On Fri, 24 Aug 2018 17:53:15 +0800
Baolin Wang <baolin.w...@linaro.org> wrote:
> The headset device will use channel 20 of ADC controller to detect events,
> but it needs the raw ADC data to do conversion according to its own formula.
>
> Thus we should configure the channel mask separately and configure channel
> 20 as IIO_CHAN_INFO_RAW, as well as adding raw data read support.
So is this a general thing, i.e. that channel is 'meant' to be used for the
headset, or just a one off for a particular board?
If it is a general thing, than I'm fine with this (unlikely we'll break any
other users), but if not we need to find a nicer way to do it.
I am a little unclear on how a channel would provide the voltage on it's pin
but that could be wrong when used for a different purpose?
If it's just a matter of unusual loading characteristics then perhaps that
is valid, but I'd like to understand this a little.
>
> Signed-off-by: Baolin Wang <baolin.w...@linaro.org>
> ---
> drivers/iio/adc/sc27xx_adc.c | 80
> ++++++++++++++++++++++++------------------
> 1 file changed, 45 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/iio/adc/sc27xx_adc.c b/drivers/iio/adc/sc27xx_adc.c
> index 2b60efe..153c311 100644
> --- a/drivers/iio/adc/sc27xx_adc.c
> +++ b/drivers/iio/adc/sc27xx_adc.c
> @@ -273,6 +273,17 @@ static int sc27xx_adc_read_raw(struct iio_dev *indio_dev,
> int ret, tmp;
>
> switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + mutex_lock(&indio_dev->mlock);
> + ret = sc27xx_adc_read(data, chan->channel, scale, &tmp);
> + mutex_unlock(&indio_dev->mlock);
> +
> + if (ret)
> + return ret;
> +
> + *val = tmp;
> + return IIO_VAL_INT;
> +
> case IIO_CHAN_INFO_PROCESSED:
> mutex_lock(&indio_dev->mlock);
> ret = sc27xx_adc_read_processed(data, chan->channel, scale,
> @@ -315,48 +326,47 @@ static int sc27xx_adc_write_raw(struct iio_dev
> *indio_dev,
> .write_raw = &sc27xx_adc_write_raw,
> };
>
> -#define SC27XX_ADC_CHANNEL(index) { \
> +#define SC27XX_ADC_CHANNEL(index, mask) { \
> .type = IIO_VOLTAGE, \
> .channel = index, \
> - .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) | \
> - BIT(IIO_CHAN_INFO_SCALE), \
> + .info_mask_separate = mask | BIT(IIO_CHAN_INFO_SCALE), \
> .datasheet_name = "CH##index", \
> .indexed = 1, \
> }
>
> static const struct iio_chan_spec sc27xx_channels[] = {
> - SC27XX_ADC_CHANNEL(0),
> - SC27XX_ADC_CHANNEL(1),
> - SC27XX_ADC_CHANNEL(2),
> - SC27XX_ADC_CHANNEL(3),
> - SC27XX_ADC_CHANNEL(4),
> - SC27XX_ADC_CHANNEL(5),
> - SC27XX_ADC_CHANNEL(6),
> - SC27XX_ADC_CHANNEL(7),
> - SC27XX_ADC_CHANNEL(8),
> - SC27XX_ADC_CHANNEL(9),
> - SC27XX_ADC_CHANNEL(10),
> - SC27XX_ADC_CHANNEL(11),
> - SC27XX_ADC_CHANNEL(12),
> - SC27XX_ADC_CHANNEL(13),
> - SC27XX_ADC_CHANNEL(14),
> - SC27XX_ADC_CHANNEL(15),
> - SC27XX_ADC_CHANNEL(16),
> - SC27XX_ADC_CHANNEL(17),
> - SC27XX_ADC_CHANNEL(18),
> - SC27XX_ADC_CHANNEL(19),
> - SC27XX_ADC_CHANNEL(20),
> - SC27XX_ADC_CHANNEL(21),
> - SC27XX_ADC_CHANNEL(22),
> - SC27XX_ADC_CHANNEL(23),
> - SC27XX_ADC_CHANNEL(24),
> - SC27XX_ADC_CHANNEL(25),
> - SC27XX_ADC_CHANNEL(26),
> - SC27XX_ADC_CHANNEL(27),
> - SC27XX_ADC_CHANNEL(28),
> - SC27XX_ADC_CHANNEL(29),
> - SC27XX_ADC_CHANNEL(30),
> - SC27XX_ADC_CHANNEL(31),
> + SC27XX_ADC_CHANNEL(0, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(1, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(2, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(3, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(4, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(5, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(6, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(7, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(8, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(9, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(10, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(11, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(12, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(13, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(14, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(15, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(16, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(17, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(18, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(19, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(20, BIT(IIO_CHAN_INFO_RAW)),
> + SC27XX_ADC_CHANNEL(21, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(22, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(23, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(24, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(25, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(26, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(27, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(28, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(29, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(30, BIT(IIO_CHAN_INFO_PROCESSED)),
> + SC27XX_ADC_CHANNEL(31, BIT(IIO_CHAN_INFO_PROCESSED)),
> };
>
> static int sc27xx_adc_enable(struct sc27xx_adc_data *data)
