[PATCH 3/3] drm/bridge: tc358767: Make sure Refclk clock are enabled

[Marek Vasut <marex@denx.de>]

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.

Fixes: 7caff0fc4296e ("drm/bridge: tc358767: Add DPI to eDP bridge driver")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Jonas Karlman <jonas@kwiboo.se>
Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Marek Vasut <marex@denx.de>
Cc: Maxime Ripard <maxime@cerno.tech>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Robert Foss <robert.foss@linaro.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
---
 drivers/gpu/drm/bridge/tc358767.c | 51 ++++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index a8bb6de9e600a..4b15acbc73c4e 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -2055,10 +2055,24 @@ 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;
+	}
+
+	clk_prepare_enable(tc->refclk);
+
+	/* 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))
-		return PTR_ERR(tc->sd_gpio);
+	if (IS_ERR(tc->sd_gpio)) {
+		ret = PTR_ERR(tc->sd_gpio);
+		goto err_clk;
+	}
 
 	if (tc->sd_gpio) {
 		gpiod_set_value_cansleep(tc->sd_gpio, 0);
@@ -2067,26 +2081,21 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 	/* Reset GPIO is optional */
 	tc->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
-	if (IS_ERR(tc->reset_gpio))
-		return PTR_ERR(tc->reset_gpio);
+	if (IS_ERR(tc->reset_gpio)) {
+		ret = PTR_ERR(tc->reset_gpio);
+		goto err_clk;
+	}
 
 	if (tc->reset_gpio) {
 		gpiod_set_value_cansleep(tc->reset_gpio, 1);
 		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);
 		dev_err(dev, "Failed to initialize regmap: %d\n", ret);
-		return ret;
+		goto err_clk;
 	}
 
 	ret = of_property_read_u32(dev->of_node, "toshiba,hpd-pin",
@@ -2096,7 +2105,7 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	} else {
 		if (tc->hpd_pin < 0 || tc->hpd_pin > 1) {
 			dev_err(dev, "failed to parse HPD number\n");
-			return ret;
+			goto err_clk;
 		}
 	}
 
@@ -2110,7 +2119,7 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 						"tc358767-irq", tc);
 		if (ret) {
 			dev_err(dev, "failed to register dp interrupt\n");
-			return ret;
+			goto err_clk;
 		}
 
 		tc->have_irq = true;
@@ -2119,12 +2128,13 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	ret = regmap_read(tc->regmap, TC_IDREG, &tc->rev);
 	if (ret) {
 		dev_err(tc->dev, "can not read device ID: %d\n", ret);
-		return ret;
+		goto err_clk;
 	}
 
 	if ((tc->rev != 0x6601) && (tc->rev != 0x6603)) {
 		dev_err(tc->dev, "invalid device ID: 0x%08x\n", tc->rev);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_clk;
 	}
 
 	tc->assr = (tc->rev == 0x6601); /* Enable ASSR for eDP panels */
@@ -2164,7 +2174,7 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	if (tc->bridge.type != DRM_MODE_CONNECTOR_DPI) { /* (e)DP output */
 		ret = tc_aux_link_setup(tc);
 		if (ret)
-			return ret;
+			goto err_clk;
 	}
 
 	tc->bridge.of_node = dev->of_node;
@@ -2176,11 +2186,15 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		ret = tc_mipi_dsi_host_attach(tc);
 		if (ret) {
 			drm_bridge_remove(&tc->bridge);
-			return ret;
+			goto err_clk;
 		}
 	}
 
 	return 0;
+
+err_clk:
+	clk_disable_unprepare(tc->refclk);
+	return ret;
 }
 
 static int tc_remove(struct i2c_client *client)
@@ -2188,6 +2202,7 @@ static int tc_remove(struct i2c_client *client)
 	struct tc_data *tc = i2c_get_clientdata(client);
 
 	drm_bridge_remove(&tc->bridge);
+	clk_disable_unprepare(tc->refclk);
 
 	return 0;
 }
-- 
2.35.1