Re: [PATCH v4 5/7] hwmon: add driver for the hwmon parts of qnap-mcu devices

Guenter Roeck
2024-08-13T16:04:01Z

On 8/10/24 11:47, Heiko Stuebner wrote:
> The MCU can be found on network-attached-storage devices made by QNAP
> and provides access to fan control including reading back its RPM as
> well as reading the temperature of the NAS case.
>
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> ---
> Documentation/hwmon/index.rst | 1 +
> Documentation/hwmon/qnap-mcu-hwmon.rst | 27 ++
> MAINTAINERS | 1 +
> drivers/hwmon/Kconfig | 12 +
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/qnap-mcu-hwmon.c | 392 +++++++++++++++++++++++++
> 6 files changed, 434 insertions(+)
> create mode 100644 Documentation/hwmon/qnap-mcu-hwmon.rst
> create mode 100644 drivers/hwmon/qnap-mcu-hwmon.c
>
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 913c11390a457..7adbe23f06597 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -199,6 +199,7 @@ Hardware Monitoring Kernel Drivers
> pxe1610
> pwm-fan
> q54sj108a2
> + qnap-mcu-hwmon
> raspberrypi-hwmon
> sbrmi
> sbtsi_temp
> diff --git a/Documentation/hwmon/qnap-mcu-hwmon.rst b/Documentation/hwmon/qnap-mcu-hwmon.rst
> new file mode 100644
> index 0000000000000..83407e3408f2b
> --- /dev/null
> +++ b/Documentation/hwmon/qnap-mcu-hwmon.rst
> @@ -0,0 +1,27 @@
> +.. SPDX-License-Identifier: GPL-2.0-or-later
> +
> +Kernel driver qnap-mcu-hwmon
> +============================
> +
> +This driver enables the use of the hardware monitoring and fan control
> +of the MCU used on some QNAP network attached storage devices.
> +
> +Author: Heiko Stuebner <heiko@sntech.de>
> +
> +Description
> +-----------
> +
> +The driver implements a simple interface for driving the fan controlled by
> +setting its PWM output value and exposes the fan rpm and case-temperature
> +to user space through hwmon's sysfs interface.
> +
> +The fan rotation speed returned via the optional 'fan1_input' is calculated
> +inside the MCU device.
> +
> +The driver provides the following sensor accesses in sysfs:
> +
> +=============== ======= =======================================================
> +fan1_input ro fan tachometer speed in RPM
> +pwm1 rw relative speed (0-255), 255=max. speed.
> +temp1_input ro Measured temperature in millicelsius
> +=============== ======= =======================================================
> diff --git a/MAINTAINERS b/MAINTAINERS
> index baaec814bea1b..282042e3d5f80 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -18655,6 +18655,7 @@ F: drivers/media/tuners/qm1d1c0042*
> QNAP MCU DRIVER
> M: Heiko Stuebner <heiko@sntech.de>
> S: Maintained
> +F: drivers/hwmon/qnap-mcu-hwmon.c
> F: drivers/input/misc/qnap-mcu-input.c
> F: drivers/leds/leds-qnap-mcu.c
> F: drivers/mfd/qnap-mcu.c
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index b60fe2e58ad6c..0118ad91057e0 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1793,6 +1793,18 @@ config SENSORS_PWM_FAN
> This driver can also be built as a module. If so, the module
> will be called pwm-fan.
>
> +config SENSORS_QNAP_MCU_HWMON
> + tristate "QNAP MCU hardware monitoring"
> + depends on MFD_QNAP_MCU
> + depends on THERMAL || THERMAL=n
> + help
> + Say yes here to enable support for fan and temperature sensor
> + connected to a QNAP MCU, as found in a number of QNAP network
> + attached storage devices.
> +
> + This driver can also be built as a module. If so, the module
> + will be called qnap-mcu-hwmon.
> +
