2020-08-15 21:54:49

by Martin Blumenstingl

Subject: [PATCH for-5.9] iio: adc: meson-saradc: Use the parent device to look up the calib data

On the older-gen 32-bit SoCs the meson-saradc driver is used to read the
SoC temperature. This requires reading calibration data from the eFuse.

Looking up the calibration data nvmem-cell requires the OF device_node
pointer to be available in the struct device which is passed to
devm_nvmem_cell_get(). This however got lost with commit 8cb631ccbb1952
("iio: Remove superfluous of_node assignments") from indio_dev->dev. As
devm_nvmem_cell_get() is called in the initialization phase the
device_node is not yet available because the NVMEM cell is looked up
before iio_device_register() is called (which would then set the
device_node automatically).
Use the parent device to look up the NVMEM cell instead to fix this
issue.

Fixes: 8cb631ccbb1952 ("iio: Remove superfluous of_node assignments")
Signed-off-by: Martin Blumenstingl <[email protected]>
---
drivers/iio/adc/meson_saradc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index 93c2252c0b89..1a9189ba69ae 100644
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -707,7 +707,7 @@ static int meson_sar_adc_temp_sensor_init(struct iio_dev *indio_dev)
size_t read_len;
int ret;

- temperature_calib = devm_nvmem_cell_get(&indio_dev->dev,
+ temperature_calib = devm_nvmem_cell_get(indio_dev->dev.parent,
"temperature_calib");
if (IS_ERR(temperature_calib)) {
ret = PTR_ERR(temperature_calib);
--
2.28.0

2020-08-22 10:43:53

by Jonathan Cameron

Subject: Re: [PATCH for-5.9] iio: adc: meson-saradc: Use the parent device to look up the calib data

On Sat, 15 Aug 2020 20:13:55 +0200
Martin Blumenstingl <[email protected]> wrote:

> On the older-gen 32-bit SoCs the meson-saradc driver is used to read the
> SoC temperature. This requires reading calibration data from the eFuse.
>
> Looking up the calibration data nvmem-cell requires the OF device_node
> pointer to be available in the struct device which is passed to
> devm_nvmem_cell_get(). This however got lost with commit 8cb631ccbb1952
> ("iio: Remove superfluous of_node assignments") from indio_dev->dev. As
> devm_nvmem_cell_get() is called in the initialization phase the
> device_node is not yet available because the NVMEM cell is looked up
> before iio_device_register() is called (which would then set the
> device_node automatically).
> Use the parent device to look up the NVMEM cell instead to fix this
> issue.
>
> Fixes: 8cb631ccbb1952 ("iio: Remove superfluous of_node assignments")
> Signed-off-by: Martin Blumenstingl <[email protected]>
Gah. I hope we don't have too many more non obvious cases like
this hiding.

Applied to the fixes-togreg branch of iio.git

Thanks,

Jonathan

> ---
> drivers/iio/adc/meson_saradc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
> index 93c2252c0b89..1a9189ba69ae 100644
> --- a/drivers/iio/adc/meson_saradc.c
> +++ b/drivers/iio/adc/meson_saradc.c
> @@ -707,7 +707,7 @@ static int meson_sar_adc_temp_sensor_init(struct iio_dev *indio_dev)
> size_t read_len;
> int ret;
>
> - temperature_calib = devm_nvmem_cell_get(&indio_dev->dev,
> + temperature_calib = devm_nvmem_cell_get(indio_dev->dev.parent,
> "temperature_calib");
> if (IS_ERR(temperature_calib)) {
> ret = PTR_ERR(temperature_calib);