iio:dac:ad5686: Add AD5681R/AD5682R/AD5683/AD5683R support

The AD5681R/AD5682R/AD5683/AD5683R are a family of one channel DACs with 12-bit,
14-bit and 16-bit precision respectively. The devices have either no built-in reference,
or built-in 2.5V reference.

These devices are simmilar to AD5691R/AD5692R/AD5693/AD5693R except that they use the
spi interface instead of i2c. Another difference is that in the write control register,
DB18 and DB17 are used for setting the power mode, while DB16 is the REF bit. In order
to accomodate this change, a new regmap type was defined and checked accordingly.

Datasheet:
	http://www.analog.com/media/en/technical-documentation/data-sheets/AD5683R_5682R_5681R_5683.pdf

Signed-off-by: Stefan Popa <[email protected]>

Author: stefpopa

drivers/iio/dac/ad5686-spi.c

@@ -1,5 +1,6 @@
 /*
- * AD5672R, AD5676, AD5676R, AD5684, AD5684R, AD5684R, AD5685R, AD5686, AD5686R
+ * AD5672R, AD5676, AD5676R, AD5681R, AD5682R, AD5683, AD5683R,
+ * AD5684, AD5684R, AD5685R, AD5686, AD5686R
  * Digital to analog converters driver
  *
  * Copyright 2018 Analog Devices Inc.
@@ -38,9 +39,15 @@ static int ad5686_spi_read(struct ad5686_state *st, u8 addr)
 		},
 	};
 	struct spi_device *spi = to_spi_device(st->dev);
+	u8 cmd;
 	int ret;
 
-	st->data[0].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_READBACK_ENABLE) |
+	if (st->chip_info->regmap_type == AD5686_REGMAP)
+		cmd = AD5686_CMD_READBACK_ENABLE;
+	else if (st->chip_info->regmap_type == AD5683_REGMAP)
+		cmd = AD5686_CMD_READBACK_ENABLE_V2;
+
+	st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) |
 				      AD5686_ADDR(addr));
 	st->data[1].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_NOOP));
 
@@ -68,6 +75,10 @@ static const struct spi_device_id ad5686_spi_id[] = {
 	{"ad5672r", ID_AD5672R},
 	{"ad5676", ID_AD5676},
 	{"ad5676r", ID_AD5676R},
+	{"ad5681r", ID_AD5681R},
+	{"ad5682r", ID_AD5682R},
+	{"ad5683", ID_AD5683},
+	{"ad5683r", ID_AD5683R},
 	{"ad5684", ID_AD5684},
 	{"ad5684r", ID_AD5684R},
 	{"ad5685r", ID_AD5685R},

drivers/iio/dac/ad5686.c

@@ -82,7 +82,8 @@ static ssize_t ad5686_write_dac_powerdown(struct iio_dev *indio_dev,
 	bool readin;
 	int ret;
 	struct ad5686_state *st = iio_priv(indio_dev);
-	unsigned int val;
+	unsigned int val, ref_bit_msk;
+	u8 shift;
 
 	ret = strtobool(buf, &readin);
 	if (ret)
@@ -93,13 +94,24 @@ static ssize_t ad5686_write_dac_powerdown(struct iio_dev *indio_dev,
 	else
 		st->pwr_down_mask &= ~(0x3 << (chan->channel * 2));
 
-	if (st->chip_info->regmap_type == AD5693_REGMAP) {
-		val = ((st->pwr_down_mask & st->pwr_down_mode) << 13) |
-			(st->use_internal_vref == true ? 0 : (1 << 12));
-	} else {
-		val = st->pwr_down_mask & st->pwr_down_mode;
+	switch (st->chip_info->regmap_type) {
+	case AD5686_REGMAP:
+		shift = 0;
+		break;
+	case AD5693_REGMAP:
+		shift = 13;
+		ref_bit_msk = AD5693_REF_BIT_MSK;
+		break;
+	case AD5683_REGMAP:
+		shift = 17;
+		ref_bit_msk = AD5683_REF_BIT_MSK;
+		break;
 	}
 
