iio: chemical: atlas-ph-sensor: add EC feature

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/devicetree/bindings/iio/chemical/atlas,ec-sm.txt

+* Atlas Scientific EC-SM OEM sensor
+
+http://www.atlas-scientific.com/_files/_datasheets/_oem/EC_oem_datasheet.pdf
+
+Required properties:
+
+  - compatible: must be "atlas,ec-sm"
+  - reg: the I2C address of the sensor
+  - interrupt-parent: should be the phandle for the interrupt controller
+  - 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,ec-sm";
+	reg = <0x64>;
+	interrupt-parent = <&gpio1>;
+	interrupts = <16 2>;
+};

drivers/iio/chemical/Kconfig

@@ -5,15 +5,17 @@
 menu "Chemical Sensors"
 
 config ATLAS_PH_SENSOR
-	tristate "Atlas Scientific OEM pH-SM sensor"
+	tristate "Atlas Scientific OEM SM sensors"
 	depends on I2C
 	select REGMAP_I2C
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
 	select IRQ_WORK
 	help
-	 Say Y here to build I2C interface support for the Atlas
-	 Scientific OEM pH-SM sensor.
+	 Say Y here to build I2C interface support for the following
+	 Atlas Scientific OEM SM sensors:
+	    * pH SM sensor
+	    * EC SM sensor
 
 	 To compile this driver as module, choose M here: the
 	 module will be called atlas-ph-sensor.

drivers/iio/chemical/atlas-ph-sensor.c

@@ -50,13 +50,28 @@
 #define ATLAS_REG_PH_CALIB_STATUS_MID	BIT(1)
 #define ATLAS_REG_PH_CALIB_STATUS_HIGH	BIT(2)
 
+#define ATLAS_REG_EC_CALIB_STATUS		0x0f
+#define ATLAS_REG_EC_CALIB_STATUS_MASK		0x0f
+#define ATLAS_REG_EC_CALIB_STATUS_DRY		BIT(0)
+#define ATLAS_REG_EC_CALIB_STATUS_SINGLE	BIT(1)
+#define ATLAS_REG_EC_CALIB_STATUS_LOW		BIT(2)
+#define ATLAS_REG_EC_CALIB_STATUS_HIGH		BIT(3)
+
 #define ATLAS_REG_PH_TEMP_DATA		0x0e
 #define ATLAS_REG_PH_DATA		0x16
 
+#define ATLAS_REG_EC_PROBE		0x08
+#define ATLAS_REG_EC_TEMP_DATA		0x10
+#define ATLAS_REG_EC_DATA		0x18
+#define ATLAS_REG_TDS_DATA		0x1c
+#define ATLAS_REG_PSS_DATA		0x20
+
 #define ATLAS_PH_INT_TIME_IN_US		450000
+#define ATLAS_EC_INT_TIME_IN_US		650000
 
 enum {
 	ATLAS_PH_SM,
+	ATLAS_EC_SM,
 };
 
 struct atlas_data {
@@ -66,12 +81,13 @@ struct atlas_data {
 	struct regmap *regmap;
 	struct irq_work work;
 
-	__be32 buffer[4]; /* 32-bit pH data + 32-bit pad + 64-bit timestamp */
+	__be32 buffer[6]; /* 96-bit data + 32-bit pad + 64-bit timestamp */
 };
 
 static const struct regmap_range atlas_volatile_ranges[] = {
 	regmap_reg_range(ATLAS_REG_INT_CONTROL, ATLAS_REG_INT_CONTROL),
 	regmap_reg_range(ATLAS_REG_PH_DATA, ATLAS_REG_PH_DATA + 4),
+	regmap_reg_range(ATLAS_REG_EC_DATA, ATLAS_REG_PSS_DATA + 4),
 };
 
 static const struct regmap_access_table atlas_volatile_table = {
@@ -86,7 +102,7 @@ static const struct regmap_config atlas_regmap_config = {
 	.val_bits = 8,
 
 	.volatile_table = &atlas_volatile_table,
-	.max_register = ATLAS_REG_PH_DATA + 4,
+	.max_register = ATLAS_REG_PSS_DATA + 4,
 	.cache_type = REGCACHE_RBTREE,
 };
 
@@ -115,6 +131,50 @@ static const struct iio_chan_spec atlas_ph_channels[] = {
 	},
 };
 
