2022-06-06 04:53:38

by Andy Shevchenko

Subject: [RFC PATCH v3 6/6] iio: adc: meson_saradc: Use regmap_read_poll_timeout() for busy wait

Simplify busy wait stages by using regmap_read_poll_timeout().

Signed-off-by: Andy Shevchenko <[email protected]>
---
v3: new patch, but RFC, not always the read_poll_timeout() can be used, would
be nice to have it tested.

drivers/iio/adc/meson_saradc.c | 31 +++++++++++++------------------
1 file changed, 13 insertions(+), 18 deletions(-)

diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index c100f933c12e..c18be3c519af 100644
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -322,22 +322,17 @@ static int meson_sar_adc_calib_val(struct iio_dev *indio_dev, int val)
static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
- int regval, timeout = 10000;
+ int val;

/*
* NOTE: we need a small delay before reading the status, otherwise
* the sample engine may not have started internally (which would
* seem to us that sampling is already finished).
*/
- do {
- udelay(1);
- regmap_read(priv->regmap, MESON_SAR_ADC_REG0, &regval);
- } while (FIELD_GET(MESON_SAR_ADC_REG0_BUSY_MASK, regval) && timeout--);
-
- if (timeout < 0)
- return -ETIMEDOUT;
-
- return 0;
+ udelay(1);
+ return regmap_read_poll_timeout_atomic(priv->regmap, MESON_SAR_ADC_REG0, val,
+ !FIELD_GET(MESON_SAR_ADC_REG0_BUSY_MASK, val),
+ 1, 10000);
}

static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
@@ -489,7 +484,7 @@ static void meson_sar_adc_stop_sample_engine(struct iio_dev *indio_dev)
static int meson_sar_adc_lock(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
- int val, timeout = 10000;
+ int val, ret;

mutex_lock(&indio_dev->mlock);

@@ -499,18 +494,18 @@ static int meson_sar_adc_lock(struct iio_dev *indio_dev)
MESON_SAR_ADC_DELAY_KERNEL_BUSY,
MESON_SAR_ADC_DELAY_KERNEL_BUSY);

+ udelay(1);
+
/*
* wait until BL30 releases it's lock (so we can use the SAR
* ADC)
*/
- do {
- udelay(1);
- regmap_read(priv->regmap, MESON_SAR_ADC_DELAY, &val);
- } while (val & MESON_SAR_ADC_DELAY_BL30_BUSY && timeout--);
-
- if (timeout < 0) {
+ ret = regmap_read_poll_timeout_atomic(priv->regmap, MESON_SAR_ADC_DELAY, val,
+ !(val & MESON_SAR_ADC_DELAY_BL30_BUSY),
+ 1, 10000);
+ if (ret) {
mutex_unlock(&indio_dev->mlock);
- return -ETIMEDOUT;
+ return ret;
}
}

--
2.35.1

2022-06-06 06:06:08

by Martin Blumenstingl

Subject: Re: [RFC PATCH v3 6/6] iio: adc: meson_saradc: Use regmap_read_poll_timeout() for busy wait

On Fri, Jun 3, 2022 at 12:00 PM Andy Shevchenko
<[email protected]> wrote:
>
> Simplify busy wait stages by using regmap_read_poll_timeout().
>
> Signed-off-by: Andy Shevchenko <[email protected]>
Reviewed-by: Martin Blumenstingl <[email protected]>

> v3: new patch, but RFC, not always the read_poll_timeout() can be used, would
> be nice to have it tested.
and also:
Tested-by: Martin Blumenstingl <[email protected]> # GXM VIM2

2022-06-06 10:35:13

by Andy Shevchenko

Subject: Re: [RFC PATCH v3 6/6] iio: adc: meson_saradc: Use regmap_read_poll_timeout() for busy wait

On Sun, Jun 05, 2022 at 11:59:53PM +0200, Martin Blumenstingl wrote:
> On Fri, Jun 3, 2022 at 12:00 PM Andy Shevchenko
> <[email protected]> wrote:
> >
> > Simplify busy wait stages by using regmap_read_poll_timeout().
> >
> > Signed-off-by: Andy Shevchenko <[email protected]>
> Reviewed-by: Martin Blumenstingl <[email protected]>
>
> > v3: new patch, but RFC, not always the read_poll_timeout() can be used, would
> > be nice to have it tested.
> and also:
> Tested-by: Martin Blumenstingl <[email protected]> # GXM VIM2

Thanks for testing!

--
With Best Regards,
Andy Shevchenko