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SubjectRe: [PATCH v7 3/6] drivers: hwmon: Add the IEI WT61P803 PUZZLE HWMON driver
On Sun, Oct 25, 2020 at 02:59:13AM +0200, Luka Kovacic wrote:
> Add the IEI WT61P803 PUZZLE HWMON driver, that handles the fan speed
> control via PWM, reading fan speed and reading on-board temperature
> sensors.
>
> The driver registers a HWMON device and a simple thermal cooling device to
> enable in-kernel fan management.
>
> This driver depends on the IEI WT61P803 PUZZLE MFD driver.
>
> Signed-off-by: Luka Kovacic <luka.kovacic@sartura.hr>
> Cc: Luka Perkov <luka.perkov@sartura.hr>
> Cc: Robert Marko <robert.marko@sartura.hr>
> ---
> drivers/hwmon/Kconfig | 8 +
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/iei-wt61p803-puzzle-hwmon.c | 412 ++++++++++++++++++++++

This requires documentation (Documentation/hwmon/iei-wt61p803-puzzle.rst).

> 3 files changed, 421 insertions(+)
> create mode 100644 drivers/hwmon/iei-wt61p803-puzzle-hwmon.c
>
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 8dc28b26916e..e0469384af2a 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -722,6 +722,14 @@ config SENSORS_IBMPOWERNV
> This driver can also be built as a module. If so, the module
> will be called ibmpowernv.
>
> +config SENSORS_IEI_WT61P803_PUZZLE_HWMON
> + tristate "IEI WT61P803 PUZZLE MFD HWMON Driver"
> + depends on MFD_IEI_WT61P803_PUZZLE
> + help
> + The IEI WT61P803 PUZZLE MFD HWMON Driver handles reading fan speed
> + and writing fan PWM values. It also supports reading on-board
> + temperature sensors.
> +
> config SENSORS_IIO_HWMON
> tristate "Hwmon driver that uses channels specified via iio maps"
> depends on IIO
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index a8f4b35b136b..b0afb2d6896f 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -83,6 +83,7 @@ obj-$(CONFIG_SENSORS_HIH6130) += hih6130.o
> obj-$(CONFIG_SENSORS_ULTRA45) += ultra45_env.o
> obj-$(CONFIG_SENSORS_I5500) += i5500_temp.o
> obj-$(CONFIG_SENSORS_I5K_AMB) += i5k_amb.o
> +obj-$(CONFIG_SENSORS_IEI_WT61P803_PUZZLE_HWMON) += iei-wt61p803-puzzle-hwmon.o
> obj-$(CONFIG_SENSORS_IBMAEM) += ibmaem.o
> obj-$(CONFIG_SENSORS_IBMPEX) += ibmpex.o
> obj-$(CONFIG_SENSORS_IBMPOWERNV)+= ibmpowernv.o
> diff --git a/drivers/hwmon/iei-wt61p803-puzzle-hwmon.c b/drivers/hwmon/iei-wt61p803-puzzle-hwmon.c
> new file mode 100644
> index 000000000000..61b06c9e61df
> --- /dev/null
> +++ b/drivers/hwmon/iei-wt61p803-puzzle-hwmon.c
> @@ -0,0 +1,412 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* IEI WT61P803 PUZZLE MCU HWMON Driver
> + *
> + * Copyright (C) 2020 Sartura Ltd.
> + * Author: Luka Kovacic <luka.kovacic@sartura.hr>
> + */
> +
> +#include <linux/err.h>
> +#include <linux/hwmon-sysfs.h>

Unnecessary include.

