[PATCH 4/8] hwmon: Add support for Azoteq IQS620AT temperature sensor

[Jeff LaBundy <jeff@labundy.com>]

This patch adds support for the Azoteq IQS620AT temperature sensor,
capable of reporting its absolute die temperature.

Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
 drivers/hwmon/Kconfig         | 12 +++++-
 drivers/hwmon/Makefile        |  1 +
 drivers/hwmon/iqs620at-temp.c | 96 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 108 insertions(+), 1 deletion(-)
 create mode 100644 drivers/hwmon/iqs620at-temp.c

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 13a6b4a..3e56be6 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -385,6 +385,16 @@ config SENSORS_ATXP1
 	  This driver can also be built as a module. If so, the module
 	  will be called atxp1.
 
+config SENSORS_IQS620AT
+	tristate "Azoteq IQS620AT temperature sensor"
+	depends on MFD_IQS62X
+	help
+	  Say Y here if you want to build support for the Azoteq IQS620AT
+	  temperature sensor.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called iqs620at-temp.
+
 config SENSORS_DS620
 	tristate "Dallas Semiconductor DS620"
 	depends on I2C
@@ -1593,7 +1603,7 @@ config SENSORS_ADS7871
 
 config SENSORS_AMC6821
 	tristate "Texas Instruments AMC6821"
-	depends on I2C 
+	depends on I2C
 	help
 	  If you say yes here you get support for the Texas Instruments
 	  AMC6821 hardware monitoring chips.
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 40c036e..2360add 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -83,6 +83,7 @@ obj-$(CONFIG_SENSORS_IIO_HWMON) += iio_hwmon.o
 obj-$(CONFIG_SENSORS_INA209)	+= ina209.o
 obj-$(CONFIG_SENSORS_INA2XX)	+= ina2xx.o
 obj-$(CONFIG_SENSORS_INA3221)	+= ina3221.o
+obj-$(CONFIG_SENSORS_IQS620AT)	+= iqs620at-temp.o
 obj-$(CONFIG_SENSORS_IT87)	+= it87.o
 obj-$(CONFIG_SENSORS_JC42)	+= jc42.o
 obj-$(CONFIG_SENSORS_K8TEMP)	+= k8temp.o
diff --git a/drivers/hwmon/iqs620at-temp.c b/drivers/hwmon/iqs620at-temp.c
new file mode 100644
index 0000000..0af49b6
--- /dev/null
+++ b/drivers/hwmon/iqs620at-temp.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Azoteq IQS620AT Temperature Sensor
+ *
+ * Copyright (C) 2019
+ * Author: Jeff LaBundy <jeff@labundy.com>
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/kernel.h>
+#include <linux/mfd/iqs62x.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define IQS620_TEMP_UI_OUT			0x1A
+
+static umode_t iqs620_temp_is_visible(const void *drvdata,
+				      enum hwmon_sensor_types type,
+				      u32 attr, int channel)
+{
+	if (type != hwmon_temp || attr != hwmon_temp_input)
+		return 0;
+
+	return 0444;
+}
+
+static int iqs620_temp_read(struct device *dev, enum hwmon_sensor_types type,
+			    u32 attr, int channel, long *val)
+{
+	struct iqs62x_core *iqs62x = dev_get_drvdata(dev);
+	int error;
+	__le16 val_buf;
+
+	if (type != hwmon_temp || attr != hwmon_temp_input)
+		return -EINVAL;
+
+	error = regmap_raw_read(iqs62x->map, IQS620_TEMP_UI_OUT, &val_buf,
+				sizeof(val_buf));
+	if (error)
+		return error;
+
+	*val = (le16_to_cpu(val_buf) - 100) * 1000;
+
+	return 0;
+}
+
+static const struct hwmon_ops iqs620_temp_ops = {
+	.is_visible = iqs620_temp_is_visible,
+	.read = iqs620_temp_read,
+};
+
+static const struct hwmon_channel_info *iqs620_temp_channel_info[] = {
+	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+	NULL
+};
+
+static const struct hwmon_chip_info iqs620_temp_chip_info = {
+	.ops = &iqs620_temp_ops,
+	.info = iqs620_temp_channel_info,
+};
+
+static int iqs620_temp_probe(struct platform_device *pdev)
+{
+	struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);
+	struct device *hdev;
+	int error = 0;
+
+	hdev = devm_hwmon_device_register_with_info(&pdev->dev,
+						    iqs62x->dev_desc->dev_name,
+						    iqs62x,
+						    &iqs620_temp_chip_info,
+						    NULL);
+	if (IS_ERR(hdev)) {
+		error = PTR_ERR(hdev);
+		dev_err(&pdev->dev, "Failed to register device: %d\n", error);
+	}
+
+	return error;
+}
+
+static struct platform_driver iqs620_temp_platform_driver = {
+	.driver = {
+		.name	= IQS620_DRV_NAME_TEMP,
+	},
+	.probe		= iqs620_temp_probe,
+};
+module_platform_driver(iqs620_temp_platform_driver);
+
+MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
+MODULE_DESCRIPTION("Azoteq IQS620AT Temperature Sensor");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" IQS620_DRV_NAME_TEMP);
-- 
2.7.4