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- // 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>
- 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_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 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, 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_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 *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;
- 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;
- 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 void emc2305_remove(struct i2c_client *client)
- {
- struct device *dev = &client->dev;
- if (IS_REACHABLE(CONFIG_THERMAL))
- emc2305_unset_tz(dev);
- }
- 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");
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