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.
Acked-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
---
v6 Changes:
* Rearranged iio_device_release_direct() calls to avoid
some gotos.
* removed of_match_ptr() from regulator_desc.
* Addressed other nits.
v5 Changes:
* enforce AD7768_REG_ANALOG2_VCM macro argument evaluation.
* switched to the new iio_device_claim/release_direct() functions.
v4 Changes:
* Added iio_device_claim_direct_mode() to regulator callbacks to avoid register access
while in buffered mode.
* Changed regulator name to "ad7768-1-vcm".
* When regulator enable is called, it will set the last voltage selector configured.
* Disabled regulator before configuring it.
* Addressed other nits.
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/Kconfig | 1 +
drivers/iio/adc/ad7768-1.c | 173 +++++++++++++++++++++++++++++++++++++
2 files changed, 174 insertions(+)
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index ad06cf556785..8dc4cc4c25af 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -329,6 +329,7 @@ config AD7766
config AD7768_1
tristate "Analog Devices AD7768-1 ADC driver"
depends on SPI
+ select REGULATOR
select REGMAP_SPI
select IIO_BUFFER
select IIO_TRIGGER
diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
index 09e4ab76e2b6..0364d73329b0 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>
@@ -80,6 +82,12 @@
#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_VCM_OFF 0x07
+
enum ad7768_conv_mode {
AD7768_CONTINUOUS,
AD7768_ONE_SHOT,
@@ -157,6 +165,8 @@ struct ad7768_state {
struct regmap *regmap;
struct regmap *regmap24;
struct regulator *vref;
+ struct regulator_dev *vcm_rdev;
+ unsigned int vcm_output_sel;
struct clk *mclk;
unsigned int mclk_freq;
unsigned int samp_freq;
@@ -644,6 +654,164 @@ static int ad7768_triggered_buffer_alloc(struct iio_dev *indio_dev)
&ad7768_buffer_ops);
}
+static int ad7768_vcm_enable(struct regulator_dev *rdev)
+{
+ struct iio_dev *indio_dev = rdev_get_drvdata(rdev);
+ struct ad7768_state *st = iio_priv(indio_dev);
+ int ret, regval;
+
+ if (!indio_dev)
+ return -EINVAL;
+
+ if (!iio_device_claim_direct(indio_dev))
+ return -EBUSY;
+
+ /* To enable, set the last selected output */
+ regval = AD7768_REG_ANALOG2_VCM(st->vcm_output_sel + 1);
+ ret = regmap_update_bits(st->regmap, AD7768_REG_ANALOG2,
+ AD7768_REG_ANALOG2_VCM_MSK, regval);
+ iio_device_release_direct(indio_dev);
+
+ return ret;
+}
+
+static int ad7768_vcm_disable(struct regulator_dev *rdev)
+{
+ struct iio_dev *indio_dev = rdev_get_drvdata(rdev);
+ struct ad7768_state *st = iio_priv(indio_dev);
+ int ret;
+
+ if (!indio_dev)
+ return -EINVAL;
+
+ if (!iio_device_claim_direct(indio_dev))
+ return -EBUSY;
+
+ ret = regmap_update_bits(st->regmap, AD7768_REG_ANALOG2,
+ AD7768_REG_ANALOG2_VCM_MSK, AD7768_VCM_OFF);
+ iio_device_release_direct(indio_dev);
+
+ return ret;
+}
+
+static int ad7768_vcm_is_enabled(struct regulator_dev *rdev)
+{
+ struct iio_dev *indio_dev = rdev_get_drvdata(rdev);
+ struct ad7768_state *st = iio_priv(indio_dev);
+ int ret, val;
+
+ if (!indio_dev)
+ return -EINVAL;
+
+ if (!iio_device_claim_direct(indio_dev))
+ return -EBUSY;
+
+ ret = regmap_read(st->regmap, AD7768_REG_ANALOG2, &val);
+ iio_device_release_direct(indio_dev);
+ if (ret)
+ return ret;
+
+ return FIELD_GET(AD7768_REG_ANALOG2_VCM_MSK, val) != AD7768_VCM_OFF;
+}
+
+static int ad7768_set_voltage_sel(struct regulator_dev *rdev,
+ unsigned int selector)
+{
+ unsigned int regval = AD7768_REG_ANALOG2_VCM(selector + 1);
+ struct iio_dev *indio_dev = rdev_get_drvdata(rdev);
+ struct ad7768_state *st = iio_priv(indio_dev);
+ int ret;
+
+ if (!indio_dev)
+ return -EINVAL;
+
+ if (!iio_device_claim_direct(indio_dev))
+ return -EBUSY;
+
+ ret = regmap_update_bits(st->regmap, AD7768_REG_ANALOG2,
+ AD7768_REG_ANALOG2_VCM_MSK, regval);
+ iio_device_release_direct(indio_dev);
+ if (ret)
+ return ret;
+
+ st->vcm_output_sel = selector;
+
+ return 0;
+}
+
+static int ad7768_get_voltage_sel(struct regulator_dev *rdev)
+{
+ struct iio_dev *indio_dev = rdev_get_drvdata(rdev);
+ struct ad7768_state *st = iio_priv(indio_dev);
+ int ret, val;
+
+ if (!indio_dev)
+ return -EINVAL;
+
+ if (!iio_device_claim_direct(indio_dev))
+ return -EBUSY;
+
