// SPDX-License-Identifier: GPL-2.0+ /* * Hardware monitoring driver for EMC2305 fan controller * * Copyright (C) 2022 Nvidia Technologies Ltd. */ #include #include #include #include #include #include static const unsigned short emc2305_normal_i2c[] = { 0x27, 0x2c, 0x2d, 0x2e, 0x2f, 0x4c, 0x4d, I2C_CLIENT_END }; #define EMC2305_REG_DRIVE_FAIL_STATUS 0x27 #define EMC2305_REG_DEVICE 0xfd #define EMC2305_REG_VENDOR 0xfe #define EMC2305_FAN_MAX 0xff #define EMC2305_FAN_MIN 0x00 #define EMC2305_FAN_MAX_STATE 10 #define EMC2305_DEVICE 0x34 #define EMC2305_VENDOR 0x5d #define EMC2305_REG_PRODUCT_ID 0xfd #define EMC2305_TACH_REGS_UNUSE_BITS 3 #define EMC2305_TACH_CNT_MULTIPLIER 0x02 #define EMC2305_TACH_RANGE_MIN 480 #define EMC2305_PWM_DUTY2STATE(duty, max_state, pwm_max) \ DIV_ROUND_CLOSEST((duty) * (max_state), (pwm_max)) #define EMC2305_PWM_STATE2DUTY(state, max_state, pwm_max) \ DIV_ROUND_CLOSEST((state) * (pwm_max), (max_state)) /* * 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 3932160 #define EMC2305_REG_FAN_DRIVE(n) (0x30 + 0x10 * (n)) #define EMC2305_REG_FAN_MIN_DRIVE(n) (0x38 + 0x10 * (n)) #define EMC2305_REG_FAN_TACH(n) (0x3e + 0x10 * (n)) enum emc230x_product_id { EMC2305 = 0x34, EMC2303 = 0x35, EMC2302 = 0x36, EMC2301 = 0x37, }; static const struct i2c_device_id emc2305_ids[] = { { "emc2305", 0 }, { "emc2303", 0 }, { "emc2302", 0 }, { "emc2301", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, emc2305_ids); /** * @cdev: cooling device; * @curr_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 thermal_cooling_device *cdev; unsigned int cur_state; unsigned long last_hwmon_state; unsigned long last_thermal_state; }; /** * @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 { struct i2c_client *client; struct device *hwmon_dev; u8 max_state; u8 pwm_num; bool pwm_separate; u8 pwm_min[EMC2305_PWM_MAX]; struct emc2305_cdev_data cdev_data[EMC2305_PWM_MAX]; }; static char *emc2305_fan_name[] = { "emc2305_fan", "emc2305_fan1", "emc2305_fan2", "emc2305_fan3", "emc2305_fan4", "emc2305_fan5", }; static void emc2305_unset_tz(struct device *dev); static int emc2305_get_max_channel(const struct emc2305_data *data) { return data->pwm_num; } static int emc2305_get_cdev_idx(struct thermal_cooling_device *cdev) { struct emc2305_data *data = cdev->devdata; size_t len = strlen(cdev->type); int ret; if (len <= 0) return -EINVAL; /* * Returns index of cooling device 0..4 in case of separate PWM setting. * Zero index is used in case of one common PWM setting. * If the mode is not set as pwm_separate, all PWMs are to be bound * to the common thermal zone and should work at the same speed * to perform cooling for the same thermal junction. * Otherwise, return specific channel that will be used in bound * related PWM to the thermal zone. */ if (!data->pwm_separate) return 0; ret = cdev->type[len - 1]; switch (ret) { case '1' ... '5': return ret - '1'; default: break; } return -EINVAL; } static int emc2305_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state) { int cdev_idx; struct emc2305_data *data = cdev->devdata; cdev_idx = emc2305_get_cdev_idx(cdev); if (cdev_idx < 0) return cdev_idx; *state = data->cdev_data[cdev_idx].cur_state; return 0; } static int emc2305_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) { struct emc2305_data *data = cdev->devdata; *state = data->max_state; return 0; } static int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) { int cdev_idx, ret; struct emc2305_data *data = cdev->devdata; struct i2c_client *client = data->client; u8 val, i; if (state > data->max_state) return -EINVAL; cdev_idx = emc2305_get_cdev_idx(cdev); if (cdev_idx < 0) return cdev_idx; /* Save thermal state. */ data->cdev_data[cdev_idx].last_thermal_state = state; state = max_t(unsigned long, state, data->cdev_data[cdev_idx].last_hwmon_state); val = EMC2305_PWM_STATE2DUTY(state, data->max_state, EMC2305_FAN_MAX); data->cdev_data[cdev_idx].cur_state = state; if (data->pwm_separate) { ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(cdev_idx), val); if (ret < 0) return ret; } else { /* * Set the same PWM value in all channels * if common PWM channel is used. */ for (i = 0; i < data->pwm_num; i++) { ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(i), val); if (ret < 0) return ret; } } return 0; } static const struct thermal_cooling_device_ops emc2305_cooling_ops = { .get_max_state = emc2305_get_max_state, .get_cur_state = emc2305_get_cur_state, .set_cur_state = emc2305_set_cur_state, }; static int emc2305_show_fault(struct device *dev, int channel) { struct emc2305_data *data = dev_get_drvdata(dev); struct i2c_client *client = data->client; int status_reg; status_reg = i2c_smbus_read_byte_data(client, EMC2305_REG_DRIVE_FAIL_STATUS); if (status_reg < 0) return status_reg; return status_reg & (1 << channel) ? 1 : 0; } static int emc2305_show_fan(struct device *dev, int channel) { struct emc2305_data *data = dev_get_drvdata(dev); struct i2c_client *client = data->client; int ret; ret = i2c_smbus_read_word_swapped(client, EMC2305_REG_FAN_TACH(channel)); if (ret <= 0) return ret; ret = ret >> EMC2305_TACH_REGS_UNUSE_BITS; ret = EMC2305_RPM_FACTOR / ret; if (ret <= EMC2305_TACH_RANGE_MIN) return 0; return ret * EMC2305_TACH_CNT_MULTIPLIER; } static int emc2305_show_pwm(struct device *dev, int channel) { struct emc2305_data *data = dev_get_drvdata(dev); struct i2c_client *client = data->client; return i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_DRIVE(channel)); } static int emc2305_set_pwm(struct device *dev, long val, int channel) { struct emc2305_data *data = dev_get_drvdata(dev); struct i2c_client *client = data->client; int ret; if (val < data->pwm_min[channel] || val > EMC2305_FAN_MAX) return -EINVAL; ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val); if (ret < 0) return ret; data->cdev_data[channel].cur_state = EMC2305_PWM_DUTY2STATE(val, data->max_state, EMC2305_FAN_MAX); return 0; } static int emc2305_set_single_tz(struct device *dev, int idx) { struct emc2305_data *data = dev_get_drvdata(dev); long pwm; int i, cdev_idx, ret; cdev_idx = (idx) ? idx - 1 : 0; pwm = data->pwm_min[cdev_idx]; data->cdev_data[cdev_idx].cdev = thermal_cooling_device_register(emc2305_fan_name[idx], data, &emc2305_cooling_ops); if (IS_ERR(data->cdev_data[cdev_idx].cdev)) { dev_err(dev, "Failed to register cooling device %s\n", emc2305_fan_name[idx]); return PTR_ERR(data->cdev_data[cdev_idx].cdev); } /* Set minimal PWM speed. */ if (data->pwm_separate) { ret = emc2305_set_pwm(dev, pwm, cdev_idx); if (ret < 0) return ret; } else { for (i = 0; i < data->pwm_num; i++) { ret = emc2305_set_pwm(dev, pwm, i); if (ret < 0) return ret; } } data->cdev_data[cdev_idx].cur_state = EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, EMC2305_FAN_MAX); data->cdev_data[cdev_idx].last_hwmon_state = EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state, EMC2305_FAN_MAX); return 0; } static int emc2305_set_tz(struct device *dev) { struct emc2305_data *data = dev_get_drvdata(dev); int i, ret; if (!data->pwm_separate) return emc2305_set_single_tz(dev, 0); for (i = 0; i < data->pwm_num; i++) { ret = emc2305_set_single_tz(dev, i + 1); if (ret) goto thermal_cooling_device_register_fail; } return 0; thermal_cooling_device_register_fail: emc2305_unset_tz(dev); return ret; } static void emc2305_unset_tz(struct device *dev) { struct emc2305_data *data = dev_get_drvdata(dev); int i; /* Unregister cooling device. */ for (i = 0; i < EMC2305_PWM_MAX; i++) if (data->cdev_data[i].cdev) thermal_cooling_device_unregister(data->cdev_data[i].cdev); } 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_data[cdev_idx].cdev, 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 = { .is_visible = emc2305_is_visible, .read = emc2305_read, .write = emc2305_write, }; static const struct hwmon_channel_info *emc2305_info[] = { HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_FAULT, HWMON_F_INPUT | HWMON_F_FAULT, HWMON_F_INPUT | HWMON_F_FAULT, HWMON_F_INPUT | HWMON_F_FAULT, HWMON_F_INPUT | HWMON_F_FAULT), HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT, HWMON_PWM_INPUT, HWMON_PWM_INPUT, HWMON_PWM_INPUT, HWMON_PWM_INPUT), NULL }; static const struct hwmon_chip_info emc2305_chip_info = { .ops = &emc2305_ops, .info = emc2305_info, }; static int emc2305_identify(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); struct emc2305_data *data = i2c_get_clientdata(client); int ret; ret = i2c_smbus_read_byte_data(client, EMC2305_REG_PRODUCT_ID); if (ret < 0) return ret; switch (ret) { case EMC2305: data->pwm_num = 5; break; case EMC2303: data->pwm_num = 3; break; case EMC2302: data->pwm_num = 2; break; case EMC2301: data->pwm_num = 1; break; default: return -ENODEV; } return 0; } static int emc2305_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct i2c_adapter *adapter = client->adapter; struct device *dev = &client->dev; struct emc2305_data *data; struct emc2305_platform_data *pdata; int vendor, device; int ret; int i; if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) return -ENODEV; vendor = i2c_smbus_read_byte_data(client, EMC2305_REG_VENDOR); if (vendor != EMC2305_VENDOR) return -ENODEV; device = i2c_smbus_read_byte_data(client, EMC2305_REG_DEVICE); if (device != EMC2305_DEVICE) return -ENODEV; data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; i2c_set_clientdata(client, data); data->client = client; ret = emc2305_identify(dev); if (ret) return ret; pdata = dev_get_platdata(&client->dev); if (pdata) { if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE) return -EINVAL; data->max_state = pdata->max_state; /* * Validate a number of active PWM channels. Note that * configured number can be less than the actual maximum * supported by the device. */ if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX) return -EINVAL; data->pwm_num = pdata->pwm_num; data->pwm_separate = pdata->pwm_separate; for (i = 0; i < EMC2305_PWM_MAX; i++) data->pwm_min[i] = pdata->pwm_min[i]; } else { data->max_state = EMC2305_FAN_MAX_STATE; data->pwm_separate = false; for (i = 0; i < EMC2305_PWM_MAX; i++) data->pwm_min[i] = EMC2305_FAN_MIN; } data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "emc2305", data, &emc2305_chip_info, NULL); if (IS_ERR(data->hwmon_dev)) return PTR_ERR(data->hwmon_dev); if (IS_REACHABLE(CONFIG_THERMAL)) { ret = emc2305_set_tz(dev); if (ret != 0) return ret; } for (i = 0; i < data->pwm_num; i++) { ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_MIN_DRIVE(i), data->pwm_min[i]); if (ret < 0) return ret; } return 0; } static int emc2305_remove(struct i2c_client *client) { struct device *dev = &client->dev; if (IS_REACHABLE(CONFIG_THERMAL)) emc2305_unset_tz(dev); return 0; } static struct i2c_driver emc2305_driver = { .class = I2C_CLASS_HWMON, .driver = { .name = "emc2305", }, .probe = emc2305_probe, .remove = emc2305_remove, .id_table = emc2305_ids, .address_list = emc2305_normal_i2c, }; module_i2c_driver(emc2305_driver); MODULE_AUTHOR("Nvidia"); MODULE_DESCRIPTION("Microchip EMC2305 fan controller driver"); MODULE_LICENSE("GPL");