[PATCH v2 2/2] iio: adc: meson-saradc: improve meson_sar_adc_read_raw_sample
From: Heiner Kallweit <hkallweit1@gmail.com>
Date: 2017-02-15 19:32:08
Subsystem:
iio subsystem and drivers, the rest · Maintainers:
Jonathan Cameron, Linus Torvalds
After sampling there should always be only one value in the FIFO. This also applies to averaging mode as the averaging is done chip-internally. So we don't have to loop and let the driver complain if there's not exactly one value in the FIFO. If the value belongs to a different channel then don't silently swallow the value but complain. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> --- v2: - rebased --- drivers/iio/adc/meson_saradc.c | 36 +++++++++++++++++------------------- 1 file changed, 17 insertions(+), 19 deletions(-)
diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index 9f186de2..cde9ca7a 100644
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c@@ -278,33 +278,31 @@ static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev, int *val) { struct meson_sar_adc_priv *priv = iio_priv(indio_dev); - int regval, fifo_chan, fifo_val, sum = 0, count = 0; + int regval, fifo_chan, fifo_val, count; if(!wait_for_completion_timeout(&priv->done, msecs_to_jiffies(MESON_SAR_ADC_TIMEOUT))) return -ETIMEDOUT; - while (meson_sar_adc_get_fifo_count(indio_dev) > 0 && - count < MESON_SAR_ADC_MAX_FIFO_SIZE) { - regmap_read(priv->regmap, MESON_SAR_ADC_FIFO_RD, ®val); - - fifo_chan = FIELD_GET(MESON_SAR_ADC_FIFO_RD_CHAN_ID_MASK, - regval); - if (fifo_chan != chan->channel) - continue; - - fifo_val = FIELD_GET(MESON_SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK, - regval); - fifo_val &= (BIT(priv->data->resolution) - 1); - - sum += fifo_val; - count++; + count = meson_sar_adc_get_fifo_count(indio_dev); + if (count != 1) { + dev_err(&indio_dev->dev, + "ADC FIFO has %d element(s) instead of one\n", count); + return -EINVAL; } - if (!count) - return -ENOENT; + regmap_read(priv->regmap, MESON_SAR_ADC_FIFO_RD, ®val); + fifo_chan = FIELD_GET(MESON_SAR_ADC_FIFO_RD_CHAN_ID_MASK, regval); + if (fifo_chan != chan->channel) { + dev_err(&indio_dev->dev, + "ADC FIFO entry belongs to channel %d instead of %d\n", + fifo_chan, chan->channel); + return -EINVAL; + } - *val = sum / count; + fifo_val = FIELD_GET(MESON_SAR_ADC_FIFO_RD_SAMPLE_VALUE_MASK, regval); + fifo_val &= GENMASK(priv->data->resolution - 1, 0); + *val = fifo_val; return 0; }
--
2.11.1