diff mbox series

[v2,1/8] usb: phy: tegra: Add delay after power up

Message ID 20201217094007.19336-2-digetx@gmail.com (mailing list archive)
State Superseded
Headers show
Series Support Runtime PM and host mode by Tegra ChipIdea USB driver | expand

Commit Message

Dmitry Osipenko Dec. 17, 2020, 9:40 a.m. UTC 
The PHY hardware needs the delay of 2ms after power up, otherwise initial
interrupt may be lost if USB controller is accessed before PHY is settled
down. Previously this issue was masked by implicit delays, but now it pops
up after squashing the older ehci-tegra driver into the ChipIdea driver.

Tested-by: Matt Merhar <mattmerhar@protonmail.com>
Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Tested-by: Peter Geis <pgwipeout@gmail.com>
Tested-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/usb/phy/phy-tegra-usb.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Thierry Reding Dec. 17, 2020, 1:25 p.m. UTC | #1 
On Thu, Dec 17, 2020 at 12:40:00PM +0300, Dmitry Osipenko wrote:
> The PHY hardware needs the delay of 2ms after power up, otherwise initial
> interrupt may be lost if USB controller is accessed before PHY is settled
> down. Previously this issue was masked by implicit delays, but now it pops
> up after squashing the older ehci-tegra driver into the ChipIdea driver.
> 
> Tested-by: Matt Merhar <mattmerhar@protonmail.com>
> Tested-by: Nicolas Chauvet <kwizart@gmail.com>
> Tested-by: Peter Geis <pgwipeout@gmail.com>
> Tested-by: Ion Agorria <ion@agorria.com>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/usb/phy/phy-tegra-usb.c | 3 +++
>  1 file changed, 3 insertions(+)

Acked-by: Thierry Reding <treding@nvidia.com>
diff mbox series

Patch

diff --git a/drivers/usb/phy/phy-tegra-usb.c b/drivers/usb/phy/phy-tegra-usb.c
index 03a333797382..1296524e1bee 100644
--- a/drivers/usb/phy/phy-tegra-usb.c
+++ b/drivers/usb/phy/phy-tegra-usb.c
@@ -784,6 +784,9 @@  static int tegra_usb_phy_power_on(struct tegra_usb_phy *phy)
 
 	phy->powered_on = true;
 
+	/* Let PHY settle down */
+	usleep_range(2000, 2500);
+
 	return 0;
 }