[PATCH v1 6/9] hwmon: Add Nuvoton NCT6694 HWMON support

[Ming Yu <a0282524688@gmail.com>]

This driver supports Hardware monitor functionality for NCT6694 MFD
device based on USB interface.

Signed-off-by: Ming Yu <tmyu0@nuvoton.com>
---
 MAINTAINERS                   |   1 +
 drivers/hwmon/Kconfig         |  10 +
 drivers/hwmon/Makefile        |   1 +
 drivers/hwmon/nct6694-hwmon.c | 407 ++++++++++++++++++++++++++++++++++
 4 files changed, 419 insertions(+)
 create mode 100644 drivers/hwmon/nct6694-hwmon.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 63387c0d4ab6..2aa87ad84156 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16439,6 +16439,7 @@ M:	Ming Yu <tmyu0@nuvoton.com>
 L:	linux-kernel@vger.kernel.org
 S:	Supported
 F:	drivers/gpio/gpio-nct6694.c
+F:	drivers/hwmon/nct6694-hwmon.c
 F:	drivers/i2c/busses/i2c-nct6694.c
 F:	drivers/mfd/nct6694.c
 F:	drivers/net/can/nct6694_canfd.c
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 08a3c863f80a..740e4afe6582 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1625,6 +1625,16 @@ config SENSORS_NCT6683
 	  This driver can also be built as a module. If so, the module
 	  will be called nct6683.
 
+config SENSORS_NCT6694
+	tristate "Nuvoton NCT6694 Hardware Monitor support"
+	depends on MFD_NCT6694
+	help
+	  Say Y here to support Nuvoton NCT6694 hardware monitoring
+	  functionality.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called nct6694-hwmon.
+
 config SENSORS_NCT6775_CORE
 	tristate
 	select REGMAP
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 9554d2fdcf7b..729961176d00 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -167,6 +167,7 @@ obj-$(CONFIG_SENSORS_MLXREG_FAN) += mlxreg-fan.o
 obj-$(CONFIG_SENSORS_MENF21BMC_HWMON) += menf21bmc_hwmon.o
 obj-$(CONFIG_SENSORS_MR75203)	+= mr75203.o
 obj-$(CONFIG_SENSORS_NCT6683)	+= nct6683.o
+obj-$(CONFIG_SENSORS_NCT6694)	+= nct6694-hwmon.o
 obj-$(CONFIG_SENSORS_NCT6775_CORE) += nct6775-core.o
 nct6775-objs			:= nct6775-platform.o
 obj-$(CONFIG_SENSORS_NCT6775)	+= nct6775.o
diff --git a/drivers/hwmon/nct6694-hwmon.c b/drivers/hwmon/nct6694-hwmon.c
new file mode 100644
index 000000000000..7d7d22a650b0
--- /dev/null
+++ b/drivers/hwmon/nct6694-hwmon.c
@@ -0,0 +1,407 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NCT6694 HWMON driver based on USB interface.
+ *
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/hwmon.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/nct6694.h>
+
+#define DRVNAME "nct6694-hwmon"
+
+/* Host interface */
+#define REQUEST_RPT_MOD			0xFF
+#define REQUEST_HWMON_MOD		0x00
+
+/* Report Channel */
+#define HWMON_FIN_IDX(x)		(0x50 + ((x) * 2))
+#define HWMON_FIN_STS(x)		(0x6E + (x))
+#define HWMON_PWM_IDX(x)		(0x70 + (x))
+
+/* Message Channel*/
+/* Command 00h */
+#define REQUEST_HWMON_CMD0_LEN		0x40
+#define REQUEST_HWMON_CMD0_OFFSET	0x0000	/* OFFSET = SEL|CMD */
+#define HWMON_FIN_EN(x)			(0x04 + (x))
+#define HWMON_PWM_FREQ_IDX(x)		(0x30 + (x))
+/* Command 02h */
+#define REQUEST_HWMON_CMD2_LEN		0x90
+#define REQUEST_HWMON_CMD2_OFFSET	0x0002	/* OFFSET = SEL|CMD */
+#define HWMON_SMI_CTRL_IDX		0x00
+#define HWMON_FIN_LIMIT_IDX(x)		(0x70 + ((x) * 2))
+#define HWMON_CMD2_HYST_MASK		0x1F
+/* Command 03h */
+#define REQUEST_HWMON_CMD3_LEN		0x08
+#define REQUEST_HWMON_CMD3_OFFSET	0x0003	/* OFFSET = SEL|CMD */
+
+struct nct6694_hwmon_data {
+	struct nct6694 *nct6694;
+
+	/* Make sure read & write commands are consecutive */
+	struct mutex hwmon_lock;
+};
+
+#define NCT6694_HWMON_FAN_CONFIG (HWMON_F_ENABLE | HWMON_F_INPUT | \
+				  HWMON_F_MIN | HWMON_F_MIN_ALARM)
+#define NCT6694_HWMON_PWM_CONFIG (HWMON_PWM_INPUT | HWMON_PWM_FREQ)
+
+static const struct hwmon_channel_info *nct6694_info[] = {
+	HWMON_CHANNEL_INFO(fan,
