iio:ad7793: Add support for the ad7798 and ad7799

The ad7798 and ad7799 are similar to the ad7792 and ad7793 but are missing some
features like the temperature sensor, being able to use an external clocksource
and a few other things. This patch adds a new 'flags' fields to the chip_info
struct which allows to specify which features a certain chip variant supports.
The setup code will then ignore any platform data fields which are related to
non supported features.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/adc/ad7793.c

@@ -106,6 +106,8 @@
 #define AD7793_ID		0xB
 #define AD7794_ID		0xF
 #define AD7795_ID		0xF
+#define AD7798_ID		0x8
+#define AD7799_ID		0x9
 #define AD7793_ID_MASK		0xF
 
 /* IO (Excitation Current Sources) Register Bit Designations (AD7793_REG_IO) */
@@ -130,10 +132,16 @@
  * The DOUT/RDY output must also be wired to an interrupt capable GPIO.
  */
 
+#define AD7793_FLAG_HAS_CLKSEL		BIT(0)
+#define AD7793_FLAG_HAS_REFSEL		BIT(1)
+#define AD7793_FLAG_HAS_VBIAS		BIT(2)
+#define AD7793_HAS_EXITATION_CURRENT	BIT(3)
+
 struct ad7793_chip_info {
 	unsigned int id;
 	const struct iio_chan_spec *channels;
 	unsigned int num_channels;
+	unsigned int flags;
 };
 
 struct ad7793_state {
@@ -154,6 +162,8 @@ enum ad7793_supported_device_ids {
 	ID_AD7793,
 	ID_AD7794,
 	ID_AD7795,
+	ID_AD7798,
+	ID_AD7799,
 };
 
 static struct ad7793_state *ad_sigma_delta_to_ad7793(struct ad_sigma_delta *sd)
@@ -205,6 +215,34 @@ static int ad7793_calibrate_all(struct ad7793_state *st)
 				   ARRAY_SIZE(ad7793_calib_arr));
 }
 
+static int ad7793_check_platform_data(struct ad7793_state *st,
+	const struct ad7793_platform_data *pdata)
+{
+	if ((pdata->current_source_direction == AD7793_IEXEC1_IEXEC2_IOUT1 ||
+		pdata->current_source_direction == AD7793_IEXEC1_IEXEC2_IOUT2) &&
+		((pdata->exitation_current != AD7793_IX_10uA) &&
+		(pdata->exitation_current != AD7793_IX_210uA)))
+		return -EINVAL;
+
+	if (!(st->chip_info->flags & AD7793_FLAG_HAS_CLKSEL) &&
+		pdata->clock_src != AD7793_CLK_SRC_INT)
+		return -EINVAL;
+
+	if (!(st->chip_info->flags & AD7793_FLAG_HAS_REFSEL) &&
+		pdata->refsel != AD7793_REFSEL_REFIN1)
+		return -EINVAL;
+
+	if (!(st->chip_info->flags & AD7793_FLAG_HAS_VBIAS) &&
+		pdata->bias_voltage != AD7793_BIAS_VOLTAGE_DISABLED)
+		return -EINVAL;
+
+	if (!(st->chip_info->flags & AD7793_HAS_EXITATION_CURRENT) &&
+		pdata->exitation_current != AD7793_IX_DISABLED)
+		return -EINVAL;
+
+	return 0;
+}
+
 static int ad7793_setup(struct iio_dev *indio_dev,
 	const struct ad7793_platform_data *pdata,
 	unsigned int vref_mv)
@@ -214,11 +252,9 @@ static int ad7793_setup(struct iio_dev *indio_dev,
 	unsigned long long scale_uv;
 	u32 id;
 
-	if ((pdata->current_source_direction == AD7793_IEXEC1_IEXEC2_IOUT1 ||
-		pdata->current_source_direction == AD7793_IEXEC1_IEXEC2_IOUT2) &&
-		((pdata->exitation_current != AD7793_IX_10uA) &&
-		(pdata->exitation_current != AD7793_IX_210uA)))
-		return -EINVAL;
+	ret = ad7793_check_platform_data(st, pdata);
+	if (ret)
+		return ret;
 
 	/* reset the serial interface */
 	ret = spi_write(st->sd.spi, (u8 *)&ret, sizeof(ret));
@@ -239,12 +275,18 @@ static int ad7793_setup(struct iio_dev *indio_dev,
 	}
 
 	st->mode = AD7793_MODE_RATE(1);
-	st->mode |= AD7793_MODE_CLKSRC(pdata->clock_src);
-	st->conf = AD7793_CONF_REFSEL(pdata->refsel);
-	st->conf |= AD7793_CONF_VBIAS(pdata->bias_voltage);
+	st->conf = 0;
+
+	if (st->chip_info->flags & AD7793_FLAG_HAS_CLKSEL)
+		st->mode |= AD7793_MODE_CLKSRC(pdata->clock_src);
+	if (st->chip_info->flags & AD7793_FLAG_HAS_REFSEL)
+		st->conf |= AD7793_CONF_REFSEL(pdata->refsel);
+	if (st->chip_info->flags & AD7793_FLAG_HAS_VBIAS)
+		st->conf |= AD7793_CONF_VBIAS(pdata->bias_voltage);
 	if (pdata->buffered)
 		st->conf |= AD7793_CONF_BUF;
-	if (pdata->boost_enable)
+	if (pdata->boost_enable &&
+		(st->chip_info->flags & AD7793_FLAG_HAS_VBIAS))
 		st->conf |= AD7793_CONF_BOOST;
 	if (pdata->burnout_current)
 		st->conf |= AD7793_CONF_BO_EN;
@@ -259,11 +301,13 @@ static int ad7793_setup(struct iio_dev *indio_dev,
 	if (ret)
 		goto out;
 