+#define ATLAS_EC_CHANNEL(_idx, _addr) \
+	{\
+		.type = IIO_CONCENTRATION, \
+		.indexed = 1, \
+		.channel = _idx, \
+		.address = _addr, \
+		.info_mask_separate = \
+			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), \
+		.scan_index = _idx + 1, \
+		.scan_type = { \
+			.sign = 'u', \
+			.realbits = 32, \
+			.storagebits = 32, \
+			.endianness = IIO_BE, \
+		}, \
+	}
+
+static const struct iio_chan_spec atlas_ec_channels[] = {
+	{
+		.type = IIO_ELECTRICALCONDUCTIVITY,
+		.address = ATLAS_REG_EC_DATA,
+		.info_mask_separate =
+			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+		.scan_index = 0,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 32,
+			.storagebits = 32,
+			.endianness = IIO_BE,
+		},
+	},
+	ATLAS_EC_CHANNEL(0, ATLAS_REG_TDS_DATA),
+	ATLAS_EC_CHANNEL(1, ATLAS_REG_PSS_DATA),
+	IIO_CHAN_SOFT_TIMESTAMP(3),
+	{
+		.type = IIO_TEMP,
+		.address = ATLAS_REG_EC_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;
@@ -142,6 +202,44 @@ static int atlas_check_ph_calibration(struct atlas_data *data)
 	return 0;
 }
 
+static int atlas_check_ec_calibration(struct atlas_data *data)
+{
+	struct device *dev = &data->client->dev;
+	int ret;
+	unsigned int val;
+
+	ret = regmap_bulk_read(data->regmap, ATLAS_REG_EC_PROBE, &val, 2);
+	if (ret)
+		return ret;
+
+	dev_info(dev, "probe set to K = %d.%.2d", be16_to_cpu(val) / 100,
+						 be16_to_cpu(val) % 100);
+
+	ret = regmap_read(data->regmap, ATLAS_REG_EC_CALIB_STATUS, &val);
+	if (ret)
+		return ret;
+
+	if (!(val & ATLAS_REG_EC_CALIB_STATUS_MASK)) {
+		dev_warn(dev, "device has not been calibrated\n");
+		return 0;
+	}
+
+	if (!(val & ATLAS_REG_EC_CALIB_STATUS_DRY))
+		dev_warn(dev, "device missing dry point calibration\n");
+
+	if (val & ATLAS_REG_EC_CALIB_STATUS_SINGLE) {
+		dev_warn(dev, "device using single point calibration\n");
+	} else {
+		if (!(val & ATLAS_REG_EC_CALIB_STATUS_LOW))
+			dev_warn(dev, "device missing low point calibration\n");
+
+		if (!(val & ATLAS_REG_EC_CALIB_STATUS_HIGH))
+			dev_warn(dev, "device missing high point calibration\n");
+	}
+
+	return 0;
+}
+
 struct atlas_device {
 	const struct iio_chan_spec *channels;
 	int num_channels;
@@ -159,6 +257,14 @@ static struct atlas_device atlas_devices[] = {
 				.calibration = &atlas_check_ph_calibration,
 				.delay = ATLAS_PH_INT_TIME_IN_US,
 	},
+	[ATLAS_EC_SM] = {
+				.channels = atlas_ec_channels,
+				.num_channels = 5,
+				.data_reg = ATLAS_REG_EC_DATA,
+				.calibration = &atlas_check_ec_calibration,
+				.delay = ATLAS_EC_INT_TIME_IN_US,
+	},
+
 };
 
 static int atlas_set_powermode(struct atlas_data *data, int on)
@@ -294,6 +400,8 @@ static int atlas_read_raw(struct iio_dev *indio_dev,
 					      (u8 *) &reg, sizeof(reg));
 			break;
 		case IIO_PH:
+		case IIO_CONCENTRATION:
+		case IIO_ELECTRICALCONDUCTIVITY:
 			mutex_lock(&indio_dev->mlock);
 
 			if (iio_buffer_enabled(indio_dev))
@@ -324,6 +432,14 @@ static int atlas_read_raw(struct iio_dev *indio_dev,
 			*val = 1; /* 0.001 */
 			*val2 = 1000;
 			break;
+		case IIO_ELECTRICALCONDUCTIVITY:
+			*val = 1; /* 0.00001 */
+			*val = 100000;
+			break;
+		case IIO_CONCENTRATION:
+			*val = 0; /* 0.000000001 */
+			*val2 = 1000;
+			return IIO_VAL_INT_PLUS_NANO;
 		default:
 			return -EINVAL;
 		}
@@ -358,12 +474,14 @@ static const struct iio_info atlas_info = {
 
 static const struct i2c_device_id atlas_id[] = {
 	{ "atlas-ph-sm", ATLAS_PH_SM},
+	{ "atlas-ec-sm", ATLAS_EC_SM},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, atlas_id);
 
 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, },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, atlas_dt_ids);