[PATCH 2/2] iio: adc: stm32-dfsdm: fix sample rate for div2 spi clock

[Fabrice Gasnier]

When channel clk source is set to "CLKOUT_F" or "CLKOUT_R" (e.g. div2),
sample rate is currently set to half the requested value.

Fixes: eca949800d2d ("IIO: ADC: add stm32 DFSDM support for PDM
microphone")

Signed-off-by: Fabrice Gasnier <fabrice.gasn...@st.com>
---
 drivers/iio/adc/stm32-dfsdm-adc.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c 
b/drivers/iio/adc/stm32-dfsdm-adc.c
index dc911b6..b28a716 100644
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -771,7 +771,7 @@ static int stm32_dfsdm_write_raw(struct iio_dev *indio_dev,
        struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
        struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
        struct stm32_dfsdm_channel *ch = &adc->dfsdm->ch_list[chan->channel];
-       unsigned int spi_freq = adc->spi_freq;
+       unsigned int spi_freq;
        int ret = -EINVAL;
 
        switch (mask) {
@@ -785,8 +785,18 @@ static int stm32_dfsdm_write_raw(struct iio_dev *indio_dev,
        case IIO_CHAN_INFO_SAMP_FREQ:
                if (!val)
                        return -EINVAL;
-               if (ch->src != DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL)
+
+               switch (ch->src) {
+               case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL:
                        spi_freq = adc->dfsdm->spi_master_freq;
+                       break;
+               case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_FALLING:
+               case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_RISING:
+                       spi_freq = adc->dfsdm->spi_master_freq / 2;
+                       break;
+               default:
+                       spi_freq = adc->spi_freq;
+               }
 
                if (spi_freq % val)
                        dev_warn(&indio_dev->dev,
-- 
1.9.1