/* * 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);