From 0dc78ff857337a82d39d7e4390e317ffbc93097f Mon Sep 17 00:00:00 2001 From: Nikhil Badola Date: Fri, 21 Nov 2014 17:25:21 +0530 Subject: drivers: usb: fsl: Workaround for Erratum A004477 Add a delay of 1 microsecond before issuing soft reset to the controller to let ongoing ULPI transaction complete. This prevents corruption of ULPI Function Control Register which eventually prevents phy clock from entering to low power mode Signed-off-by: Nikhil Badola Reviewed-by: York Sun --- drivers/usb/host/ehci-fsl.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'drivers/usb/host') diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c index 2dca524..5fd618d 100644 --- a/drivers/usb/host/ehci-fsl.c +++ b/drivers/usb/host/ehci-fsl.c @@ -138,6 +138,16 @@ int ehci_hcd_init(int index, enum usb_init_type init, if (has_erratum_a007798()) set_txfifothresh(ehci, TXFIFOTHRESH); + if (has_erratum_a004477()) { + /* + * When reset is issued while any ULPI transaction is ongoing + * then it may result to corruption of ULPI Function Control + * Register which eventually causes phy clock to enter low + * power mode which stops the clock. Thus delay is required + * before reset to let ongoing ULPI transaction complete. + */ + udelay(1); + } return 0; } -- cgit v1.1