On 09/17/2012 01:26 PM, Lars-Peter Clausen wrote:
> Add support for the ad7091r 12 bit ADC to the ad7476 driver. Although the
> ad7091r is not really related to any of the other devices supported by this
> driver, luckily for us there are not so many ways (which are not totally insane)
> how sampling a single channel ADC via SPI can be implemented and support for the
> ad7091r can be added to the driver with just a few adjustments.
Yup, eveything is nice and simple when there is only one channel ;)
>
> The ad7091r requires an external "conversion start" pulse to start a sample
> conversion. After the conversion has finished the result can be read via SPI. We
> depend on a IIO trigger to generate this signal, as a result only sampling in
> buffered mode and not in manual mode is available.
This is a little restrictive given we could wire up some magic with a gpio to
do this, but I guess things like that can be added as and when people care.
We may need some way of 'knowing' whether a more general trigger has done
the start pulse or not... Something for another day.
merged to togreg branch of iio.git
Thanks.
>
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
> ---
> drivers/iio/adc/ad7476.c | 30 ++++++++++++++++++++++++++----
> 1 file changed, 26 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7476.c b/drivers/iio/adc/ad7476.c
> index be2098d..7f2f45a 100644
> --- a/drivers/iio/adc/ad7476.c
> +++ b/drivers/iio/adc/ad7476.c
> @@ -23,9 +23,12 @@
>
> #define RES_MASK(bits) ((1 << (bits)) - 1)
>
> +struct ad7476_state;
> +
> struct ad7476_chip_info {
> unsigned int int_vref_uv;
> struct iio_chan_spec channel[2];
> + void (*reset)(struct ad7476_state *);
> };
>
> struct ad7476_state {
> @@ -45,6 +48,7 @@ struct ad7476_state {
> };
>
> enum ad7476_supported_device_ids {
> + ID_AD7091R,
> ID_AD7276,
> ID_AD7277,
> ID_AD7278,
> @@ -79,6 +83,12 @@ done:
> return IRQ_HANDLED;
> }
>
> +static void ad7091_reset(struct ad7476_state *st)
> +{
> + /* Any transfers with 8 scl cycles will reset the device */
> + spi_read(st->spi, st->data, 1);
> +}
> +
> static int ad7476_scan_direct(struct ad7476_state *st)
> {
> int ret;
> @@ -130,11 +140,11 @@ static int ad7476_read_raw(struct iio_dev *indio_dev,
> return -EINVAL;
> }
>
> -#define _AD7476_CHAN(bits, _shift) \
> +#define _AD7476_CHAN(bits, _shift, _info_mask) \
> { \
> .type = IIO_VOLTAGE, \
> .indexed = 1, \
> - .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | \
> + .info_mask = _info_mask | \
> IIO_CHAN_INFO_SCALE_SHARED_BIT, \
> .scan_type = { \
> .sign = 'u', \
> @@ -145,10 +155,18 @@ static int ad7476_read_raw(struct iio_dev *indio_dev,
> }, \
> }
>
> -#define AD7476_CHAN(bits) _AD7476_CHAN((bits), 13 - (bits))
> -#define AD7940_CHAN(bits) _AD7476_CHAN((bits), 15 - (bits))
> +#define AD7476_CHAN(bits) _AD7476_CHAN((bits), 13 - (bits), \
> + IIO_CHAN_INFO_RAW_SEPARATE_BIT)
> +#define AD7940_CHAN(bits) _AD7476_CHAN((bits), 15 - (bits), \
> + IIO_CHAN_INFO_RAW_SEPARATE_BIT)
> +#define AD7091R_CHAN(bits) _AD7476_CHAN((bits), 16 - (bits), 0)
>
> static const struct ad7476_chip_info ad7476_chip_info_tbl[] = {
> + [ID_AD7091R] = {
> + .channel[0] = AD7091R_CHAN(12),
> + .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
> + .reset = ad7091_reset,
> + },
> [ID_AD7276] = {
> .channel[0] = AD7940_CHAN(12),
> .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
> @@ -238,6 +256,9 @@ static int __devinit ad7476_probe(struct spi_device *spi)
> if (ret)
> goto error_disable_reg;
>
> + if (st->chip_info->reset)
> + st->chip_info->reset(st);
> +
> ret = iio_device_register(indio_dev);
> if (ret)
> goto error_ring_unregister;
> @@ -271,6 +292,7 @@ static int __devexit ad7476_remove(struct spi_device *spi)
> }
>
> static const struct spi_device_id ad7476_id[] = {
> + {"ad7091r", ID_AD7091R},
> {"ad7273", ID_AD7277},
> {"ad7274", ID_AD7276},
> {"ad7276", ID_AD7276},
>
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