diff options
Diffstat (limited to 'drivers/hwmon/max6650.c')
| -rw-r--r-- | drivers/hwmon/max6650.c | 830 |
1 files changed, 830 insertions, 0 deletions
diff --git a/drivers/hwmon/max6650.c b/drivers/hwmon/max6650.c new file mode 100644 index 000000000..f8d4534ce --- /dev/null +++ b/drivers/hwmon/max6650.c @@ -0,0 +1,830 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * max6650.c - Part of lm_sensors, Linux kernel modules for hardware + * monitoring. + * + * (C) 2007 by Hans J. Koch <hjk@hansjkoch.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. + * + * The datasheet was last seen at: + * + * http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf + */ + +#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/of_device.h> +#include <linux/thermal.h> + +/* + * 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, 0444); +module_param(prescaler, int, 0444); +module_param(clock, int, 0444); + +/* + * 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)) +#define DAC_LIMIT(v12) ((v12) ? 180 : 76) + +/* + * Client data (each client gets its own) + */ + +struct max6650_data { + struct i2c_client *client; + struct mutex update_lock; /* protect alarm register updates */ + int nr_fans; + bool valid; /* false 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; + u8 alarm_en; + unsigned long cooling_dev_state; +}; + +static const u8 tach_reg[] = { + MAX6650_REG_TACH0, + MAX6650_REG_TACH1, + MAX6650_REG_TACH2, + MAX6650_REG_TACH3, +}; + +static const struct of_device_id __maybe_unused max6650_dt_match[] = { + { + .compatible = "maxim,max6650", + .data = (void *)1 + }, + { + .compatible = "maxim,max6651", + .data = (void *)4 + }, + { }, +}; +MODULE_DEVICE_TABLE(of, max6650_dt_match); + +static int dac_to_pwm(int dac, bool v12) +{ + /* + * Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans. + * Lower DAC values mean higher speeds. + */ + return clamp_val(255 - (255 * dac) / DAC_LIMIT(v12), 0, 255); +} + +static u8 pwm_to_dac(unsigned int pwm, bool v12) +{ + int limit = DAC_LIMIT(v12); + + return limit - (limit * pwm) / 255; +} + +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 reg, err = 0; + int i; + + mutex_lock(&data->update_lock); + + if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { + for (i = 0; i < data->nr_fans; i++) { + reg = i2c_smbus_read_byte_data(client, tach_reg[i]); + if (reg < 0) { + err = reg; + goto error; + } + data->tach[i] = reg; + } + + /* + * 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. + */ + reg = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM); + if (reg < 0) { + err = reg; + goto error; + } + data->alarm |= reg; + data->last_updated = jiffies; + data->valid = true; + } + +error: + mutex_unlock(&data->update_lock); + if (err) + data = ERR_PTR(err); + 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; +} + +/* + * 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 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); +} + +/* + * Get gpio alarm status: + * Possible values: + * 0 = no alarm + * 1 = alarm + */ + +static ssize_t alarm_show(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); + bool alarm; + + if (IS_ERR(data)) + return PTR_ERR(data); + + alarm = data->alarm & attr->index; + if (alarm) { + mutex_lock(&data->update_lock); + data->alarm &= ~attr->index; + data->valid = false; + mutex_unlock(&data->update_lock); + } + + return sprintf(buf, "%d\n", alarm); +} + +static SENSOR_DEVICE_ATTR_RO(gpio1_alarm, alarm, MAX6650_ALRM_GPIO1); +static SENSOR_DEVICE_ATTR_RO(gpio2_alarm, alarm, MAX6650_ALRM_GPIO2); + +static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a, + int n) +{ + struct device *dev = kobj_to_dev(kobj); + struct max6650_data *data = dev_get_drvdata(dev); + 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_gpio1_alarm.dev_attr || + devattr == &sensor_dev_attr_gpio2_alarm.dev_attr) { + if (!(data->alarm_en & to_sensor_dev_attr(devattr)->index)) + return 0; + } + + return a->mode; +} + +static struct attribute *max6650_attrs[] = { + &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 const struct attribute_group *max6650_groups[] = { + &max6650_group, + NULL +}; + +static int max6650_init_client(struct max6650_data *data, + struct i2c_client *client) +{ + struct device *dev = &client->dev; + int reg; + int err; + 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; + + reg = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG); + if (reg < 0) { + dev_err(dev, "Error reading config register, aborting.