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Subject[PATCH 4.16 30/47] iio: adc: stm32-dfsdm: fix sample rate for div2 spi clock
Date
4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Fabrice Gasnier <fabrice.gasnier@st.com>

commit d58109dcf37fc9baec354385ec9fdcd8878d174d upstream.

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.gasnier@st.com>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/iio/adc/stm32-dfsdm-adc.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

--- 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
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
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,

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