_REG_SET_CNT, data->set_cnt); |
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mutex_unlock(&data->update_lock); |
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return count; |
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} |
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static DEVICE_ATTR_RW(pwm1); |
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static DEVICE_ATTR_RO(fan1_input); |
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static DEVICE_ATTR_RO(fan1_alarm); |
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static struct attribute *g760a_attrs[] = { |
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&dev_attr_pwm1.attr, |
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&dev_attr_fan1_input.attr, |
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&dev_attr_fan1_alarm.attr, |
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NULL |
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}; |
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ATTRIBUTE_GROUPS(g760a); |
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/* |
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* new-style driver model code |
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*/ |
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static int g760a_probe(struct i2c_client *client) |
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{ |
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struct device *dev = &client->dev; |
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struct g760a_data *data; |
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struct device *hwmon_dev; |
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) |
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return -EIO; |
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data = devm_kzalloc(dev, sizeof(struct g760a_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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/* setup default configuration for now */ |
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data->fan_div = G760A_DEFAULT_FAN_DIV; |
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data->clk = G760A_DEFAULT_CLK; |
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hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
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data, |
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g760a_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 g760a_id[] = { |
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{ "g760a", 0 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, g760a_id); |
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static struct i2c_driver g760a_driver = { |
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.driver = { |
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.name = "g760a", |
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}, |
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.probe_new = g760a_probe, |
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.id_table = g760a_id, |
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}; |
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module_i2c_driver(g760a_driver); |
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MODULE_AUTHOR("Herbert Valerio Riedel <[email protected]>"); |
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MODULE_DESCRIPTION("GMT G760A driver"); |
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MODULE_LICENSE("GPL");
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