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@pengutronix.de 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 --- V2: - Use devm_add_action_or_reset() to add clock disable hook instead of wall of failpath V3: - Swap devm_add_action_or_reset()/clk_prepare_enable() to avoid clock disable imbalance - Add RB from Lucas V4: - Check return value of clk_prepare_enable() --- drivers/gpu/drm/bridge/tc358767.c | 32 ++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c index 45ea829d56601..6c6177028742e 100644 --- a/drivers/gpu/drm/bridge/tc358767.c +++ b/drivers/gpu/drm/bridge/tc358767.c @@ -2033,6 +2033,13 @@ static int tc_probe_bridge_endpoint(struct tc_data *tc) return -EINVAL; }

+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; @@ -2049,6 +2056,24 @@ 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)) @@ -2069,13 +2094,6 @@ 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);