Messages in this thread | | | From | Simon Goldschmidt <> | Date | Wed, 8 Aug 2018 13:58:35 +0200 | Subject | Re: [PATCH] spi: dw: support 4-16 bits per word |
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On Wed, Aug 8, 2018 at 11:45 AM Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > > On Wed, Aug 8, 2018 at 10:14 AM, Simon Goldschmidt > <simon.k.r.goldschmidt@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
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