diff mbox series

[v5,08/14] iio: adc: ad7768-1: add regulator to control VCM output

Message ID 7753dcd690f07f855100fc28e7b8ae746082de1c.1744325346.git.Jonathan.Santos@analog.com
State New
Headers show
Series iio: adc: ad7768-1: Add features, improvements, and fixes | expand

Commit Message

Jonathan Santos April 11, 2025, 3:57 p.m. UTC 
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>
---
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.
* Adressed 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 | 176 +++++++++++++++++++++++++++++++++++++
 2 files changed, 177 insertions(+)

Comments

Jonathan Cameron April 12, 2025, 6:02 p.m. UTC | #1 
On Fri, 11 Apr 2025 12:57:42 -0300
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.
> 
> Acked-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
> Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
Just one question from me inline.

> diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
> index 66087fabe181..13d17a13b6ea 100644
> --- a/drivers/iio/adc/ad7768-1.c
> +++ b/drivers/iio/adc/ad7768-1.c

> +static const struct regulator_desc vcm_desc = {
> +	.name = "ad7768-1-vcm",
> +	.of_match = of_match_ptr("vcm-output"),
> +	.regulators_node = of_match_ptr("regulators"),
I see this use of of_match_ptr() is common but not universal in regulator
drivers.  Any idea if it really is just to save a string or if there
some more fundamental reason to make these go away when device
tree support is not built?

We spent a while getting other uses of this out of IIO so  I'd like to know
more about this one!

Jonathan

> +	.n_voltages = ARRAY_SIZE(vcm_voltage_table),
> +	.volt_table = vcm_voltage_table,
> +	.ops = &vcm_regulator_ops,
> +	.type = REGULATOR_VOLTAGE,
> +	.owner = THIS_MODULE,
> +};
diff mbox series

Patch

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index da3463a1d0bc..f1600a0fa5f2 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -322,6 +322,7 @@  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 66087fabe181..13d17a13b6ea 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 +654,167 @@  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);
+	if (ret)
+		goto err_release;
+
+	ret = FIELD_GET(AD7768_REG_ANALOG2_VCM_MSK, val) != AD7768_VCM_OFF;
+err_release:
+	iio_device_release_direct(indio_dev);
+
+	return ret;
+}
+
+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);
+	st->vcm_output_sel = selector;
+
+	return ret;
+}
+
+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);
+	if (ret)
+		goto err_release;
+
+	val = FIELD_GET(AD7768_REG_ANALOG2_VCM_MSK, val);
+	ret = clamp(val, 1, (int)rdev->desc->n_voltages) - 1;
+err_release:
+	iio_device_release_direct(indio_dev);
+
+	return ret;
+}
+
+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 = 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 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 -EINVAL;
+
+	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 +879,11 @@  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");