iio: chemical: atlas-sensor: add DO-SM module support

diff --git a/Documentation/devicetree/bindings/iio/chemical/atlas,do-sm.txt b/Documentation/devicetree/bindings/iio/chemical/atlas,do-sm.txt
new file mode 100644
index 000000000000..fc741ea794c4
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/chemical/atlas,do-sm.txt
@@ -0,0 +1,21 @@ 
+* Atlas Scientific DO-SM OEM sensor
+
+http://www.atlas-scientific.com/_files/_datasheets/_oem/DO_oem_datasheet.pdf
+
+Required properties:
+
+  - compatible: must be "atlas,do-sm"
+  - reg: the I2C address of the sensor
+  - interrupts: the sole interrupt generated by the device
+
+  Refer to interrupt-controller/interrupts.txt for generic interrupt client
+  node bindings.
+
+Example:
+
+atlas@64 {
+	compatible = "atlas,do-sm";
+	reg = <0x67>;
+	interrupt-parent = <&gpio1>;
+	interrupts = <16 2>;
+};
diff --git a/drivers/iio/chemical/atlas-sensor.c b/drivers/iio/chemical/atlas-sensor.c
index 2f0a6fed2589..42ad1ed76144 100644
--- a/drivers/iio/chemical/atlas-sensor.c
+++ b/drivers/iio/chemical/atlas-sensor.c
@@ -48,6 +48,11 @@ 
 #define ATLAS_REG_EC_CALIB_STATUS_LOW		BIT(2)
 #define ATLAS_REG_EC_CALIB_STATUS_HIGH		BIT(3)
 
+#define ATLAS_REG_DO_CALIB_STATUS		0x09
+#define ATLAS_REG_DO_CALIB_STATUS_MASK		0x03
+#define ATLAS_REG_DO_CALIB_STATUS_PRESSURE	BIT(0)
+#define ATLAS_REG_DO_CALIB_STATUS_DO		BIT(1)
+
 #define ATLAS_REG_PH_TEMP_DATA		0x0e
 #define ATLAS_REG_PH_DATA		0x16
 
@@ -60,14 +65,19 @@ 
 #define ATLAS_REG_ORP_CALIB_STATUS	0x0d
 #define ATLAS_REG_ORP_DATA		0x0e
 
+#define ATLAS_REG_DO_TEMP_DATA		0x12
+#define ATLAS_REG_DO_DATA		0x22
+
 #define ATLAS_PH_INT_TIME_IN_MS		450
 #define ATLAS_EC_INT_TIME_IN_MS		650
 #define ATLAS_ORP_INT_TIME_IN_MS	450
+#define ATLAS_DO_INT_TIME_IN_MS		450
 
 enum {
 	ATLAS_PH_SM,
 	ATLAS_EC_SM,
 	ATLAS_ORP_SM,
+	ATLAS_DO_SM,
 };
 
 struct atlas_data {
@@ -121,7 +131,7 @@  static const struct iio_chan_spec atlas_ph_channels[] = {
 	},
 };
 
-#define ATLAS_EC_CHANNEL(_idx, _addr) \
+#define ATLAS_CONCENTRATION_CHANNEL(_idx, _addr) \
 	{\
 		.type = IIO_CONCENTRATION, \
 		.indexed = 1, \
@@ -152,8 +162,8 @@  static const struct iio_chan_spec atlas_ec_channels[] = {
 			.endianness = IIO_BE,
 		},
 	},
-	ATLAS_EC_CHANNEL(0, ATLAS_REG_TDS_DATA),
-	ATLAS_EC_CHANNEL(1, ATLAS_REG_PSS_DATA),
+	ATLAS_CONCENTRATION_CHANNEL(0, ATLAS_REG_TDS_DATA),
+	ATLAS_CONCENTRATION_CHANNEL(1, ATLAS_REG_PSS_DATA),
 	IIO_CHAN_SOFT_TIMESTAMP(3),
 	{
 		.type = IIO_TEMP,
@@ -182,6 +192,19 @@  static const struct iio_chan_spec atlas_orp_channels[] = {
 	IIO_CHAN_SOFT_TIMESTAMP(1),
 };
 
+static const struct iio_chan_spec atlas_do_channels[] = {
+	ATLAS_CONCENTRATION_CHANNEL(0, ATLAS_REG_DO_DATA),
+	IIO_CHAN_SOFT_TIMESTAMP(1),
+	{
+		.type = IIO_TEMP,
+		.address = ATLAS_REG_DO_TEMP_DATA,
+		.info_mask_separate =
+			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+		.output = 1,
+		.scan_index = -1
+	},
+};
+
 static int atlas_check_ph_calibration(struct atlas_data *data)
 {
 	struct device *dev = &data->client->dev;
@@ -262,7 +285,31 @@  static int atlas_check_orp_calibration(struct atlas_data *data)
 		dev_warn(dev, "device has not been calibrated\n");
 
 	return 0;
-};
+}
+
+static int atlas_check_do_calibration(struct atlas_data *data)
+{
+	struct device *dev = &data->client->dev;
+	int ret;
+	unsigned int val;
+
+	ret = regmap_read(data->regmap, ATLAS_REG_DO_CALIB_STATUS, &val);
+	if (ret)
+		return ret;
+
+	if (!(val & ATLAS_REG_DO_CALIB_STATUS_MASK)) {
+		dev_warn(dev, "device has not been calibrated\n");
+		return 0;
+	}
+
+	if (!(val & ATLAS_REG_DO_CALIB_STATUS_PRESSURE))
+		dev_warn(dev, "device missing atmospheric pressure calibration\n");
+
+	if (!(val & ATLAS_REG_DO_CALIB_STATUS_DO))
+		dev_warn(dev, "device missing dissolved oxygen calibration\n");
+
+	return 0;
+}
 
 struct atlas_device {
 	const struct iio_chan_spec *channels;
@@ -295,6 +342,13 @@  static struct atlas_device atlas_devices[] = {
 				.calibration = &atlas_check_orp_calibration,
 				.delay = ATLAS_ORP_INT_TIME_IN_MS,
 	},
+	[ATLAS_DO_SM] = {
+				.channels = atlas_do_channels,
+				.num_channels = 3,
+				.data_reg = ATLAS_REG_DO_DATA,
+				.calibration = &atlas_check_do_calibration,
+				.delay = ATLAS_DO_INT_TIME_IN_MS,
+	},
 };
 
 static int atlas_set_powermode(struct atlas_data *data, int on)
@@ -507,6 +561,7 @@  static const struct i2c_device_id atlas_id[] = {
 	{ "atlas-ph-sm", ATLAS_PH_SM},
 	{ "atlas-ec-sm", ATLAS_EC_SM},
 	{ "atlas-orp-sm", ATLAS_ORP_SM},
+	{ "atlas-do-sm", ATLAS_DO_SM},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, atlas_id);
@@ -515,6 +570,7 @@  static const struct of_device_id atlas_dt_ids[] = {
 	{ .compatible = "atlas,ph-sm", .data = (void *)ATLAS_PH_SM, },
 	{ .compatible = "atlas,ec-sm", .data = (void *)ATLAS_EC_SM, },
 	{ .compatible = "atlas,orp-sm", .data = (void *)ATLAS_ORP_SM, },
+	{ .compatible = "atlas,do-sm", .data = (void *)ATLAS_DO_SM, },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, atlas_dt_ids);