> config SENSORS_RASPBERRYPI_HWMON
> tristate "Raspberry Pi voltage monitor"
> depends on RASPBERRYPI_FIRMWARE || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE)
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index b1c7056c37db5..d60f46a03cc96 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -187,6 +187,7 @@ obj-$(CONFIG_SENSORS_POWERZ) += powerz.o
> obj-$(CONFIG_SENSORS_POWR1220) += powr1220.o
> obj-$(CONFIG_SENSORS_PT5161L) += pt5161l.o
> obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o
> +obj-$(CONFIG_SENSORS_QNAP_MCU_HWMON) += qnap-mcu-hwmon.o
> obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o
> obj-$(CONFIG_SENSORS_SBTSI) += sbtsi_temp.o
> obj-$(CONFIG_SENSORS_SBRMI) += sbrmi.o
> diff --git a/drivers/hwmon/qnap-mcu-hwmon.c b/drivers/hwmon/qnap-mcu-hwmon.c
> new file mode 100644
> index 0000000000000..f106fe8b012ea
> --- /dev/null
> +++ b/drivers/hwmon/qnap-mcu-hwmon.c
> @@ -0,0 +1,392 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +/*
> + * Driver for hwmon elements found on QNAP-MCU devices
> + *
> + * Copyright (C) 2024 Heiko Stuebner <heiko@sntech.de>
> + */
> +
> +#include <linux/fwnode.h>
> +#include <linux/hwmon.h>
> +#include <linux/mfd/qnap-mcu.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/thermal.h>
> +
> +struct qnap_mcu_hwmon {
> + struct qnap_mcu *mcu;
> + struct device *dev;
> +
> + unsigned int pwm_min;
> + unsigned int pwm_max;
> +
> + struct fwnode_handle *fan_node;
> + unsigned int fan_state;
> + unsigned int fan_max_state;
> + unsigned int *fan_cooling_levels;
> +
> + struct thermal_cooling_device *cdev;
> + struct hwmon_chip_info info;
> +};
> +
> +static int qnap_mcu_hwmon_get_rpm(struct qnap_mcu_hwmon *hwm)
> +{
> + static const u8 cmd[] = {
> + [0] = 0x40, /* @ */
> + [1] = 0x46, /* F */
> + [2] = 0x41 /* A */
> + };
> + u8 reply[6];
> + int ret;
> +
> + /* poll the fan rpm */
> + ret = qnap_mcu_exec(hwm->mcu, cmd, sizeof(cmd), reply, sizeof(reply));
> + if (ret)
> + return ret;
> +
> + /* First 2 bytes must mirror the sent command */
> + if (memcmp(cmd, reply, 2))
> + return -EIO;
> +
> + return reply[4] * 30;
> +}
> +
> +static int qnap_mcu_hwmon_get_pwm(struct qnap_mcu_hwmon *hwm)
> +{
> + static const u8 cmd[] = {
> + [0] = 0x40, /* @ */
> + [1] = 0x46, /* F */
> + [2] = 0x5a, /* Z */
> + [3] = 0x30 /* 0 ... fan-id? */
> + };
> + u8 reply[4];
> + int ret;
> +
> + /* poll the fan pwm */
> + ret = qnap_mcu_exec(hwm->mcu, cmd, sizeof(cmd), reply, sizeof(reply));
> + if (ret)
> + return ret;
> +
> + /* First 3 bytes must mirror the sent command */
> + if (memcmp(cmd, reply, 3))
> + return -EIO;
> +
> + return reply[3];
> +}
> +
> +static int qnap_mcu_hwmon_set_pwm(struct qnap_mcu_hwmon *hwm, u8 pwm)
> +{
> + const u8 cmd[] = {
> + [0] = 0x40, /* @ */
> + [1] = 0x46, /* F */
> + [2] = 0x57, /* W */
> + [3] = 0x30, /* 0 ... fan-id? */
> + [4] = pwm
> + };
> +
> + /* set the fan pwm */
> + return qnap_mcu_exec_with_ack(hwm->mcu, cmd, sizeof(cmd));
> +}
> +
> +static int qnap_mcu_hwmon_get_temp(struct qnap_mcu_hwmon *hwm)
> +{
> + static const u8 cmd[] = {
> + [0] = 0x40, /* @ */
> + [1] = 0x54, /* T */
> + [2] = 0x33 /* 3 */
> + };
> + u8 reply[4];
> + int ret;
> +
> + /* poll the fan rpm */
> + ret = qnap_mcu_exec(hwm->mcu, cmd, sizeof(cmd), reply, sizeof(reply));
> + if (ret)
> + return ret;
> +
> + /* First bytes must mirror the sent command */
> + if (memcmp(cmd, reply, sizeof(cmd)))
> + return -EIO;
> +
> + /*
> + * There is an unknown bit set in bit7.
