hwmon: add initial NXP MC34VR500 PMIC monitoring support

Add initial monitoring support for the MC34VR500 PMIC. In its current
state, input voltage and temperature alarms are reported to hwmon.

Datasheet:
 - https://www.nxp.com/docs/en/data-sheet/MC34VR500.pdfSigned-off-by: Mario Kicherer <dev@kicherer.org>
Link: https://lore.kernel.org/r/20230118123019.3041303-4-dev@kicherer.org
[groeck: Silence stray compiler warning, terminate struct of_device_id]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/Kconfig

@@ -1175,6 +1175,13 @@ config SENSORS_MAX31790
 	  This driver can also be built as a module. If so, the module
 	  will be called max31790.
 
+config SENSORS_MC34VR500
+	tristate "NXP MC34VR500 hardware monitoring driver"
+	depends on I2C
+	help
+	  If you say yes here you get support for the temperature and input
+	  voltage sensors of the NXP MC34VR500.
+
 config SENSORS_MCP3021
 	tristate "Microchip MCP3021 and compatibles"
 	depends on I2C

drivers/hwmon/Makefile

@@ -150,6 +150,7 @@ obj-$(CONFIG_SENSORS_MAX6650)	+= max6650.o
 obj-$(CONFIG_SENSORS_MAX6697)	+= max6697.o
 obj-$(CONFIG_SENSORS_MAX31790)	+= max31790.o
 obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
+obj-$(CONFIG_SENSORS_MC34VR500)	+= mc34vr500.o
 obj-$(CONFIG_SENSORS_MCP3021)	+= mcp3021.o
 obj-$(CONFIG_SENSORS_TC654)	+= tc654.o
 obj-$(CONFIG_SENSORS_TPS23861)	+= tps23861.o