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN0 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN1 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN2 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN3 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN4 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN5 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN6 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN7 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN8 */
+			   NCT6694_HWMON_FAN_CONFIG),	/* FIN9 */
+
+	HWMON_CHANNEL_INFO(pwm,
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM0 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM1 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM2 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM3 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM4 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM5 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM6 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM7 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM8 */
+			   NCT6694_HWMON_PWM_CONFIG),	/* PWM9 */
+	NULL
+};
+
+static int nct6694_fan_read(struct device *dev, u32 attr, int channel,
+			    long *val)
+{
+	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
+	unsigned char buf[2];
+	int ret;
+
+	switch (attr) {
+	case hwmon_fan_enable:
+		ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
+				       REQUEST_HWMON_CMD0_OFFSET,
+				       REQUEST_HWMON_CMD0_LEN,
+				       HWMON_FIN_EN(channel / 8),
+				       1, buf);
+		if (ret)
+			return -EINVAL;
+
+		*val = buf[0] & BIT(channel % 8) ? 1 : 0;
+
+		break;
+
+	case hwmon_fan_input:
+		ret = nct6694_read_msg(data->nct6694, REQUEST_RPT_MOD,
+				       HWMON_FIN_IDX(channel), 2, 0,
+				       2, buf);
+		if (ret)
+			return -EINVAL;
+
+		*val = (buf[1] | (buf[0] << 8)) & 0xFFFF;
+
+		break;
+
+	case hwmon_fan_min:
+		ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
+				       REQUEST_HWMON_CMD2_OFFSET,
+				       REQUEST_HWMON_CMD2_LEN,
+				       HWMON_FIN_LIMIT_IDX(channel),
+				       2, buf);
+		if (ret)
+			return -EINVAL;
+
+		*val = (buf[1] | (buf[0] << 8)) & 0xFFFF;
+
+		break;
+
+	case hwmon_fan_min_alarm:
+		ret = nct6694_read_msg(data->nct6694, REQUEST_RPT_MOD,
+				       HWMON_FIN_STS(channel / 8),
+				       1, 0, 1, buf);
+		if (ret)
+			return -EINVAL;
+
+		*val = buf[0] & BIT(channel % 8);
+
+		break;
+
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int nct6694_pwm_read(struct device *dev, u32 attr, int channel,
+			    long *val)
+{
+	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
+	unsigned char buf;
+	int ret;
+
+	switch (attr) {
+	case hwmon_pwm_input:
+		ret = nct6694_read_msg(data->nct6694, REQUEST_RPT_MOD,
+				       HWMON_PWM_IDX(channel),
+				       1, 0, 1, &buf);
+		if (ret)
+			return -EINVAL;
+
+		*val = buf;
+
+		break;
+	case hwmon_pwm_freq:
+		ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
+				       REQUEST_HWMON_CMD0_OFFSET,
+				       REQUEST_HWMON_CMD0_LEN,
+				       HWMON_PWM_FREQ_IDX(channel),
+				       1, &buf);
+		if (ret)
+			return -EINVAL;
+
+		*val = buf * 25000 / 255;
+
+		break;
+
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int nct6694_fan_write(struct device *dev, u32 attr, int channel,
+			     long val)
+{
+	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
+	unsigned char enable_buf[REQUEST_HWMON_CMD0_LEN] = {0};
+	unsigned char buf[REQUEST_HWMON_CMD2_LEN] = {0};
+	u16 fan_val = (u16)val;
+	int ret;
+
+	switch (attr) {
+	case hwmon_fan_enable:
+		mutex_lock(&data->hwmon_lock);
+		ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
+				       REQUEST_HWMON_CMD0_OFFSET,
+				       REQUEST_HWMON_CMD0_LEN, 0,
+				       REQUEST_HWMON_CMD0_LEN,
+				       enable_buf);
+		if (ret)
+			goto err;
+
+		if (val)
+			enable_buf[HWMON_FIN_EN(channel / 8)] |= BIT(channel % 8);
+		else
+			enable_buf[HWMON_FIN_EN(channel / 8)] &= ~BIT(channel % 8);
+
+		ret = nct6694_write_msg(data->nct6694, REQUEST_HWMON_MOD,
+					REQUEST_HWMON_CMD0_OFFSET,
+					REQUEST_HWMON_CMD0_LEN, enable_buf);
+		if (ret)
+			goto err;
+
+		break;
+
+	case hwmon_fan_min:
+		mutex_lock(&data->hwmon_lock);