\n"); + return reg; + } + + switch (voltage) { + case 0: + break; + case 5: + reg &= ~MAX6650_CFG_V12; + break; + case 12: + reg |= MAX6650_CFG_V12; + break; + default: + dev_err(dev, "illegal value for fan_voltage (%d)\n", voltage); + } + + switch (prescale) { + case 0: + break; + case 1: + reg &= ~MAX6650_CFG_PRESCALER_MASK; + break; + case 2: + reg = (reg & ~MAX6650_CFG_PRESCALER_MASK) + | MAX6650_CFG_PRESCALER_2; + break; + case 4: + reg = (reg & ~MAX6650_CFG_PRESCALER_MASK) + | MAX6650_CFG_PRESCALER_4; + break; + case 8: + reg = (reg & ~MAX6650_CFG_PRESCALER_MASK) + | MAX6650_CFG_PRESCALER_8; + break; + case 16: + reg = (reg & ~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", + (reg & MAX6650_CFG_V12) ? 12 : 5, + 1 << (reg & MAX6650_CFG_PRESCALER_MASK)); + + err = i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, reg); + if (err) { + dev_err(dev, "Config write error, aborting.\n"); + return err; + } + data->config = reg; + + reg = i2c_smbus_read_byte_data(client, MAX6650_REG_SPEED); + if (reg < 0) { + dev_err(dev, "Failed to read speed register, aborting.\n"); + return reg; + } + data->speed = reg; + + reg = i2c_smbus_read_byte_data(client, MAX6650_REG_DAC); + if (reg < 0) { + dev_err(dev, "Failed to read DAC register, aborting.\n"); + return reg; + } + data->dac = reg; + + reg = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT); + if (reg < 0) { + dev_err(dev, "Failed to read count register, aborting.\n"); + return reg; + } + data->count = reg; + + reg = i2c_smbus_read_byte_data(client, MAX6650_REG_ALARM_EN); + if (reg < 0) { + dev_err(dev, "Failed to read alarm configuration, aborting.\n"); + return reg; + } + data->alarm_en = reg; + + 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_get_max_state(struct thermal_cooling_device *cdev, + unsigned long *state) +{ + *state = 255; + + return 0; +} + +static int max6650_get_cur_state(struct thermal_cooling_device *cdev, + unsigned long *state) +{ + struct max6650_data *data = cdev->devdata; + + *state = data->cooling_dev_state; + + return 0; +} + +static int max6650_set_cur_state(struct thermal_cooling_device *cdev, + unsigned long state) +{ + struct max6650_data *data = cdev->devdata; + struct i2c_client *client = data->client; + int err; + + state = clamp_val(state, 0, 255); + + mutex_lock(&data->update_lock); + + data->dac = pwm_to_dac(state, data->config & MAX6650_CFG_V12); + err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac); + if (!err) { + max6650_set_operating_mode(data, state ? + MAX6650_CFG_MODE_OPEN_LOOP : + MAX6650_CFG_MODE_OFF); + data->cooling_dev_state = state; + } + + mutex_unlock(&data->update_lock); + + return err; +} + +static const struct thermal_cooling_device_ops max6650_cooling_ops = { + .get_max_state = max6650_get_max_state, + .get_cur_state = max6650_get_cur_state, + .set_cur_state = max6650_set_cur_state, +}; + +static int max6650_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + struct max6650_data *data = max6650_update_device(dev); + int mode; + + if (IS_ERR(data)) + return PTR_ERR(data); + + switch (type) { + case hwmon_pwm: + switch (attr) { + case hwmon_pwm_input: + *val = dac_to_pwm(data->dac, + data->config & MAX6650_CFG_V12); + break; + case hwmon_pwm_enable: + /* + * 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 + */ + mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4; + *val = (4 - mode) & 3; /* {0 1 2 3} -> {0 3 2 1} */ + break; + default: + return -EOPNOTSUPP; + } + break; + case hwmon_fan: + switch (attr) { + case hwmon_fan_input: + /* + * Calculation details: + * + * Each tachometer counts over an interval given by the + * "count" register (0.25, 0.5, 1 or 2 seconds). + * The driver assumes that the fans produce two pulses + * per revolution (this seems to be the most common). + */ + *val = DIV_ROUND_CLOSEST(data->tach[channel] * 120, + DIV_FROM_REG(data->count)); + break; + case hwmon_fan_div: + *val = DIV_FROM_REG(data->count); + break; + case hwmon_fan_target: + /* + * Use the datasheet equation: + * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)] + * then multiply by 60 to give rpm. + */ + *val = 60 * DIV_FROM_REG(data->config) * clock / + (256 * (data->speed + 1)); + break; + case hwmon_fan_min_alarm: + *val = !!(data->alarm & MAX6650_ALRM_MIN); + data->alarm &= ~MAX6650_ALRM_MIN; + data->valid = false; + break; + case hwmon_fan_max_alarm: + *val = !!(data->alarm & MAX6650_ALRM_MAX); + data->alarm &= ~MAX6650_ALRM_MAX; + data->valid = false; + break; + case hwmon_fan_fault: + *val = !!