> +#include <linux/hwmon.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/math64.h>
> +#include <linux/mfd/iei-wt61p803-puzzle.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/slab.h>
> +#include <linux/thermal.h>
> +
> +#define IEI_WT61P803_PUZZLE_HWMON_MAX_TEMP 2
> +#define IEI_WT61P803_PUZZLE_HWMON_MAX_FAN 5
> +#define IEI_WT61P803_PUZZLE_HWMON_MAX_PWM 2
> +#define IEI_WT61P803_PUZZLE_HWMON_MAX_PWM_VAL 255
> +
> +/**
> + * struct iei_wt61p803_puzzle_thermal_cooling_device - Thermal cooling device instance
> + * @mcu_hwmon: Parent driver struct pointer
> + * @tcdev: Thermal cooling device pointer
> + * @name: Thermal cooling device name
> + * @pwm_channel: Controlled PWM channel (0 or 1)
> + * @cooling_levels: Thermal cooling device cooling levels (DT)
> + */
> +struct iei_wt61p803_puzzle_thermal_cooling_device {
> + struct iei_wt61p803_puzzle_hwmon *mcu_hwmon;
> + struct thermal_cooling_device *tcdev;
> + char name[THERMAL_NAME_LENGTH];
> + int pwm_channel;
> + u8 *cooling_levels;
> +};
> +
> +/**
> + * struct iei_wt61p803_puzzle_hwmon - MCU HWMON Driver
> + * @mcu: MCU struct pointer
> + * @response_buffer Global MCU response buffer allocation
> + * @thermal_cooling_dev_present: Per-channel thermal cooling device control indicator
> + * @cdev: Per-channel thermal cooling device private structure
> + */
> +struct iei_wt61p803_puzzle_hwmon {
> + struct iei_wt61p803_puzzle *mcu;
> + unsigned char *response_buffer;
> + bool thermal_cooling_dev_present[IEI_WT61P803_PUZZLE_HWMON_MAX_PWM];
> + struct iei_wt61p803_puzzle_thermal_cooling_device
> + *cdev[IEI_WT61P803_PUZZLE_HWMON_MAX_PWM];
> +};
> +
> +#define raw_temp_to_milidegree_celsius(x) (((x) - 0x80) * 1000)
> +static int iei_wt61p803_puzzle_read_temp_sensor(struct iei_wt61p803_puzzle_hwmon *mcu_hwmon,
> + int channel, long *value)
> +{
> + unsigned char *resp_buf = mcu_hwmon->response_buffer;
> + static unsigned char temp_sensor_ntc_cmd[4] = {
> + IEI_WT61P803_PUZZLE_CMD_HEADER_START,
> + IEI_WT61P803_PUZZLE_CMD_TEMP,
> + IEI_WT61P803_PUZZLE_CMD_TEMP_ALL,
> + };
> + size_t reply_size = 0;
> + int ret;
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu_hwmon->mcu, temp_sensor_ntc_cmd,
> + sizeof(temp_sensor_ntc_cmd), resp_buf,
> + &reply_size);
> +
> + if (ret)
> + return ret;
> +
> + if (reply_size != 7)
> + return -EIO;
> +
> + /* Check the number of NTC values */
> + if (resp_buf[3] != '2')
> + return -EIO;

resp_buf always points to mcu_hwmon->response_buffer, yet the use of that buffer is
not mutex protected. This will result in race conditions all over the place
if there is more than one reader/writer.

