// 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 #include #include #include #define EMC2305_REG_DRIVE_FAIL_STATUS 0x27 #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_DEFAULT_OUTPUT 0x0 #define EMC2305_DEFAULT_POLARITY 0x0 #define EMC2305_REG_POLARITY 0x2a #define EMC2305_REG_DRIVE_PWM_OUT 0x2b #define EMC2305_OPEN_DRAIN 0x0 #define EMC2305_PUSH_PULL 0x1 #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)) /* Supported base PWM frequencies */ static const unsigned int base_freq_table[] = { 2441, 4882, 19530, 26000 }; enum emc230x_product_id { EMC2305 = 0x34, EMC2303 = 0x35, EMC2302 = 0x36, EMC2301 = 0x37, }; static const struct i2c_device_id emc2305_ids[] = { { "emc2305" }, { "emc2303" }, { "emc2302" }, { "emc2301" }, { } }; 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 thermal_cooling_device *cdev; unsigned int cur_state; unsigned long last_hwmon_state; unsigned long last_thermal_state; }; /** * 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_output_mask: PWM output mask * @pwm_polarity_mask: PWM polarity mask * @pwm_separate: separate PWM settings for every channel * @pwm_min: array of minimum PWM per channel * @pwm_freq: array of PWM frequency 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; u8 pwm_output_mask; u8 pwm_polarity_mask; bool pwm_separate; u8 pwm_min[EMC2305_PWM_MAX]; u16 pwm_freq[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 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 emc2305_data *data, int cdev_idx, unsigned long state) { int ret; struct i2c_client *client = data->client; u8 val, i; 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 int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) { int cdev_idx, ret; struct emc2305_data *data = cdev->devdata; 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; ret = __emc2305_set_cur_state(data, cdev_idx, state); 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, struct device_node *fan_node, 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 = devm_thermal_of_cooling_device_register(dev, fan_node, 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); } if (data->cdev_data[cdev_idx].cur_state > 0) /* Update pwm when temperature is above trips */ pwm = EMC2305_PWM_STATE2DUTY(data->cdev_data[cdev_idx].cur_state, data->max_state, EMC2305_FAN_MAX); /* 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(pwm, data->max_state, EMC2305_FAN_MAX); data->cdev_data[cdev_idx].last_hwmon_state = EMC2305_PWM_DUTY2STATE(pwm, 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, dev->of_node, 0); for (i = 0; i < data->pwm_num; i++) { ret = emc2305_set_single_tz(dev, dev->of_node, i + 1); if (ret) return ret; } return 0; } 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 = { .is_visible = emc2305_is_visible, .read = emc2305_read, .write = emc2305_write, }; static const struct hwmon_channel_info * const 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_of_parse_pwm_child(struct device *dev, struct device_node *child, struct emc2305_data *data) { u32 ch; int ret; struct of_phandle_args args; ret = of_property_read_u32(child, "reg", &ch); if (ret) { dev_err(dev, "missing reg property of %pOFn\n", child); return ret; } ret = of_parse_phandle_with_args(child, "pwms", "#pwm-cells", 0, &args); if (ret) return ret; if (args.args_count > 0) { data->pwm_freq[ch] = find_closest(args.args[0], base_freq_table, ARRAY_SIZE(base_freq_table)); } else { data->pwm_freq[ch] = base_freq_table[3]; } if (args.args_count > 1) { if (args.args[1] == PWM_POLARITY_NORMAL || args.args[1] == PWM_POLARITY_INVERSED) data->pwm_polarity_mask |= args.args[1] << ch; else dev_err(dev, "Wrong PWM polarity config provided: %d\n", args.args[0]); } else { data->pwm_polarity_mask |= PWM_POLARITY_NORMAL << ch; } if (args.args_count > 2) { if (args.args[2] == EMC2305_PUSH_PULL || args.args[2] <= EMC2305_OPEN_DRAIN) data->pwm_output_mask |= args.args[2] << ch; else dev_err(dev, "Wrong PWM output config provided: %d\n", args.args[1]); } else { data->pwm_output_mask |= EMC2305_OPEN_DRAIN << ch; } return 0; } static int emc2305_probe_childs_from_dt(struct device *dev) { struct emc2305_data *data = dev_get_drvdata(dev); struct device_node *child; int ret, count = 0; data->pwm_output_mask = 0x0; data->pwm_polarity_mask = 0x0; for_each_child_of_node(dev->of_node, child) { if (of_property_present(child, "reg")) { ret = emc2305_of_parse_pwm_child(dev, child, data); if (ret) { of_node_put(child); continue; } count++; } } return count; } static int emc2305_probe(struct i2c_client *client) { struct i2c_adapter *adapter = client->adapter; struct device *dev = &client->dev; struct device_node *child; struct emc2305_data *data; struct emc2305_platform_data *pdata; int vendor; int ret; int i; int pwm_childs; 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; 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; pwm_childs = emc2305_probe_childs_from_dt(dev); pdata = dev_get_platdata(&client->dev); if (!pwm_childs) { 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_output_mask = pdata->pwm_output_mask; data->pwm_polarity_mask = pdata->pwm_polarity_mask; data->pwm_separate = pdata->pwm_separate; for (i = 0; i < EMC2305_PWM_MAX; i++) { data->pwm_min[i] = pdata->pwm_min[i]; data->pwm_freq[i] = pdata->pwm_freq[i]; } } else { data->max_state = EMC2305_FAN_MAX_STATE; data->pwm_separate = false; data->pwm_output_mask = EMC2305_DEFAULT_OUTPUT; data->pwm_polarity_mask = EMC2305_DEFAULT_POLARITY; for (i = 0; i < EMC2305_PWM_MAX; i++) { data->pwm_min[i] = EMC2305_FAN_MIN; data->pwm_freq[i] = base_freq_table[3]; } } } 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)) { /* Parse and check for the available PWM child nodes */ if (pwm_childs > 0) { i = 0; for_each_child_of_node(dev->of_node, child) { ret = emc2305_set_single_tz(dev, child, i); if (ret != 0) return ret; i++; } } else { ret = emc2305_set_tz(dev); if (ret != 0) return ret; } } ret = i2c_smbus_write_byte_data(client, EMC2305_REG_DRIVE_PWM_OUT, data->pwm_output_mask); if (ret < 0) dev_err(dev, "Failed to configure pwm output, using default\n"); ret = i2c_smbus_write_byte_data(client, EMC2305_REG_POLARITY, data->pwm_polarity_mask); if (ret < 0) dev_err(dev, "Failed to configure pwm polarity, using default\n"); 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 const struct of_device_id of_emc2305_match_table[] = { { .compatible = "microchip,emc2305", }, {}, }; MODULE_DEVICE_TABLE(of, of_emc2305_match_table); static struct i2c_driver emc2305_driver = { .driver = { .name = "emc2305", .of_match_table = of_emc2305_match_table, }, .probe = emc2305_probe, .id_table = emc2305_ids, }; module_i2c_driver(emc2305_driver); MODULE_AUTHOR("Nvidia"); MODULE_DESCRIPTION("Microchip EMC2305 fan controller driver"); MODULE_LICENSE("GPL");