Hello Jean, On Sun, 2007-11-25 at 18:47 +0100, Jean Delvare wrote: > fan1_div is only indirectly related to the number of pulse per > revolutions emitted by the fan. Please read: > http://www.lm-sensors.org/browser/lm-sensors/trunk/doc/fan-divisors I found the description to be a bit misleading btw: So changing the fan divisor will NOT change the nominal RPM reading, it will only affect the minimum and maximum readings and the accuracy of the readings. ... The actual formula is RPM = (60 * 22500) / (count * divisor) ...to me it seems, that changing 'divisor' does change the 'RPM' value (if 'count' stays the same)... :-) however, I've tried to incorporate your comments (the way I understood them :-), see below cheers, hvr From: Herbert Valerio Riedel <hvr at gnu.org> Date: Mon, 17 Dec 2007 10:30:42 +0100 Subject: [RFC, PATCH] hwmon: add support for GMT G760A fan speed PWM controller This controller can be found on the D-Link DNS-323 for instance, where it is to be configured via static i2c_board_info in the board-specific mach-orion/dns323-setup.c; this driver supports only the new-style driver model. Signed-off-by: Herbert Valerio Riedel <hvr at gnu.org> Cc: Jean Delvare <khali at linux-fr.org> --- Documentation/hwmon/g760a | 39 ++++++ drivers/hwmon/Kconfig | 10 ++ drivers/hwmon/Makefile | 1 + drivers/hwmon/g760a.c | 296 +++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 346 insertions(+), 0 deletions(-) create mode 100644 Documentation/hwmon/g760a create mode 100644 drivers/hwmon/g760a.c diff --git a/Documentation/hwmon/g760a b/Documentation/hwmon/g760a new file mode 100644 index 0000000..3aa700a --- /dev/null +++ b/Documentation/hwmon/g760a @@ -0,0 +1,39 @@ +Kernel driver g760a +=================== + +Supported chips: + * Global Mixed-mode Technology Inc. G760A + Prefix: 'g760a' + Datasheet: Publicly available at the GMT website + http://www.gmt.com.tw/datasheet/g760a.pdf + +Author: Herbert Valerio Riedel <hvr at gnu.org> + +Description +----------- + +The GMT G760A Fan Speed PWM Controller is connected directly to a fan +and performs closed-loop control of the fan speed. + +The fan speed is programmed by setting the desired target speed via +`fan1_target` in rpm which is rounded up to the next supported rpm value; +a rpm value of -1 requests the maximum speed (i.e. pwm duty cycle of 100%). +For convenience it's also possible to programm the controller via `pwm1` +(setting pwm1 to 0 stops the fan; 255 sets fan to maximum speed), which still +performs closed-loop control. + +The measured fan rotation speed returned via 'fan1_input' is derived +from the measured speed pulse period by assuming again a 32kHz clock +source and a N=2 pulse-per-revolution fan via the the formula +rpm = (clk * 30)/(clk_counts * N). `fan1_min` contains the lowest possible +rpm value that can be reported by the controller. + +The 'fan1_alarm' file provides access to the alarm bit provided by +the G760A chip's status register: Its value is 1 when the actual fan +speed differs more than 20% with respect to the programmed fan speed; +otherwise 0. + +The g760a driver will not update its reported values more frequently +than every second; reading them more often will do no harm, but will return +'old' values. + diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index a0445be..6ce8c12 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -291,6 +291,16 @@ config SENSORS_FSCHMD This driver can also be built as a module. If so, the module will be called fschmd. +config SENSORS_G760A + tristate "GMT G760A" + depends on I2C + help + If you say yes here you get support for Global Mixed-mode + Technology Inc G760A fan speed pwm controller chips. + + This driver can also be built as a module. If so, the module + will be called g760a. + config SENSORS_GL518SM tristate "Genesys Logic GL518SM" depends on I2C diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index 55595f6..93d78a8 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -35,6 +35,7 @@ obj-$(CONFIG_SENSORS_F75375S) += f75375s.o obj-$(CONFIG_SENSORS_FSCHER) += fscher.o obj-$(CONFIG_SENSORS_FSCHMD) += fschmd.o obj-$(CONFIG_SENSORS_FSCPOS) += fscpos.o +obj-$(CONFIG_SENSORS_G760A) += g760a.o obj-$(CONFIG_SENSORS_GL518SM) += gl518sm.o obj-$(CONFIG_SENSORS_GL520SM) += gl520sm.o obj-$(CONFIG_SENSORS_HDAPS) += hdaps.o diff --git a/drivers/hwmon/g760a.c b/drivers/hwmon/g760a.c new file mode 100644 index 0000000..4bc5a7e --- /dev/null +++ b/drivers/hwmon/g760a.c @@ -0,0 +1,296 @@ +/* + g760a - Driver for the Global Mixed-mode Technology Inc. G760A + fan speed PWM controller chip + + Copyright (C) 2007 Herbert Valerio Riedel <hvr at gnu.org> + + Complete datasheet is available at GMT's website: + http://www.gmt.com.tw/datasheet/g760a.pdf + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. +*/ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/jiffies.h> +#include <linux/i2c.h> +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> +#include <linux/err.h> +#include <linux/mutex.h> +#include <linux/sysfs.h> + +enum g760a_regs { + G760A_REG_SET_CNT = 0x00, + G760A_REG_ACT_CNT = 0x01, + G760A_REG_FAN_STA = 0x02 +}; + +#define G760A_REG_FAN_STA_RPM_OFF 0x1 /* >+-20% off */ +#define G760A_REG_FAN_STA_RPM_LOW 0x2 /* below fan1_min */ + +/* register data is read (and cached) at most once per second */ +#define G760A_UPDATE_INTERVAL (HZ) + +struct g760a_data { + struct i2c_client *client; + struct device *hwmon_dev; + struct mutex update_lock; + + /* g760a register cache */ + int valid:1; + unsigned long last_updated; /* In jiffies */ + + u8 set_cnt; /* closed loop count number; 0xff stops fan */ + u8 act_cnt; /* formula: cnt = (CLK * 30)/(rpm * P) */ + u8 fan_sta; /* bit 0: set when actual fan speed more than %20 + * outside requested fan speed + * bit 1: set when fan speed causes counter overflow + */ +}; + +#define G760A_DEFAULT_CLK 32768 +#define G760A_DEFAULT_FAN_DIV 1 +#define G760A_DEFAULT_FAN_MIN g760a_rpm_from_reg(0xff) + +static inline int g760a_rpm_from_reg(unsigned regval) +{ + if (!regval) + return -1; + return (G760A_DEFAULT_CLK*15)/(regval*G760A_DEFAULT_FAN_DIV); +} + +static inline u8 g760a_rpm_to_reg(unsigned rpm) +{ + unsigned regval; + + if (!rpm) + return 0xff; /* turn off */ + regval = (G760A_DEFAULT_CLK*15)/(rpm*G760A_DEFAULT_FAN_DIV); + return SENSORS_LIMIT(regval, 0x00, 0xfe); +} + +#define PWM_FROM_CNT(cnt) (0xff-(cnt)) +#define PWM_TO_CNT(pwm) (0xff-(pwm)) + +/**************************************************************************** + * sysfs attributes + */ + +static struct g760a_data *g760a_update_client(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + struct g760a_data *data = i2c_get_clientdata(client); + + mutex_lock(&data->update_lock); + + if (time_after(jiffies, data->last_updated + G760A_UPDATE_INTERVAL) + || !data->valid) { + dev_dbg(&client->dev, "Starting g760a update\n"); + + data->set_cnt = i2c_smbus_read_byte_data(client, + G760A_REG_SET_CNT); + data->act_cnt = i2c_smbus_read_byte_data(client, + G760A_REG_ACT_CNT); + data->fan_sta = i2c_smbus_read_byte_data(client, + G760A_REG_FAN_STA); + + data->last_updated = jiffies; + data->valid = 1; + } + + mutex_unlock(&data->update_lock); + + return data; +} + +static ssize_t show_fan_input(struct device *dev, struct device_attribute *da, + char *buf) +{ + struct g760a_data *data = g760a_update_client(dev); + int rpm = 0; + + mutex_lock(&data->update_lock); + if (!(data->fan_sta & G760A_REG_FAN_STA_RPM_LOW)) + rpm = g760a_rpm_from_reg(data->act_cnt); + mutex_unlock(&data->update_lock); + + return sprintf(buf, "%d\n", rpm); +} + +static ssize_t show_fan_target(struct device *dev, struct device_attribute *da, + char *buf) +{ + struct g760a_data *data = g760a_update_client(dev); + int rpm = 0; + + mutex_lock(&data->update_lock); + rpm = (0xff == data->set_cnt) ? 