drivers/hwmon/mc34vr500.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * An hwmon driver for the NXP MC34VR500 PMIC
+ *
+ * Author: Mario Kicherer <dev@kicherer.org>
+ */
+
+#include <linux/bits.h>
+#include <linux/dev_printk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#define MC34VR500_I2C_ADDR		0x08
+#define MC34VR500_DEVICEID_VALUE	0x14
+
+/* INTSENSE0 */
+#define ENS_BIT		BIT(0)
+#define LOWVINS_BIT	BIT(1)
+#define THERM110S_BIT	BIT(2)
+#define THERM120S_BIT	BIT(3)
+#define THERM125S_BIT	BIT(4)
+#define THERM130S_BIT	BIT(5)
+
+#define MC34VR500_DEVICEID	0x00
+
+#define MC34VR500_SILICONREVID	0x03
+#define MC34VR500_FABID		0x04
+#define MC34VR500_INTSTAT0	0x05
+#define MC34VR500_INTMASK0	0x06
+#define MC34VR500_INTSENSE0	0x07
+
+struct mc34vr500_data {
+	struct device *hwmon_dev;
+	struct regmap *regmap;
+};
+
+static irqreturn_t mc34vr500_process_interrupt(int irq, void *userdata)
+{
+	struct mc34vr500_data *data = (struct mc34vr500_data *)userdata;
+	unsigned int reg;
+	int ret;
+
+	ret = regmap_read(data->regmap, MC34VR500_INTSTAT0, &reg);
+	if (ret < 0)
+		return IRQ_HANDLED;
+
+	if (reg) {
+		if (reg & LOWVINS_BIT)
+			hwmon_notify_event(data->hwmon_dev, hwmon_in,
+					   hwmon_in_min_alarm, 0);
+
+		if (reg & THERM110S_BIT)
+			hwmon_notify_event(data->hwmon_dev, hwmon_temp,
+					   hwmon_temp_max_alarm, 0);
+
+		if (reg & THERM120S_BIT)
+			hwmon_notify_event(data->hwmon_dev, hwmon_temp,
+					   hwmon_temp_crit_alarm, 0);
+
+		if (reg & THERM130S_BIT)
+			hwmon_notify_event(data->hwmon_dev, hwmon_temp,
+					   hwmon_temp_emergency_alarm, 0);
+
+		/* write 1 to clear */
+		regmap_write(data->regmap, MC34VR500_INTSTAT0, LOWVINS_BIT |
+			     THERM110S_BIT | THERM120S_BIT | THERM130S_BIT);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static umode_t mc34vr500_is_visible(const void *data,
+				    enum hwmon_sensor_types type,
+				    u32 attr, int channel)
+{
+	switch (attr) {
+	case hwmon_in_min_alarm:
+	case hwmon_temp_max_alarm:
+	case hwmon_temp_crit_alarm:
+	case hwmon_temp_emergency_alarm:
+		return 0444;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int mc34vr500_alarm_read(struct mc34vr500_data *data, int index,
+				long *val)
+{
+	unsigned int reg;
+	int ret;
+
+	ret = regmap_read(data->regmap, MC34VR500_INTSENSE0, &reg);
+	if (ret < 0)
+		return ret;
+
+	*val = !!(reg & index);
+
+	return 0;
+}
+
+static int mc34vr500_read(struct device *dev, enum hwmon_sensor_types type,
+			  u32 attr, int channel, long *val)
+{
+	struct mc34vr500_data *data = dev_get_drvdata(dev);
+
+	switch (type) {
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_min_alarm:
+			return mc34vr500_alarm_read(data, LOWVINS_BIT, val);
+		default:
+			return -EOPNOTSUPP;
+		}
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_max_alarm:
+			return mc34vr500_alarm_read(data, THERM110S_BIT, val);
+		case hwmon_temp_crit_alarm:
+			return mc34vr500_alarm_read(data, THERM120S_BIT, val);
+		case hwmon_temp_emergency_alarm:
+			return mc34vr500_alarm_read(data, THERM130S_BIT, val);
+		default:
+			return -EOPNOTSUPP;
+		}
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static const struct hwmon_channel_info *mc34vr500_info[] = {
+	HWMON_CHANNEL_INFO(in, HWMON_I_MIN_ALARM),
+	HWMON_CHANNEL_INFO(temp, HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM
+			   | HWMON_T_EMERGENCY_ALARM),
+	NULL,
+};
+
+static const struct hwmon_ops mc34vr500_hwmon_ops = {
+	.is_visible = mc34vr500_is_visible,
+	.read = mc34vr500_read,
+};
+
+static const struct hwmon_chip_info mc34vr500_chip_info = {
+	.ops = &mc34vr500_hwmon_ops,
+	.info = mc34vr500_info,
+};
+
+static const struct regmap_config mc34vr500_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = MC34VR500_INTSENSE0,
+};
+
+static int mc34vr500_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct mc34vr500_data *data;
+	struct device *hwmon_dev;
+	int ret;
+	unsigned int reg, revid, fabid;
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_i2c(client, &mc34vr500_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	data = devm_kzalloc(dev, sizeof(struct mc34vr500_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->regmap = regmap;
+
+	ret = regmap_read(regmap, MC34VR500_DEVICEID, &reg);
+	if (ret < 0)
+		return ret;
+
+	if (reg != MC34VR500_DEVICEID_VALUE)
+		return -ENODEV;
+
+	ret = regmap_read(regmap, MC34VR500_SILICONREVID, &revid);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_read(regmap, MC34VR500_FABID, &fabid);
+	if (ret < 0)
+		return ret;
+
+	dev_dbg(dev, "mc34vr500: revid 0x%x fabid 0x%x\n", revid, fabid);
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
+							 data,
+							 &mc34vr500_chip_info,
+							 NULL);
+	if (IS_ERR(hwmon_dev))
+		return PTR_ERR(hwmon_dev);
+
+	data->hwmon_dev = hwmon_dev;
+
+	if (client->irq) {
+		ret = devm_request_threaded_irq(dev, client->irq, NULL,
+						mc34vr500_process_interrupt,
+						IRQF_TRIGGER_RISING |
+						IRQF_ONESHOT |
+						IRQF_SHARED,
+						dev_name(dev), data);
+		if (ret)
+			return ret;
+
+		/* write 1 to clear interrupts */
+		ret = regmap_write(regmap, MC34VR500_INTSTAT0, LOWVINS_BIT |
+				   THERM110S_BIT | THERM120S_BIT |
+				   THERM130S_BIT);
+		if (ret)
+			return ret;
+
+		/* unmask interrupts */
+		ret = regmap_write(regmap, MC34VR500_INTMASK0,
+				   (unsigned int) ~(LOWVINS_BIT | THERM110S_BIT |
+						    THERM120S_BIT | THERM130S_BIT));
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct i2c_device_id mc34vr500_id[] = {
+	{ "mc34vr500", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, mc34vr500_id);
+
+static const struct of_device_id __maybe_unused mc34vr500_of_match[] = {
+	{ .compatible = "nxp,mc34vr500" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, mc34vr500_of_match);
+
+static struct i2c_driver mc34vr500_driver = {
+	.driver = {
+		   .name = "mc34vr500",
+		   .of_match_table = of_match_ptr(mc34vr500_of_match),
+		    },
+	.probe_new = mc34vr500_probe,
+	.id_table = mc34vr500_id,
+};
+
+module_i2c_driver(mc34vr500_driver);
+
+MODULE_AUTHOR("Mario Kicherer <dev@kicherer.org>");
+
+MODULE_DESCRIPTION("MC34VR500 driver");
+MODULE_LICENSE("GPL");