[PATCH v2] drm/bridge: ti-sn65dsi86: Check bridge connection failure

[Wolfram Sang]

From: Phong Hoang <phong.hoang.wz at renesas.com>

Add a check to the very first register access function when attaching a
bridge device, so we can bail out if I2C communication does not work.

Signed-off-by: Phong Hoang <phong.hoang.wz at renesas.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
Signed-off-by: Wolfram Sang <wsa+renesas at sang-engineering.com>
---

Build tested only!

Changes since v1:

* rebased to v6.14-rc6
* add Laurent's tag (Thanks!)
* update patch description according to Tomi's suggestions (Thanks!)

 drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index e4d9006b59f1..59508e82a991 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -696,6 +696,7 @@ static struct ti_sn65dsi86 *bridge_to_ti_sn65dsi86(struct drm_bridge *bridge)
 
 static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86 *pdata)
 {
+	int ret;
 	int val;
 	struct mipi_dsi_host *host;
 	struct mipi_dsi_device *dsi;
@@ -720,8 +721,11 @@ static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86
 
 	/* check if continuous dsi clock is required or not */
 	pm_runtime_get_sync(dev);
-	regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
+	ret = regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
 	pm_runtime_put_autosuspend(dev);
+	if (ret)
+		return ret;
+
 	if (!(val & DPPLL_CLK_SRC_DSICLK))
 		dsi->mode_flags |= MIPI_DSI_CLOCK_NON_CONTINUOUS;
 
-- 
2.47.2