+		ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
+				       REQUEST_HWMON_CMD2_OFFSET,
+				       REQUEST_HWMON_CMD2_LEN, 0,
+				       REQUEST_HWMON_CMD2_LEN, buf);
+		if (ret)
+			goto err;
+
+		buf[HWMON_FIN_LIMIT_IDX(channel)] = (u8)((fan_val >> 8) & 0xFF);
+		buf[HWMON_FIN_LIMIT_IDX(channel) + 1] = (u8)(fan_val & 0xFF);
+		ret = nct6694_write_msg(data->nct6694, REQUEST_HWMON_MOD,
+					REQUEST_HWMON_CMD2_OFFSET,
+					REQUEST_HWMON_CMD2_LEN, buf);
+		if (ret)
+			goto err;
+
+		break;
+
+	default:
+		ret = -EOPNOTSUPP;
+		goto err;
+	}
+
+err:
+	mutex_unlock(&data->hwmon_lock);
+	return ret;
+}
+
+static int nct6694_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+	switch (type) {
+	case hwmon_fan:	/* in RPM */
+		return nct6694_fan_read(dev, attr, channel, val);
+
+	case hwmon_pwm:	/* in value 0~255 */
+		return nct6694_pwm_read(dev, attr, channel, val);
+
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int nct6694_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
+{
+	switch (type) {
+	case hwmon_fan:
+		return nct6694_fan_write(dev, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static umode_t nct6694_is_visible(const void *data, enum hwmon_sensor_types type,
+				  u32 attr, int channel)
+{
+	switch (type) {
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_enable:
+		case hwmon_fan_min:
+			return 0644;
+
+		case hwmon_fan_input:
+		case hwmon_fan_min_alarm:
+			return 0444;
+
+		default:
+			return 0;
+		}
+
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+		case hwmon_pwm_freq:
+			return 0444;
+		default:
+			return 0;
+		}
+
+	default:
+		return 0;
+	}
+
+	return 0;
+}
+
+static const struct hwmon_ops nct6694_hwmon_ops = {
+	.is_visible = nct6694_is_visible,
+	.read = nct6694_read,
+	.write = nct6694_write,
+};
+
+static const struct hwmon_chip_info nct6694_chip_info = {
+	.ops = &nct6694_hwmon_ops,
+	.info = nct6694_info,
+};
+
+static int nct6694_hwmon_init(struct nct6694_hwmon_data *data)
+{
+	unsigned char buf[REQUEST_HWMON_CMD2_LEN] = {0};
+	int ret;
+
+	/* Set Fan input Real Time alarm mode */
+	mutex_lock(&data->hwmon_lock);
+	ret = nct6694_read_msg(data->nct6694, REQUEST_HWMON_MOD,
+			       REQUEST_HWMON_CMD2_OFFSET,
+			       REQUEST_HWMON_CMD2_LEN, 0,
+			       REQUEST_HWMON_CMD2_LEN, buf);
+	if (ret)
+		goto err;
+
+	buf[HWMON_SMI_CTRL_IDX] = 0x02;
+
+	ret = nct6694_write_msg(data->nct6694, REQUEST_HWMON_MOD,
+				REQUEST_HWMON_CMD2_OFFSET,
+				REQUEST_HWMON_CMD2_LEN, buf);
+	if (ret)
+		goto err;
+
+err:
+	mutex_unlock(&data->hwmon_lock);
+	return ret;
+}
+
+static int nct6694_hwmon_probe(struct platform_device *pdev)
+{
+	struct nct6694_hwmon_data *data;
+	struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
+	struct device *hwmon_dev;
+	int ret;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->nct6694 = nct6694;
+	mutex_init(&data->hwmon_lock);
+	platform_set_drvdata(pdev, data);
+
+	ret = nct6694_hwmon_init(data);
+	if (ret)
+		return -EIO;
+
+	/* Register hwmon device to HWMON framework */
+	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
+							 "nct6694", data,
+							 &nct6694_chip_info,
+							 NULL);
+	if (IS_ERR(hwmon_dev)) {
+		dev_err(&pdev->dev, "%s: Failed to register hwmon device!\n",
+			__func__);
+		return PTR_ERR(hwmon_dev);
+	}
+
+	return 0;
+}
+
+static struct platform_driver nct6694_hwmon_driver = {
+	.driver = {
+		.name	= DRVNAME,
+	},
+	.probe		= nct6694_hwmon_probe,
+};
+
+static int __init nct6694_init(void)
+{
+	int err;
+
+	err = platform_driver_register(&nct6694_hwmon_driver);
+	if (!err) {
+		if (err)
+			platform_driver_unregister(&nct6694_hwmon_driver);
+	}
+
+	return err;
+}
+subsys_initcall(nct6694_init);
+
+static void __exit nct6694_exit(void)
+{
+	platform_driver_unregister(&nct6694_hwmon_driver);
+}
+module_exit(nct6694_exit);
+
+MODULE_DESCRIPTION("USB-HWMON driver for NCT6694");
+MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
+MODULE_LICENSE("GPL");
-- 
2.34.1