On Tue, Sep 13, 2016 at 01:41:44PM -0700, Stephen Boyd wrote: > Quoting Peter Chen (2016-09-13 00:03:58) > > On Wed, Sep 07, 2016 at 02:35:19PM -0700, Stephen Boyd wrote: > > > The high-speed phy on qcom SoCs is controlled via the ULPI > > > viewport. > > > > > > > Hi Stephen, I am a little puzzled how this driver co-work with chipidea > > driver. According to nxp IC guys, the ULPI PHY's clock needs to be enabled > > before access portsc.pts (calling hw_phymode_configure), otherwise, > > the system will hang. But I find you call hw_phymode_configure before > > phy->power_on, doesn't your design have this requirement? > > Which clk needs to be enabled? The xcvr_clk? I believe that clk > corresponds to the "core" clk that we enable in the msm glue driver > layer. When that clk is enabled, the ULPI phy is able to respond to > register read/writes via the ULPI viewport. > The input clock for ULPI PHY, maybe it is ref_clk at this PHY driver, so in your platform, even PHY clock is gated, you can still access portsc.pts to configure PHY mode at controller register? > > > > Besides, you read ulpi id before phy->power_on, how can read work before > > phy power on? > > > > I've found that even having the link clk enabled before phy->power_on > doesn't mean it's possible to read the id registers though. That's > because there can be other power supplies, like regulators, which need > to be on for the phy to operate properly. > Then I am puzzled the current initialization for your case, in my mind, it should like below: qcom_usb_hs_phy_probe->qcom_usb_hs_phy_power_on->ci_ulpi_init Like other PHYs, it should get PHY first, then power on it, after that, you can access its register. -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
