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ARM: tegra: fix USB ULPI PHY reset signal inversion confusion

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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>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
This commit is contained in:
Stephen Warren 2016-09-15 12:19:37 -06:00 committed by Tom Warren
parent fc607d9ab9
commit 2f6a7e8ce5
3 changed files with 15 additions and 4 deletions
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3
arch/arm/dts/tegra20-colibri.dts
View File

@ -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>;
};

3
arch/arm/dts/tegra20-harmony.dts
View File

@ -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 {

13
drivers/usb/host/ehci-tegra.c
View File

@ -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 */