Patch "drm/bridge: tc358767: Make sure Refclk clock are enabled" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/bridge: tc358767: Make sure Refclk clock are enabled

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-bridge-tc358767-make-sure-refclk-clock-are-enabl.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit ce2b1aeb24d0b4ad863139149865249bf1709f25
Author: Marek Vasut <marex@xxxxxxx>
Date:   Fri May 20 14:15:43 2022 +0200

    drm/bridge: tc358767: Make sure Refclk clock are enabled
    
    [ Upstream commit 0b4c48f3e315d172e4cc06e10f2c8ba180788baf ]
    
    The Refclk may be supplied by SoC clock output instead of crystal
    oscillator, make sure the clock are enabled before any other action
    is performed with the bridge chip, otherwise it may either fail to
    operate at all, or miss reset GPIO toggle.
    
    Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
    Fixes: 7caff0fc4296e ("drm/bridge: tc358767: Add DPI to eDP bridge driver")
    Signed-off-by: Marek Vasut <marex@xxxxxxx>
    Cc: Jonas Karlman <jonas@xxxxxxxxx>
    Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
    Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
    Cc: Marek Vasut <marex@xxxxxxx>
    Cc: Maxime Ripard <maxime@xxxxxxxxxx>
    Cc: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
    Cc: Robert Foss <robert.foss@xxxxxxxxxx>
    Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
    Reviewed-by: Maxime Ripard <maxime@xxxxxxxxxx>
    Link: https://patchwork.freedesktop.org/patch/msgid/20220520121543.11550-1-marex@xxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index 9af564cf92e5..3e365cd7d0a3 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -1562,6 +1562,13 @@ static int tc_probe_edp_bridge_endpoint(struct tc_data *tc)
 	return ret;
 }
 
+static void tc_clk_disable(void *data)
+{
+	struct clk *refclk = data;
+
+	clk_disable_unprepare(refclk);
+}
+
 static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
@@ -1578,6 +1585,24 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	if (ret)
 		return ret;
 
+	tc->refclk = devm_clk_get(dev, "ref");
+	if (IS_ERR(tc->refclk)) {
+		ret = PTR_ERR(tc->refclk);
+		dev_err(dev, "Failed to get refclk: %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(tc->refclk);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, tc_clk_disable, tc->refclk);
+	if (ret)
+		return ret;
+
+	/* tRSTW = 100 cycles , at 13 MHz that is ~7.69 us */
+	usleep_range(10, 15);
+
 	/* Shut down GPIO is optional */
 	tc->sd_gpio = devm_gpiod_get_optional(dev, "shutdown", GPIOD_OUT_HIGH);
 	if (IS_ERR(tc->sd_gpio))
@@ -1598,13 +1623,6 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		usleep_range(5000, 10000);
 	}
 
-	tc->refclk = devm_clk_get(dev, "ref");
-	if (IS_ERR(tc->refclk)) {
-		ret = PTR_ERR(tc->refclk);
-		dev_err(dev, "Failed to get refclk: %d\n", ret);
-		return ret;
-	}
-
 	tc->regmap = devm_regmap_init_i2c(client, &tc_regmap_config);
 	if (IS_ERR(tc->regmap)) {
 		ret = PTR_ERR(tc->regmap);