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SubjectRe: [PATCH RESEND 3/5] spi: imx: Use correct number of bytes per words
On Tue, Jul 17, 2018 at 04:31:52PM +0200, Maxime Chevallier wrote:
> The SPI core enforces that we always use the next power-of-two number of
> bytes to store words. As a result, a 24 bits word will be stored in 4
> bytes.
>
> This commit fixes the spi_imx_bytes_per_word function to return the
> correct number of bytes.
>
> This also allows to get rid of unnecessary checks in the can_dma
> function, since the SPI core validates that we always have a transfer
> length that is a multiple of the number of bytes per word.
>
> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>

Sascha

> ---
> drivers/spi/spi-imx.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index ecafbda5ec94..3ae706dac660 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -202,7 +202,12 @@ static unsigned int spi_imx_clkdiv_2(unsigned int fin,
>
> static int spi_imx_bytes_per_word(const int bits_per_word)
> {
> - return DIV_ROUND_UP(bits_per_word, BITS_PER_BYTE);
> + if (bits_per_word <= 8)
> + return 1;
> + else if (bits_per_word <= 16)
> + return 2;
> + else
> + return 4;
> }
>
> static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
> @@ -219,9 +224,6 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
>
> bytes_per_word = spi_imx_bytes_per_word(transfer->bits_per_word);
>
> - if (bytes_per_word != 1 && bytes_per_word != 2 && bytes_per_word != 4)
> - return false;
> -
> for (i = spi_imx->devtype_data->fifo_size / 2; i > 0; i--) {
> if (!(transfer->len % (i * bytes_per_word)))
> break;
> --
> 2.11.0
>
>

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