// SPDX-License-Identifier: GPL-2.0+ /* * Hardware monitoring driver for EMC2305 fan controller * * Copyright (C) 2022 Nvidia Technologies Ltd. */ #include <linux/err.h> #include <linux/hwmon.h> #include <linux/i2c.h> #include <linux/module.h> #include <linux/platform_data/emc2305.h> #include <linux/thermal.h> #define EMC2305_REG_DRIVE_FAIL_STATUS … #define EMC2305_REG_VENDOR … #define EMC2305_FAN_MAX … #define EMC2305_FAN_MIN … #define EMC2305_FAN_MAX_STATE … #define EMC2305_DEVICE … #define EMC2305_VENDOR … #define EMC2305_REG_PRODUCT_ID … #define EMC2305_TACH_REGS_UNUSE_BITS … #define EMC2305_TACH_CNT_MULTIPLIER … #define EMC2305_TACH_RANGE_MIN … #define EMC2305_PWM_DUTY2STATE(duty, max_state, pwm_max) … #define EMC2305_PWM_STATE2DUTY(state, max_state, pwm_max) … /* * Factor by equations [2] and [3] from data sheet; valid for fans where the number of edges * equal (poles * 2 + 1). */ #define EMC2305_RPM_FACTOR … #define EMC2305_REG_FAN_DRIVE(n) … #define EMC2305_REG_FAN_MIN_DRIVE(n) … #define EMC2305_REG_FAN_TACH(n) … enum emc230x_product_id { … }; static const struct i2c_device_id emc2305_ids[] = …; MODULE_DEVICE_TABLE(i2c, emc2305_ids); /** * struct emc2305_cdev_data - device-specific cooling device state * @cdev: cooling device * @cur_state: cooling current state * @last_hwmon_state: last cooling state updated by hwmon subsystem * @last_thermal_state: last cooling state updated by thermal subsystem * * The 'last_hwmon_state' and 'last_thermal_state' fields are provided to support fan low limit * speed feature. The purpose of this feature is to provides ability to limit fan speed * according to some system wise considerations, like absence of some replaceable units (PSU or * line cards), high system ambient temperature, unreliable transceivers temperature sensing or * some other factors which indirectly impacts system's airflow * Fan low limit feature is supported through 'hwmon' interface: 'hwmon' 'pwm' attribute is * used for setting low limit for fan speed in case 'thermal' subsystem is configured in * kernel. In this case setting fan speed through 'hwmon' will never let the 'thermal' * subsystem to select a lower duty cycle than the duty cycle selected with the 'pwm' * attribute. * From other side, fan speed is to be updated in hardware through 'pwm' only in case the * requested fan speed is above last speed set by 'thermal' subsystem, otherwise requested fan * speed will be just stored with no PWM update. */ struct emc2305_cdev_data { … }; /** * struct emc2305_data - device-specific data * @client: i2c client * @hwmon_dev: hwmon device * @max_state: maximum cooling state of the cooling device * @pwm_num: number of PWM channels * @pwm_separate: separate PWM settings for every channel * @pwm_min: array of minimum PWM per channel * @cdev_data: array of cooling devices data */ struct emc2305_data { … }; static char *emc2305_fan_name[] = …; static void emc2305_unset_tz(struct device *dev); static int emc2305_get_max_channel(const struct emc2305_data *data) { … } static int emc2305_get_cdev_idx(struct thermal_cooling_device *cdev) { … } static int emc2305_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state) { … } static int emc2305_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) { … } static int __emc2305_set_cur_state(struct emc2305_data *data, int cdev_idx, unsigned long state) { … } static int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) { … } static const struct thermal_cooling_device_ops emc2305_cooling_ops = …; static int emc2305_show_fault(struct device *dev, int channel) { … } static int emc2305_show_fan(struct device *dev, int channel) { … } static int emc2305_show_pwm(struct device *dev, int channel) { … } static int emc2305_set_pwm(struct device *dev, long val, int channel) { … } static int emc2305_set_single_tz(struct device *dev, int idx) { … } static int emc2305_set_tz(struct device *dev) { … } static void emc2305_unset_tz(struct device *dev) { … } static umode_t emc2305_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel) { int max_channel = emc2305_get_max_channel(data); /* Don't show channels which are not physically connected. */ if (channel >= max_channel) return 0; switch (type) { case hwmon_fan: switch (attr) { case hwmon_fan_input: return 0444; case hwmon_fan_fault: return 0444; default: break; } break; case hwmon_pwm: switch (attr) { case hwmon_pwm_input: return 0644; default: break; } break; default: break; } return 0; }; static int emc2305_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val) { struct emc2305_data *data = dev_get_drvdata(dev); int cdev_idx; switch (type) { case hwmon_pwm: switch (attr) { case hwmon_pwm_input: /* If thermal is configured - handle PWM limit setting. */ if (IS_REACHABLE(CONFIG_THERMAL)) { if (data->pwm_separate) cdev_idx = channel; else cdev_idx = 0; data->cdev_data[cdev_idx].last_hwmon_state = EMC2305_PWM_DUTY2STATE(val, data->max_state, EMC2305_FAN_MAX); /* * Update PWM only in case requested state is not less than the * last thermal state. */ if (data->cdev_data[cdev_idx].last_hwmon_state >= data->cdev_data[cdev_idx].last_thermal_state) return __emc2305_set_cur_state(data, cdev_idx, data->cdev_data[cdev_idx].last_hwmon_state); return 0; } return emc2305_set_pwm(dev, val, channel); default: break; } break; default: break; } return -EOPNOTSUPP; }; static int emc2305_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val) { int ret; switch (type) { case hwmon_fan: switch (attr) { case hwmon_fan_input: ret = emc2305_show_fan(dev, channel); if (ret < 0) return ret; *val = ret; return 0; case hwmon_fan_fault: ret = emc2305_show_fault(dev, channel); if (ret < 0) return ret; *val = ret; return 0; default: break; } break; case hwmon_pwm: switch (attr) { case hwmon_pwm_input: ret = emc2305_show_pwm(dev, channel); if (ret < 0) return ret; *val = ret; return 0; default: break; } break; default: break; } return -EOPNOTSUPP; }; static const struct hwmon_ops emc2305_ops = …; static const struct hwmon_channel_info * const emc2305_info[] = …; static const struct hwmon_chip_info emc2305_chip_info = …; static int emc2305_identify(struct device *dev) { … } static int emc2305_probe(struct i2c_client *client) { … } static void emc2305_remove(struct i2c_client *client) { … } static struct i2c_driver emc2305_driver = …; module_i2c_driver(…) …; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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