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 clamps max_chunk to the word size, preventing the transfer from being rejected.
Signed-off-by: Yunhao Tian t123yh.xyz@gmail.com --- drivers/gpu/drm/drm_mipi_dbi.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c index 71b646c4131f..440dc9fec6cc 100644 --- a/drivers/gpu/drm/drm_mipi_dbi.c +++ b/drivers/gpu/drm/drm_mipi_dbi.c @@ -1182,6 +1182,15 @@ int mipi_dbi_spi_transfer(struct spi_device *spi, u32 speed_hz, struct spi_message m; size_t chunk; int ret; + int w_size; + + if (bpw <= 8) + w_size = 1; + else if (bpw <= 16) + w_size = 2; + else + w_size = 4; + max_chunk -= (max_chunk % w_size);
spi_message_init_with_transfers(&m, &tr, 1);