From: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx>
The VCM output voltage can be used as a common-mode voltage within the
amplifier preconditioning circuits external to the AD7768-1.
This change exports the VCM as an iio attribute and makes it available
for configuration.
Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx>
---
drivers/iio/adc/ad7768-1.c | 56 ++++++++++++++++++++++++++++++++++++++
1 file changed, 56 insertions(+)
diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
index eaa9a12737ac..574d735f2c3a 100644
--- a/drivers/iio/adc/ad7768-1.c
+++ b/drivers/iio/adc/ad7768-1.c
@@ -119,6 +119,17 @@ struct ad7768_clk_configuration {
enum ad7768_pwrmode pwrmode;
};
+static const char * const ad7768_vcm_modes[] = {
+ "(AVDD1-AVSS)/2",
+ "2V5",
+ "2V05",
+ "1V9",
+ "1V65",
+ "1V1",
+ "0V9",
+ "OFF",
+};
+
static const struct ad7768_clk_configuration ad7768_clk_config[] = {
{ AD7768_MCLK_DIV_2, AD7768_DEC_RATE_8, 16, AD7768_FAST_MODE },
{ AD7768_MCLK_DIV_2, AD7768_DEC_RATE_16, 32, AD7768_FAST_MODE },
@@ -133,12 +144,34 @@ static const struct ad7768_clk_configuration ad7768_clk_config[] = {
{ AD7768_MCLK_DIV_16, AD7768_DEC_RATE_1024, 16384, AD7768_ECO_MODE },
};
+static int ad7768_get_vcm(struct iio_dev *dev, const struct iio_chan_spec *chan);
+static int ad7768_set_vcm(struct iio_dev *dev, const struct iio_chan_spec *chan,
+ unsigned int mode);
+
+static const struct iio_enum ad7768_vcm_mode_enum = {
+ .items = ad7768_vcm_modes,
+ .num_items = ARRAY_SIZE(ad7768_vcm_modes),
+ .set = ad7768_set_vcm,
+ .get = ad7768_get_vcm,
+};
+
+static struct iio_chan_spec_ext_info ad7768_ext_info[] = {
+ IIO_ENUM("common_mode_voltage",
+ IIO_SHARED_BY_ALL,
+ &ad7768_vcm_mode_enum),
+ IIO_ENUM_AVAILABLE("common_mode_voltage",
+ IIO_SHARED_BY_ALL,
+ &ad7768_vcm_mode_enum),
+ { },
+};
+
static const struct iio_chan_spec ad7768_channels[] = {
{
.type = IIO_VOLTAGE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ .ext_info = ad7768_ext_info,
.indexed = 1,
.channel = 0,
.scan_index = 0,
@@ -159,6 +192,7 @@ struct ad7768_state {
struct clk *mclk;
unsigned int mclk_freq;
unsigned int samp_freq;
+ unsigned int common_mode_voltage;
struct completion completion;
struct iio_trigger *trig;
struct gpio_desc *gpio_sync_in;
@@ -329,6 +363,28 @@ static int ad7768_set_freq(struct ad7768_state *st,
return 0;
}
+static int ad7768_get_vcm(struct iio_dev *dev, const struct iio_chan_spec *chan)
+{
+ struct ad7768_state *st = iio_priv(dev);
+
+ return st->common_mode_voltage;
+}
+
+static int ad7768_set_vcm(struct iio_dev *dev,
+ const struct iio_chan_spec *chan,
+ unsigned int mode)
+{
+ int ret;
+ struct ad7768_state *st = iio_priv(dev);
+
+ ret = ad7768_spi_reg_write(st, AD7768_REG_ANALOG2, mode);
+
+ if (ret == 0)
+ st->common_mode_voltage = mode;
+
+ return ret;
+}
+
static ssize_t ad7768_sampling_freq_avail(struct device *dev,
struct device_attribute *attr,
char *buf)
--
2.34.1