0 : g760a_rpm_from_reg(data->set_cnt); + mutex_unlock(&data->update_lock); + + return sprintf(buf, "%d\n", rpm); +} + +static ssize_t set_fan_target(struct device *dev, struct device_attribute *da, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct g760a_data *data = i2c_get_clientdata(client); + + const long val = simple_strtol(buf, NULL, 10); + + mutex_lock(&data->update_lock); + data->set_cnt = g760a_rpm_to_reg(val); + i2c_smbus_write_byte_data(client, G760A_REG_SET_CNT, data->set_cnt); + mutex_unlock(&data->update_lock); + + return count; +} + +static ssize_t show_fan_alarm(struct device *dev, struct device_attribute *da, + char *buf) +{ + struct g760a_data *data = g760a_update_client(dev); + + int fan_alarm = (data->fan_sta & G760A_REG_FAN_STA_RPM_OFF) ? 1 : 0; + + return sprintf(buf, "%d\n", fan_alarm); +} + +static ssize_t show_fan_min(struct device *dev, struct device_attribute *da, + char *buf) +{ + return sprintf(buf, "%d\n", G760A_DEFAULT_FAN_MIN); +} + + +static ssize_t show_pwm(struct device *dev, struct device_attribute *da, + char *buf) +{ + struct g760a_data *data = g760a_update_client(dev); + + return sprintf(buf, "%d\n", PWM_FROM_CNT(data->set_cnt)); +} + +static ssize_t set_pwm(struct device *dev, struct device_attribute *da, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct g760a_data *data = i2c_get_clientdata(client); + + const long val = simple_strtol(buf, NULL, 10); + + mutex_lock(&data->update_lock); + data->set_cnt = PWM_TO_CNT(SENSORS_LIMIT(val, 0, 255)); + i2c_smbus_write_byte_data(client, G760A_REG_SET_CNT, data->set_cnt); + mutex_unlock(&data->update_lock); + + return count; +} + +static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, show_pwm, set_pwm); +static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, show_fan_target, + set_fan_target); +static DEVICE_ATTR(fan1_input, S_IRUGO, show_fan_input, NULL); +static DEVICE_ATTR(fan1_min, S_IRUGO, show_fan_min, NULL); +static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL); + +static struct attribute *g760a_attributes[] = { + &dev_attr_pwm1.attr, + &dev_attr_fan1_target.attr, + &dev_attr_fan1_input.attr, + &dev_attr_fan1_min.attr, + &dev_attr_fan1_alarm.attr, + NULL +}; + +static const struct attribute_group g760a_group = { + .attrs = g760a_attributes, +}; + +/**************************************************************************** + * new-style driver model code + */ + +static int g760a_probe(struct i2c_client *client) +{ + struct g760a_data *data; + int err; + + if (!i2c_check_functionality(client->adapter, + I2C_FUNC_SMBUS_BYTE_DATA)) + return -EIO; + + data = kzalloc(sizeof(struct g760a_data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + i2c_set_clientdata(client, data); + + data->client = client; + mutex_init(&data->update_lock); + + /* Register sysfs hooks */ + err = sysfs_create_group(&client->dev.kobj, &g760a_group); + if (err) + goto error_sysfs_create_group; + + data->hwmon_dev = hwmon_device_register(&client->dev); + if (IS_ERR(data->hwmon_dev)) { + err = PTR_ERR(data->hwmon_dev); + goto error_hwmon_device_register; + } + + return 0; + +error_hwmon_device_register: + sysfs_remove_group(&client->dev.kobj, &g760a_group); +error_sysfs_create_group: + kfree(data); + i2c_set_clientdata(client, NULL); + + return err; +} + +static int g760a_remove(struct i2c_client *client) +{ + struct g760a_data *data = i2c_get_clientdata(client); + + hwmon_device_unregister(data->hwmon_dev); + sysfs_remove_group(&client->dev.kobj, &g760a_group); + kfree(data); + i2c_set_clientdata(client, NULL); + + return 0; +} + +static struct i2c_driver g760a_driver = { + .driver = { + .name = "g760a", + }, + .probe = g760a_probe, + .remove = g760a_remove, +}; + +/* module management */ + +static int __init g760a_init(void) +{ + return i2c_add_driver(&g760a_driver); +} + +static void __exit g760a_exit(void) +{ + i2c_del_driver(&g760a_driver); +} + +MODULE_AUTHOR("Herbert Valerio Riedel <hvr at gnu.org>"); +MODULE_DESCRIPTION("GMT G760A driver"); +MODULE_LICENSE("GPL"); + +module_init(g760a_init); +module_exit(g760a_exit); -- 1.5.2.5
