[PATCH] usb: chipidea: Fix ULPI on imx51
From: nikita.yoush@cogentembedded.com (Nikita Yushchenko)
Date: 2018-06-21 14:25:08
Also in:
linux-usb, lkml
21.06.2018 17:12, Nikita Yushchenko wrote:
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This patches causes a regression on a imx51-babbage running 4.18-rc1: I get a kernel hang. If I revert it on top of 4.18-rc1, then it boots fine and USB host is functional. I understand this patch fixes a kernel hang for you, so which commit is responsible for the hang you observe?I never assumed it was a regression and that USB worked on RDU1 board before, so I never tried to see if this was a regression. I can only tell you that it hangs as soon as any PORTSC registers are accessed.Hang at register access usually means that module that owns the register is not clocked.
On RDU1, call to usb_phy_init() actually calls usb_gen_phy_init() that does regulator_enable() for &vusb_reg and clk_prepare_enable() for &clk_26M_usb. I thing some of these two is actually needed to avoid hang on register access.