The VCM output voltage can be used as a common-mode voltage within the
amplifier preconditioning circuits external to the AD7768-1.
This change allows the user to configure VCM output using the regulator
framework.
Signed-off-by: Jonathan Santos <Jonathan.Santos@xxxxxxxxxx>
---
v3 Changes:
* Register VCM output via the regulator framework for improved flexibility
and external integration.
v2 Changes:
* VCM output support is now defined by a devicetree property, instead of
and IIO attribute.
---
drivers/iio/adc/ad7768-1.c | 138 +++++++++++++++++++++++++++++++++++++
1 file changed, 138 insertions(+)
diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
index 378245bce199..a359cd8fceca 100644
--- a/drivers/iio/adc/ad7768-1.c
+++ b/drivers/iio/adc/ad7768-1.c
@@ -12,8 +12,10 @@
#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
+#include <linux/regulator/driver.h>
#include <linux/sysfs.h>
#include <linux/spi/spi.h>
@@ -80,9 +82,15 @@
#define AD7768_CONV_MODE_MSK GENMASK(2, 0)
#define AD7768_CONV_MODE(x) FIELD_PREP(AD7768_CONV_MODE_MSK, x)
+/* AD7768_REG_ANALOG2 */
+#define AD7768_REG_ANALOG2_VCM_MSK GENMASK(2, 0)
+#define AD7768_REG_ANALOG2_VCM(x) FIELD_PREP(AD7768_REG_ANALOG2_VCM_MSK, x)
+
#define AD7768_RD_FLAG_MSK(x) (BIT(6) | ((x) & 0x3F))
#define AD7768_WR_FLAG_MSK(x) ((x) & 0x3F)
+#define AD7768_VCM_OFF 0x08
+
enum ad7768_conv_mode {
AD7768_CONTINUOUS,
AD7768_ONE_SHOT,
@@ -160,6 +168,7 @@ struct ad7768_state {
struct regmap *regmap;
struct regmap *regmap24;
struct regulator *vref;
+ struct regulator_dev *vcm_rdev;
struct clk *mclk;
unsigned int mclk_freq;
unsigned int samp_freq;
@@ -643,6 +652,130 @@ static int ad7768_triggered_buffer_alloc(struct iio_dev *indio_dev)
&ad7768_buffer_ops);
}
+static int ad7768_vcm_enable(struct regulator_dev *rdev)
+{
+ struct ad7768_state *st = rdev_get_drvdata(rdev);
+ int ret, val;
+
+ if (!st)
+ return -EINVAL;
+
+ ret = regmap_read(st->regmap, AD7768_REG_ANALOG2, &val);
+ if (ret)
+ return ret;
+
+ /* if regulator is off, turn it on */
+ if (FIELD_GET(AD7768_REG_ANALOG2_VCM_MSK, val) == AD7768_VCM_OFF)
+ return regmap_update_bits(st->regmap, AD7768_REG_ANALOG2,
+ AD7768_REG_ANALOG2_VCM_MSK, 0x00);
+
+ return 0;
+}
+
+static int ad7768_vcm_disable(struct regulator_dev *rdev)
+{
+ struct ad7768_state *st = rdev_get_drvdata(rdev);
+
+ if (!st)
+ return -EINVAL;
+
+ return regmap_update_bits(st->regmap, AD7768_REG_ANALOG2,
+ AD7768_REG_ANALOG2_VCM_MSK, AD7768_VCM_OFF);
+}
+
+static int ad7768_vcm_is_enabled(struct regulator_dev *rdev)
+{
+ struct ad7768_state *st = rdev_get_drvdata(rdev);
+ int ret, val;
+
+ if (!st)
+ return -EINVAL;
+
+ ret = regmap_read(st->regmap, AD7768_REG_ANALOG2, &val);
+ if (ret)
+ return ret;
+
+ if (FIELD_GET(AD7768_REG_ANALOG2_VCM_MSK, val) == AD7768_VCM_OFF)
+ return 0;
+
+ return 1;
+}
+
+static int ad7768_set_voltage_sel(struct regulator_dev *rdev,
+ unsigned int selector)
+{
+ unsigned int regval = AD7768_REG_ANALOG2_VCM(selector + 1);
+ struct ad7768_state *st = rdev_get_drvdata(rdev);
+
+ if (!st)
+ return -EINVAL;
+
+ return regmap_update_bits(st->regmap, AD7768_REG_ANALOG2,
+ AD7768_REG_ANALOG2_VCM_MSK, regval);
+}
+
+static int ad7768_get_voltage_sel(struct regulator_dev *rdev)
+{
+ struct ad7768_state *st = rdev_get_drvdata(rdev);
+ int ret, val;
+
+ if (!st)
+ return -EINVAL;
+
+ ret = regmap_read(st->regmap, AD7768_REG_ANALOG2, &val);
+ if (ret)
+ return ret;
+
+ val = FIELD_GET(AD7768_REG_ANALOG2_VCM_MSK, val) - 1;
+ val = clamp(val, 0, 8);
+
+ return val;
+}
+
+static const struct regulator_ops vcm_regulator_ops = {
+ .enable = ad7768_vcm_enable,
+ .disable = ad7768_vcm_disable,
+ .is_enabled = ad7768_vcm_is_enabled,
+ .list_voltage = regulator_list_voltage_table,
+ .set_voltage_sel = ad7768_set_voltage_sel,
+ .get_voltage_sel = ad7768_get_voltage_sel,
+};
+
+static const unsigned int vcm_voltage_table[] = {
+ 2500000,
+ 2050000,
+ 1650000,
+ 1900000,
+ 1100000,
+ 900000,
+};
+
+static const struct regulator_desc vcm_desc = {
+ .name = "vcm_output",
+ .of_match = of_match_ptr("vcm_output"),
+ .regulators_node = of_match_ptr("regulators"),
+ .n_voltages = ARRAY_SIZE(vcm_voltage_table),
+ .volt_table = vcm_voltage_table,
+ .ops = &vcm_regulator_ops,
+ .type = REGULATOR_VOLTAGE,
+ .owner = THIS_MODULE,
+};
+
+static int ad7768_register_regulators(struct device *dev, struct ad7768_state *st)
+{
+ struct regulator_config config = {
+ .dev = dev,
+ .driver_data = st,
+ };
+
+ st->vcm_rdev = devm_regulator_register(dev, &vcm_desc, &config);
+ if (IS_ERR(st->vcm_rdev))
+ return dev_err_probe(dev, PTR_ERR(st->vcm_rdev),
+ "failed to register VCM regulator\n");
+
+ return 0;
+}
+
static int ad7768_probe(struct spi_device *spi)
{
struct ad7768_state *st;
@@ -707,6 +840,11 @@ static int ad7768_probe(struct spi_device *spi)
indio_dev->info = &ad7768_info;
indio_dev->modes = INDIO_DIRECT_MODE;
+ /* Register VCM output regulator */
+ ret = ad7768_register_regulators(&spi->dev, st);
+ if (ret)
+ return ret;
+
ret = ad7768_setup(st);
if (ret < 0) {
dev_err(&spi->dev, "AD7768 setup failed\n");
--
2.34.1
