This is a note to let you know that I've just added the patch titled
phy: lantiq: rcu-usb2: wait after clock enable
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the char-misc-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 36acd5e24e3000691fb8d1ee31cf959cb1582d35 Mon Sep 17 00:00:00 2001
From: Mathias Kresin <dev@xxxxxxxxx>
Date: Thu, 7 Jan 2021 23:49:01 +0100
Subject: phy: lantiq: rcu-usb2: wait after clock enable
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.
Signed-off-by: Mathias Kresin <dev@xxxxxxxxx>
Acked-by: Hauke Mehrtens <hauke@xxxxxxxxxx>
Acked-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v5.7+
Link: https://lore.kernel.org/r/20210107224901.2102479-1-dev@xxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
---
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;
}
--
2.30.1
