From: Douglas Anderson Date: Fri, 8 May 2020 23:33:29 +0000 (-0700) Subject: drm/bridge: ti-sn65dsi86: Clear old error bits before AUX transfers X-Git-Tag: v5.4.59~179 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7669b6beb4fd322f40503ee28ccd5e3a44737f59;p=users%2Fdwmw2%2Flinux.git drm/bridge: ti-sn65dsi86: Clear old error bits before AUX transfers [ Upstream commit baef4d56195b6d6e0f681f6eac03d8c6db011d34 ] The AUX channel transfer error bits in the status register are latched and need to be cleared. Clear them before doing our transfer so we don't see old bits and get confused. Without this patch having a single failure would mean that all future transfers would look like they failed. Fixes: b814ec6d4535 ("drm/bridge: ti-sn65dsi86: Implement AUX channel") Signed-off-by: Douglas Anderson Reviewed-by: Rob Clark Signed-off-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20200508163314.1.Idfa69d5d3fc9623083c0ff78572fea87dccb199c@changeid Signed-off-by: Sasha Levin --- diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index 0a580957c8cf1..f1de4bb6558ca 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -647,6 +647,12 @@ static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux, buf[i]); } + /* Clear old status bits before start so we don't get confused */ + regmap_write(pdata->regmap, SN_AUX_CMD_STATUS_REG, + AUX_IRQ_STATUS_NAT_I2C_FAIL | + AUX_IRQ_STATUS_AUX_RPLY_TOUT | + AUX_IRQ_STATUS_AUX_SHORT); + regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val | AUX_CMD_SEND); ret = regmap_read_poll_timeout(pdata->regmap, SN_AUX_CMD_REG, val,