diff options
Diffstat (limited to 'drivers/hwmon/max6650.c')
| -rw-r--r-- | drivers/hwmon/max6650.c | 693 |
1 files changed, 693 insertions, 0 deletions
diff --git a/drivers/hwmon/max6650.c b/drivers/hwmon/max6650.c new file mode 100644 index 0000000..8415664 --- /dev/null +++ b/drivers/hwmon/max6650.c @@ -0,0 +1,693 @@ +/* + * max6650.c - Part of lm_sensors, Linux kernel modules for hardware + * monitoring. + * + * (C) 2007 by Hans J. Koch <hjk@linutronix.de> + * + * based on code written by John Morris <john.morris@spirentcom.com> + * Copyright (c) 2003 Spirent Communications + * and Claus Gindhart <claus.gindhart@kontron.com> + * + * This module has only been tested with the MAX6650 chip. It should + * also work with the MAX6651. It does not distinguish max6650 and max6651 + * chips. + * + * Tha datasheet was last seen at: + * + * http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#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> + +/* + * Addresses to scan. There are four disjoint possibilities, by pin config. + */ + +static unsigned short normal_i2c[] = {0x1b, 0x1f, 0x48, 0x4b, I2C_CLIENT_END}; + +/* + * Insmod parameters + */ + +/* fan_voltage: 5=5V fan, 12=12V fan, 0=don't change */ +static int fan_voltage; +/* prescaler: Possible values are 1, 2, 4, 8, 16 or 0 for don't change */ +static int prescaler; +/* clock: The clock frequency of the chip the driver should assume */ +static int clock = 254000; + +module_param(fan_voltage, int, S_IRUGO); +module_param(prescaler, int, S_IRUGO); +module_param(clock, int, S_IRUGO); + +I2C_CLIENT_INSMOD_1(max6650); + +/* + * MAX 6650/6651 registers + */ + +#define MAX6650_REG_SPEED 0x00 +#define MAX6650_REG_CONFIG 0x02 +#define MAX6650_REG_GPIO_DEF 0x04 +#define MAX6650_REG_DAC 0x06 +#define MAX6650_REG_ALARM_EN 0x08 +#define MAX6650_REG_ALARM 0x0A +#define MAX6650_REG_TACH0 0x0C +#define MAX6650_REG_TACH1 0x0E +#define MAX6650_REG_TACH2 0x10 +#define MAX6650_REG_TACH3 0x12 +#define MAX6650_REG_GPIO_STAT 0x14 +#define MAX6650_REG_COUNT 0x16 + +/* + * Config register bits + */ + +#define MAX6650_CFG_V12 0x08 +#define MAX6650_CFG_PRESCALER_MASK 0x07 +#define MAX6650_CFG_PRESCALER_2 0x01 +#define MAX6650_CFG_PRESCALER_4 0x02 +#define MAX6650_CFG_PRESCALER_8 0x03 +#define MAX6650_CFG_PRESCALER_16 0x04 +#define MAX6650_CFG_MODE_MASK 0x30 +#define MAX6650_CFG_MODE_ON 0x00 +#define MAX6650_CFG_MODE_OFF 0x10 +#define MAX6650_CFG_MODE_CLOSED_LOOP 0x20 +#define MAX6650_CFG_MODE_OPEN_LOOP 0x30 +#define MAX6650_COUNT_MASK 0x03 + +/* Minimum and maximum values of the FAN-RPM */ +#define FAN_RPM_MIN 240 +#define FAN_RPM_MAX 30000 + +#define DIV_FROM_REG(reg) (1 << (reg & 7)) + +static int max6650_attach_adapter(struct i2c_adapter *adapter); +static int max6650_detect(struct i2c_adapter *adapter, int address, int kind); +static int max6650_init_client(struct i2c_client *client); +static int max6650_detach_client(struct i2c_client *client); +static struct max6650_data *max6650_update_device(struct device *dev); + +/* + * Driver data (common to all clients) + */ + +static struct i2c_driver max6650_driver = { + .driver = { + .name = "max6650", + }, + .attach_adapter = max6650_attach_adapter, + .detach_client = max6650_detach_client, +}; + +/* + * Client data (each client gets its own) + */ + +struct max6650_data +{ + struct i2c_client client; + struct class_device *class_dev; + struct mutex update_lock; + char valid; /* zero until following fields are valid */ + unsigned long last_updated; /* in jiffies */ + + /* register values */ + u8 speed; + u8 config; + u8 tach[4]; + u8 count; + u8 dac; +}; + +static ssize_t get_fan(struct device *dev, struct device_attribute *devattr, + char *buf) +{ + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); + struct max6650_data *data = max6650_update_device(dev); + int rpm; + + /* + * Calculation details: + * + * Each tachometer counts over an interval given by the "count" + * register (0.25, 0.5, 1 or 2 seconds). This module assumes + * that the fans produce two pulses per revolution (this seems + * to be the most common). + */ + + rpm = ((data->tach[attr->index] * 120) / DIV_FROM_REG(data->count)); + return sprintf(buf, "%d\n", rpm); +} + +/* + * Set the fan speed to the specified RPM (or read back the RPM setting). + * This works in closed loop mode only. Use pwm1 for open loop speed setting. + * + * The MAX6650/1 will automatically control fan speed when in closed loop + * mode. + * + * Assumptions: + * + * 1) The MAX6650/1 internal 254kHz clock frequency is set correctly. Use + * the clock module parameter if you need to fine tune this. + * + * 2) The prescaler (low three bits of the config register) has already + * been set to an appropriate value. Use the prescaler module parameter + * if your BIOS doesn't initialize the chip properly. + * + * The relevant equations are given on pages 21 and 22 of the datasheet. + * + * From the datasheet, the relevant equation when in regulation is: + * + * [fCLK / (128 x (KTACH + 1))] = 2 x FanSpeed / KSCALE + * + * where: + * + * fCLK is the oscillator frequency (either the 254kHz internal + * oscillator or the externally applied clock) + * + * KTACH is the value in the speed register + * + * FanSpeed is the speed of the fan in rps + * + * KSCALE is the prescaler value (1, 2, 4, 8, or 16) + * + * When reading, we need to solve for FanSpeed. When writing, we need to + * solve for KTACH. + * + * Note: this tachometer is completely separate from the tachometers + * used to measure the fan speeds. Only one fan's speed (fan1) is + * controlled. + */ + +static ssize_t get_target(struct device *dev, struct device_attribute *devattr, + char *buf) +{ + struct max6650_data *data = max6650_update_device(dev); + int kscale, ktach, rpm; + + /* + * Use the datasheet equation: + * + * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)] + * + * then multiply by 60 to give rpm. + */ + + kscale = DIV_FROM_REG(data->config); + ktach = data->speed; + rpm = 60 * kscale * clock / (256 * (ktach + 1)); + return sprintf(buf, "%d\n", rpm); +} + +static ssize_t set_target(struct device *dev, struct device_attribute *devattr, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct max6650_data *data = i2c_get_clientdata(client); + int rpm = simple_strtoul(buf, NULL, 10); + int kscale, ktach; + + rpm = SENSORS_LIMIT(rpm, FAN_RPM_MIN, FAN_RPM_MAX); + + /* + * Divide the required speed by 60 to get from rpm to rps, then + * use the datasheet equation: + * + * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1 + */ + + mutex_lock(&data->update_lock); + + kscale = DIV_FROM_REG(data->config); + ktach = ((clock * kscale) / (256 * rpm / 60)) - 1; + if (ktach < 0) + ktach = 0; + if (ktach > 255) + ktach = 255; + data->speed = ktach; + + i2c_smbus_write_byte_data(client, MAX6650_REG_SPEED, data->speed); + + mutex_unlock(&data->update_lock); + + return count; +} + +/* + * Get/set the fan speed in open loop mode using pwm1 sysfs file. + * Speed is given as a relative value from 0 to 255, where 255 is maximum + * speed. Note that this is done by writing directly to the chip's DAC, + * it won't change the closed loop speed set by fan1_target. + * Also note that due to rounding errors it is possible that you don't read + * back exactly the value you have set. + */ + +static ssize_t get_pwm(struct device *dev, struct device_attribute *devattr, + char *buf) +{ + int pwm; + struct max6650_data *data = max6650_update_device(dev); + + /* Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans. + Lower DAC values mean higher speeds. */ + if (data->config & MAX6650_CFG_V12) + pwm = 255 - (255 * (int)data->dac)/180; + else + pwm = 255 - (255 * (int)data->dac)/76; + + if (pwm < 0) + pwm = 0; + + return sprintf(buf, "%d\n", pwm); +} + +static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct max6650_data *data = i2c_get_clientdata(client); + int pwm = simple_strtoul(buf, NULL, 10); + + pwm = SENSORS_LIMIT(pwm, 0, 255); + + mutex_lock(&data->update_lock); + + if (data->config & MAX6650_CFG_V12) + data->dac = 180 - (180 * pwm)/255; + else + data->dac = 76 - (76 * pwm)/255; + + i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac); + + mutex_unlock(&data->update_lock); + + return count; +} + +/* + * Get/Set controller mode: + * Possible values: + * 0 = Fan always on + * 1 = Open loop, Voltage is set according to speed, not regulated. + * 2 = Closed loop, RPM for all fans regulated by fan1 tachometer + */ + +static ssize_t get_enable(struct device *dev, struct device_attribute *devattr, + char *buf) +{ + struct max6650_data *data = max6650_update_device(dev); + int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4; + int sysfs_modes[4] = {0, 1, 2, 1}; + + return sprintf(buf, "%d\n", sysfs_modes[mode]); +} + +static ssize_t set_enable(struct device *dev, struct device_attribute *devattr, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct max6650_data *data = i2c_get_clientdata(client); + int mode = simple_strtoul(buf, NULL, 10); + int max6650_modes[3] = {0, 3, 2}; + + if ((mode < 0)||(mode > 2)) { + dev_err(&client->dev, + "illegal value for pwm1_enable (%d)\n", mode); + return -EINVAL; + } + + mutex_lock(&data->update_lock); + + data->config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG); + data->config = (data->config & ~MAX6650_CFG_MODE_MASK) + | (max6650_modes[mode] << 4); + + i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, data->config); + + mutex_unlock(&data->update_lock); + + return count; +} + +/* + * Read/write functions for fan1_div sysfs file. The MAX6650 has no such + * divider. We handle this by converting between divider and counttime: + * + * (counttime == k) <==> (divider == 2^k), k = 0, 1, 2, or 3 + * + * Lower values of k allow to connect a faster fan without the risk of + * counter overflow. The price is lower resolution. You can also set counttime + * using the module parameter. Note that the module parameter "prescaler" also + * influences the behaviour. Unfortunately, there's no sysfs attribute + * defined for that. See the data sheet for details. + */ + +static ssize_t get_div(struct device *dev, struct device_attribute *devattr, + char *buf) +{ + struct max6650_data *data = max6650_update_device(dev); + + return sprintf(buf, "%d\n", DIV_FROM_REG(data->count)); +} + +static ssize_t set_div(struct device *dev, struct device_attribute *devattr, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct max6650_data *data = i2c_get_clientdata(client); + int div = simple_strtoul(buf, NULL, 10); + + mutex_lock(&data->update_lock); + switch (div) { + case 1: + data->count = 0; + break; + case 2: + data->count = 1; + break; + case 4: + data->count = 2; + break; + case 8: + data->count = 3; + break; + default: + dev_err(&client->dev, + "illegal value for fan divider (%d)\n", div); + return -EINVAL; + } + + i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count); + mutex_unlock(&data->update_lock); + + return count; +} + +static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0); +static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1); +static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2); +static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3); +static DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO, get_target, set_target); +static DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO, get_div, set_div); +static DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO, get_enable, set_enable); +static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm); + + +static struct attribute *max6650_attrs[] = { + &sensor_dev_attr_fan1_input.dev_attr.attr, + &sensor_dev_attr_fan2_input.dev_attr.attr, + &sensor_dev_attr_fan3_input.dev_attr.attr, + &sensor_dev_attr_fan4_input.dev_attr.attr, + &dev_attr_fan1_target.attr, + &dev_attr_fan1_div.attr, + &dev_attr_pwm1_enable.attr, + &dev_attr_pwm1.attr, + NULL +}; + +static struct attribute_group max6650_attr_grp = { + .attrs = max6650_attrs, +}; + +/* + * Real code + */ + +static int max6650_attach_adapter(struct i2c_adapter *adapter) +{ + if (!(adapter->class & I2C_CLASS_HWMON)) { + dev_dbg(&adapter->dev, + "FATAL: max6650_attach_adapter class HWMON not set\n"); + return 0; + } + + return i2c_probe(adapter, &addr_data, max6650_detect); +} + +/* + * The following function does more than just detection. If detection + * succeeds, it also registers the new chip. + */ + +static int max6650_detect(struct i2c_adapter *adapter, int address, int kind) +{ + struct i2c_client *client; + struct max6650_data *data; + int err = -ENODEV; + + dev_dbg(&adapter->dev, "max6650_detect called, kind = %d\n", kind); + + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) { + dev_dbg(&adapter->dev, "max6650: I2C bus doesn't support " + "byte read mode, skipping.\n"); + return 0; + } + + if (!(data = kzalloc(sizeof(struct max6650_data), GFP_KERNEL))) { + dev_err(&adapter->dev, "max6650: out of memory.\n"); + return -ENOMEM; + } + + client = &data->client; + i2c_set_clientdata(client, data); + client->addr = address; + client->adapter = adapter; + client->driver = &max6650_driver; + + /* + * Now we do the remaining detection. A negative kind means that + * the driver was loaded with no force parameter (default), so we + * must both detect and identify the chip (actually there is only + * one possible kind of chip for now, max6650). A zero kind means that + * the driver was loaded with the force parameter, the detection + * step shall be skipped. A positive kind means that the driver + * was loaded with the force parameter and a given kind of chip is + * requested, so both the detection and the identification steps + * are skipped. + * + * Currently I can find no way to distinguish between a MAX6650 and + * a MAX6651. This driver has only been tried on the former. + */ + + if ((kind < 0) && + ( (i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG) & 0xC0) + ||(i2c_smbus_read_byte_data(client, MAX6650_REG_GPIO_STAT) & 0xE0) + ||(i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN) & 0xE0) + ||(i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM) & 0xE0) + ||(i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT) & 0xFC))) { + dev_dbg(&adapter->dev, + "max6650: detection failed at 0x%02x.\n", address); + goto err_free; + } + + dev_info(&adapter->dev, "max6650: chip found at 0x%02x.\n", address); + + strlcpy(client->name, "max6650", I2C_NAME_SIZE); + mutex_init(&data->update_lock); + + if ((err = i2c_attach_client(client))) { + dev_err(&adapter->dev, "max6650: failed to attach client.\n"); + goto err_free; + } + + /* + * Initialize the max6650 chip + */ + if (max6650_init_client(client)) + goto err_detach; + + err = sysfs_create_group(&client->dev.kobj, &max6650_attr_grp); + if (err) + goto err_detach; + + data->class_dev = hwmon_device_register(&client->dev); + if (!IS_ERR(data->class_dev)) + return 0; + + err = PTR_ERR(data->class_dev); + dev_err(&client->dev, "error registering hwmon device.