diff mbox series

[v7,3/6] iio: adc: ad7192: Add aincom supply

Message ID 20240430162946.589423-4-alisa.roman@analog.com (mailing list archive)
State Changes Requested
Headers show
Series iio: adc: ad7192: Add AD7194 support | expand

Commit Message

Alisa-Dariana Roman April 30, 2024, 4:29 p.m. UTC 
AINCOM should actually be a supply. AINx inputs are referenced to AINCOM
in pseudo-differential operation mode. AINCOM voltage represents the
offset of corresponding channels.

Signed-off-by: Alisa-Dariana Roman <alisa.roman@analog.com>
---
 drivers/iio/adc/ad7192.c | 41 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 2 deletions(-)

Comments

Andy Shevchenko April 30, 2024, 8:28 p.m. UTC | #1 
On Tue, Apr 30, 2024 at 7:30 PM Alisa-Dariana Roman
<alisadariana@gmail.com> wrote:
>
> AINCOM should actually be a supply. AINx inputs are referenced to AINCOM
> in pseudo-differential operation mode. AINCOM voltage represents the
> offset of corresponding channels.

...

> +               ret = regulator_enable(aincom);
> +               if (ret)
> +                       return dev_err_probe(&spi->dev, ret,
> +                                            "Failed to enable specified AINCOM supply\n");
> +
> +               ret = devm_add_action_or_reset(&spi->dev, ad7192_reg_disable, aincom);
> +               if (ret)
> +                       return ret;
> +
> +               ret = regulator_get_voltage(aincom);
> +               if (ret < 0)
> +                       return dev_err_probe(&spi->dev, ret,
> +                                            "Device tree error, AINCOM voltage undefined\n");
> +               st->aincom_mv = ret / 1000;

MILLI ?
David Lechner May 1, 2024, 4:54 p.m. UTC | #2 
On Tue, Apr 30, 2024 at 11:30 AM Alisa-Dariana Roman
<alisadariana@gmail.com> wrote:
>
> AINCOM should actually be a supply. AINx inputs are referenced to AINCOM
> in pseudo-differential operation mode. AINCOM voltage represents the
> offset of corresponding channels.
>
> Signed-off-by: Alisa-Dariana Roman <alisa.roman@analog.com>
> ---
>  drivers/iio/adc/ad7192.c | 41 ++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 39 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
> index ace81e3817a1..3e797ff48086 100644
> --- a/drivers/iio/adc/ad7192.c
> +++ b/drivers/iio/adc/ad7192.c
> @@ -20,6 +20,7 @@
>  #include <linux/module.h>
>  #include <linux/mod_devicetable.h>
>  #include <linux/property.h>
> +#include <linux/units.h>
>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> @@ -186,6 +187,7 @@ struct ad7192_state {
>         struct regulator                *vref;
>         struct clk                      *mclk;
>         u16                             int_vref_mv;
> +       u32                             aincom_mv;
>         u32                             fclk;
>         u32                             mode;
>         u32                             conf;
> @@ -742,10 +744,19 @@ static int ad7192_read_raw(struct iio_dev *indio_dev,
>                         *val = -(1 << (chan->scan_type.realbits - 1));
>                 else
>                         *val = 0;

nit: add blank line before switch for readability

> +               switch (chan->type) {
> +               case IIO_VOLTAGE:

Comment could be helpful here as a few things might not be obvious:
* Only applies to pseudo-differential inputs (!chan->differential)
* AINCOM voltage has to be converted to "raw" units.

> +                       if (st->aincom_mv && !chan->differential)
> +                               *val += DIV_ROUND_CLOSEST_ULL((u64)st->aincom_mv * NANO,
> +                                                             st->scale_avail[gain][1]);
> +                       return IIO_VAL_INT;
>                 /* Kelvin to Celsius */
> -               if (chan->type == IIO_TEMP)
> +               case IIO_TEMP:
>                         *val -= 273 * ad7192_get_temp_scale(unipolar);
> -               return IIO_VAL_INT;
> +                       return IIO_VAL_INT;
> +               default:
> +                       return -EINVAL;
> +               }
>         case IIO_CHAN_INFO_SAMP_FREQ:
>                 *val = DIV_ROUND_CLOSEST(ad7192_get_f_adc(st), 1024);
>                 return IIO_VAL_INT;
> @@ -1052,6 +1063,7 @@ static int ad7192_probe(struct spi_device *spi)
>  {
>         struct ad7192_state *st;
>         struct iio_dev *indio_dev;
> +       struct regulator *aincom;
>         int ret;
>
>         if (!spi->irq) {
> @@ -1067,6 +1079,31 @@ static int ad7192_probe(struct spi_device *spi)
>
>         mutex_init(&st->lock);
>
> +       /*
> +        * Regulator aincom is optional to maintain compatibility with older DT.
> +        * Newer firmware should provide a zero volt fixed supply if wired to
> +        * ground.
> +        */
> +       aincom = devm_regulator_get_optional(&spi->dev, "aincom");

Do we need to consider other errors separate from -EINVAL?