Guenter

> +
> + *value = raw_temp_to_milidegree_celsius(resp_buf[4 + channel]);
> +
> + return 0;
> +}
> +
> +#define raw_fan_val_to_rpm(x, y) ((((x) << 8 | (y)) / 2) * 60)
> +static int iei_wt61p803_puzzle_read_fan_speed(struct iei_wt61p803_puzzle_hwmon *mcu_hwmon,
> + int channel, long *value)
> +{
> + unsigned char *resp_buf = mcu_hwmon->response_buffer;
> + unsigned char fan_speed_cmd[4] = {};
> + size_t reply_size = 0;
> + int ret;
> +
> + fan_speed_cmd[0] = IEI_WT61P803_PUZZLE_CMD_HEADER_START;
> + fan_speed_cmd[1] = IEI_WT61P803_PUZZLE_CMD_FAN;
> + fan_speed_cmd[2] = IEI_WT61P803_PUZZLE_CMD_FAN_RPM(channel);
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu_hwmon->mcu, fan_speed_cmd,
> + sizeof(fan_speed_cmd), resp_buf,
> + &reply_size);
> + if (ret)
> + return ret;
> +
> + if (reply_size != 7)
> + return -EIO;
> +
> + *value = raw_fan_val_to_rpm(resp_buf[3], resp_buf[4]);
> +
> + return 0;
> +}
> +
> +static int iei_wt61p803_puzzle_write_pwm_channel(struct iei_wt61p803_puzzle_hwmon *mcu_hwmon,
> + int channel, long pwm_set_val)
> +{
> + unsigned char *resp_buf = mcu_hwmon->response_buffer;
> + unsigned char pwm_set_cmd[6] = {};
> + size_t reply_size = 0;
> + int ret;
> +
> + pwm_set_cmd[0] = IEI_WT61P803_PUZZLE_CMD_HEADER_START;
> + pwm_set_cmd[1] = IEI_WT61P803_PUZZLE_CMD_FAN;
> + pwm_set_cmd[2] = IEI_WT61P803_PUZZLE_CMD_FAN_PWM_WRITE;
> + pwm_set_cmd[3] = IEI_WT61P803_PUZZLE_CMD_FAN_PWM(channel);
> + pwm_set_cmd[4] = (unsigned char)pwm_set_val;
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu_hwmon->mcu, pwm_set_cmd,
> + sizeof(pwm_set_cmd), resp_buf,
> + &reply_size);
> + if (ret)
> + return ret;
> +
> + if (reply_size != 3)
> + return -EIO;
> +
> + if (!(resp_buf[0] == IEI_WT61P803_PUZZLE_CMD_HEADER_START &&
> + resp_buf[1] == IEI_WT61P803_PUZZLE_CMD_RESPONSE_OK &&
> + resp_buf[2] == IEI_WT61P803_PUZZLE_CHECKSUM_RESPONSE_OK))
> + return -EIO;
> +
> + return 0;
> +}
> +
> +static int iei_wt61p803_puzzle_read_pwm_channel(struct iei_wt61p803_puzzle_hwmon *mcu_hwmon,
> + int channel, long *value)
> +{
> + unsigned char *resp_buf = mcu_hwmon->response_buffer;
> + unsigned char pwm_get_cmd[5] = {};
> + size_t reply_size = 0;
> + int ret;
> +
> + pwm_get_cmd[0] = IEI_WT61P803_PUZZLE_CMD_HEADER_START;
> + pwm_get_cmd[1] = IEI_WT61P803_PUZZLE_CMD_FAN;
> + pwm_get_cmd[2] = IEI_WT61P803_PUZZLE_CMD_FAN_PWM_READ;
> + pwm_get_cmd[3] = IEI_WT61P803_PUZZLE_CMD_FAN_PWM(channel);
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu_hwmon->mcu, pwm_get_cmd,
> + sizeof(pwm_get_cmd), resp_buf,
> + &reply_size);
> + if (ret)
> + return ret;
> +
> + if (reply_size != 5)
> + return -EIO;
> +
> + if (resp_buf[2] != IEI_WT61P803_PUZZLE_CMD_FAN_PWM_READ)
> + return -EIO;
> +
> + *value = resp_buf[3];
> +
> + return 0;
> +}
> +
> +static int iei_wt61p803_puzzle_read(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long *val)
> +{
> + struct iei_wt61p803_puzzle_hwmon *mcu_hwmon = dev_get_drvdata(dev->parent);
> +
> + switch (type) {
> + case hwmon_pwm:
> + return iei_wt61p803_puzzle_read_pwm_channel(mcu_hwmon, channel, val);
> + case hwmon_fan:
> + return iei_wt61p803_puzzle_read_fan_speed(mcu_hwmon, channel, val);
> + case hwmon_temp:
> + return iei_wt61p803_puzzle_read_temp_sensor(mcu_hwmon, channel, val);
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int iei_wt61p803_puzzle_write(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long val)
> +{
> + struct iei_wt61p803_puzzle_hwmon *mcu_hwmon = dev_get_drvdata(dev->parent);
> +
> + if (attr != hwmon_pwm_input)
> + return -EINVAL;

This check is unnecesary.

> + if (mcu_hwmon->thermal_cooling_dev_present[channel]) {
> + /*
> + * The Thermal Framework has already claimed this specific PWM
> + * channel.
> + */
> + return -EBUSY;
> + }

The sensor should not be marked as writeable in this case.
iei_wt61p803_puzzle_is_visible() should check for the condition and
mark the affected attribute(s) read-only.

