From: Stephen Warren swarren@nvidia.com
USB ULPI PHY reset signals are typically active low. Consequently, they should be marked as GPIO_ACTIVE_LOW in device tree, and indeed they are in the Linux kernel DTs, and in DT properties that U-Boot doesn't yet use. However, in DT properties that U-Boot does use, the value has been set to 0 (== GPIO_ACTIVE_HIGH) to work around a bug in U-Boot.
This change fixes the DT to correctly represent the HW, and fixes the Tegra USB driver to cope with the fact that dm_gpio_set_value() internally handles any inversions implied by the DT value GPIO_ACTIVE_LOW.
Cc: Marcel Ziswiler marcel.ziswiler@toradex.com Signed-off-by: Stephen Warren swarren@nvidia.com --- arch/arm/dts/tegra20-colibri.dts | 3 ++- arch/arm/dts/tegra20-harmony.dts | 3 ++- drivers/usb/host/ehci-tegra.c | 13 +++++++++++-- 3 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/arch/arm/dts/tegra20-colibri.dts b/arch/arm/dts/tegra20-colibri.dts index a291d93c7d01..777f63e5bdb6 100644 --- a/arch/arm/dts/tegra20-colibri.dts +++ b/arch/arm/dts/tegra20-colibri.dts @@ -39,7 +39,8 @@ usb@c5004000 { statuc = "okay"; /* VBUS_LAN */ - nvidia,phy-reset-gpio = <&gpio TEGRA_GPIO(V, 1) GPIO_ACTIVE_HIGH>; + nvidia,phy-reset-gpio = <&gpio TEGRA_GPIO(V, 1) + GPIO_ACTIVE_LOW>; nvidia,vbus-gpio = <&gpio TEGRA_GPIO(BB, 1) GPIO_ACTIVE_HIGH>; };
diff --git a/arch/arm/dts/tegra20-harmony.dts b/arch/arm/dts/tegra20-harmony.dts index cace74339483..5aec150b5e61 100644 --- a/arch/arm/dts/tegra20-harmony.dts +++ b/arch/arm/dts/tegra20-harmony.dts @@ -626,7 +626,8 @@
usb@c5004000 { status = "okay"; - nvidia,phy-reset-gpio = <&gpio TEGRA_GPIO(V, 1) 0>; + nvidia,phy-reset-gpio = <&gpio TEGRA_GPIO(V, 1) + GPIO_ACTIVE_LOW>; };
usb-phy@c5004000 { diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c index 31d54ab285bf..c10597861873 100644 --- a/drivers/usb/host/ehci-tegra.c +++ b/drivers/usb/host/ehci-tegra.c @@ -600,9 +600,18 @@ static int init_ulpi_usb_controller(struct fdt_usb *config,
/* reset ULPI phy */ if (dm_gpio_is_valid(&config->phy_reset_gpio)) { - dm_gpio_set_value(&config->phy_reset_gpio, 0); - mdelay(5); + /* + * This GPIO is typically active-low, and marked as such in + * device tree. dm_gpio_set_value() takes this into account + * and inverts the value we pass here if required. In other + * words, this first call logically asserts the reset signal, + * which typically results in driving the physical GPIO low, + * and the second call logically de-asserts the reset signal, + * which typically results in driver the GPIO high. + */ dm_gpio_set_value(&config->phy_reset_gpio, 1); + mdelay(5); + dm_gpio_set_value(&config->phy_reset_gpio, 0); }
/* Reset the usb controller */