I've done something like this in other drivers:

if (IS_ERR(aincom)) {
    if (PTR_ERR(aincom) != -EINVAL)
        return dev_err_probe(...);

    st->aincom_mv = 0;
} else {
   ...
    st->aincom_mv = ...;
}
> +       if (IS_ERR(aincom)) {
> +               st->aincom_mv = 0;
> +       } else {
> +               ret = regulator_enable(aincom);
> +               if (ret)
> +                       return dev_err_probe(&spi->dev, ret,
> +                                            "Failed to enable specified AINCOM supply\n");
> +
> +               ret = devm_add_action_or_reset(&spi->dev, ad7192_reg_disable, aincom);
> +               if (ret)
> +                       return ret;
> +
> +               ret = regulator_get_voltage(aincom);
> +               if (ret < 0)
> +                       return dev_err_probe(&spi->dev, ret,
> +                                            "Device tree error, AINCOM voltage undefined\n");
> +               st->aincom_mv = ret / 1000;
> +       }
> +
>         st->avdd = devm_regulator_get(&spi->dev, "avdd");
>         if (IS_ERR(st->avdd))
>                 return PTR_ERR(st->avdd);
> --
> 2.34.1
>
diff mbox series

Patch

diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
index ace81e3817a1..3e797ff48086 100644
--- a/drivers/iio/adc/ad7192.c
+++ b/drivers/iio/adc/ad7192.c
@@ -20,6 +20,7 @@ 
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/property.h>
+#include <linux/units.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -186,6 +187,7 @@  struct ad7192_state {
 	struct regulator		*vref;
 	struct clk			*mclk;
 	u16				int_vref_mv;
+	u32				aincom_mv;
 	u32				fclk;
 	u32				mode;
 	u32				conf;
@@ -742,10 +744,19 @@  static int ad7192_read_raw(struct iio_dev *indio_dev,
 			*val = -(1 << (chan->scan_type.realbits - 1));
 		else
 			*val = 0;
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			if (st->aincom_mv && !chan->differential)
+				*val += DIV_ROUND_CLOSEST_ULL((u64)st->aincom_mv * NANO,
+							      st->scale_avail[gain][1]);
+			return IIO_VAL_INT;
 		/* Kelvin to Celsius */
-		if (chan->type == IIO_TEMP)
+		case IIO_TEMP:
 			*val -= 273 * ad7192_get_temp_scale(unipolar);
-		return IIO_VAL_INT;
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		*val = DIV_ROUND_CLOSEST(ad7192_get_f_adc(st), 1024);
 		return IIO_VAL_INT;
@@ -1052,6 +1063,7 @@  static int ad7192_probe(struct spi_device *spi)
 {
 	struct ad7192_state *st;
 	struct iio_dev *indio_dev;
+	struct regulator *aincom;
 	int ret;
 
 	if (!spi->irq) {
@@ -1067,6 +1079,31 @@  static int ad7192_probe(struct spi_device *spi)
 
 	mutex_init(&st->lock);
 
+	/*
+	 * Regulator aincom is optional to maintain compatibility with older DT.
+	 * Newer firmware should provide a zero volt fixed supply if wired to
+	 * ground.
+	 */
+	aincom = devm_regulator_get_optional(&spi->dev, "aincom");
+	if (IS_ERR(aincom)) {
+		st->aincom_mv = 0;
+	} else {
+		ret = regulator_enable(aincom);
+		if (ret)
+			return dev_err_probe(&spi->dev, ret,
+					     "Failed to enable specified AINCOM supply\n");
+
+		ret = devm_add_action_or_reset(&spi->dev, ad7192_reg_disable, aincom);
+		if (ret)
+			return ret;
+
+		ret = regulator_get_voltage(aincom);
+		if (ret < 0)
+			return dev_err_probe(&spi->dev, ret,
+					     "Device tree error, AINCOM voltage undefined\n");
+		st->aincom_mv = ret / 1000;
+	}
+
 	st->avdd = devm_regulator_get(&spi->dev, "avdd");
 	if (IS_ERR(st->avdd))
 		return PTR_ERR(st->avdd);