iio: light: add support for UVIS25 sensor

add support for STMicroelectronics UVIS25 uv sensor
http://www.st.com/resource/en/datasheet/uvis25.pdf

- continuos mode support
- i2c support
- spi support
- trigger mode support
- system PM support

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/light/Kconfig

@@ -334,6 +334,30 @@ config STK3310
 	 Choosing M will build the driver as a module. If so, the module
 	 will be called stk3310.
 
+config ST_UVIS25
+	tristate "STMicroelectronics UVIS25 sensor driver"
+	depends on (I2C || SPI)
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	select ST_UVIS25_I2C if (I2C)
+	select ST_UVIS25_SPI if (SPI_MASTER)
+	help
+	  Say yes here to build support for STMicroelectronics UVIS25
+	  uv sensor
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called st_uvis25.
+
+config ST_UVIS25_I2C
+	tristate
+	depends on ST_UVIS25
+	select REGMAP_I2C
+
+config ST_UVIS25_SPI
+	tristate
+	depends on ST_UVIS25
+	select REGMAP_SPI
+
 config TCS3414
 	tristate "TAOS TCS3414 digital color sensor"
 	depends on I2C

drivers/iio/light/Makefile

@@ -33,6 +33,9 @@ obj-$(CONFIG_RPR0521)		+= rpr0521.o
 obj-$(CONFIG_SENSORS_TSL2563)	+= tsl2563.o
 obj-$(CONFIG_SI1145)		+= si1145.o
 obj-$(CONFIG_STK3310)          += stk3310.o
+obj-$(CONFIG_ST_UVIS25)		+= st_uvis25_core.o
+obj-$(CONFIG_ST_UVIS25_I2C)	+= st_uvis25_i2c.o
+obj-$(CONFIG_ST_UVIS25_SPI)	+= st_uvis25_spi.o
 obj-$(CONFIG_TCS3414)		+= tcs3414.o
 obj-$(CONFIG_TCS3472)		+= tcs3472.o
 obj-$(CONFIG_TSL2583)		+= tsl2583.o

drivers/iio/light/st_uvis25.h

@@ -0,0 +1,37 @@
+/*
+ * STMicroelectronics uvis25 sensor driver
+ *
+ * Copyright 2017 STMicroelectronics Inc.
+ *
+ * Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#ifndef ST_UVIS25_H
+#define ST_UVIS25_H
+
+#define ST_UVIS25_DEV_NAME		"uvis25"
+
+#include <linux/iio/iio.h>
+
+/**
+ * struct st_uvis25_hw - ST UVIS25 sensor instance
+ * @regmap: Register map of the device.
+ * @trig: The trigger in use by the driver.
+ * @enabled: Status of the sensor (false->off, true->on).
+ * @irq: Device interrupt line (I2C or SPI).
+ */
+struct st_uvis25_hw {
+	struct regmap *regmap;
+
+	struct iio_trigger *trig;
+	bool enabled;
+	int irq;
+};
+
+extern const struct dev_pm_ops st_uvis25_pm_ops;
+
+int st_uvis25_probe(struct device *dev, int irq, struct regmap *regmap);
+
+#endif /* ST_UVIS25_H */