+ ret = regmap_read(st->regmap, AD7768_REG_ANALOG2, &val);
+ iio_device_release_direct(indio_dev);
+ if (ret)
+ return ret;
+
+ val = FIELD_GET(AD7768_REG_ANALOG2_VCM_MSK, val);
+ return clamp(val, 1, (int)rdev->desc->n_voltages) - 1;
+}
+
+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 = "ad7768-1-vcm",
+ .of_match = "vcm-output",
+ .regulators_node = "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 iio_dev *indio_dev)
+{
+ struct regulator_config config = {
+ .dev = dev,
+ .driver_data = indio_dev,
+ };
+ int ret;
+
+ /* Disable the regulator before registering it */
+ ret = regmap_update_bits(st->regmap, AD7768_REG_ANALOG2,
+ AD7768_REG_ANALOG2_VCM_MSK, AD7768_VCM_OFF);
+ if (ret)
+ return ret;
+
+ 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;
@@ -708,6 +876,11 @@ 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, indio_dev);
+ if (ret)
+ return ret;
+
ret = ad7768_setup(st);
if (ret < 0) {
dev_err(&spi->dev, "AD7768 setup failed\n");
--
2.34.1On 4/27/25 7:13 PM, Jonathan Santos wrote: > 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. > > Acked-by: Marcelo Schmitt <marcelo.schmitt@analog.com> > Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com> > --- With the issues that Andy pointed out addressed: Reviewed-by: David Lechner <dlechner@baylibre.com>
On Mon, Apr 28, 2025 at 3:13 AM Jonathan Santos
<Jonathan.Santos@analog.com> wrote:
>
> 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.
...
> #include <linux/gpio/consumer.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/of.h>
Why?
> #include <linux/regmap.h>
> #include <linux/regulator/consumer.h>
> +#include <linux/regulator/driver.h>
...
> +static int ad7768_vcm_enable(struct regulator_dev *rdev)
> +{
> + struct iio_dev *indio_dev = rdev_get_drvdata(rdev);
> + struct ad7768_state *st = iio_priv(indio_dev);
> + int ret, regval;
> + if (!indio_dev)
> + return -EINVAL;
Isn't it a dead code? Or i.o.w. under which circumstances can this be true?
Ditto for other functions with the same check.
> + if (!iio_device_claim_direct(indio_dev))
> + return -EBUSY;
> +
> + /* To enable, set the last selected output */
> + regval = AD7768_REG_ANALOG2_VCM(st->vcm_output_sel + 1);
> + ret = regmap_update_bits(st->regmap, AD7768_REG_ANALOG2,
> + AD7768_REG_ANALOG2_VCM_MSK, regval);
> + iio_device_release_direct(indio_dev);
> +
> + return ret;
> +}
...
> + return clamp(val, 1, (int)rdev->desc->n_voltages) - 1;
No explicit castings in min/max/clamp, please. This may lead to subtle
mistakes. Also, don't forget to include minmax.h.
--
With Best Regards,
Andy Shevchenko
On 04/28, Andy Shevchenko wrote:
> On Mon, Apr 28, 2025 at 3:13 AM Jonathan Santos
> <Jonathan.Santos@analog.com> wrote:
> >
> > 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.
>
> ...
>
> > #include <linux/gpio/consumer.h>
> > #include <linux/kernel.h>
> > #include <linux/module.h>
> > +#include <linux/of.h>
>
> Why?
>
I was using of_match_ptr() before, but forgot to remove it, sorry.
> > #include <linux/regmap.h>
> > #include <linux/regulator/consumer.h>
> > +#include <linux/regulator/driver.h>
>
> ...
>
> > +static int ad7768_vcm_enable(struct regulator_dev *rdev)
> > +{
> > + struct iio_dev *indio_dev = rdev_get_drvdata(rdev);
> > + struct ad7768_state *st = iio_priv(indio_dev);
> > + int ret, regval;
>
> > + if (!indio_dev)
> > + return -EINVAL;
>
> Isn't it a dead code? Or i.o.w. under which circumstances can this be true?
> Ditto for other functions with the same check.
>
Yes, you're right. Since I defined the driver data below, there was no
need for the check.
> > + if (!iio_device_claim_direct(indio_dev))
> > + return -EBUSY;
> > +
> > + /* To enable, set the last selected output */
> > + regval = AD7768_REG_ANALOG2_VCM(st->vcm_output_sel + 1);
> > + ret = regmap_update_bits(st->regmap, AD7768_REG_ANALOG2,
> > + AD7768_REG_ANALOG2_VCM_MSK, regval);
> > + iio_device_release_direct(indio_dev);
> > +
> > + return ret;
> > +}
>
> ...
>
> > + return clamp(val, 1, (int)rdev->desc->n_voltages) - 1;
>
> No explicit castings in min/max/clamp, please. This may lead to subtle
> mistakes. Also, don't forget to include minmax.h.
>
Okay, thanks.
> --
> With Best Regards,
> Andy Shevchenko
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