Commit 65dc2e725286 ("usb: dwc2: Update Core Reset programming flow.")
revealed that the phy isn't ready immediately after enabling it's
clocks. The dwc2_check_core_version() fails and the dwc2 usb driver
errors out.
Add a short delay to let the phy get up and running. There isn't any
documentation how much time is required, the value was chosen based on
tests.
Cc: <[email protected]> # v5.7+
Signed-off-by: Mathias Kresin <[email protected]>
---
drivers/phy/lantiq/phy-lantiq-rcu-usb2.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c b/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c
index a7d126192cf1..29d246ea24b4 100644
--- a/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c
+++ b/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c
@@ -124,8 +124,16 @@ static int ltq_rcu_usb2_phy_power_on(struct phy *phy)
reset_control_deassert(priv->phy_reset);
ret = clk_prepare_enable(priv->phy_gate_clk);
- if (ret)
+ if (ret) {
dev_err(dev, "failed to enable PHY gate\n");
+ return ret;
+ }
+
+ /*
+ * at least the xrx200 usb2 phy requires some extra time to be
+ * operational after enabling the clock
+ */
+ usleep_range(100, 200);
return ret;
}
--
2.25.1
On 1/7/21 11:49 PM, Mathias Kresin wrote:
> Commit 65dc2e725286 ("usb: dwc2: Update Core Reset programming flow.")
> revealed that the phy isn't ready immediately after enabling it's
> clocks. The dwc2_check_core_version() fails and the dwc2 usb driver
> errors out.
>
> Add a short delay to let the phy get up and running. There isn't any
> documentation how much time is required, the value was chosen based on
> tests.
>
> Cc: <[email protected]> # v5.7+
> Signed-off-by: Mathias Kresin <[email protected]>
Acked-by: Hauke Mehrtens <[email protected]>
I do not know how long you have to wait here, but this looks ok, when it
works.
Hauke
> ---
> drivers/phy/lantiq/phy-lantiq-rcu-usb2.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c b/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c
> index a7d126192cf1..29d246ea24b4 100644
> --- a/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c
> +++ b/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c
> @@ -124,8 +124,16 @@ static int ltq_rcu_usb2_phy_power_on(struct phy *phy)
> reset_control_deassert(priv->phy_reset);
>
> ret = clk_prepare_enable(priv->phy_gate_clk);
> - if (ret)
> + if (ret) {
> dev_err(dev, "failed to enable PHY gate\n");
> + return ret;
> + }
> +
> + /*
> + * at least the xrx200 usb2 phy requires some extra time to be
> + * operational after enabling the clock
> + */
> + usleep_range(100, 200);
>
> return ret;
> }
>
On Thu, Jan 7, 2021 at 11:49 PM Mathias Kresin <[email protected]> wrote:
>
> Commit 65dc2e725286 ("usb: dwc2: Update Core Reset programming flow.")
> revealed that the phy isn't ready immediately after enabling it's
> clocks. The dwc2_check_core_version() fails and the dwc2 usb driver
> errors out.
>
> Add a short delay to let the phy get up and running. There isn't any
> documentation how much time is required, the value was chosen based on
> tests.
>
> Cc: <[email protected]> # v5.7+
> Signed-off-by: Mathias Kresin <[email protected]>
Acked-by: Martin Blumenstingl <[email protected]>
On 07-01-21, 23:49, Mathias Kresin wrote:
> Commit 65dc2e725286 ("usb: dwc2: Update Core Reset programming flow.")
> revealed that the phy isn't ready immediately after enabling it's
> clocks. The dwc2_check_core_version() fails and the dwc2 usb driver
> errors out.
>
> Add a short delay to let the phy get up and running. There isn't any
> documentation how much time is required, the value was chosen based on
> tests.
Applied, thanks
--
~Vinod