Hi Jonathan,
On 25 August 2018 at 16:38, Jonathan Cameron <ji...@kernel.org> wrote:
> 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.
Yes, it is a general thing. Now channel 20 is always used for the headset.
> 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.
On our platform, the headset will use this voltage value reading from
ADC to check the headset events: headset buttons, headset plugin and
so on.
>>
>> 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)
>
--
Baolin Wang
Best Regards
