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

Heiko Stuebner
2024-07-25T19:49:08Z

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>
---
drivers/hwmon/Kconfig | 12 ++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/qnap-mcu-hwmon.c | 352 +++++++++++++++++++++++++++++++++
3 files changed, 365 insertions(+)
create mode 100644 drivers/hwmon/qnap-mcu-hwmon.c

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index e14ae18a973b3..87b6ee463a967 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1806,6 +1806,18 @@ 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 fans and temperatures sensors
+ 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 e3f25475d1f04..b72c6a059e4af 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -188,6 +188,7 @@ 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..c4925ece165e2
--- /dev/null
+++ b/drivers/hwmon/qnap-mcu-hwmon.c
@@ -0,0 +1,352 @@
+// 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/module.h>
+#include <linux/hwmon.h>
+#include <linux/mfd/qnap-mcu.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;
+
+ unsigned int pwm_value;
+ bool pwm_enabled;
+
+ 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)
+{
+ 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)) {
+ dev_err(hwm->dev, "malformed data received\n");
+ return -EIO;
+ }
+
+ return reply[4] * 450;
+}
+
+static int qnap_mcu_hwmon_update_fan(struct qnap_mcu_hwmon *hwm)
+{
+ u8 cmd[] = {
+ [0] = 0x40, /* @ */
+ [1] = 0x46, /* F */
+ [2] = 0x57, /* W */
+ [3] = 0x30, /* 0 ... fan-id? */
+ [4] = hwm->pwm_enabled ? hwm->pwm_value : 0
+ };
+
+ /* poll the fan rpm */
+ return qnap_mcu_exec_with_ack(hwm->mcu, cmd, sizeof(cmd));
+}
+
+static int qnap_mcu_hwmon_get_temp(struct qnap_mcu_hwmon *hwm)
+{
+ 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))) {
+ dev_err(hwm->dev, "malformed data received\n");
+ 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;
+}
+
+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 < hwm->pwm_min || val > hwm->pwm_max)
+ return -EINVAL;
+
+ hwm->pwm_value = val;
+ return qnap_mcu_hwmon_update_fan(hwm);
+ case hwmon_pwm_enable:
+ if (val < 0 || val > 1)
+ return -EINVAL;
+
+ hwm->pwm_enabled = val;
+ return qnap_mcu_hwmon_update_fan(hwm);
+ 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);
+
+ switch (type) {
+ case hwmon_pwm:
+ switch (attr) {
+ case hwmon_pwm_input:
+ *val = hwm->pwm_value;
+ return 0;
+ case hwmon_pwm_enable:
+ *val = hwm->pwm_enabled;
+ return 0;
+ }
+ return -EOPNOTSUPP;
+ case hwmon_fan:
+ *val = qnap_mcu_hwmon_get_rpm(hwm);
+ return 0;
+ case hwmon_temp:
+ *val = qnap_mcu_hwmon_get_temp(hwm);
+ 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;
+
+ if (hwm->fan_cooling_levels[state]) {
+ hwm->pwm_enabled = 1;
+ hwm->pwm_value = hwm->fan_cooling_levels[state];
+ } else {
+ hwm->pwm_enabled = 0;
+ }
+
+ ret = qnap_mcu_hwmon_update_fan(hwm);
+ 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 int qnap_mcu_hwmon_get_cooling_data(struct device *dev, struct qnap_mcu_hwmon *hwm)
+{
+ int num, i, ret;
+
+ if (!device_property_present(dev->parent, "cooling-levels"))
+ return 0;
+
+ ret = device_property_count_u32(dev->parent, "cooling-levels");
+ if (ret <= 0) {
+ dev_err(dev, "Wrong data!\n");
+ return ret ? : -EINVAL;
+ }
+
+ num = ret;
+ hwm->fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
+ GFP_KERNEL);
+ if (!hwm->fan_cooling_levels)
+ return -ENOMEM;
+
+ ret = device_property_read_u32_array(dev->parent, "cooling-levels",
+ hwm->fan_cooling_levels, num);
+ if (ret) {
+ dev_err(dev, "Property 'cooling-levels' cannot be read!\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;
+ }
+ }
+
+ 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_PWM_ENABLE),
+ 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 and enable PWM output as well as
+ * the regulator. In case of error nothing is changed
+ */
+ hwm->pwm_value = hwm->pwm_max;
+ hwm->pwm_enabled = 1;
+ qnap_mcu_hwmon_update_fan(hwm);
+
+ hwm->info.ops = &qnap_mcu_hwmon_hwmon_ops;
+ hwm->info.info = qnap_mcu_hwmon_channels;
+
+ 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");
+
+ ret = qnap_mcu_hwmon_get_cooling_data(dev, hwm);
+ if (ret)
+ return ret;
+
+ hwm->fan_state = hwm->fan_max_state;
+
+ if (IS_ENABLED(CONFIG_THERMAL)) {
+ cdev = devm_thermal_of_cooling_device_register(dev,
+ dev->parent->of_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");