From: Yunhao Tian t123yh.xyz@gmail.com
[ Upstream commit 435c249008cba04ed6a7975e9411f3b934620204 ]
In __spi_validate, there's a validation that no partial transfers are accepted (xfer->len % w_size must be zero). When max_chunk is not a multiple of bpw (e.g. max_chunk = 65535, bpw = 16), the transfer will be rejected.
This patch aligns max_chunk to 2 bytes (the maximum value of bpw is 16), so that no partial transfer will occur.
Fixes: d23d4d4dac01 ("drm/tinydrm: Move tinydrm_spi_transfer()")
Signed-off-by: Yunhao Tian t123yh.xyz@gmail.com Signed-off-by: Noralf Trønnes noralf@tronnes.org Link: https://patchwork.freedesktop.org/patch/msgid/20220510030219.2486687-1-t123y... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/drm_mipi_dbi.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c index 9314f2ead79f..09e4edb5a992 100644 --- a/drivers/gpu/drm/drm_mipi_dbi.c +++ b/drivers/gpu/drm/drm_mipi_dbi.c @@ -1199,6 +1199,13 @@ int mipi_dbi_spi_transfer(struct spi_device *spi, u32 speed_hz, size_t chunk; int ret;
+ /* In __spi_validate, there's a validation that no partial transfers + * are accepted (xfer->len % w_size must be zero). + * Here we align max_chunk to multiple of 2 (16bits), + * to prevent transfers from being rejected. + */ + max_chunk = ALIGN_DOWN(max_chunk, 2); + spi_message_init_with_transfers(&m, &tr, 1);
while (len) {