+	val = ((st->pwr_down_mask & st->pwr_down_mode) << shift);
+	if (!st->use_internal_vref)
+		val |= ref_bit_msk;
+
 	ret = ad5686_write(st, AD5686_CMD_POWERDOWN_DAC, 0, val, 0);
 
 	return ret ? ret : len;
@@ -259,6 +271,29 @@ static const struct ad5686_chip_info ad5686_chip_info_tbl[] = {
 		.num_channels = 8,
 		.regmap_type = AD5686_REGMAP,
 	},
+	[ID_AD5681R] = {
+		.channels = ad5691r_channels,
+		.int_vref_mv = 2500,
+		.num_channels = 1,
+		.regmap_type = AD5683_REGMAP,
+	},
+	[ID_AD5682R] = {
+		.channels = ad5692r_channels,
+		.int_vref_mv = 2500,
+		.num_channels = 1,
+		.regmap_type = AD5683_REGMAP,
+	},
+	[ID_AD5683] = {
+		.channels = ad5693_channels,
+		.num_channels = 1,
+		.regmap_type = AD5683_REGMAP,
+	},
+	[ID_AD5683R] = {
+		.channels = ad5693_channels,
+		.int_vref_mv = 2500,
+		.num_channels = 1,
+		.regmap_type = AD5683_REGMAP,
+	},
 	[ID_AD5684] = {
 		.channels = ad5684_channels,
 		.num_channels = 4,
@@ -339,7 +374,8 @@ int ad5686_probe(struct device *dev, enum ad5686_supported_device_ids chip_type,
 {
 	struct ad5686_state *st;
 	struct iio_dev *indio_dev;
-	u8 shift, cmd;
+	u8 cmd;
+	unsigned int val, ref_bit_msk;
 	int ret, i, voltage_uv = 0;
 
 	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
@@ -384,16 +420,26 @@ int ad5686_probe(struct device *dev, enum ad5686_supported_device_ids chip_type,
 	indio_dev->channels = st->chip_info->channels;
 	indio_dev->num_channels = st->chip_info->num_channels;
 
-	if (st->chip_info->regmap_type == AD5693_REGMAP) {
+	switch (st->chip_info->regmap_type) {
+	case AD5686_REGMAP:
+		cmd = AD5686_CMD_INTERNAL_REFER_SETUP;
+		ref_bit_msk = 0;
+		break;
+	case AD5693_REGMAP:
+		cmd = AD5686_CMD_CONTROL_REG;
+		ref_bit_msk = AD5693_REF_BIT_MSK;
 		st->use_internal_vref = !voltage_uv;
+		break;
+	case AD5683_REGMAP:
 		cmd = AD5686_CMD_CONTROL_REG;
-		shift = 12;
-	} else {
-		cmd = AD5686_CMD_INTERNAL_REFER_SETUP;
-		shift = 0;
+		ref_bit_msk = AD5683_REF_BIT_MSK;
+		st->use_internal_vref = !voltage_uv;
+		break;
 	}
 
-	ret = ad5686_write(st, cmd, 0, !!voltage_uv, shift);
+	val = (voltage_uv | ref_bit_msk);
+
+	ret = ad5686_write(st, cmd, 0, !!val, 0);
 	if (ret)
 		goto error_disable_reg;
 

drivers/iio/dac/ad5686.h

@@ -29,6 +29,9 @@
 #define AD5686_LDAC_PWRDN_3STATE		0x3
 
 #define AD5686_CMD_CONTROL_REG			0x4
+#define AD5686_CMD_READBACK_ENABLE_V2		0x5
+#define AD5683_REF_BIT_MSK			BIT(16)
+#define AD5693_REF_BIT_MSK			BIT(12)
 
 /**
  * ad5686_supported_device_ids:
@@ -39,6 +42,10 @@ enum ad5686_supported_device_ids {
 	ID_AD5675R,
 	ID_AD5676,
 	ID_AD5676R,
+	ID_AD5681R,
+	ID_AD5682R,
+	ID_AD5683,
+	ID_AD5683R,
 	ID_AD5684,
 	ID_AD5684R,
 	ID_AD5685R,
@@ -56,8 +63,9 @@ enum ad5686_supported_device_ids {
 };
 
 enum ad5686_regmap_type {
+	AD5683_REGMAP,
 	AD5686_REGMAP,
-	AD5693_REGMAP
+	AD5693_REGMAP,
 };
 
 struct ad5686_state;
@@ -90,8 +98,7 @@ struct ad5686_chip_info {
  * @vref_mv:		actual reference voltage used
  * @pwr_down_mask:	power down mask
  * @pwr_down_mode:	current power down mode
- * @use_internal_vref:	set to true if the internal reference voltage should be
- *			used.
+ * @use_internal_vref:	set to true if the internal reference voltage is used
  * @data:		spi transfer buffers
  */