From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Goldschmidt Subject: [PATCH v3] spi: dw: support 4-16 bits per word Date: Tue, 4 Sep 2018 21:49:44 +0200 Message-ID: <20180904194944.19721-1-simon.k.r.goldschmidt@gmail.com> References: <20180817070105.1725-1-simon.k.r.goldschmidt@gmail.com> Cc: Simon Goldschmidt To: Mark Brown , linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, Andy Shevchenko , Trent Piepho Return-path: In-Reply-To: <20180817070105.1725-1-simon.k.r.goldschmidt@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org 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 Reviewed-by: Andy Shevchenko --- Changes in v3 - remove the check for valid 'bits_per_word' from dw_spi_transfer_one() - add reviewed-by tag 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 +307,10 @@ 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 { - 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