From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>,
Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Mark Brown <broonie@kernel.org>,
linux-spi <linux-spi@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] spi: dw: support 4-16 bits per word
Date: Fri, 17 Aug 2018 14:17:08 +0300 [thread overview]
Message-ID: <CAHp75Vc5bJEeX3tB8EbzWMf1GdFaSFgk+3u3CdZ2SVy3dWfVkA@mail.gmail.com> (raw)
In-Reply-To: <20180817070105.1725-1-simon.k.r.goldschmidt@gmail.com>
On Fri, Aug 17, 2018 at 10:01 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.
>
LGTM,
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
> ---
>
> Changes in v2:
> - use DIV_ROUND_UP to calculate number of bytes per word instead of
> if/else range checks
>
> drivers/spi/spi-dw.c | 16 +++++++---------
> 1 file changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
> index f693bfe95ab9..58a7caf31d59 100644
> --- a/drivers/spi/spi-dw.c
> +++ b/drivers/spi/spi-dw.c
> @@ -307,15 +307,13 @@ 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) {
> - dws->n_bytes = 1;
> - dws->dma_width = 1;
> - } else if (transfer->bits_per_word == 16) {
> - dws->n_bytes = 2;
> - dws->dma_width = 2;
> - } else {
> +
> + if ((transfer->bits_per_word < 4) || (transfer->bits_per_word > 16))
> return -EINVAL;
> - }
> +
> + dws->n_bytes = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE);
> + dws->dma_width = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE);
> +
> /* Default SPI mode is SCPOL = 0, SCPH = 0 */
> cr0 = (transfer->bits_per_word - 1)
> | (chip->type << SPI_FRF_OFFSET)
> @@ -493,7 +491,7 @@ 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;
> --
> 2.17.1
>
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2018-08-17 11:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-08 7:14 [PATCH] spi: dw: support 4-16 bits per word Simon Goldschmidt
2018-08-08 9:45 ` Andy Shevchenko
2018-08-08 11:58 ` Simon Goldschmidt
2018-08-08 12:26 ` Andy Shevchenko
2018-08-17 7:01 ` [PATCH v2] " Simon Goldschmidt
2018-08-17 11:17 ` Andy Shevchenko [this message]
2018-08-17 16:32 ` Trent Piepho
2018-08-18 8:37 ` Simon Goldschmidt
2018-09-04 19:49 ` [PATCH v3] " Simon Goldschmidt
2018-09-06 11:09 ` Mark Brown
2018-09-06 11:23 ` Simon Goldschmidt
2018-09-06 13:23 ` Mark Brown
2018-09-06 13:37 ` Simon Goldschmidt
2018-09-06 11:10 ` Applied "spi: dw: support 4-16 bits per word" to the spi tree Mark Brown
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