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Commit 6a5ade10 authored by Yunhao Tian's avatar Yunhao Tian Committed by Greg Kroah-Hartman
Browse files

drm/mipi-dbi: align max_chunk to 2 in spi_transfer 



[ 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: d23d4d4d ("drm/tinydrm: Move tinydrm_spi_transfer()")

Signed-off-by: default avatarYunhao Tian <t123yh.xyz@gmail.com>
Signed-off-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220510030219.2486687-1-t123yh.xyz@gmail.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent f52b31ec

drivers/gpu/drm/drm_mipi_dbi.c

+7 −0
Original line number Diff line number Diff line
@@ -1156,6 +1156,13 @@ 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) {