On Wed, Aug 8, 2018 at 11:45 AM Andy Shevchenko
<andy.shevche...@gmail.com> wrote:
>
> On Wed, Aug 8, 2018 at 10:14 AM, Simon Goldschmidt
> <simon.k.r.goldschm...@gmail.com> wrote:
> > The spi-dw driver currently only supports 8 or 16 bits per word.
> >
> > Since the hardware supports 4-16 bits per word, adapt the driver
> > to also support this.
> >
> > Tested on socfpga cyclone5 with a 9-bit SPI display.
>
> > + if ((transfer->bits_per_word < 4) || (transfer->bits_per_word > 16))
> > + return -EINVAL;
>
> > + if (transfer->bits_per_word <= 8) {
> > dws->n_bytes = 1;
> > dws->dma_width = 1;
> > - } else if (transfer->bits_per_word == 16) {
> > + } else {
> > dws->n_bytes = 2;
> > dws->dma_width = 2;
> > }
>
> Now these can be just
>
> n_bytes = round_up(8);
> dma_width = round_up(8);
I guess you mean:
n_bytes = round_up(transfer->bits_per_word, 8);
But that would yield 8 or 16 where we need 1 or 2.
Reading spi-imx.c, this might work:
n_bytes = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE);
Simon
