[PATCH] iio: pressure: ms5611: add support for MS5803 temperature and pressure sensor

[Tomasz Duszynski <tduszyns@gmail.com>]

MS5803 is factory calibrated temperature and pressure sensor capable
of providing precise 24bit measurements. Sensor supports  both I2C and SPI
and uses the same command protocol as MS5611/MS5607.

Signed-off-by: Tomasz Duszynski <tduszyns@gmail.com>
---
 drivers/iio/pressure/Kconfig       |  2 +-
 drivers/iio/pressure/ms5611.h      |  1 +
 drivers/iio/pressure/ms5611_core.c | 43 ++++++++++++++++++++++++++++++++++++++
 drivers/iio/pressure/ms5611_i2c.c  |  1 +
 drivers/iio/pressure/ms5611_spi.c  |  1 +
 5 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/pressure/Kconfig b/drivers/iio/pressure/Kconfig
index 4745179..5f339b7 100644
--- a/drivers/iio/pressure/Kconfig
+++ b/drivers/iio/pressure/Kconfig
@@ -56,7 +56,7 @@ config MS5611
 	tristate "Measurement Specialties MS5611 pressure sensor driver"
 	help
 	  Say Y here to build support for the Measurement Specialties
-	  MS5611, MS5607 pressure and temperature sensors.
+	  MS5611, MS5607, MS5803 pressure and temperature sensors.
 
 	  To compile this driver as a module, choose M here: the module will
 	  be called ms5611_core.
diff --git a/drivers/iio/pressure/ms5611.h b/drivers/iio/pressure/ms5611.h
index 23b93c7..07500b6 100644
--- a/drivers/iio/pressure/ms5611.h
+++ b/drivers/iio/pressure/ms5611.h
@@ -30,6 +30,7 @@
 enum {
 	MS5611,
 	MS5607,
+	MS5803
 };
 
 struct ms5611_chip_info {
diff --git a/drivers/iio/pressure/ms5611_core.c b/drivers/iio/pressure/ms5611_core.c
index 2f3d9b4..173d7bf 100644
--- a/drivers/iio/pressure/ms5611_core.c
+++ b/drivers/iio/pressure/ms5611_core.c
@@ -10,6 +10,7 @@
  * Data sheet:
  *  http://www.meas-spec.com/downloads/MS5611-01BA03.pdf
  *  http://www.meas-spec.com/downloads/MS5607-02BA03.pdf
+ *  http://www.meas-spec.com/downloads/MS5803-01BA.pdf
  *
  */
 
@@ -157,6 +158,45 @@ static int ms5607_temp_and_pressure_compensate(struct ms5611_chip_info *chip_inf
 	return 0;
 }
 
+static int ms5803_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info,
+					       s32 *temp, s32 *pressure)
+{
+	s32 t = *temp, p = *pressure;
+	s64 off, sens, dt, off2, sens2, t2;
+
+	dt = t - (chip_info->prom[5] << 8);
+	off = ((s64)chip_info->prom[2] << 16) + ((chip_info->prom[4] * dt) >> 7);
+	sens = ((s64)chip_info->prom[1] << 15) + ((chip_info->prom[3] * dt) >> 8);
+
+	t = 2000 + ((chip_info->prom[6] * dt) >> 23);
+	if (t < 2000) {
+		s64 tmp = (t - 2000) * (t - 2000);
+
+		t2 = (dt * dt) >> 31;
+		off2 = 3 * tmp;
+		sens2 = (7 * tmp) >> 3;
+
+		if (t < -1500)
+			sens2 += 2 * (t + 1500) * (t + 1500);
+	} else {
+		t2 = 0;
+		off2 = 0;
+		sens2 = 0;
+
+		if (t >= 4500)
+			sens2 -= ((t - 4500) * (t - 4500)) >> 3;
+	}
+
+	t -= t2;
+	off -= off2;
+	sens -= sens2;
+
+	*temp = t;
+	*pressure = (((p * sens) >> 21) - off) >> 15;
+
+	return 0;
+}
+
 static int ms5611_reset(struct iio_dev *indio_dev)
 {
 	int ret;
@@ -212,6 +252,9 @@ static struct ms5611_chip_info chip_info_tbl[] = {
 	},
 	[MS5607] = {
 		.temp_and_pressure_compensate = ms5607_temp_and_pressure_compensate,
+	},
+	[MS5803] = {
+		.temp_and_pressure_compensate = ms5803_temp_and_pressure_compensate,
 	}
 };
 
diff --git a/drivers/iio/pressure/ms5611_i2c.c b/drivers/iio/pressure/ms5611_i2c.c
index 245797d..7125055 100644
--- a/drivers/iio/pressure/ms5611_i2c.c
+++ b/drivers/iio/pressure/ms5611_i2c.c
@@ -110,6 +110,7 @@ static int ms5611_i2c_probe(struct i2c_client *client,
 static const struct i2c_device_id ms5611_id[] = {
 	{ "ms5611", MS5611 },
 	{ "ms5607", MS5607 },
+	{ "ms5803", MS5803 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, ms5611_id);
diff --git a/drivers/iio/pressure/ms5611_spi.c b/drivers/iio/pressure/ms5611_spi.c
index 08ee6e8..59a60ed 100644
--- a/drivers/iio/pressure/ms5611_spi.c
+++ b/drivers/iio/pressure/ms5611_spi.c
@@ -110,6 +110,7 @@ static int ms5611_spi_probe(struct spi_device *spi)
 static const struct spi_device_id ms5611_id[] = {
 	{ "ms5611", MS5611 },
 	{ "ms5607", MS5607 },
+	{ "ms5803", MS5803 },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, ms5611_id);
-- 
2.4.5