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SubjectRe: [PATCH v3 2/4] iio: adc: ad7091r5: Add scale and external VREF support
On Thu, 7 Nov 2019 17:07:57 +0200
Beniamin Bia <beniamin.bia@analog.com> wrote:

> From: Paul Cercueil <paul.cercueil@analog.com>
>
> The scale can now be obtained with the "in_voltage_scale" file.
> By default, the scale returned corresponds to the internal VREF of 2.5V.
>
> It is possible to use an external VREF (through the REFIN/REFOUT pin of
> the chip), by passing a regulator to the driver. The scale will then be
> calculated according to the voltage reported by the regulator.
>
> Signed-off-by: Paul Cercueil <paul.cercueil@analog.com>
> Co-developed-by: Beniamin Bia <beniamin.bia@analog.com>
> Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>

A suggestion inline for how to simplify the code a little by only
registering the regulator disable if we actually have a regulator.

Thanks,

Jonathan

> ---
> Changes in v3:
> -type cast from void* in remove function removed
> -error checking for devm_add_action_or_reset
>
> drivers/iio/adc/ad7091r-base.c | 41 ++++++++++++++++++++++++++++++++++
> drivers/iio/adc/ad7091r-base.h | 1 +
> drivers/iio/adc/ad7091r5.c | 5 +++++
> 3 files changed, 47 insertions(+)
>
> diff --git a/drivers/iio/adc/ad7091r-base.c b/drivers/iio/adc/ad7091r-base.c
> index 2ebc40dfd927..abb0d9c2ea9c 100644
> --- a/drivers/iio/adc/ad7091r-base.c
> +++ b/drivers/iio/adc/ad7091r-base.c
> @@ -11,6 +11,7 @@
> #include <linux/interrupt.h>
> #include <linux/module.h>
> #include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
>
> #include "ad7091r-base.h"
>
> @@ -42,6 +43,7 @@ enum ad7091r_mode {
> struct ad7091r_state {
> struct device *dev;
> struct regmap *map;
> + struct regulator *reg;
> const struct ad7091r_chip_info *chip_info;
> enum ad7091r_mode mode;
> struct mutex lock;
> @@ -142,6 +144,21 @@ static int ad7091r_read_raw(struct iio_dev *iio_dev,
> ret = IIO_VAL_INT;
> break;
>
> + case IIO_CHAN_INFO_SCALE:
> + if (st->reg) {
> + ret = regulator_get_voltage(st->reg);
> + if (ret < 0)
> + goto unlock;
> +
> + *val = ret / 1000;
> + } else {
> + *val = st->chip_info->vref_mV;
> + }
> +
> + *val2 = chan->scan_type.realbits;
> + ret = IIO_VAL_FRACTIONAL_LOG2;
> + break;
> +
> default:
> ret = -EINVAL;
> break;
> @@ -184,6 +201,14 @@ static irqreturn_t ad7091r_event_handler(int irq, void *private)
> return IRQ_HANDLED;
> }
>
> +static void ad7091r_remove(void *data)
> +{
> + struct ad7091r_state *st = data;
> +
> + if (st->reg)
> + regulator_disable(st->reg);
> +}
> +
> int ad7091r_probe(struct device *dev, const char *name,
> const struct ad7091r_chip_info *chip_info,
> struct regmap *map, int irq)
> @@ -217,6 +242,22 @@ int ad7091r_probe(struct device *dev, const char *name,
> return ret;
> }
>
> + st->reg = devm_regulator_get_optional(dev, "vref");
> + if (IS_ERR(st->reg)) {
> + if (PTR_ERR(st->reg) == EPROBE_DEFER)
> + return -EPROBE_DEFER;
> +
> + st->reg = NULL;
> + } else {
> + ret = regulator_enable(st->reg);
> + if (ret)
> + return ret;
> + }
> +
> + ret = devm_add_action_or_reset(dev, ad7091r_remove, st);
> + if (ret)
> + return ret;
> +
This is more complex than it needs to be...

st->reg = devm_regulator_get_optional(dev, "vref");
if (IS_ERR(st->reg)) {
if (PTR_ERR(st->reg) == EPROBE_DEFER)
return -EPROBE_DEFER;

st->reg = NULL;
} else {
ret = regulator_enable(st->reg);
if (ret)
return ret;
ret = devm_add_action_or_reset(dec, ad7091r_dis_reg, st);
if (ret)
return ret;
}

with
static void ad7091r_dis_reg(void *data)
{
struct ad7091r_state *st = data;

regulator_disable(st->reg);
}

That way the disable is only registered if we actually have a reg
and hence we don't need to check if we do.

Also, give it a more specific name than reg. Chances are someone
will add the main power supply control sometime in the future.


> /* Use command mode by default to convert only desired channels*/
> ret = ad7091r_set_mode(st, AD7091R_MODE_COMMAND);
> if (ret)
> diff --git a/drivers/iio/adc/ad7091r-base.h b/drivers/iio/adc/ad7091r-base.h
> index 5f1147735953..76b76968d071 100644
> --- a/drivers/iio/adc/ad7091r-base.h
> +++ b/drivers/iio/adc/ad7091r-base.h
> @@ -14,6 +14,7 @@ struct ad7091r_state;
> struct ad7091r_chip_info {
> unsigned int num_channels;
> const struct iio_chan_spec *channels;
> + unsigned int vref_mV;
> };
>
> extern const struct regmap_config ad7091r_regmap_config;
> diff --git a/drivers/iio/adc/ad7091r5.c b/drivers/iio/adc/ad7091r5.c
> index f7b3326032e8..73d18ddfd2c9 100644
> --- a/drivers/iio/adc/ad7091r5.c
> +++ b/drivers/iio/adc/ad7091r5.c
> @@ -35,10 +35,13 @@ static const struct iio_event_spec ad7091r5_events[] = {
> #define AD7091R_CHANNEL(idx, bits, ev, num_ev) { \
> .type = IIO_VOLTAGE, \
> .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> .indexed = 1, \
> .channel = idx, \
> .event_spec = ev, \
> .num_event_specs = num_ev, \
> + .scan_type.storagebits = 16, \
> + .scan_type.realbits = bits, \
> }
> static const struct iio_chan_spec ad7091r5_channels_irq[] = {
> AD7091R_CHANNEL(0, 12, ad7091r5_events, ARRAY_SIZE(ad7091r5_events)),
> @@ -58,11 +61,13 @@ static const struct iio_chan_spec ad7091r5_channels_noirq[] = {
> static const struct ad7091r_chip_info ad7091r5_chip_info_irq = {
> .channels = ad7091r5_channels_irq,
> .num_channels = ARRAY_SIZE(ad7091r5_channels_irq),
> + .vref_mV = 2500,
> };
>
> static const struct ad7091r_chip_info ad7091r5_chip_info_noirq = {
> .channels = ad7091r5_channels_noirq,
> .num_channels = ARRAY_SIZE(ad7091r5_channels_noirq),
> + .vref_mV = 2500,
> };
>
> static int ad7091r5_i2c_probe(struct i2c_client *i2c,

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