> + return iei_wt61p803_puzzle_write_pwm_channel(mcu_hwmon, channel, val);
> +}
> +
> +static umode_t iei_wt61p803_puzzle_is_visible(const void *data, enum hwmon_sensor_types type,
> + u32 attr, int channel)
> +{
> + switch (type) {
> + case hwmon_pwm:
> + if (attr == hwmon_pwm_input)
> + return 0644;
> + break;
> + case hwmon_fan:
> + if (attr == hwmon_fan_input)
> + return 0444;
> + break;
> + case hwmon_temp:
> + if (attr == hwmon_temp_input)
> + return 0444;
> + break;
> + default:
> + return 0;
> + }
> +
> + return 0;
> +}
> +
> +static const struct hwmon_ops iei_wt61p803_puzzle_hwmon_ops = {
> + .is_visible = iei_wt61p803_puzzle_is_visible,
> + .read = iei_wt61p803_puzzle_read,
> + .write = iei_wt61p803_puzzle_write,
> +};
> +
> +static const struct hwmon_channel_info *iei_wt61p803_puzzle_info[] = {
> + HWMON_CHANNEL_INFO(pwm,
> + HWMON_PWM_INPUT,
> + HWMON_PWM_INPUT),
> + HWMON_CHANNEL_INFO(fan,
> + HWMON_F_INPUT,
> + HWMON_F_INPUT,
> + HWMON_F_INPUT,
> + HWMON_F_INPUT,
> + HWMON_F_INPUT),
> + HWMON_CHANNEL_INFO(temp,
> + HWMON_T_INPUT,
> + HWMON_T_INPUT),
> + NULL
> +};
> +
> +static const struct hwmon_chip_info iei_wt61p803_puzzle_chip_info = {
> + .ops = &iei_wt61p803_puzzle_hwmon_ops,
> + .info = iei_wt61p803_puzzle_info,
> +};
> +
> +static int iei_wt61p803_puzzle_get_max_state(struct thermal_cooling_device *tcdev,
> + unsigned long *state)
> +{
> + *state = IEI_WT61P803_PUZZLE_HWMON_MAX_PWM_VAL;
> +
> + return 0;
> +}
> +
> +static int iei_wt61p803_puzzle_get_cur_state(struct thermal_cooling_device *tcdev,
> + unsigned long *state)
> +{
> + struct iei_wt61p803_puzzle_thermal_cooling_device *cdev = tcdev->devdata;
> + struct iei_wt61p803_puzzle_hwmon *mcu_hwmon = cdev->mcu_hwmon;
> + long value;
> + int ret;
> +
> + ret = iei_wt61p803_puzzle_read_pwm_channel(mcu_hwmon, cdev->pwm_channel, &value);
> + if (ret)
> + return ret;
> +
> + *state = value;
> +
> + return 0;
> +}
> +
> +static int iei_wt61p803_puzzle_set_cur_state(struct thermal_cooling_device *tcdev,
> + unsigned long state)
> +{
> + struct iei_wt61p803_puzzle_thermal_cooling_device *cdev = tcdev->devdata;
> + struct iei_wt61p803_puzzle_hwmon *mcu_hwmon = cdev->mcu_hwmon;
> +
> + return iei_wt61p803_puzzle_write_pwm_channel(mcu_hwmon, cdev->pwm_channel, state);
> +}
> +
> +static const struct thermal_cooling_device_ops iei_wt61p803_puzzle_cooling_ops = {
> + .get_max_state = iei_wt61p803_puzzle_get_max_state,
> + .get_cur_state = iei_wt61p803_puzzle_get_cur_state,
> + .set_cur_state = iei_wt61p803_puzzle_set_cur_state,
> +};
> +
> +static int iei_wt61p803_puzzle_enable_thermal_cooling_dev(struct device *dev,
> + struct fwnode_handle *child,
> + struct iei_wt61p803_puzzle_hwmon *mcu_hwmon)
> +{
> + struct iei_wt61p803_puzzle_thermal_cooling_device *cdev;
> + u32 pwm_channel;
> + u8 num_levels;
> + int ret;
> +
> + ret = fwnode_property_read_u32(child, "reg", &pwm_channel);
> + if (ret)
> + return ret;
> +
