2020-11-27 09:45:31

by Alexandru Ardelean

[permalink] [raw]
Subject: [PATCH 1/2] iio: adc: ad7298: convert probe to device-managed functions

This change converts the probe of this driver to use device-managed
register functions, and a devm_add_action_or_reset() for the regulator
disable.

With this, the exit & error paths can be removed.
Another side-effect is that this should avoid some static-analyzer's check
with respect to a potential null dereference of the regulator. The null
dereference isn't likely to happen (under normal operation), so there isn't
a requirement to have this fixed/backported in other releases.

As a note: this is removing spi_set_drvdata() since there is no other
spi_get_drvdata() (or dev_get_drvdata()) call that need it.

Cc: Colin Ian King <[email protected]>
Signed-off-by: Alexandru Ardelean <[email protected]>
---
drivers/iio/adc/ad7298.c | 46 +++++++++++++---------------------------
1 file changed, 15 insertions(+), 31 deletions(-)

diff --git a/drivers/iio/adc/ad7298.c b/drivers/iio/adc/ad7298.c
index fa1047f74a1f..ecdb01bd5b2f 100644
--- a/drivers/iio/adc/ad7298.c
+++ b/drivers/iio/adc/ad7298.c
@@ -279,6 +279,13 @@ static const struct iio_info ad7298_info = {
.update_scan_mode = ad7298_update_scan_mode,
};

+static void ad7298_reg_disable(void *data)
+{
+ struct regulator *reg = data;
+
+ regulator_disable(reg);
+}
+
static int ad7298_probe(struct spi_device *spi)
{
struct ad7298_state *st;
@@ -306,9 +313,12 @@ static int ad7298_probe(struct spi_device *spi)
ret = regulator_enable(st->reg);
if (ret)
return ret;
- }

- spi_set_drvdata(spi, indio_dev);
+ ret = devm_add_action_or_reset(&spi->dev, ad7298_reg_disable,
+ st->reg);
+ if (ret)
+ return ret;
+ }

st->spi = spi;

@@ -334,37 +344,12 @@ static int ad7298_probe(struct spi_device *spi)
spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);

- ret = iio_triggered_buffer_setup(indio_dev, NULL,
+ ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
&ad7298_trigger_handler, NULL);
if (ret)
- goto error_disable_reg;
-
- ret = iio_device_register(indio_dev);
- if (ret)
- goto error_cleanup_ring;
-
- return 0;
-
-error_cleanup_ring:
- iio_triggered_buffer_cleanup(indio_dev);
-error_disable_reg:
- if (st->ext_ref)
- regulator_disable(st->reg);
-
- return ret;
-}
-
-static int ad7298_remove(struct spi_device *spi)
-{
- struct iio_dev *indio_dev = spi_get_drvdata(spi);
- struct ad7298_state *st = iio_priv(indio_dev);
-
- iio_device_unregister(indio_dev);
- iio_triggered_buffer_cleanup(indio_dev);
- if (st->ext_ref)
- regulator_disable(st->reg);
+ return ret;

- return 0;
+ return devm_iio_device_register(&spi->dev, indio_dev);
}

static const struct spi_device_id ad7298_id[] = {
@@ -378,7 +363,6 @@ static struct spi_driver ad7298_driver = {
.name = "ad7298",
},
.probe = ad7298_probe,
- .remove = ad7298_remove,
.id_table = ad7298_id,
};
module_spi_driver(ad7298_driver);
--
2.27.0


2020-11-28 21:55:49

by Jonathan Cameron

[permalink] [raw]
Subject: Re: [PATCH 1/2] iio: adc: ad7298: convert probe to device-managed functions

On Fri, 27 Nov 2020 11:40:37 +0200
Alexandru Ardelean <[email protected]> wrote:

> This change converts the probe of this driver to use device-managed
> register functions, and a devm_add_action_or_reset() for the regulator
> disable.
>
> With this, the exit & error paths can be removed.
> Another side-effect is that this should avoid some static-analyzer's check
> with respect to a potential null dereference of the regulator. The null
> dereference isn't likely to happen (under normal operation), so there isn't
> a requirement to have this fixed/backported in other releases.
>
> As a note: this is removing spi_set_drvdata() since there is no other
> spi_get_drvdata() (or dev_get_drvdata()) call that need it.
>
> Cc: Colin Ian King <[email protected]>
> Signed-off-by: Alexandru Ardelean <[email protected]>
Series applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to work their magic.

Thanks,

Jonathan

> ---
> drivers/iio/adc/ad7298.c | 46 +++++++++++++---------------------------
> 1 file changed, 15 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7298.c b/drivers/iio/adc/ad7298.c
> index fa1047f74a1f..ecdb01bd5b2f 100644
> --- a/drivers/iio/adc/ad7298.c
> +++ b/drivers/iio/adc/ad7298.c
> @@ -279,6 +279,13 @@ static const struct iio_info ad7298_info = {
> .update_scan_mode = ad7298_update_scan_mode,
> };
>
> +static void ad7298_reg_disable(void *data)
> +{
> + struct regulator *reg = data;
> +
> + regulator_disable(reg);
> +}
> +
> static int ad7298_probe(struct spi_device *spi)
> {
> struct ad7298_state *st;
> @@ -306,9 +313,12 @@ static int ad7298_probe(struct spi_device *spi)
> ret = regulator_enable(st->reg);
> if (ret)
> return ret;
> - }
>
> - spi_set_drvdata(spi, indio_dev);
> + ret = devm_add_action_or_reset(&spi->dev, ad7298_reg_disable,
> + st->reg);
> + if (ret)
> + return ret;
> + }
>
> st->spi = spi;
>
> @@ -334,37 +344,12 @@ static int ad7298_probe(struct spi_device *spi)
> spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
> spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);
>
> - ret = iio_triggered_buffer_setup(indio_dev, NULL,
> + ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
> &ad7298_trigger_handler, NULL);
> if (ret)
> - goto error_disable_reg;
> -
> - ret = iio_device_register(indio_dev);
> - if (ret)
> - goto error_cleanup_ring;
> -
> - return 0;
> -
> -error_cleanup_ring:
> - iio_triggered_buffer_cleanup(indio_dev);
> -error_disable_reg:
> - if (st->ext_ref)
> - regulator_disable(st->reg);
> -
> - return ret;
> -}
> -
> -static int ad7298_remove(struct spi_device *spi)
> -{
> - struct iio_dev *indio_dev = spi_get_drvdata(spi);
> - struct ad7298_state *st = iio_priv(indio_dev);
> -
> - iio_device_unregister(indio_dev);
> - iio_triggered_buffer_cleanup(indio_dev);
> - if (st->ext_ref)
> - regulator_disable(st->reg);
> + return ret;
>
> - return 0;
> + return devm_iio_device_register(&spi->dev, indio_dev);
> }
>
> static const struct spi_device_id ad7298_id[] = {
> @@ -378,7 +363,6 @@ static struct spi_driver ad7298_driver = {
> .name = "ad7298",
> },
> .probe = ad7298_probe,
> - .remove = ad7298_remove,
> .id_table = ad7298_id,
> };
> module_spi_driver(ad7298_driver);