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iio: adc: at91-sama5d2_adc: disable/prepare buffer on suspend/resume

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In case triggered buffers are enabled while system is suspended they will
not work anymore after resume. For this call at91_adc_buffer_postdisable()
on suspend and at91_adc_buffer_prepare() on resume. On tests it has been
seen that at91_adc_buffer_postdisable() call is not necessary but it has
been kept because it also does the book keeping for DMA. On resume path
there is no need to call at91_adc_configure_touch() as it is embedded in
at91_adc_buffer_prepare().

Fixes: 073c662017 ("iio: adc: at91-sama5d2_adc: add support for DMA")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220803102855.2191070-5-claudiu.beznea@microchip.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Claudiu Beznea 2022-08-03 13:28:40 +03:00 committed by Jonathan Cameron
parent 9780a23ed5
commit 808175e21d
1 changed files with 7 additions and 7 deletions
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14
drivers/iio/adc/at91-sama5d2_adc.c
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@ -2116,6 +2116,9 @@ static int at91_adc_suspend(struct device *dev)
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct at91_adc_state *st = iio_priv(indio_dev);
if (iio_buffer_enabled(indio_dev))
at91_adc_buffer_postdisable(indio_dev);
/*
* Do a sofware reset of the ADC before we go to suspend.
* this will ensure that all pins are free from being muxed by the ADC
@ -2159,14 +2162,11 @@ static int at91_adc_resume(struct device *dev)
if (!iio_buffer_enabled(indio_dev))
return 0;
/* check if we are enabling triggered buffer or the touchscreen */
if (at91_adc_current_chan_is_touch(indio_dev))
return at91_adc_configure_touch(st, true);
else
return at91_adc_configure_trigger(st->trig, true);
ret = at91_adc_buffer_prepare(indio_dev);
if (ret)
goto vref_disable_resume;
/* not needed but more explicit */
return 0;
return at91_adc_configure_trigger(st->trig, true);
vref_disable_resume:
regulator_disable(st->vref);