[PATCH 4/4] iio: dac: mcp4922: add support for mcp48xx series chips

[Nicolas Frattaroli <frattaroli.nicolas@gmail.com>]

The MCP4801, MCP4802, MCP4811, MCP4812, MCP4821 and MCP4822
DACs are analogous to their MCP49XX counterparts, but contain
an internal 2.048V voltage reference. Add support for them by
refactoring the driver to allow for chips without a vref supply,
and add the necessary device IDs.

Signed-off-by: Nicolas Frattaroli <frattaroli.nicolas@gmail.com>
---
 drivers/iio/dac/mcp4922.c | 112 ++++++++++++++++++++++++++++----------
 1 file changed, 84 insertions(+), 28 deletions(-)

diff --git a/drivers/iio/dac/mcp4922.c b/drivers/iio/dac/mcp4922.c
index 0b9458cbbcff..56dcb90c8464 100644
--- a/drivers/iio/dac/mcp4922.c
+++ b/drivers/iio/dac/mcp4922.c
@@ -3,7 +3,8 @@
  * mcp4922.c
  *
  * Driver for Microchip Digital to Analog Converters.
- * Supports MCP4902, MCP4912, and MCP4922.
+ * Supports MCP4902, MCP4912, MCP4921, MCP4922, MCP4801, MCP4802, MCP4811,
+ * MCP4812, MCP4821, and MCP4822.
  *
  * Copyright (c) 2014 EMAC Inc.
  */
@@ -16,14 +17,21 @@
 #include <linux/regulator/consumer.h>
 #include <linux/bitops.h>
 
-#define MCP4922_NUM_CHANNELS	2
-#define MCP4921_NUM_CHANNELS	1
+#define MCP4922_NUM_CHANNELS		2
+#define MCP4921_NUM_CHANNELS		1
+#define MCP48XX_INTERNAL_VREF_MV	2048
 
 enum mcp4922_supported_device_ids {
 	ID_MCP4902,
 	ID_MCP4912,
 	ID_MCP4921,
 	ID_MCP4922,
+	ID_MCP4801,
+	ID_MCP4802,
+	ID_MCP4811,
+	ID_MCP4812,
+	ID_MCP4821,
+	ID_MCP4822,
 };
 
 struct mcp4922_state {
@@ -50,6 +58,35 @@ struct mcp4922_state {
 	},						\
 }
 
+static bool mcp4922_needs_vref(int device_id)
+{
+	switch (device_id) {
+	case ID_MCP4902:
+	case ID_MCP4912:
+	case ID_MCP4921:
+	case ID_MCP4922:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static int mcp4922_num_channels(int device_id)
+{
+	switch (device_id) {
+	case ID_MCP4902:
+	case ID_MCP4912:
+	case ID_MCP4922:
+	case ID_MCP4802:
+	case ID_MCP4812:
+	case ID_MCP4822:
+		return MCP4922_NUM_CHANNELS;
+	default:
+		return MCP4921_NUM_CHANNELS;
+	}
+
+}
+
 static int mcp4922_spi_write(struct mcp4922_state *state, u8 addr, u32 val)
 {
 	state->mosi[1] = val & 0xff;
@@ -108,11 +145,17 @@ static int mcp4922_write_raw(struct iio_dev *indio_dev,
 	}
 }
 
-static const struct iio_chan_spec mcp4922_channels[4][MCP4922_NUM_CHANNELS] = {
+static const struct iio_chan_spec mcp4922_channels[10][MCP4922_NUM_CHANNELS] = {
 	[ID_MCP4902] = { MCP4922_CHAN(0, 8),	MCP4922_CHAN(1, 8) },
 	[ID_MCP4912] = { MCP4922_CHAN(0, 10),	MCP4922_CHAN(1, 10) },
 	[ID_MCP4921] = { MCP4922_CHAN(0, 12),	{} },
 	[ID_MCP4922] = { MCP4922_CHAN(0, 12),	MCP4922_CHAN(1, 12) },
+	[ID_MCP4801] = { MCP4922_CHAN(0, 8),	{} },
+	[ID_MCP4802] = { MCP4922_CHAN(0, 8),	MCP4922_CHAN(1, 8) },
+	[ID_MCP4811] = { MCP4922_CHAN(0, 10),	{} },
+	[ID_MCP4812] = { MCP4922_CHAN(0, 10),	MCP4922_CHAN(1, 10) },
+	[ID_MCP4821] = { MCP4922_CHAN(0, 12),	{} },
+	[ID_MCP4822] = { MCP4922_CHAN(0, 12),	MCP4922_CHAN(1, 12) },
 };
 
 static const struct iio_info mcp4922_info = {
@@ -133,25 +176,31 @@ static int mcp4922_probe(struct spi_device *spi)
 
