// 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 = container_of(kobj, struct device, 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 int max6650_probe(struct i2c_client *client, const struct i2c_device_id *id) { 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 : id->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 = max6650_probe, .id_table = max6650_id, }; module_i2c_driver(max6650_driver); MODULE_AUTHOR("Hans J. Koch"); MODULE_DESCRIPTION("MAX6650 sensor driver"); MODULE_LICENSE("GPL");