> + * Bits [6:0] report the actual temperature as returned by the
> + * original qnap firmware-tools, so just drop bit7 for now.
> + */
> + return (reply[3] & 0x7f) * 1000;
> +}
> +
> +static int qnap_mcu_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long val)
> +{
> + struct qnap_mcu_hwmon *hwm = dev_get_drvdata(dev);
> +
> + switch (attr) {
> + case hwmon_pwm_input:
> + if (val < 0 || val > 255)
> + return -EINVAL;
> +
> + if (val != 0)
> + val = clamp_val(val, hwm->pwm_min, hwm->pwm_max);
> +
> + return qnap_mcu_hwmon_set_pwm(hwm, val);
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + return 0;
> +}
> +
> +static int qnap_mcu_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long *val)
> +{
> + struct qnap_mcu_hwmon *hwm = dev_get_drvdata(dev);
> + int ret;
> +
> + switch (type) {
> + case hwmon_pwm:
> + switch (attr) {
> + case hwmon_pwm_input:
> + ret = qnap_mcu_hwmon_get_pwm(hwm);
> + if (ret < 0)
> + return ret;
> +
> + *val = ret;
> + return 0;
> + default:
> + return -EOPNOTSUPP;
> + }
> + case hwmon_fan:
> + ret = qnap_mcu_hwmon_get_rpm(hwm);
> + if (ret < 0)
> + return ret;
> +
> + *val = ret;
> + return 0;
> + case hwmon_temp:
> + ret = qnap_mcu_hwmon_get_temp(hwm);
> + if (ret < 0)
> + return ret;
> +
> + *val = ret;
> + return 0;
> + default:
> + return -EOPNOTSUPP;
> + }
> +}
> +
> +static umode_t qnap_mcu_hwmon_is_visible(const void *data,
> + enum hwmon_sensor_types type,
> + u32 attr, int channel)
> +{
> + switch (type) {
> + case hwmon_temp:
> + return 0444;
> +
> + case hwmon_pwm:
> + return 0644;
> +
> + case hwmon_fan:
> + return 0444;
> +
> + default:
> + return 0;
> + }
> +}
> +
> +static const struct hwmon_ops qnap_mcu_hwmon_hwmon_ops = {
> + .is_visible = qnap_mcu_hwmon_is_visible,
> + .read = qnap_mcu_hwmon_read,
> + .write = qnap_mcu_hwmon_write,
> +};
> +
> +/* thermal cooling device callbacks */
> +static int qnap_mcu_hwmon_get_max_state(struct thermal_cooling_device *cdev,
> + unsigned long *state)
> +{
> + struct qnap_mcu_hwmon *hwm = cdev->devdata;
> +
> + if (!hwm)
> + return -EINVAL;
> +
> + *state = hwm->fan_max_state;
> +
> + return 0;
> +}
> +
> +static int qnap_mcu_hwmon_get_cur_state(struct thermal_cooling_device *cdev,
> + unsigned long *state)
> +{
> + struct qnap_mcu_hwmon *hwm = cdev->devdata;
> +
> + if (!hwm)
> + return -EINVAL;
> +
> + *state = hwm->fan_state;
> +
> + return 0;
> +}
> +
> +static int qnap_mcu_hwmon_set_cur_state(struct thermal_cooling_device *cdev,
> + unsigned long state)
> +{
> + struct qnap_mcu_hwmon *hwm = cdev->devdata;
> + int ret;
> +
> + if (!hwm || state > hwm->fan_max_state)
> + return -EINVAL;
> +
> + if (state == hwm->fan_state)
> + return 0;
> +
> + ret = qnap_mcu_hwmon_set_pwm(hwm, hwm->fan_cooling_levels[state]);
> + if (ret)
> + return ret;
> +
> + hwm->fan_state = state;
> +
> + return ret;
> +}
> +
> +static const struct thermal_cooling_device_ops qnap_mcu_hwmon_cooling_ops = {
> + .get_max_state = qnap_mcu_hwmon_get_max_state,
> + .get_cur_state = qnap_mcu_hwmon_get_cur_state,
> + .set_cur_state = qnap_mcu_hwmon_set_cur_state,
> +};
> +
> +static void devm_fan_node_release(void *data)
> +{
> + struct qnap_mcu_hwmon *hwm = data;
> +
> + fwnode_handle_put(hwm->fan_node);
> +}
> +
> +static int qnap_mcu_hwmon_get_cooling_data(struct device *dev, struct qnap_mcu_hwmon *hwm)
> +{
> + struct fwnode_handle *fwnode;
> + int num, i, ret;
> +
> + fwnode = device_get_named_child_node(dev->parent, "fan-0");

