--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Hardware monitoring driver for EMC2305 fan controller
+ *
+ * Copyright (C) 2022 Nvidia Technologies Ltd and Delta Networks, Inc.
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/thermal.h>
+#include <linux/version.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_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_PWM_MAX 5
+#define EMC2305_PWM_CHNL_CMN 0
+
+#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);
+
+static const struct of_device_id emc2305_dt_ids[] = {
+ { .compatible = "smsc,emc2305" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, emc2305_dt_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_max: maximum PWM;
+ * @pwm_min: minimum PWM;
+ * @pwm_channel: maximum number of PWM channels;
+ * @cdev_data: array of cooling devices data;
+ */
+struct emc2305_data {
+ struct i2c_client *client;
+ struct device *hwmon_dev;
+ u8 max_state;
+ u8 pwm_max;
+ u8 pwm_min;
+ u8 pwm_num;
+ u8 pwm_channel;
+ 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(struct emc2305_data *data)
+{
+ if (data->pwm_channel == EMC2305_PWM_CHNL_CMN)
+ return data->pwm_num;
+ else
+ return data->pwm_channel;
+}
+
+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;
+
+ /* Retuns 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 set as EMC2305_PWM_CHNL_CMN, 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_channel == EMC2305_PWM_CHNL_CMN)
+ 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;
+ 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, data->pwm_max);
+ if (val > EMC2305_FAN_MAX)
+ return -EINVAL;
+
+ data->cdev_data[cdev_idx].cur_state = state;
+ if (data->pwm_channel == EMC2305_PWM_CHNL_CMN)
+ /* Set the same PWM value in all channels
+ * if common PWM channel is used.
+ */
+ for (i = 0; i < data->pwm_num; i++)
+ i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(i), val);
+ else
+ i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(cdev_idx), val);
+
+ 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);
+ 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;
+ return EMC2305_RPM_FACTOR * EMC2305_TACH_CNT_MULTIPLIER / (ret > 0 ? ret : 1);
+}
+
+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;
+
+ if (val < data->pwm_min || val > data->pwm_max)
+ return -EINVAL;
+
+ i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val);
+ data->cdev_data[channel].cur_state = EMC2305_PWM_DUTY2STATE(val, data->max_state,
+ data->pwm_max);
+ return 0;
+}
+
+static int emc2305_get_tz_of(struct device *dev)
+{
+ struct device_node *np = dev->of_node;
+ struct emc2305_data *data = dev_get_drvdata(dev);
+ int ret = 0;
+
+ /* OF parameters are optional - overwrite default setting
+ * if some of them are provided.
+ */
+
+ if (of_find_property(np, "emc2305,cooling-levels", NULL)) {
+ ret = of_property_read_u8(np, "emc2305,cooling-levels", &data->max_state);
+ if (ret)
+ return ret;
+ }
+
+ if (of_find_property(np, "emc2305,pwm-max", NULL)) {
+ ret = of_property_read_u8(np, "emc2305,pwm-max", &data->pwm_max);
+ if (ret)
+ return ret;
+ }
+
+ if (of_find_property(np, "emc2305,pwm-min", NULL)) {
+ ret = of_property_read_u8(np, "emc2305,pwm-min", &data->pwm_min);
+ if (ret)
+ return ret;
+ }
+
+ /* Not defined or 0 means one thermal zone over all colling devices.
+ * Otherwise - separted thermal zones for each PWM channel.
+ */
+ if (of_find_property(np, "emc2305,pwm-channel", NULL)) {
+ ret = of_property_read_u8(np, "emc2305,pwm-channel", &data->pwm_channel);
+ if (ret)
+ return ret;
+ }
+
+ return ret;
+}
+
+static int emc2305_set_single_tz(struct device *dev, int idx)
+{
+ struct emc2305_data *data = dev_get_drvdata(dev);
+ long pwm = data->pwm_max;
+ int cdev_idx;
+
+ cdev_idx = (idx) ? idx - 1 : 0;
+
+ if (dev->of_node)
+ data->cdev_data[cdev_idx].cdev =
+ devm_thermal_of_cooling_device_register(dev, dev->of_node,
+ emc2305_fan_name[idx], data,
+ &emc2305_cooling_ops);
+ else
+ 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);
+ }
+ emc2305_set_pwm(dev, pwm, cdev_idx);
+ data->cdev_data[cdev_idx].cur_state = data->max_state;
+ /* Set minimal PWM speed. */
+ data->cdev_data[cdev_idx].last_hwmon_state = EMC2305_PWM_DUTY2STATE(data->pwm_min,
+ data->max_state,
+ data->pwm_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_channel == EMC2305_PWM_CHNL_CMN)
+ return emc2305_set_single_tz(dev, 0);
+
+ for (i = 0; i < data->pwm_channel; 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 in case they have been registered by
+ * thermal_cooling_device_unregister(). No need for clean-up flow in case they
+ * have been registered by devm_thermal_of_cooling_device_register()
+ */
+ if (!dev->of_node) {
+ 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((struct emc2305_data *)data);
+
+ /* Don't show channels which are not physically connected. */
+ if ((channel + 1) > 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);
+
+ switch (type) {
+ case hwmon_pwm:
+ switch (attr) {
+ case hwmon_pwm_input:
+ /* If thermal is configured - handle PWM limit setting. */
+ if (IS_REACHABLE(CONFIG_THERMAL)) {
+ data->cdev_data[channel].last_hwmon_state =
+ EMC2305_PWM_DUTY2STATE(val, data->max_state, data->pwm_max);
+ /* Update PWM only in case requested state is not less than the
+ * last thermal state.
+ */
+ if (data->cdev_data[channel].last_hwmon_state >=
+ data->cdev_data[channel].last_thermal_state)
+ return emc2305_set_cur_state(data->cdev_data[channel].cdev,
+ data->cdev_data[channel].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 -EINVAL;
+ }
+
+ 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;
+ 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;
+
+ data->max_state = EMC2305_FAN_MAX_STATE;
+ data->pwm_max = EMC2305_FAN_MAX;
+ data->pwm_min = EMC2305_FAN_MIN;
+ data->pwm_channel = EMC2305_PWM_CHNL_CMN;
+ if (dev->of_node) {
+ ret = emc2305_get_tz_of(dev);
+ if (ret < 0)
+ return ret;
+ }
+
+ 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++)
+ i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_MIN_DRIVE(i), data->pwm_min);
+
+ 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",
+ .of_match_table = emc2305_dt_ids,
+ },
+ .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");
projects / platform / kernel / linux-rpi.git / commitdiff