Hi,
On 01/07/2013 19:16, Alexandre Belloni wrote:
> The mxs LRADC is able to read an internal die temperature sensor. The
> temperature has to be calculated from the value read on channel 8 and channel 9.
> To be able to expose the result to hwmon, implement iio channel 8 as
> (channel 9 - channel 8). Then, implement IIO_CHAN_INFO_SCALE and
> IIO_CHAN_INFO_OFFSET so that it can be processed by hwmon through the in kernel
> provider/consumer mechanism.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
I didn't get any review on that patch. I know it will already conflict
with what Hector has been working on but would that be the good way to go ?
> ---
> drivers/staging/iio/adc/mxs-lradc.c | 99 ++++++++++++++++++++++++++++++-------
> 1 file changed, 82 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
> index 163c638..df1d81e 100644
> --- a/drivers/staging/iio/adc/mxs-lradc.c
> +++ b/drivers/staging/iio/adc/mxs-lradc.c
> @@ -225,26 +225,14 @@ struct mxs_lradc {
> #define LRADC_CTRL4_LRADCSELECT_MASK(n) (0xf << ((n) * 4))
> #define LRADC_CTRL4_LRADCSELECT_OFFSET(n) ((n) * 4)
>
> -/*
> - * Raw I/O operations
> - */
> -static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
> - const struct iio_chan_spec *chan,
> - int *val, int *val2, long m)
> +static int mxs_lradc_read_single(struct iio_dev *iio_dev, int chan, int *val)
> {
> struct mxs_lradc *lradc = iio_priv(iio_dev);
> int ret;
> unsigned long mask;
>
> - if (m != IIO_CHAN_INFO_RAW)
> - return -EINVAL;
> -
> - /* Check for invalid channel */
> - if (chan->channel > LRADC_MAX_TOTAL_CHANS)
> - return -EINVAL;
> -
> /* Validate the channel if it doesn't intersect with reserved chans. */
> - bitmap_set(&mask, chan->channel, 1);
> + bitmap_set(&mask, chan, 1);
> ret = iio_validate_scan_mask_onehot(iio_dev, &mask);
> if (ret)
> return -EINVAL;
> @@ -273,7 +261,7 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
> /* Clean the slot's previous content, then set new one. */
> writel(LRADC_CTRL4_LRADCSELECT_MASK(0),
> lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
> - writel(chan->channel, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
> + writel(chan, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
>
> writel(0, lradc->base + LRADC_CH(0));
>
> @@ -302,6 +290,74 @@ err:
> return ret;
> }
>
> +static int mxs_lradc_read_temp(struct iio_dev *iio_dev, int *val)
> +{
> + int ret, min, max;
> +
> + ret = mxs_lradc_read_single(iio_dev, 8, &min);
> + if (ret != IIO_VAL_INT)
> + return ret;
> +
> + ret = mxs_lradc_read_single(iio_dev, 9, &max);
> + if (ret != IIO_VAL_INT)
> + return ret;
> +
> + *val = max - min;
> +
> + return IIO_VAL_INT;
> +}
> +
> +/*
> + * Raw I/O operations
> + */
> +static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
> + const struct iio_chan_spec *chan,
> + int *val, int *val2, long m)
> +{
> + /* Check for invalid channel */
> + if (chan->channel > LRADC_MAX_TOTAL_CHANS)
> + return -EINVAL;
> +
> + switch (m) {
> + case IIO_CHAN_INFO_RAW:
> + if (chan->type == IIO_TEMP)
> + return mxs_lradc_read_temp(iio_dev, val);
> +
> + return mxs_lradc_read_single(iio_dev, chan->channel, val);
> +
> + case IIO_CHAN_INFO_SCALE:
> + if (chan->type == IIO_TEMP) {
> + /* From the datasheet, we have to multiply by 1.012 and
> + * divide by 4
> + */
> + *val = 0;
> + *val2 = 253000;
> + return IIO_VAL_INT_PLUS_MICRO;
> + }
> +
> + return -EINVAL;
> +
> + case IIO_CHAN_INFO_OFFSET:
> + if (chan->type == IIO_TEMP) {
> + /* The calculated value from the ADC is in Kelvin, we
> + * want Celsius for hwmon so the offset is
> + * -272.15 * scale
> + */
> + *val = -1075;
> + *val2 = 691699;
> +
> + return IIO_VAL_INT_PLUS_MICRO;
> + }
> +
> + return -EINVAL;
> +
> + default:
> + break;
> + }
> +
> + return -EINVAL;
> +}
> +
> static const struct iio_info mxs_lradc_iio_info = {
> .driver_module = THIS_MODULE,
> .read_raw = mxs_lradc_read_raw,
> @@ -836,8 +892,17 @@ static const struct iio_chan_spec mxs_lradc_chan_spec[] = {
> MXS_ADC_CHAN(5, IIO_VOLTAGE),
> MXS_ADC_CHAN(6, IIO_VOLTAGE),
> MXS_ADC_CHAN(7, IIO_VOLTAGE), /* VBATT */
> - MXS_ADC_CHAN(8, IIO_TEMP), /* Temp sense 0 */
> - MXS_ADC_CHAN(9, IIO_TEMP), /* Temp sense 1 */
> + /* Combined Temperature sensors */
> + {
> + .type = IIO_TEMP,
> + .indexed = 1,
> + .scan_index = 8,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_OFFSET) |
> + BIT(IIO_CHAN_INFO_SCALE),
> + .channel = 8,
> + .scan_type = {.sign = 'u', .realbits = 18, .storagebits = 32,},
> + },
> MXS_ADC_CHAN(10, IIO_VOLTAGE), /* VDDIO */
> MXS_ADC_CHAN(11, IIO_VOLTAGE), /* VTH */
> MXS_ADC_CHAN(12, IIO_VOLTAGE), /* VDDA */
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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