-	ret = ad_sd_write_reg(&st->sd, AD7793_REG_IO, 1,
-				   pdata->exitation_current |
-			       (pdata->current_source_direction << 2));
-	if (ret)
-		goto out;
+	if (st->chip_info->flags & AD7793_HAS_EXITATION_CURRENT) {
+		ret = ad_sd_write_reg(&st->sd, AD7793_REG_IO, 1,
+				pdata->exitation_current |
+				(pdata->current_source_direction << 2));
+		if (ret)
+			goto out;
+	}
 
 	ret = ad7793_calibrate_all(st);
 	if (ret)
@@ -525,37 +569,79 @@ const struct iio_chan_spec _name##_channels[] = { \
 	IIO_CHAN_SOFT_TIMESTAMP(9), \
 }
 
+#define DECLARE_AD7799_CHANNELS(_name, _b, _sb) \
+const struct iio_chan_spec _name##_channels[] = { \
+	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7793_CH_AIN1P_AIN1M, (_b), (_sb), 0), \
+	AD_SD_DIFF_CHANNEL(1, 1, 1, AD7793_CH_AIN2P_AIN2M, (_b), (_sb), 0), \
+	AD_SD_DIFF_CHANNEL(2, 2, 2, AD7793_CH_AIN3P_AIN3M, (_b), (_sb), 0), \
+	AD_SD_SHORTED_CHANNEL(3, 0, AD7793_CH_AIN1M_AIN1M, (_b), (_sb), 0), \
+	AD_SD_SUPPLY_CHANNEL(4, 3, AD7793_CH_AVDD_MONITOR, (_b), (_sb), 0), \
+	IIO_CHAN_SOFT_TIMESTAMP(5), \
+}
+
 static DECLARE_AD7793_CHANNELS(ad7785, 20, 32, 4);
 static DECLARE_AD7793_CHANNELS(ad7792, 16, 32, 0);
 static DECLARE_AD7793_CHANNELS(ad7793, 24, 32, 0);
 static DECLARE_AD7795_CHANNELS(ad7794, 16, 32);
 static DECLARE_AD7795_CHANNELS(ad7795, 24, 32);
+static DECLARE_AD7799_CHANNELS(ad7798, 16, 16);
+static DECLARE_AD7799_CHANNELS(ad7799, 24, 32);
 
 static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
 	[ID_AD7785] = {
 		.id = AD7785_ID,
 		.channels = ad7785_channels,
 		.num_channels = ARRAY_SIZE(ad7785_channels),
+		.flags = AD7793_FLAG_HAS_CLKSEL |
+			AD7793_FLAG_HAS_REFSEL |
+			AD7793_FLAG_HAS_VBIAS |
+			AD7793_HAS_EXITATION_CURRENT,
 	},
 	[ID_AD7792] = {
 		.id = AD7792_ID,
 		.channels = ad7792_channels,
 		.num_channels = ARRAY_SIZE(ad7792_channels),
+		.flags = AD7793_FLAG_HAS_CLKSEL |
+			AD7793_FLAG_HAS_REFSEL |
+			AD7793_FLAG_HAS_VBIAS |
+			AD7793_HAS_EXITATION_CURRENT,
 	},
 	[ID_AD7793] = {
 		.id = AD7793_ID,
 		.channels = ad7793_channels,
 		.num_channels = ARRAY_SIZE(ad7793_channels),
+		.flags = AD7793_FLAG_HAS_CLKSEL |
+			AD7793_FLAG_HAS_REFSEL |
+			AD7793_FLAG_HAS_VBIAS |
+			AD7793_HAS_EXITATION_CURRENT,
 	},
 	[ID_AD7794] = {
 		.id = AD7794_ID,
 		.channels = ad7794_channels,
 		.num_channels = ARRAY_SIZE(ad7794_channels),
+		.flags = AD7793_FLAG_HAS_CLKSEL |
+			AD7793_FLAG_HAS_REFSEL |
+			AD7793_FLAG_HAS_VBIAS |
+			AD7793_HAS_EXITATION_CURRENT,
 	},
 	[ID_AD7795] = {
 		.id = AD7795_ID,
 		.channels = ad7795_channels,
 		.num_channels = ARRAY_SIZE(ad7795_channels),
+		.flags = AD7793_FLAG_HAS_CLKSEL |
+			AD7793_FLAG_HAS_REFSEL |
+			AD7793_FLAG_HAS_VBIAS |
+			AD7793_HAS_EXITATION_CURRENT,
+	},
+	[ID_AD7798] = {
+		.id = AD7798_ID,
+		.channels = ad7798_channels,
+		.num_channels = ARRAY_SIZE(ad7798_channels),
+	},
+	[ID_AD7799] = {
+		.id = AD7799_ID,
+		.channels = ad7799_channels,
+		.num_channels = ARRAY_SIZE(ad7799_channels),
 	},
 };
 
@@ -671,6 +757,8 @@ static const struct spi_device_id ad7793_id[] = {
 	{"ad7793", ID_AD7793},
 	{"ad7794", ID_AD7794},
 	{"ad7795", ID_AD7795},
+	{"ad7798", ID_AD7798},
+	{"ad7799", ID_AD7799},
 	{}
 };
 MODULE_DEVICE_TABLE(spi, ad7793_id);