> + mcu_hwmon->thermal_cooling_dev_present[pwm_channel] = true;
> +
> + num_levels = fwnode_property_count_u8(child, "cooling-levels");
> + if (!num_levels)
> + return -EINVAL;
> +
> + cdev = devm_kzalloc(dev, sizeof(*cdev), GFP_KERNEL);
> + if (!cdev)
> + return -ENOMEM;
> +
> + cdev->cooling_levels = devm_kmalloc_array(dev, num_levels, sizeof(u8), GFP_KERNEL);
> + if (!cdev->cooling_levels)
> + return -ENOMEM;
> +
> + ret = fwnode_property_read_u8_array(child, "cooling-levels",
> + cdev->cooling_levels,
> + num_levels);
> + if (ret) {
> + dev_err(dev, "Couldn't read property 'cooling-levels'");
> + return ret;
> + }
> +
> + snprintf(cdev->name, THERMAL_NAME_LENGTH, "iei_wt61p803_puzzle_%d", pwm_channel);
> +
> + cdev->tcdev = devm_thermal_of_cooling_device_register(dev, NULL, cdev->name, cdev,
> + &iei_wt61p803_puzzle_cooling_ops);
> + if (IS_ERR(cdev->tcdev))
> + return PTR_ERR(cdev->tcdev);
> +
> + cdev->mcu_hwmon = mcu_hwmon;
> + cdev->pwm_channel = pwm_channel;
> +
> + mcu_hwmon->cdev[pwm_channel] = cdev;
> +
> + return 0;
> +}
> +
> +static int iei_wt61p803_puzzle_hwmon_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev->parent);
> + struct iei_wt61p803_puzzle_hwmon *mcu_hwmon;
> + struct fwnode_handle *child;
> + struct device *hwmon_dev;
> + int ret;
> +
> + mcu_hwmon = devm_kzalloc(dev, sizeof(*mcu_hwmon), GFP_KERNEL);
> + if (!mcu_hwmon)
> + return -ENOMEM;
> +
> + mcu_hwmon->response_buffer = devm_kzalloc(dev, IEI_WT61P803_PUZZLE_BUF_SIZE, GFP_KERNEL);
> + if (!mcu_hwmon->response_buffer)
> + return -ENOMEM;
> +
> + mcu_hwmon->mcu = mcu;
> + platform_set_drvdata(pdev, mcu_hwmon);
> +
> + hwmon_dev = devm_hwmon_device_register_with_info(dev, "iei_wt61p803_puzzle",
> + mcu_hwmon,
> + &iei_wt61p803_puzzle_chip_info,
> + NULL);
> +
> + if (IS_ERR(hwmon_dev))
> + return PTR_ERR(hwmon_dev);
> +
> + /* Control fans via PWM lines via Linux Kernel */
> + if (IS_ENABLED(CONFIG_THERMAL)) {
> + device_for_each_child_node(dev, child) {
> + ret = iei_wt61p803_puzzle_enable_thermal_cooling_dev(dev, child, mcu_hwmon);
> + if (ret) {
> + dev_err(dev, "Enabling the PWM fan failed\n");
> + fwnode_handle_put(child);
> + return ret;
> + }
> + }
> + }
> + return 0;
> +}
> +
> +static const struct of_device_id iei_wt61p803_puzzle_hwmon_id_table[] = {
> + { .compatible = "iei,wt61p803-puzzle-hwmon" },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, iei_wt61p803_puzzle_hwmon_id_table);
> +
> +static struct platform_driver iei_wt61p803_puzzle_hwmon_driver = {
> + .driver = {
> + .name = "iei-wt61p803-puzzle-hwmon",
> + .of_match_table = iei_wt61p803_puzzle_hwmon_id_table,
> + },
> + .probe = iei_wt61p803_puzzle_hwmon_probe,
> +};
> +
> +module_platform_driver(iei_wt61p803_puzzle_hwmon_driver);
> +
> +MODULE_DESCRIPTION("IEI WT61P803 PUZZLE MCU HWMON Driver");
> +MODULE_AUTHOR("Luka Kovacic <luka.kovacic@sartura.hr>");
> +MODULE_LICENSE("GPL");

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