From 163ddf1fea590229c30a8dc4c29ff4febfb895c3 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Thu, 17 Apr 2025 18:24:46 +0300 Subject: [PATCH] spi: Add spi_bpw_to_bytes() helper and use it This helper converts the given bits per word to bytes. The result will always be power-of-two, e.g., =============== ================= Input (in bits) Output (in bytes) =============== ================= 5 1 9 2 21 4 37 8 =============== ================= It will return 0 for the 0 input. There are a couple of cases in SPI that are using the same approach and at least one more (in IIO) would benefit of it. Add a helper for everyone. Signed-off-by: Andy Shevchenko Reviewed-by: David Lechner Link: https://patch.msgid.link/20250417152529.490582-2-andriy.shevchenko@linux.intel.com Acked-by: Mukesh Kumar Savaliya Signed-off-by: Mark Brown --- drivers/spi/spi.c | 2 +- include/linux/spi/spi.h | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 90e27729ef6b..cdec46a5ab72 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -3802,7 +3802,7 @@ int spi_split_transfers_maxwords(struct spi_controller *ctlr, size_t maxsize; int ret; - maxsize = maxwords * roundup_pow_of_two(BITS_TO_BYTES(xfer->bits_per_word)); + maxsize = maxwords * spi_bpw_to_bytes(xfer->bits_per_word); if (xfer->len > maxsize) { ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer, maxsize); diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 0ba5e49bace4..5b872fe3b1a2 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -1325,6 +1325,32 @@ static inline bool spi_is_bpw_supported(struct spi_device *spi, u32 bpw) return false; } +/** + * spi_bpw_to_bytes - Covert bits per word to bytes + * @bpw: Bits per word + * + * This function converts the given @bpw to bytes. The result is always + * power-of-two, e.g., + * + * =============== ================= + * Input (in bits) Output (in bytes) + * =============== ================= + * 5 1 + * 9 2 + * 21 4 + * 37 8 + * =============== ================= + * + * It will return 0 for the 0 input. + * + * Returns: + * Bytes for the given @bpw. + */ +static inline u32 spi_bpw_to_bytes(u32 bpw) +{ + return roundup_pow_of_two(BITS_TO_BYTES(bpw)); +} + /** * spi_controller_xfer_timeout - Compute a suitable timeout value * @ctlr: SPI device -- 2.50.1