\n"); + sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp); +err_detach: + i2c_detach_client(client); +err_free: + kfree(data); + return err; +} + +static int max6650_detach_client(struct i2c_client *client) +{ + struct max6650_data *data = i2c_get_clientdata(client); + int err; + + sysfs_remove_group(&client->dev.kobj, &max6650_attr_grp); + hwmon_device_unregister(data->class_dev); + err = i2c_detach_client(client); + if (!err) + kfree(data); + return err; +} + +static int max6650_init_client(struct i2c_client *client) +{ + struct max6650_data *data = i2c_get_clientdata(client); + int config; + int err = -EIO; + + config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG); + + if (config < 0) { + dev_err(&client->dev, "Error reading config, aborting.\n"); + return err; + } + + switch (fan_voltage) { + case 0: + break; + case 5: + config &= ~MAX6650_CFG_V12; + break; + case 12: + config |= MAX6650_CFG_V12; + break; + default: + dev_err(&client->dev, + "illegal value for fan_voltage (%d)\n", + fan_voltage); + } + + dev_info(&client->dev, "Fan voltage is set to %dV.\n", + (config & MAX6650_CFG_V12) ? 12 : 5); + + switch (prescaler) { + case 0: + break; + case 1: + config &= ~MAX6650_CFG_PRESCALER_MASK; + break; + case 2: + config = (config & ~MAX6650_CFG_PRESCALER_MASK) + | MAX6650_CFG_PRESCALER_2; + break; + case 4: + config = (config & ~MAX6650_CFG_PRESCALER_MASK) + | MAX6650_CFG_PRESCALER_4; + break; + case 8: + config = (config & ~MAX6650_CFG_PRESCALER_MASK) + | MAX6650_CFG_PRESCALER_8; + break; + case 16: + config = (config & ~MAX6650_CFG_PRESCALER_MASK) + | MAX6650_CFG_PRESCALER_16; + break; + default: + dev_err(&client->dev, + "illegal value for prescaler (%d)\n", + prescaler); + } + + dev_info(&client->dev, "Prescaler is set to %d.\n", + 1 << (config & MAX6650_CFG_PRESCALER_MASK)); + + /* If mode is set to "full off", we change it to "open loop" and + * set DAC to 255, which has the same effect. We do this because + * there's no "full off" mode defined in hwmon specifcations. + */ + + if ((config & MAX6650_CFG_MODE_MASK) == MAX6650_CFG_MODE_OFF) { + dev_dbg(&client->dev, "Change mode to open loop, full off.\n"); + config = (config & ~MAX6650_CFG_MODE_MASK) + | MAX6650_CFG_MODE_OPEN_LOOP; + if (i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, 255)) { + dev_err(&client->dev, "DAC write error, aborting.\n"); + return err; + } + } + + if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) { + dev_err(&client->dev, "Config write error, aborting.\n"); + return err; + } + + data->config = config; + data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT); + + return 0; +} + +static const u8 tach_reg[] = { + MAX6650_REG_TACH0, + MAX6650_REG_TACH1, + MAX6650_REG_TACH2, + MAX6650_REG_TACH3, +}; + +static struct max6650_data *max6650_update_device(struct device *dev) +{ + int i; + struct i2c_client *client = to_i2c_client(dev); + struct max6650_data *data = i2c_get_clientdata(client); + + mutex_lock(&data->update_lock); + + if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { + data->speed = i2c_smbus_read_byte_data(client, + MAX6650_REG_SPEED); + data->config = i2c_smbus_read_byte_data(client, + MAX6650_REG_CONFIG); + for (i = 0; i < 4; i++) { + data->tach[i] = i2c_smbus_read_byte_data(client, + tach_reg[i]); + } + data->count = i2c_smbus_read_byte_data(client, + MAX6650_REG_COUNT); + data->dac = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC); + + data->last_updated = jiffies; + data->valid = 1; + } + + mutex_unlock(&data->update_lock); + + return data; +} + +static int __init sensors_max6650_init(void) +{ + return i2c_add_driver(&max6650_driver); +} + +static void __exit sensors_max6650_exit(void) +{ + i2c_del_driver(&max6650_driver); +} + +MODULE_AUTHOR("Hans J. Koch"); +MODULE_DESCRIPTION("MAX6650 sensor driver"); +MODULE_LICENSE("GPL"); + +module_init(sensors_max6650_init); +module_exit(sensors_max6650_exit); |
