Dear Hector, On 03/07/2013 12:06, Hector Palacios wrote: > Most LRADC channels have an optional divisor by two which allows > a maximum input voltage of VDDIO - 50mV. This patch adds the scaling > info flag to these channels (all except 7 -VBATT-, 10 -VDDIO- and > 15 -VDD5V-) to allow enabled divide_by_two read operation. > > Reference: http://www.spinics.net/lists/linux-iio/msg08876.html > Signed-off-by: Hector Palacios <hector.palacios@xxxxxxxx> > --- > drivers/staging/iio/adc/mxs-lradc.c | 52 +++++++++++++++++++++++-------------- > 1 file changed, 33 insertions(+), 19 deletions(-) > > diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c > index 51f781f..4363bb6 100644 > --- a/drivers/staging/iio/adc/mxs-lradc.c > +++ b/drivers/staging/iio/adc/mxs-lradc.c > @@ -197,6 +197,7 @@ struct mxs_lradc { > #define LRADC_CTRL1_LRADC_IRQ_OFFSET 0 > > #define LRADC_CTRL2 0x20 > +#define LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET 24 > #define LRADC_CTRL2_TEMPSENSE_PWD (1 << 15) > > #define LRADC_STATUS 0x40 > @@ -234,7 +235,7 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev, > struct mxs_lradc *lradc = iio_priv(iio_dev); > int ret; > > - if (m != IIO_CHAN_INFO_RAW) > + if (m != IIO_CHAN_INFO_RAW && m != IIO_CHAN_INFO_SCALE) > return -EINVAL; > > /* Check for invalid channel */ > @@ -262,6 +263,11 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev, > lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR); > writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR); > > + /* Enable DIVIDE_BY_TWO on channel 0 if reading scaled value */ > + if (IIO_CHAN_INFO_SCALE == m) > + writel(1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET, > + lradc->base + LRADC_CTRL2 + STMP_OFFSET_REG_SET); > + > /* Clean the slot's previous content, then set new one. */ > writel(LRADC_CTRL4_LRADCSELECT_MASK(0), > lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR); > @@ -286,6 +292,10 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev, > ret = IIO_VAL_INT; > > err: > + /* Disable DIVIDE_BY_TWO on channel 0 if reading scaled value */ > + if (IIO_CHAN_INFO_SCALE == m) > + writel(1 << LRADC_CTRL2_DIVIDE_BY_TWO_OFFSET, > + lradc->base + LRADC_CTRL2 + STMP_OFFSET_REG_CLR); > writel(LRADC_CTRL1_LRADC_IRQ_EN(0), > lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR); > > @@ -806,11 +816,11 @@ static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = { > * Driver initialization > */ > > -#define MXS_ADC_CHAN(idx, chan_type) { \ > +#define MXS_ADC_CHAN(idx, chan_type, info) { \ > .type = (chan_type), \ > .indexed = 1, \ > .scan_index = (idx), \ > - .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT, \ > + .info_mask = (info), \ > .channel = (idx), \ > .scan_type = { \ > .sign = 'u', \ > @@ -819,23 +829,27 @@ static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = { > }, \ > } > > +#define RAW IIO_CHAN_INFO_RAW_SEPARATE_BIT > +#define RAW_SCALED (IIO_CHAN_INFO_RAW_SEPARATE_BIT | \ > + IIO_CHAN_INFO_SCALE_SEPARATE_BIT) > + > static const struct iio_chan_spec mxs_lradc_chan_spec[] = { > - MXS_ADC_CHAN(0, IIO_VOLTAGE), > - MXS_ADC_CHAN(1, IIO_VOLTAGE), > - MXS_ADC_CHAN(2, IIO_VOLTAGE), > - MXS_ADC_CHAN(3, IIO_VOLTAGE), > - MXS_ADC_CHAN(4, IIO_VOLTAGE), > - 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 */ > - MXS_ADC_CHAN(10, IIO_VOLTAGE), /* VDDIO */ > - MXS_ADC_CHAN(11, IIO_VOLTAGE), /* VTH */ > - MXS_ADC_CHAN(12, IIO_VOLTAGE), /* VDDA */ > - MXS_ADC_CHAN(13, IIO_VOLTAGE), /* VDDD */ > - MXS_ADC_CHAN(14, IIO_VOLTAGE), /* VBG */ > - MXS_ADC_CHAN(15, IIO_VOLTAGE), /* VDD5V */ > + MXS_ADC_CHAN(0, IIO_VOLTAGE, RAW_SCALED), > + MXS_ADC_CHAN(1, IIO_VOLTAGE, RAW_SCALED), > + MXS_ADC_CHAN(2, IIO_VOLTAGE, RAW_SCALED), > + MXS_ADC_CHAN(3, IIO_VOLTAGE, RAW_SCALED), > + MXS_ADC_CHAN(4, IIO_VOLTAGE, RAW_SCALED), > + MXS_ADC_CHAN(5, IIO_VOLTAGE, RAW_SCALED), > + MXS_ADC_CHAN(6, IIO_VOLTAGE, RAW_SCALED), > + MXS_ADC_CHAN(7, IIO_VOLTAGE, RAW), /* VBATT */ > + MXS_ADC_CHAN(8, IIO_TEMP, RAW_SCALED), /* Temp sense 0 */ > + MXS_ADC_CHAN(9, IIO_TEMP, RAW_SCALED), /* Temp sense 1 */ > + MXS_ADC_CHAN(10, IIO_VOLTAGE, RAW), /* VDDIO */ > + MXS_ADC_CHAN(11, IIO_VOLTAGE, RAW_SCALED), /* VTH */ > + MXS_ADC_CHAN(12, IIO_VOLTAGE, RAW_SCALED), /* VDDA */ > + MXS_ADC_CHAN(13, IIO_VOLTAGE, RAW_SCALED), /* VDDD */ > + MXS_ADC_CHAN(14, IIO_VOLTAGE, RAW_SCALED), /* VBG */ > + MXS_ADC_CHAN(15, IIO_VOLTAGE, RAW), /* VDD5V */ > }; > > static void mxs_lradc_hw_init(struct mxs_lradc *lradc) This is not how it is supposed to work. you should actually add IIO_CHAN_INFO_SCALE_SEPARATE_BIT to all channels .info_mask_separate. Then, you will get two files: in_voltageX_raw and in_voltageX_scale. Userland should calculate in_voltageX_raw * in_voltageX_scale. So when reading in_voltageX_scale, you actually want to read the current scale. To set the scale, you'll have to implement a write_raw. Also, it would probably be a good idea to expose a in_voltageX_scale_available file. -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
