[PATCH v4 03/20] usb: phy: tegra: Clean up ulpi_phy_power_off

[Dmitry Osipenko <digetx@gmail.com>]

Firstly, the PHY's clock needs to unprepared to keep prepare count
balanced. Secondly, downstream code suggests that reset is synchronous
and thus it should be asserted before disabling clock.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/usb/phy/phy-tegra-usb.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/phy/phy-tegra-usb.c b/drivers/usb/phy/phy-tegra-usb.c
index ea7ef1dc0b42..99acfde4ab8d 100644
--- a/drivers/usb/phy/phy-tegra-usb.c
+++ b/drivers/usb/phy/phy-tegra-usb.c
@@ -757,8 +757,19 @@ static int ulpi_phy_power_on(struct tegra_usb_phy *phy)
 
 static int ulpi_phy_power_off(struct tegra_usb_phy *phy)
 {
-	clk_disable(phy->clk);
-	return gpio_direction_output(phy->reset_gpio, 0);
+	int err;
+
+	err = gpio_direction_output(phy->reset_gpio, 0);
+	if (err) {
+		dev_err(phy->u_phy.dev, "reset GPIO not asserted: %d\n", err);
+		return err;
+	}
+
+	usleep_range(5000, 6000);
+
+	clk_disable_unprepare(phy->clk);
+
+	return 0;
 }
 
 static void tegra_usb_phy_close(struct tegra_usb_phy *phy)
-- 
2.24.0