From: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
To: Mark Brown <broonie@kernel.org>,
linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Trent Piepho <tpiepho@impinj.com>
Cc: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Subject: [PATCH v3] spi: dw: support 4-16 bits per word
Date: Tue, 4 Sep 2018 21:49:44 +0200 [thread overview]
Message-ID: <20180904194944.19721-1-simon.k.r.goldschmidt@gmail.com> (raw)
In-Reply-To: <20180817070105.1725-1-simon.k.r.goldschmidt@gmail.com>
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>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
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
next prev parent reply other threads:[~2018-09-04 19:50 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
2018-08-17 16:32 ` Trent Piepho
2018-08-18 8:37 ` Simon Goldschmidt
2018-09-04 19:49 ` Simon Goldschmidt [this message]
2018-09-06 11:09 ` [PATCH v3] " 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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