Some platforms, e.g. 8183/8192, use low level latch way to keep wakeup signal, it may latch a wrong signal if debounce more time, and enable wakeup earlier. ____________________ ip_sleep ____/ __________ ___________________ wakeup_signal ____________/ ______ _______________________________ wakeup_en _______/ ^ ^ |(1) |(2) latch wakeup_signal mistakenly at (1), should latch it at (2);
Workaround: delay about 100us to enable wakeup, meanwhile decrease debounce time.
Fixes: b1a344589eea ("usb: mtu3: support ip-sleep wakeup for MT8183") Cc: stable@vger.kernel.org Signed-off-by: Chunfeng Yun chunfeng.yun@mediatek.com --- drivers/usb/mtu3/mtu3_host.c | 2 +- drivers/usb/mtu3/mtu3_plat.c | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/mtu3/mtu3_host.c b/drivers/usb/mtu3/mtu3_host.c index 7d528f3c2482..f3903367a6a0 100644 --- a/drivers/usb/mtu3/mtu3_host.c +++ b/drivers/usb/mtu3/mtu3_host.c @@ -62,7 +62,7 @@ static void ssusb_wakeup_ip_sleep_set(struct ssusb_mtk *ssusb, bool enable) case SSUSB_UWK_V1_1: reg = ssusb->uwk_reg_base + PERI_WK_CTRL0; msk = WC0_IS_EN | WC0_IS_C(0xf) | WC0_IS_P; - val = enable ? (WC0_IS_EN | WC0_IS_C(0x8)) : 0; + val = enable ? (WC0_IS_EN | WC0_IS_C(0x1)) : 0; break; case SSUSB_UWK_V1_2: reg = ssusb->uwk_reg_base + PERI_WK_CTRL0; diff --git a/drivers/usb/mtu3/mtu3_plat.c b/drivers/usb/mtu3/mtu3_plat.c index 5b3f7f73cb40..f13531022f4a 100644 --- a/drivers/usb/mtu3/mtu3_plat.c +++ b/drivers/usb/mtu3/mtu3_plat.c @@ -63,6 +63,9 @@ static int wait_for_ip_sleep(struct ssusb_mtk *ssusb) if (ret) { dev_err(ssusb->dev, "ip sleep failed!!!\n"); ret = -EBUSY; + } else { + /* workaround: avoid wrong wakeup signal latch for some soc */ + usleep_range(100, 200); }
return ret;