Hi Heiko, On 2016/8/6 0:05, Heiko St?bner wrote: > Hi Frank, > > Am Freitag, 5. August 2016, 16:34:42 schrieb Frank Wang: >> On 2016/8/5 3:10, Heiko St?bner wrote: >>> Am Dienstag, 2. August 2016, 15:19:56 schrieb Xing Zheng: >>>> Export these source clocks for usbphy. >>>> >>>> Signed-off-by: Xing Zheng <zhengxing at rock-chips.com> >>> can you please provide a rationale why you need manual control over that >>> intermediate clock? >> Well, From below graph, you can see that 'clk_usbphyX_480m' is generated >> from usb2phy, and 'clk_usbphy_480m' which select from >> clk_usbphyX_480m_src via a gate (G13[12]) provided 480M clock to other >> modules. >> >> xin24m >> |__ clk_usb2phy0_ref >> | | >> | |__ clk_usbphy0_480m >> | | >> | |__clk_usbphy0_480m_src >> | | >> | |__clk_usbphy_480m >> | |__ ... ... >> | >> |__ clk_usb2phy1_ref >> | >> |__ clk_usbphy1_480m >> | >> |__clk_usbphy1_480m_src >>> The two usbphys seem to use the clk_usb2phyX_ref clocks, generate the >>> 480m >>> clocks, but do not seem to need the clk_usbphyX_480m_src gates. >> Yeah, they used to be. However, the story went something like this, >> >> Some PM suspend process related ehci/ohci controller are base on 480m >> clocks, unfortunately, usb2-phy suspended earlier than ehci/ohci >> (usb2-phy will be auto suspended if no devices plug-in), and the >> clk-480m provided by it was disabled if no module used. As a result, the >> PM suspend process was blocked when it run into ehci/ohci module. > ah, so the ehci controller needs that 480m clock as well? Do you happen to > have example patches for the ehci/ohci side already? I'd like to peak at what > you mean with "some PM suspend process related" things. Actually, no patches for it, I just make below steps manually :-). 1. set two usb2-phy into suspend mode. 2. disable 480m clock on each usb2-phy (assume only usb2-phy used it). 3. press power button let system into PM suspend. Then, the kernel will be blocked and you can see the following log from console. ... .... [ 123.763848] calling usb6+ @ 166, parent: xhci-hcd.0.auto [ 123.764503] call usb6+ returned 0 after 163 usecs [ 123.765106] calling usb5+ @ 166, parent: xhci-hcd.0.auto [ 123.765719] call usb5+ returned 0 after 121 usecs [ 123.766294] calling usb4+ @ 166, parent: fe3e0000.usb [ 123.766917] calling usb3+ @ 55, parent: fe3a0000.usb > > Depending on what is actually needed, you could also pull the usbphy out of > autosuspend in a pm-prepare callback of the phy driver itself ... see > http://lxr.free-electrons.com/source/include/linux/pm.h#L86 > > Like > - in the .prepare callback make sure to unsuspend the phy > and deactivate the autosuspend > - ehci/ohci will poweroff the phy in it s suspend callback (already does that) Hmm, do you remember that we have previously discussed there are some oddities in ehci/ohci driver? phy_power_on() gets called twice at ehci/ohci driver probe time, one is at pdata->power_on(); another is at usb_add_hcd(), then the power_count of phy increases to 2, but phy_power_off() is just invoked one time when ehci/ohci goes to PM suspend, so phy->ops->power_off is never be invoked. In this way, the usb-phy maybe never go to suspend. > - suspend -> resume > - ehci/ohci will poweron the phy > - in the phy's .complete callback you can reactivate the autosuspend timer > > Because it looks more like you actually need the phy and not the clock alone. > So it would be nicer to use mechanisms already in place instead of creating > new dependencies. > Theoretically, phy_init() will be invoked when ehci/ohci power on, and the sm_work will be reactivated (have already implemented) in phy->ops->init, but unfortunately, the same issue as phy_power_on() mentioned above, it never run there too . >> Hence, we are planing to refer clk_usbphyX_480m_src into each ehci/ohci >> driver. Maybe you will challenge why not refer clk_usbphy_480m directly? >> because there are two ehci/ohci connected in the different usb2phy, and >> only one clk_usbphy_480m clock was selected in clock tree. > Nope, no argument from me as I fully understand that each phy provides its own > 480m clock :-) . > > > Heiko > >
