Messages in this thread | | | From | Anton Tikhomirov <> | Subject | RE: [PATCH v4 3/9] phy: Add new Exynos USB PHY driver | Date | Wed, 18 Dec 2013 09:54:33 +0900 |
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Hi Kamil,
> Hi Anton, > > > From: Anton Tikhomirov [mailto:av.tikhomirov@samsung.com] > > Sent: Tuesday, December 10, 2013 3:43 AM > > > > Hi Kamil, > > > > Same USB2.0 PHY may be used by several HCDs, for example EHCI and > OHCI. > > Consider the situation, when EHCI stops using the PHY and calls > > power_off, then OHCI becomes non-operational. In other words, PHY > > power_on and power_off calls must be balanced. > > > > Shall we handle it in your driver? (usage count?) > > Please look in the drivers/phy/phy-core.c file. Usage count is handled > there - see phy_power_on and phy_power_off functions. I understand that > after both EHCI and OHCI power on the phy, the usage count is 2. So > powering off one of them (EHCI for instance) the usage count is still > 1, so the OHCI should still work properly.
Oops, sorry, missed that.
> > [snip] > > Best wishes, > -- > Kamil Debski > Samsung R&D Institute Poland
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