diff options
| author |  Louis Chauvet <louis.chauvet@bootlin.com>
| 2024-03-27 09:43:38 +0100 |
|---|---|---|
| committer |  Mark Brown <broonie@kernel.org>
| 2024-03-28 15:52:33 +0000 |
| commit | e64d3b6fc9a388d7dc516668651cf4404bffec9b (patch) | |
| tree | e040ff2c9da166df23f1057329c893c803671f17 | |
| parent | spi: omap2-mcspi: Add support for MULTI-mode (diff) | |
| download | linux-e64d3b6fc9a388d7dc516668651cf4404bffec9b.tar.gz linux-e64d3b6fc9a388d7dc516668651cf4404bffec9b.tar.bz2 linux-e64d3b6fc9a388d7dc516668651cf4404bffec9b.zip | |
spi: omap2-mcpsi: Enable MULTI-mode in more situations
Enable multimode when a transfer of multiple small words can be
transformed in a transfer with a single bigger word. This is allowed as
long as the result on the cable is the same, so word_delay must be zero.
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Link: https://msgid.link/r/20240327-spi-omap2-mcspi-multi-mode-v3-3-c4ac329dd5a2@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
| -rw-r--r-- | drivers/spi/spi-omap2-mcspi.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c index 002f29dbcea6..7e3083b83534 100644 --- a/drivers/spi/spi-omap2-mcspi.c +++ b/drivers/spi/spi-omap2-mcspi.c @@ -1277,11 +1277,24 @@ static int omap2_mcspi_prepare_message(struct spi_controller *ctlr, /* * Check if this transfer contains only one word; + * OR contains 1 to 4 words, with bits_per_word == 8 and no delay between each word + * OR contains 1 to 2 words, with bits_per_word == 16 and no delay between each word + * + * If one of the two last case is true, this also change the bits_per_word of this + * transfer to make it a bit faster. + * It's not an issue to change the bits_per_word here even if the multi-mode is not + * applicable for this message, the signal on the wire will be the same. */ if (bits_per_word < 8 && tr->len == 1) { /* multi-mode is applicable, only one word (1..7 bits) */ + } else if (tr->word_delay.value == 0 && bits_per_word == 8 && tr->len <= 4) { + /* multi-mode is applicable, only one "bigger" word (8,16,24,32 bits) */ + tr->bits_per_word = tr->len * bits_per_word; + } else if (tr->word_delay.value == 0 && bits_per_word == 16 && tr->len <= 2) { + /* multi-mode is applicable, only one "bigger" word (16,32 bits) */ + tr->bits_per_word = tr->len * bits_per_word / 2; } else if (bits_per_word >= 8 && tr->len == bits_per_word / 8) { - /* multi-mode is applicable, only one word (8..32 bits) */ + /* multi-mode is applicable, only one word (9..15,17..32 bits) */ } else { /* multi-mode is not applicable: more than one word in the transfer */ mcspi->use_multi_mode = false; |