/* * max6650.c - Part of lm_sensors, Linux kernel modules for hardware * monitoring. * * (C) 2007 by Hans J. Koch * * based on code written by John Morris * Copyright (c) 2003 Spirent Communications * and Claus Gindhart * * 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. * * The 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 #include #include #include #include #include #include #include #include /* * 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 (max6651 can be clocked externally) */ static int clock = 254000; module_param(fan_voltage, int, S_IRUGO); module_param(prescaler, int, S_IRUGO); module_param(clock, int, S_IRUGO); /* * 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 /* * Alarm status register bits */ #define MAX6650_ALRM_MAX 0x01 #define MAX6650_ALRM_MIN 0x02 #define MAX6650_ALRM_TACH 0x04 #define MAX6650_ALRM_GPIO1 0x08 #define MAX6650_ALRM_GPIO2 0x10 /* 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)) /* * Client data (each client gets its own) */ struct max6650_data { struct i2c_client *client; const struct attribute_group *groups[3]; struct mutex update_lock; int nr_fans; 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; u8 alarm; }; static const u8 tach_reg[] = { MAX6650_REG_TACH0, MAX6650_REG_TACH1, MAX6650_REG_TACH2, MAX6650_REG_TACH3, }; static const struct of_device_id max6650_dt_match[] = { { .compatible = "maxim,max6650", .data = (void *)1 }, { .compatible = "maxim,max6651", .data = (void *)4 }, { }, }; MODULE_DEVICE_TABLE(of, max6650_dt_match); static struct max6650_data *max6650_update_device(struct device *dev) { struct max6650_data *data = dev_get_drvdata(dev); struct i2c_client *client = data->client; int i; 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 < data->nr_fans; 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); /* * Alarms are cleared on read in case the condition that * caused the alarm is removed. Keep the value latched here * for providing the register through different alarm files. */ data->alarm |= i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM); data->last_updated = jiffies; data->valid = 1; } mutex_unlock(&data->update_lock); return data; } /* * Change the operating mode of the chip (if needed). * mode is one of the MAX6650_CFG_MODE_* values. */ static int max6650_set_operating_mode(struct max6650_data *data, u8 mode) { int result; u8 config = data->config; if (mode == (config & MAX6650_CFG_MODE_MASK)) return 0; config = (config & ~MAX6650_CFG_MODE_MASK) | mode; result = i2c_smbus_write_byte_data(data->client, MAX6650_REG_CONFIG, config); if (result < 0) return result; data->config = config; return 0; } 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 fan1_target_show(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 int max6650_set_target(struct max6650_data *data, unsigned long rpm) { int kscale, ktach; if (rpm == 0) return max6650_set_operating_mode(data, MAX6650_CFG_MODE_OFF); rpm = clamp_val(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 */ 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; return i2c_smbus_write_byte_data(data->client, MAX6650_REG_SPEED, data->speed); } static ssize_t fan1_target_store(struct device *dev, struct device_attribute *devattr, const char *buf, size_t count) { struct max6650_data *data = dev_get_drvdata(dev); unsigned long rpm; int err; err = kstrtoul(buf, 10, &rpm); if (err) return err; mutex_lock(&data->update_lock); err = max6650_set_target(data, rpm); mutex_unlock(&data->update_lock); if (err < 0) return err; 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 pwm1_show(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 pwm1_store(struct device *dev, struct device_attribute *devattr, const char *buf, size_t count) { struct max6650_data *data = dev_get_drvdata(dev); struct i2c_client *client = data->client; unsigned long pwm; int err; err = kstrtoul(buf, 10, &pwm); if (err) return err; pwm = clamp_val(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; err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac); mutex_unlock(&data->update_lock); return err < 0 ? err : 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 * 3 = Fan off */ static ssize_t pwm1_enable_show(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, 3, 2, 1}; return sprintf(buf, "%d\n", sysfs_modes[mode]); } static ssize_t pwm1_enable_store(struct device *dev, struct device_attribute *devattr, const char *buf, size_t count) { struct max6650_data *data = dev_get_drvdata(dev); unsigned long mode; int err; const u8 max6650_modes[] = { MAX6650_CFG_MODE_ON, MAX6650_CFG_MODE_OPEN_LOOP, MAX6650_CFG_MODE_CLOSED_LOOP, MAX6650_CFG_MODE_OFF, }; err = kstrtoul(buf, 10, &mode); if (err) return err; if (mode >= ARRAY_SIZE(max6650_modes)) return -EINVAL; mutex_lock(&data->update_lock); max6650_set_operating_mode(data, max6650_modes[mode]); 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 fan1_div_show(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 fan1_div_store(struct device *dev, struct device_attribute *devattr, const char *buf, size_t count) { struct max6650_data *data = dev_get_drvdata(dev); struct i2c_client *client = data->client; unsigned long div; int err; err = kstrtoul(buf, 10, &div); if (err) return err; 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: mutex_unlock(&data->update_lock); return -EINVAL; } i2c_smbus_write_byte_data(client, MAX6650_REG_COUNT, data->count); mutex_unlock(&data->update_lock); return