drm/bridge: ti-sn65dsi86: Avoid possible buffer overflow

[ Upstream commit 95011f267c44a4d1f9ca1769e8a29ab2c559e004 ]

Smatch error:buffer overflow 'ti_sn_bridge_refclk_lut' 5 <= 5.

Fixes: cea86c5bb442 ("drm/bridge: ti-sn65dsi86: Implement the pwm_chip")
Signed-off-by: Su Hui <suhui@nfschina.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230608012443.839372-1-suhui@nfschina.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index aeca9c0..d16775c 100644 (file)
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -298,6 +298,10 @@ static void ti_sn_bridge_set_refclk_freq(struct ti_sn65dsi86 *pdata)
                if (refclk_lut[i] == refclk_rate)
                        break;
 
+       /* avoid buffer overflow and "1" is the default rate in the datasheet. */
+       if (i >= refclk_lut_size)
+               i = 1;
+
        regmap_update_bits(pdata->regmap, SN_DPPLL_SRC_REG, REFCLK_FREQ_MASK,
                           REFCLK_FREQ(i));