From: Louis Chauvet Date: Wed, 27 Mar 2024 08:43:38 +0000 (+0100) Subject: spi: omap2-mcpsi: Enable MULTI-mode in more situations X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e64d3b6fc9a388d7dc516668651cf4404bffec9b;p=linux.git 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 Link: https://msgid.link/r/20240327-spi-omap2-mcspi-multi-mode-v3-3-c4ac329dd5a2@bootlin.com Signed-off-by: Mark Brown --- diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c index 002f29dbcea6e..7e3083b835348 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;