Re: [PATCH v2 1/2] iio: adc: ti-ads8344: properly byte swap value

From: Jonathan Cameron
Date: Sat Apr 18 2020 - 11:06:15 EST


On Thu, 16 Apr 2020 22:54:27 +0200
Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> wrote:

> The first received byte is the MSB, followed by the LSB so the value needs
> to be byte swapped.
>
> Also, the ADC actually has a delay of one clock on the SPI bus. Read three
> bytes to get the last bit.
>
> Fixes: 8dd2d7c0fed7 ("iio: adc: Add driver for the TI ADS8344 A/DC chips")
> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>

Applied to the fixes-togreg branch of iio.git. Marked for stable.

Random aside that I'll probably forget to clean up.

Driver includes iio/buffer.h and doesn't use it...

Thanks,

Jonathan


> ---
> drivers/iio/adc/ti-ads8344.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/adc/ti-ads8344.c b/drivers/iio/adc/ti-ads8344.c
> index 9a460807d46d..abe4b56c847c 100644
> --- a/drivers/iio/adc/ti-ads8344.c
> +++ b/drivers/iio/adc/ti-ads8344.c
> @@ -29,7 +29,7 @@ struct ads8344 {
> struct mutex lock;
>
> u8 tx_buf ____cacheline_aligned;
> - u16 rx_buf;
> + u8 rx_buf[3];
> };
>
> #define ADS8344_VOLTAGE_CHANNEL(chan, si) \
> @@ -89,11 +89,11 @@ static int ads8344_adc_conversion(struct ads8344 *adc, int channel,
>
> udelay(9);
>
> - ret = spi_read(spi, &adc->rx_buf, 2);
> + ret = spi_read(spi, adc->rx_buf, sizeof(adc->rx_buf));
> if (ret)
> return ret;
>
> - return adc->rx_buf;
> + return adc->rx_buf[0] << 9 | adc->rx_buf[1] << 1 | adc->rx_buf[2] >> 7;
> }
>
> static int ads8344_read_raw(struct iio_dev *iio,