Add ms5637 meas-spec driver support

Support for MS5637 temperature & pressure sensor

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

drivers/iio/pressure/Kconfig

···
 	  To compile this driver as a module, choose M here: the module will
 	  be called ms5611_spi.
 
+config MS5637
+	tristate "Measurement Specialties MS5637 pressure & temperature sensor"
+	depends on I2C
+        select IIO_MS_SENSORS_I2C
+	help
+	  If you say yes here you get support for the Measurement Specialties
+	  MS5637 pressure and temperature sensor.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called ms5637.
+
 config IIO_ST_PRESS
 	tristate "STMicroelectronics pressure sensor Driver"
 	depends on (I2C || SPI_MASTER) && SYSFS

drivers/iio/pressure/Makefile

···
 obj-$(CONFIG_MS5611) += ms5611_core.o
 obj-$(CONFIG_MS5611_I2C) += ms5611_i2c.o
 obj-$(CONFIG_MS5611_SPI) += ms5611_spi.o
+obj-$(CONFIG_MS5637) += ms5637.o
 obj-$(CONFIG_IIO_ST_PRESS) += st_pressure.o
 st_pressure-y := st_pressure_core.o
 st_pressure-$(CONFIG_IIO_BUFFER) += st_pressure_buffer.o

drivers/iio/pressure/ms5637.c

···
+/*
+ * ms5637.c - Support for Measurement-Specialties ms5637
+ *            pressure & temperature sensor
+ *
+ * Copyright (c) 2015 Measurement-Specialties
+ *
+ * Licensed under the GPL-2.
+ *
+ * (7-bit I2C slave address 0x76)
+ *
+ * Datasheet:
+ *  http://www.meas-spec.com/downloads/MS5637-02BA03.pdf
+ */
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/stat.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/mutex.h>
+
+#include "../common/ms_sensors/ms_sensors_i2c.h"
+
+static const int ms5637_samp_freq[6] = { 960, 480, 240, 120, 60, 30 };
+/* String copy of the above const for readability purpose */
+static const char ms5637_show_samp_freq[] = "960 480 240 120 60 30";
+
+static int ms5637_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *channel, int *val,
+			   int *val2, long mask)
+{
+	int ret;
+	int temperature;
+	unsigned int pressure;
+	struct ms_tp_dev *dev_data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
+		ret = ms_sensors_read_temp_and_pressure(dev_data,
+							&temperature,
+							&pressure);
+		if (ret)
+			return ret;
+
+		switch (channel->type) {
+		case IIO_TEMP:	/* in milli °C */
+			*val = temperature;
+
+			return IIO_VAL_INT;
+		case IIO_PRESSURE:	/* in kPa */
+			*val = pressure / 1000;
+			*val2 = (pressure % 1000) * 1000;
+
+			return IIO_VAL_INT_PLUS_MICRO;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = ms5637_samp_freq[dev_data->res_index];
+
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ms5637_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val, int val2, long mask)
+{
+	struct ms_tp_dev *dev_data = iio_priv(indio_dev);
+	int i;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		i = ARRAY_SIZE(ms5637_samp_freq);
+		while (i-- > 0)
+			if (val == ms5637_samp_freq[i])
+				break;
+		if (i < 0)
+			return -EINVAL;
+		dev_data->res_index = i;
+
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_chan_spec ms5637_channels[] = {
+	{
+		.type = IIO_TEMP,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	},
+	{
+		.type = IIO_PRESSURE,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	}
+};
+
+static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(ms5637_show_samp_freq);
+
+static struct attribute *ms5637_attributes[] = {
+	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ms5637_attribute_group = {
+	.attrs = ms5637_attributes,
+};
+
+static const struct iio_info ms5637_info = {
+	.read_raw = ms5637_read_raw,
+	.write_raw = ms5637_write_raw,
+	.attrs = &ms5637_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
+static int ms5637_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct ms_tp_dev *dev_data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_READ_WORD_DATA |
+				     I2C_FUNC_SMBUS_WRITE_BYTE |
+				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+		dev_err(&client->dev,
+			"Adapter does not support some i2c transaction\n");
+		return -ENODEV;
+	}
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	dev_data = iio_priv(indio_dev);
+	dev_data->client = client;
+	dev_data->res_index = 5;
+	mutex_init(&dev_data->lock);
+
+	indio_dev->info = &ms5637_info;
+	indio_dev->name = id->name;
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ms5637_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ms5637_channels);
+
+	i2c_set_clientdata(client, indio_dev);
+
+	ret = ms_sensors_reset(client, 0x1E, 3000);
+	if (ret)
+		return ret;
+
+	ret = ms_sensors_tp_read_prom(dev_data);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id ms5637_id[] = {
+	{"ms5637", 0},
+	{}
+};
+
+static struct i2c_driver ms5637_driver = {
+	.probe = ms5637_probe,
+	.id_table = ms5637_id,
+	.driver = {
+		   .name = "ms5637"
+		   },
+};
+
+module_i2c_driver(ms5637_driver);
+
+MODULE_DESCRIPTION("Measurement-Specialties ms5637 temperature & pressure driver");
+MODULE_AUTHOR("William Markezana <[e-mail]>");
+MODULE_AUTHOR("Ludovic Tancerel <[e-mail]>");
+MODULE_LICENSE("GPL v2");