Add ms8607 meas-spec driver support

Support for MS8607 temperature, pressure & humidity sensor.
This part is using functions from MS5637 for temperature and pressure
and HTU21 for humidity

Signed-off-by: Ludovic Tancerel <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

Documentation/ABI/testing/sysfs-bus-iio-meas-spec

···
                 Reading returns either '1' or '0'. '1' means that the
                 battery level supplied to sensor is below 2.25V.
                 This ABI is available for tsys02d, htu21, ms8607
+		This ABI is available for htu21, ms8607

drivers/iio/humidity/Kconfig

···
 	help
 	  If you say yes here you get support for the Measurement Specialties
 	  HTU21 humidity and temperature sensor.
+	  This driver is also used for MS8607 temperature, pressure & humidity
+	  sensor
 
 	  This driver can also be built as a module. If so, the module will
 	  be called htu21.

drivers/iio/humidity/htu21.c

···
 /*
  * htu21.c - Support for Measurement-Specialties
  *           htu21 temperature & humidity sensor
+ *	     and humidity part of MS8607 sensor
  *
  * Copyright (c) 2014 Measurement-Specialties
  *
···
  *
  * Datasheet:
  *  http://www.meas-spec.com/downloads/HTU21D.pdf
+ * Datasheet:
+ *  http://www.meas-spec.com/downloads/MS8607-02BA01.pdf
  */
 
 #include <linux/init.h>
···
 #include "../common/ms_sensors/ms_sensors_i2c.h"
 
 #define HTU21_RESET				0xFE
+
+enum {
+	HTU21,
+	MS8607
+};
 
 static const int htu21_samp_freq[4] = { 20, 40, 70, 120 };
 /* String copy of the above const for readability purpose */
···
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
 		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	 },
+	{
+		.type = IIO_HUMIDITYRELATIVE,
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	 }
+};
+
+/*
+ * Meas Spec recommendation is to not read temperature
+ * on this driver part for MS8607
+ */
+static const struct iio_chan_spec ms8607_channels[] = {
 	{
 		.type = IIO_HUMIDITYRELATIVE,
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
···
 	indio_dev->name = id->name;
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->modes = INDIO_DIRECT_MODE;
-	indio_dev->channels = htu21_channels;
-	indio_dev->num_channels = ARRAY_SIZE(htu21_channels);
+
+	if (id->driver_data == MS8607) {
+		indio_dev->channels = ms8607_channels;
+		indio_dev->num_channels = ARRAY_SIZE(ms8607_channels);
+	} else {
+		indio_dev->channels = htu21_channels;
+		indio_dev->num_channels = ARRAY_SIZE(htu21_channels);
+	}
 
 	i2c_set_clientdata(client, indio_dev);
 
···
 }
 
 static const struct i2c_device_id htu21_id[] = {
-	{"htu21", 0},
+	{"htu21", HTU21},
+	{"ms8607-humidity", MS8607},
 	{}
 };
 

drivers/iio/pressure/Kconfig

···
 	help
 	  If you say yes here you get support for the Measurement Specialties
 	  MS5637 pressure and temperature sensor.
+	  This driver is also used for MS8607 temperature, pressure & humidity
+	  sensor
 
 	  This driver can also be built as a module. If so, the module will
 	  be called ms5637.

drivers/iio/pressure/ms5637.c

···
 /*
- * ms5637.c - Support for Measurement-Specialties ms5637
+ * ms5637.c - Support for Measurement-Specialties ms5637 and ms8607
  *            pressure & temperature sensor
  *
  * Copyright (c) 2015 Measurement-Specialties
···
  *
  * Datasheet:
  *  http://www.meas-spec.com/downloads/MS5637-02BA03.pdf
+ * Datasheet:
+ *  http://www.meas-spec.com/downloads/MS8607-02BA01.pdf
  */
+
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
···
 
 static const struct i2c_device_id ms5637_id[] = {
 	{"ms5637", 0},
+	{"ms8607-temppressure", 1},
 	{}
 };