(data->alarm & MAX6650_ALRM_TACH); + data->alarm &= ~MAX6650_ALRM_TACH; + data->valid = false; + break; + default: + return -EOPNOTSUPP; + } + break; + default: + return -EOPNOTSUPP; + } + return 0; +} + +static const u8 max6650_pwm_modes[] = { + MAX6650_CFG_MODE_ON, + MAX6650_CFG_MODE_OPEN_LOOP, + MAX6650_CFG_MODE_CLOSED_LOOP, + MAX6650_CFG_MODE_OFF, +}; + +static int max6650_write(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long val) +{ + struct max6650_data *data = dev_get_drvdata(dev); + int ret = 0; + u8 reg; + + mutex_lock(&data->update_lock); + + switch (type) { + case hwmon_pwm: + switch (attr) { + case hwmon_pwm_input: + reg = pwm_to_dac(clamp_val(val, 0, 255), + data->config & MAX6650_CFG_V12); + ret = i2c_smbus_write_byte_data(data->client, + MAX6650_REG_DAC, reg); + if (ret) + break; + data->dac = reg; + break; + case hwmon_pwm_enable: + if (val < 0 || val >= ARRAY_SIZE(max6650_pwm_modes)) { + ret = -EINVAL; + break; + } + ret = max6650_set_operating_mode(data, + max6650_pwm_modes[val]); + break; + default: + ret = -EOPNOTSUPP; + break; + } + break; + case hwmon_fan: + switch (attr) { + case hwmon_fan_div: + switch (val) { + case 1: + reg = 0; + break; + case 2: + reg = 1; + break; + case 4: + reg = 2; + break; + case 8: + reg = 3; + break; + default: + ret = -EINVAL; + goto error; + } + ret = i2c_smbus_write_byte_data(data->client, + MAX6650_REG_COUNT, reg); + if (ret) + break; + data->count = reg; + break; + case hwmon_fan_target: + if (val < 0) { + ret = -EINVAL; + break; + } + ret = max6650_set_target(data, val); + break; + default: + ret = -EOPNOTSUPP; + break; + } + break; + default: + ret = -EOPNOTSUPP; + break; + } + +error: + mutex_unlock(&data->update_lock); + return ret; +} + +static umode_t max6650_is_visible(const void *_data, + enum hwmon_sensor_types type, u32 attr, + int channel) +{ + const struct max6650_data *data = _data; + + if (channel && (channel >= data->nr_fans || type != hwmon_fan)) + return 0; + + switch (type) { + case hwmon_fan: + switch (attr) { + case hwmon_fan_input: + return 0444; + case hwmon_fan_target: + case hwmon_fan_div: + return 0644; + case hwmon_fan_min_alarm: + if (data->alarm_en & MAX6650_ALRM_MIN) + return 0444; + break; + case hwmon_fan_max_alarm: + if (data->alarm_en & MAX6650_ALRM_MAX) + return 0444; + break; + case hwmon_fan_fault: + if (data->alarm_en & MAX6650_ALRM_TACH) + return 0444; + break; + default: + break; + } + break; + case hwmon_pwm: + switch (attr) { + case hwmon_pwm_input: + case hwmon_pwm_enable: + return 0644; + default: + break; + } + break; + default: + break; + } + return 0; +} + +static const struct hwmon_channel_info *max6650_info[] = { + HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_DIV | + HWMON_F_MIN_ALARM | HWMON_F_MAX_ALARM | + HWMON_F_FAULT, + HWMON_F_INPUT, HWMON_F_INPUT, HWMON_F_INPUT), + HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_ENABLE), + NULL +}; + +static const struct hwmon_ops max6650_hwmon_ops = { + .read = max6650_read, + .write = max6650_write, + .is_visible = max6650_is_visible, +}; + +static const struct hwmon_chip_info max6650_chip_info = { + .ops = &max6650_hwmon_ops, + .info = max6650_info, +}; + +static const struct i2c_device_id max6650_id[]; + +static int max6650_probe(struct i2c_client *client) +{ + struct thermal_cooling_device *cooling_dev; + 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; + i2c_set_clientdata(client, data); + mutex_init(&data->update_lock); + data->nr_fans = of_id ? (int)(uintptr_t)of_id->data : + i2c_match_id(max6650_id, client)->driver_data; + + /* + * Initialize the max6650 chip + */ + err = max6650_init_client(data, client); + if (err) + return err; + + hwmon_dev = devm_hwmon_device_register_with_info(dev, + client->name, data, + &max6650_chip_info, + max6650_groups); + err = PTR_ERR_OR_ZERO(hwmon_dev); + if (err) + return err; + + if (IS_ENABLED(CONFIG_THERMAL)) { + cooling_dev = devm_thermal_of_cooling_device_register(dev, + dev->of_node, client->name, + data, &max6650_cooling_ops); + if (IS_ERR(cooling_dev)) { + dev_warn(dev, "thermal cooling device register failed: %ld\n", + PTR_ERR(cooling_dev)); + } + } + + return 0; +} + +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_new = max6650_probe, + .id_table = max6650_id, +}; + +module_i2c_driver(max6650_driver); + +MODULE_AUTHOR("Hans J. Koch"); +MODULE_DESCRIPTION("MAX6650 sensor driver"); +MODULE_LICENSE("GPL"); |