count; } /* * Get alarm stati: * Possible values: * 0 = no alarm * 1 = alarm */ static ssize_t get_alarm(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); struct i2c_client *client = data->client; int alarm = 0; if (data->alarm & attr->index) { mutex_lock(&data->update_lock); alarm = 1; data->alarm &= ~attr->index; data->alarm |= i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM); mutex_unlock(&data->update_lock); } return sprintf(buf, "%d\n", alarm); } 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_RW(fan1_target); static DEVICE_ATTR_RW(fan1_div); static DEVICE_ATTR_RW(pwm1_enable); static DEVICE_ATTR_RW(pwm1); static SENSOR_DEVICE_ATTR(fan1_max_alarm, S_IRUGO, get_alarm, NULL, MAX6650_ALRM_MAX); static SENSOR_DEVICE_ATTR(fan1_min_alarm, S_IRUGO, get_alarm, NULL, MAX6650_ALRM_MIN); static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_alarm, NULL, MAX6650_ALRM_TACH); static SENSOR_DEVICE_ATTR(gpio1_alarm, S_IRUGO, get_alarm, NULL, MAX6650_ALRM_GPIO1); static SENSOR_DEVICE_ATTR(gpio2_alarm, S_IRUGO, get_alarm, NULL, MAX6650_ALRM_GPIO2); static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a, int n) { struct device *dev = container_of(kobj, struct device, kobj); struct max6650_data *data = dev_get_drvdata(dev); struct i2c_client *client = data->client; u8 alarm_en = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN); struct device_attribute *devattr; /* * Hide the alarms that have not been enabled by the firmware */ devattr = container_of(a, struct device_attribute, attr); if (devattr == &sensor_dev_attr_fan1_max_alarm.dev_attr || devattr == &sensor_dev_attr_fan1_min_alarm.dev_attr || devattr == &sensor_dev_attr_fan1_fault.dev_attr || devattr == &sensor_dev_attr_gpio1_alarm.dev_attr || devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) { if (!(alarm_en & to_sensor_dev_attr(devattr)->index)) return 0; } return a->mode; } static struct attribute *max6650_attrs[] = { &sensor_dev_attr_fan1_input.dev_attr.attr, &dev_attr_fan1_target.attr, &dev_attr_fan1_div.attr, &dev_attr_pwm1_enable.attr, &dev_attr_pwm1.attr, &sensor_dev_attr_fan1_max_alarm.dev_attr.attr, &sensor_dev_attr_fan1_min_alarm.dev_attr.attr, &sensor_dev_attr_fan1_fault.dev_attr.attr, &sensor_dev_attr_gpio1_alarm.dev_attr.attr, &sensor_dev_attr_gpio2_alarm.dev_attr.attr, NULL }; static const struct attribute_group max6650_group = { .attrs = max6650_attrs, .is_visible = max6650_attrs_visible, }; static struct attribute *max6651_attrs[] = { &sensor_dev_attr_fan2_input.dev_attr.attr, &sensor_dev_attr_fan3_input.dev_attr.attr, &sensor_dev_attr_fan4_input.dev_attr.attr, NULL }; static const struct attribute_group max6651_group = { .attrs = max6651_attrs, }; /* * Real code */ static int max6650_init_client(struct max6650_data *data, struct i2c_client *client) { struct device *dev = &client->dev; int config; int err = -EIO; u32 voltage; u32 prescale; u32 target_rpm; if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt", &voltage)) voltage = fan_voltage; else voltage /= 1000000; /* Microvolts to volts */ if (of_property_read_u32(dev->of_node, "maxim,fan-prescale", &prescale)) prescale = prescaler; config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG); if (config < 0) { dev_err(dev, "Error reading config, aborting.\n"); return err; } switch (voltage) { case 0: break; case 5: config &= ~MAX6650_CFG_V12; break; case 12: config |= MAX6650_CFG_V12; break; default: dev_err(dev, "illegal value for fan_voltage (%d)\n", voltage); } switch (prescale) { 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(dev, "illegal value for prescaler (%d)\n", prescale); } dev_info(dev, "Fan voltage: %dV, prescaler: %d.\n", (config & MAX6650_CFG_V12) ? 12 : 5, 1 << (config & MAX6650_CFG_PRESCALER_MASK)); if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) { dev_err(dev, "Config write error, aborting.\n"); return err; } data->config = config; data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT); if (!of_property_read_u32(client->dev.of_node, "maxim,fan-target-rpm", &target_rpm)) { max6650_set_target(data, target_rpm); max6650_set_operating_mode(data, MAX6650_CFG_MODE_CLOSED_LOOP); } return 0; } static int max6650_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct device *dev = &client->dev; const struct of_device_id *of_id = of_match_device(of_match_ptr(max6650_dt_match), dev); struct max6650_data *data; struct device *hwmon_dev; int err; data = devm_kzalloc(dev, sizeof(struct max6650_data), GFP_KERNEL); if (!data) return -ENOMEM; data->client = client; mutex_init(&data->update_lock); data->nr_fans = of_id ? (int)(uintptr_t)of_id->data : id->driver_data; /* * Initialize the max6650 chip */ err = max6650_init_client(data, client); if (err) return err; data->groups[0] = &max6650_group; /* 3 additional fan inputs for the MAX6651 */ if (data->nr_fans == 4) data->groups[1] = &max6651_group; hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, data, data->groups); return PTR_ERR_OR_ZERO(hwmon_dev); } static const struct i2c_device_id max6650_id[] = { { "max6650", 1 }, { "max6651", 4 }, { } }; MODULE_DEVICE_TABLE(i2c, max6650_id); static struct i2c_driver max6650_driver = { .driver = { .name = "max6650", .of_match_table = of_match_ptr(max6650_dt_match), }, .probe = max6650_probe, .id_table = max6650_id, }; module_i2c_driver(max6650_driver); MODULE_AUTHOR("Hans J. Koch"); MODULE_DESCRIPTION("MAX6650 sensor driver"); MODULE_LICENSE("GPL");