From 990a9a75ab76823d44f251c870f928990ea8625f Mon Sep 17 00:00:00 2001
From: Douglas Anderson <dianders@chromium.org>
Date: Fri, 8 May 2020 16:33:29 -0700
Subject: drm/bridge: ti-sn65dsi86: Clear old error bits before AUX transfers
Git-commit: baef4d56195b6d6e0f681f6eac03d8c6db011d34
Patch-mainline: v5.9-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
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 <dianders@chromium.org>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200508163314.1.Idfa69d5d3fc9623083c0ff78572fea87dccb199c@changeid
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 3b91fa0ebdf9..03a29c797784 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -869,6 +869,12 @@ 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,
--
2.29.2