| Message ID | 20180808071421.32707-1-simon.k.r.goldschmidt@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | spi: dw: support 4-16 bits per word | expand |
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);
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 -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Aug 8, 2018 at 2:58 PM, Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com> wrote: > 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: >> 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. Indeed. > Reading spi-imx.c, this might work: > > n_bytes = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE); Yes.
diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c index f693bfe95ab9..2ecbb6b19cea 100644 --- a/drivers/spi/spi-dw.c +++ b/drivers/spi/spi-dw.c @@ -307,14 +307,14 @@ static int dw_spi_transfer_one(struct spi_controller *master, dws->current_freq = transfer->speed_hz; spi_set_clk(dws, chip->clk_div); } - if (transfer->bits_per_word == 8) { + 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; - } else { - return -EINVAL; } /* Default SPI mode is SCPOL = 0, SCPH = 0 */ cr0 = (transfer->bits_per_word - 1) @@ -493,7 +493,7 @@ int dw_spi_add_host(struct device *dev, struct dw_spi *dws) } master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP; - master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16); + master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16); master->bus_num = dws->bus_num; master->num_chipselect = dws->num_cs; master->setup = dw_spi_setup;
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. Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com> --- drivers/spi/spi-dw.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)