Is the dummy "-0" index mandated somewhere ?

I don't care either way, it just seems odd. Either case,

Acked-by: Guenter Roeck <linux@roeck-us.net>

> + if (!fwnode)
> + return 0;
> +
> + /* if we found the fan-node, we're keeping it until device-unbind */
> + hwm->fan_node = fwnode;
> + ret = devm_add_action_or_reset(dev, devm_fan_node_release, hwm);
> + if (ret)
> + return ret;
> +
> + if (!fwnode_property_present(fwnode, "cooling-levels"))
> + return 0;
> +

Side note: One could argue that a sub-node with no content does not really
make sense and should be invalid.

> + ret = fwnode_property_count_u32(fwnode, "cooling-levels");
> + if (ret <= 0) {
> + dev_err(dev, "Failed to count elements in 'cooling-levels'\n");
> + return ret ? : -EINVAL;
> + }
> +
> + num = ret;

Another side note: Using ret here isn't necessary. I'd just have used
'num' directly.

> + hwm->fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
> + GFP_KERNEL);
> + if (!hwm->fan_cooling_levels)
> + return -ENOMEM;
> +
> + ret = fwnode_property_read_u32_array(fwnode, "cooling-levels",
> + hwm->fan_cooling_levels, num);
> + if (ret) {
> + dev_err(dev, "Failed to read 'cooling-levels'\n");
> + return ret;
> + }
> +
> + for (i = 0; i < num; i++) {
> + if (hwm->fan_cooling_levels[i] > hwm->pwm_max) {
> + dev_err(dev, "fan state[%d]:%d > %d\n", i,
> + hwm->fan_cooling_levels[i], hwm->pwm_max);
> + return -EINVAL;

In case you send another version, you might want to consider using dev_err_probe().

> + }
> + }
> +
> + hwm->fan_max_state = num - 1;
> +
> + return 0;
> +}
> +
> +static const struct hwmon_channel_info * const qnap_mcu_hwmon_channels[] = {
> + HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT),
> + HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
> + HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
> + NULL
> +};
> +
> +static int qnap_mcu_hwmon_probe(struct platform_device *pdev)
> +{
> + struct qnap_mcu *mcu = dev_get_drvdata(pdev->dev.parent);
> + const struct qnap_mcu_variant *variant = qnap_mcu_get_variant_data(mcu);
> + struct qnap_mcu_hwmon *hwm;
> + struct thermal_cooling_device *cdev;
> + struct device *dev = &pdev->dev;
> + struct device *hwmon;
> + int ret;
> +
> + hwm = devm_kzalloc(dev, sizeof(*hwm), GFP_KERNEL);
> + if (!hwm)
> + return -ENOMEM;
> +
> + hwm->mcu = mcu;
> + hwm->dev = &pdev->dev;
> + hwm->pwm_min = variant->fan_pwm_min;
> + hwm->pwm_max = variant->fan_pwm_max;
> +
> + platform_set_drvdata(pdev, hwm);
> +
> + /*
> + * Set duty cycle to maximum allowed.
> + */
> + ret = qnap_mcu_hwmon_set_pwm(hwm, hwm->pwm_max);
> + if (ret)
> + return ret;
> +
> + hwm->info.ops = &qnap_mcu_hwmon_hwmon_ops;
> + hwm->info.info = qnap_mcu_hwmon_channels;
> +
> + ret = qnap_mcu_hwmon_get_cooling_data(dev, hwm);
> + if (ret)
> + return ret;
> +
> + hwm->fan_state = hwm->fan_max_state;
> +
> + hwmon = devm_hwmon_device_register_with_info(dev, "qnapmcu",
> + hwm, &hwm->info, NULL);
> + if (IS_ERR(hwmon))
> + return dev_err_probe(dev, PTR_ERR(hwmon), "Failed to register hwmon device\n");
> +
> + /*
> + * Only register cooling device when we found cooling-levels.
> + * qnap_mcu_hwmon_get_cooling_data() will fail when reading malformed
> + * levels and only succeed with either no or correct cooling levels.
> + */
> + if (IS_ENABLED(CONFIG_THERMAL) && hwm->fan_cooling_levels) {
> + cdev = devm_thermal_of_cooling_device_register(dev,
> + to_of_node(hwm->fan_node), "qnap-mcu-hwmon",
> + hwm, &qnap_mcu_hwmon_cooling_ops);
> + if (IS_ERR(cdev))
> + return dev_err_probe(dev, PTR_ERR(cdev),
> + "Failed to register qnap-mcu-hwmon as cooling device\n");
> + hwm->cdev = cdev;
> + }
> +
> + return 0;
> +}
> +
> +static struct platform_driver qnap_mcu_hwmon_driver = {
> + .probe = qnap_mcu_hwmon_probe,
> + .driver = {
> + .name = "qnap-mcu-hwmon",
> + },
> +};
> +module_platform_driver(qnap_mcu_hwmon_driver);
> +
> +MODULE_ALIAS("platform:qnap-mcu-hwmon");
> +MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
> +MODULE_DESCRIPTION("QNAP MCU hwmon driver");
> +MODULE_LICENSE("GPL");