diff options
| author | Mathias Kresin <dev@kresin.me> | 2021-01-07 23:49:01 +0100 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2021-01-13 19:29:03 +0530 |
| commit | 36acd5e24e3000691fb8d1ee31cf959cb1582d35 (patch) | |
| tree | ab9a0c68b60acf293f0fac1ab727056867cbf50a /drivers/phy | |
| parent | c188365402f65fbc1d1561aeaf4a20f09b0b4f22 (diff) | |
| download | lwn-36acd5e24e3000691fb8d1ee31cf959cb1582d35.tar.gz lwn-36acd5e24e3000691fb8d1ee31cf959cb1582d35.zip | |
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@kresin.me>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: <stable@vger.kernel.org> # v5.7+
Link: https://lore.kernel.org/r/20210107224901.2102479-1-dev@kresin.me
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/phy')
| -rw-r--r-- | drivers/phy/lantiq/phy-lantiq-rcu-usb2.c | 10 |
1 files changed, 9 insertions, 1 deletions
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; } |