 	state = iio_priv(indio_dev);
 	state->spi = spi;
-	state->vref_reg = devm_regulator_get(&spi->dev, "vref");
-	if (IS_ERR(state->vref_reg))
-		return dev_err_probe(&spi->dev, PTR_ERR(state->vref_reg),
-				     "Vref regulator not specified\n");
+	id = spi_get_device_id(spi);
+	if (mcp4922_needs_vref(id->driver_data)) {
+		state->vref_reg = devm_regulator_get(&spi->dev, "vref");
+		if (IS_ERR(state->vref_reg))
+			return dev_err_probe(&spi->dev, PTR_ERR(state->vref_reg),
+					"Vref regulator not specified\n");
 
-	ret = regulator_enable(state->vref_reg);
-	if (ret) {
-		dev_err(&spi->dev, "Failed to enable vref regulator: %d\n",
-				ret);
-		return ret;
-	}
+		ret = regulator_enable(state->vref_reg);
+		if (ret) {
+			dev_err(&spi->dev, "Failed to enable vref regulator: %d\n",
+					ret);
+			return ret;
+		}
 
-	ret = regulator_get_voltage(state->vref_reg);
-	if (ret < 0) {
-		dev_err(&spi->dev, "Failed to read vref regulator: %d\n",
-				ret);
-		goto error_disable_vref_reg;
+		ret = regulator_get_voltage(state->vref_reg);
+		if (ret < 0) {
+			dev_err(&spi->dev, "Failed to read vref regulator: %d\n",
+					ret);
+			goto error_disable_vref_reg;
+		}
+		state->vref_mv = ret / 1000;
+	} else {
+		state->vref_mv = MCP48XX_INTERNAL_VREF_MV;
 	}
-	state->vref_mv = ret / 1000;
+
 
 	state->vdd_reg = devm_regulator_get(&spi->dev, "vdd");
 	if (IS_ERR(state->vdd_reg)) {
@@ -167,14 +216,10 @@ static int mcp4922_probe(struct spi_device *spi)
 	}
 
 	spi_set_drvdata(spi, indio_dev);
-	id = spi_get_device_id(spi);
 	indio_dev->info = &mcp4922_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = mcp4922_channels[id->driver_data];
-	if (id->driver_data == ID_MCP4921)
-		indio_dev->num_channels = MCP4921_NUM_CHANNELS;
-	else
-		indio_dev->num_channels = MCP4922_NUM_CHANNELS;
+	indio_dev->num_channels = mcp4922_num_channels(id->driver_data);
 	indio_dev->name = id->name;
 
 	ret = iio_device_register(indio_dev);
@@ -188,7 +233,9 @@ static int mcp4922_probe(struct spi_device *spi)
 error_disable_vdd_reg:
 	regulator_disable(state->vdd_reg);
 error_disable_vref_reg:
-	regulator_disable(state->vref_reg);
+	if (mcp4922_needs_vref(id->driver_data))
+		regulator_disable(state->vref_reg);
+
 
 	return ret;
 }
@@ -197,11 +244,14 @@ static void mcp4922_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	struct mcp4922_state *state;
+	const struct spi_device_id *id = spi_get_device_id(spi);
 
 	iio_device_unregister(indio_dev);
 	state = iio_priv(indio_dev);
 	regulator_disable(state->vdd_reg);
-	regulator_disable(state->vref_reg);
+	if (mcp4922_needs_vref(id->driver_data)) {
+		regulator_disable(state->vref_reg);
+	}
 }
 
 static const struct spi_device_id mcp4922_id[] = {
@@ -209,6 +259,12 @@ static const struct spi_device_id mcp4922_id[] = {
 	{"mcp4912", ID_MCP4912},
 	{"mcp4921", ID_MCP4921},
 	{"mcp4922", ID_MCP4922},
+	{"mcp4801", ID_MCP4801},
+	{"mcp4802", ID_MCP4802},
+	{"mcp4811", ID_MCP4811},
+	{"mcp4812", ID_MCP4812},
+	{"mcp4821", ID_MCP4821},
+	{"mcp4822", ID_MCP4822},
 	{}
 };
 MODULE_DEVICE_TABLE(spi, mcp4922_id);
@@ -224,5 +280,5 @@ static struct spi_driver mcp4922_driver = {
 module_spi_driver(mcp4922_driver);
 
 MODULE_AUTHOR("Michael Welling <mwelling@ieee.org>");
-MODULE_DESCRIPTION("Microchip MCP4902, MCP4912, MCP4922 DAC");
+MODULE_DESCRIPTION("Microchip MCP49XX and MCP48XX DAC");
 MODULE_LICENSE("GPL v2");
-- 
2.40.0