--- /dev/null
+// 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[] = { '@', 'F', '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[] = { '@', 'F', 'Z', '0' }; /* 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[] = { '@', 'F', 'W', '0', pwm }; /* 0 = fan-id?, pwm 0-255 */
+
+ /* 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[] = { '@', 'T', '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");
+ 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;
+
+ num = fwnode_property_count_u32(fwnode, "cooling-levels");
+ if (num <= 0)
+ return dev_err_probe(dev, num ? : -EINVAL,
+ "Failed to count elements in 'cooling-levels'\n");
+
+ 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)
+ return dev_err_probe(dev, ret, "Failed to read 'cooling-levels'\n");
+
+ for (i = 0; i < num; i++) {
+ if (hwm->fan_cooling_levels[i] > hwm->pwm_max)
+ return dev_err_probe(dev, -EINVAL, "fan state[%d]:%d > %d\n", i,
+ hwm->fan_cooling_levels[i], hwm->pwm_max);
+ }
+
+ 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 = pdev->dev.platform_data;
+ 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");
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