| Message ID | 20250417151958.490174-2-andriy.shevchenko@linux.intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | spi: Introduce and use spi_bpw_to_bytes() | expand |
On Thu, Apr 17, 2025 at 06:17:52PM +0300, Andy Shevchenko wrote: > 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) > =============== ================= > 0 0 > 5 1 > 9 2 > 2 4 > 3 8 My gosh, it lost the couple of characters here, should be 21 and 37 respectively... I'll fix this in v3. > =============== ================= ... > + * This function converts the given @bpw to bytes. The result is always > + * power-of-two, e.g., > + * > + * =============== ================= > + * Input (in bits) Output (in bytes) > + * =============== ================= > + * 0 0 > + * 5 1 > + * 9 2 > + * 2 4 > + * 3 8 As per above, > + * =============== =================
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index b0e7702951fe..1bc0fdbb1bd7 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -3800,7 +3800,7 @@ 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 834a09bd8ccc..2611f86180a3 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -1340,6 +1340,31 @@ 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) + * =============== ================= + * 0 0 + * 5 1 + * 9 2 + * 2 4 + * 3 8 + * =============== ================= + * + * 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
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) =============== ================= 0 0 5 1 9 2 2 4 3 8 =============== ================= 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 <andriy.shevchenko@linux.intel.com> --- drivers/spi/spi.c | 2 +- include/linux/spi/spi.h | 25 +++++++++++++++++++++++++ 2 files changed, 26 insertions(+), 1 deletion(-)