Hi Rajeshwari,
[Ccing Mark Brown]
On Tuesday 24 of September 2013 19:30:35 Rajeshwari S Shinde wrote:
> This patch enables word transfer for s3c64xx spi driver.
> User can set bits_per_word to 32 before calling spi_setup,
> which would enable the word transfer mode.
>
> Signed-off-by: Rajeshwari S Shinde <rajeshwari.s@xxxxxxxxxxx>
> ---
> drivers/spi/spi-s3c64xx.c | 28 ++++++++++++++++++----------
> 1 file changed, 18 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index 512b889..893361b 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -498,6 +498,17 @@ static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
> chcfg = readl(regs + S3C64XX_SPI_CH_CFG);
> chcfg &= ~S3C64XX_SPI_CH_TXCH_ON;
>
> + if(sdd->cur_bpw == 32) {
> + /* For word transfer we need to swap bytes */
> + u32 swapcfg = (S3C64XX_SPI_SWAP_TX_EN | S3C64XX_SPI_SWAP_TX_BYTE |
> + S3C64XX_SPI_SWAP_TX_HALF_WORD |
> + S3C64XX_SPI_SWAP_RX_EN |
> + S3C64XX_SPI_SWAP_RX_BYTE |
> + S3C64XX_SPI_SWAP_RX_HALF_WORD);
> + writel(swapcfg, regs + S3C64XX_SPI_SWAP_CFG);
Wasn't this driver already supposed to support 16 and 32 bits per word
transfers? I fail to see any mention in the documentation about the need
to enable these swaps in these cases.
In this case, wouldn't 16 bits per word transfers also need swapping?
> + } else
> + writel(0, regs + S3C64XX_SPI_SWAP_CFG);
nit: Coding style. If you use braces for one branch, then you should use
them for the other one as well.
> +
> if (dma_mode) {
> chcfg &= ~S3C64XX_SPI_CH_RXCH_ON;
> } else {
> @@ -905,19 +916,16 @@ static int s3c64xx_spi_transfer_one_message(struct spi_master *master,
> bpw = xfer->bits_per_word;
> speed = xfer->speed_hz ? : spi->max_speed_hz;
>
> - if (xfer->len % (bpw / 8)) {
> - dev_err(&spi->dev,
> - "Xfer length(%u) not a multiple of word size(%u)\n",
> - xfer->len, bpw / 8);
> - status = -EIO;
> - goto out;
Why is this check removed in this patch?
> + if (speed != sdd->cur_speed) {
> + sdd->cur_speed = speed;
This change does not seem to be related to $subject.
> }
>
> - if (bpw != sdd->cur_bpw || speed != sdd->cur_speed) {
> + if (xfer->len % (bpw / 8))
> + sdd->cur_bpw = 8;
> + else
> sdd->cur_bpw = bpw;
> - sdd->cur_speed = speed;
> - s3c64xx_spi_config(sdd);
> - }
> +
> + s3c64xx_spi_config(sdd);
Why s3c64xx_spi_config() can't be called only if one of the parameters
changed, as it was before this patch?
Best regards,
Tomasz
P.S. Please remember to always add respective maintainers on Cc. You can
use scripts/get_maintainer.pl script to quickly get a list of people
potentially interested in a patch.
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