Re: [PATCH v7 3/6] drivers: hwmon: Add the IEI WT61P803 PUZZLE HWMON driver

[Luka Kovacic <luka.kovacic@sartura.hr>]

Hello Guenter,

On Sun, Nov 8, 2020 at 5:51 PM Guenter Roeck <linux@roeck-us.net> wrote:
>
> 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).

Okay, I'll add it.

>
>
> >  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.

Okay, I can add a mutex for the buffer.

>
> 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.

Ok, I'll remove it.

>
> > +     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.

Ok, I'll move the condition to iei_wt61p803_puzzle_is_visible().

>
> > +     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");

Kind regards,
Luka