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authorPaul Cercueil <paul@crapouillou.net>2020-07-03 16:13:41 +0200
committerSam Ravnborg <sam@ravnborg.org>2020-07-27 20:29:44 +0200
commit900ab59e2621053b009f707f80b2c19ce0af5dee (patch)
tree3a25cabc151deb118911fd423df55a01b098b745 /drivers/gpu
parent2a1658bf922ffd9b7907e270a7d9cdc9643fc45d (diff)
drm/dbi: Fix SPI Type 1 (9-bit) transfer
The function mipi_dbi_spi1_transfer() will transfer its payload as 9-bit data, the 9th (MSB) bit being the data/command bit. In order to do that, it unpacks the 8-bit values into 16-bit values, then sets the 9th bit if the byte corresponds to data, clears it otherwise. The 7 MSB are padding. The array of now 16-bit values is then passed to the SPI core for transfer. This function was broken since its introduction, as the length of the SPI transfer was set to the payload size before its conversion, but the payload doubled in size due to the 8-bit -> 16-bit conversion. Fixes: 02dd95fe3169 ("drm/tinydrm: Add MIPI DBI support") Cc: <stable@vger.kernel.org> # 5.4+ Signed-off-by: Paul Cercueil <paul@crapouillou.net> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Noralf Trønnes <noralf@tronnes.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20200703141341.1266263-1-paul@crapouillou.net
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/drm_mipi_dbi.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
index bb27c82757f1..bf7888ad9ad4 100644
--- a/drivers/gpu/drm/drm_mipi_dbi.c
+++ b/drivers/gpu/drm/drm_mipi_dbi.c
@@ -923,7 +923,7 @@ static int mipi_dbi_spi1_transfer(struct mipi_dbi *dbi, int dc,
}
}
- tr.len = chunk;
+ tr.len = chunk * 2;
len -= chunk;
ret = spi_sync(spi, &m);