Hi Jose, On Wednesday 01 Mar 2017 16:25:46 Jose Abreu wrote: > On 01-03-2017 11:09, Laurent Pinchart wrote: > > On Thursday 05 Jan 2017 15:06:49 Jose Abreu wrote: > >> On 05-01-2017 12:29, Laurent Pinchart wrote: > >>> On Tuesday 20 Dec 2016 12:17:23 Jose Abreu wrote: > >>>> On 20-12-2016 11:45, Russell King - ARM Linux wrote: > >>>>> On Tue, Dec 20, 2016 at 03:33:48AM +0200, Laurent Pinchart wrote: > >>>>>> Instead of spreading version-dependent PHY power handling code > >>>>>> around, group it in two functions to power the PHY on and off and use > >>>>>> them through the driver. > >>>>>> > >>>>>> Powering off the PHY at the beginning of the setup phase is currently > >>>>>> split in two locations for first and second generation PHYs, group > >>>>>> all the operations in the dw_hdmi_phy_init() function. > >>>>> > >>>>> This changes the behaviour of the driver. > >>>>> > >>>>>> +static void dw_hdmi_phy_power_off(struct dw_hdmi *hdmi) > >>>>>> +{ > >>>>>> + if (hdmi->phy->gen == 1) { > >>>>>> + dw_hdmi_phy_enable_tmds(hdmi, 0); > >>>>>> + dw_hdmi_phy_enable_powerdown(hdmi, true); > >>>>>> + } else { > >>>>>> + dw_hdmi_phy_gen2_txpwron(hdmi, 0); > >>>>>> + dw_hdmi_phy_gen2_pddq(hdmi, 1); > >>>>>> + } > >>>>>> +} > >>>>>> @@ -1290,9 +1302,7 @@ static void dw_hdmi_phy_disable(struct dw_hdmi > >>>>>> *hdmi) > >>>>>> if (!hdmi->phy_enabled) > >>>>>> return; > >>>>>> > >>>>>> - dw_hdmi_phy_enable_tmds(hdmi, 0); > >>>>>> - dw_hdmi_phy_enable_powerdown(hdmi, true); > >>>>>> - > >>>>>> + dw_hdmi_phy_power_off(hdmi); > >>>>> > >>>>> This makes dw_hdmi_phy_disable() power down a gen2 phy. > >>>>> > >>>>> The iMX6 has a DW_HDMI_PHY_DWC_HDMI_3D_TX_PHY phy, which you list as a > >>>>> gen2 phy. I've been carrying this change for a while, which I've had > >>>>> to revert (and finally expunge), as it causes problems on iMX6: > >>>>> > >>>>> @@ -1112,6 +1112,14 @@ static void dw_hdmi_phy_disable(struct dw_hdmi > >>>>> *hdmi) > >>>>> if (!hdmi->phy_enabled) > >>>>> return; > >>>>> > >>>>> + /* Actually set the phy into low power mode */ > >>>>> + dw_hdmi_phy_gen2_txpwron(hdmi, 0); > >>>>> + > >>>>> + /* FIXME: We should wait for TX_READY to be deasserted */ > >>>>> + > >>>>> + dw_hdmi_phy_gen2_pddq(hdmi, 1); > >>>>> + > >>>>> + /* This appears to have no effect on iMX6 */ > >>>>> dw_hdmi_phy_enable_tmds(hdmi, 0); > >>>>> dw_hdmi_phy_enable_powerdown(hdmi, true); > >>>>> > >>>>> So, I think your change here will cause problems for iMX6. > >>>>> > >>>>> From what I remember, it seems that iMX6 has issues with RXSENSE/HPD > >>>>> bouncing when the PHY is powered down. I can't promise when I'll be > >>>>> able to check for that again. > >>>> > >>>> Indeed TX_READY must be low before asserting pddq. > >>> > >>> The TX_READY signal is documented in the i.MX6 datasheet as being a PHY > >>> output signal, but there seems to be no HDMI TX register from which its > >>> state can be read. Do I need to poll the HDMI_PHY_PTRPT_ENBL register > >>> through I2C ? How long is the PHY expected to take to set TX_READY to 0 > >>> ? > >> > >> TX_READY can be read from register 0x1A of phy, BIT(2) (through > >> I2C). Not sure if same offset for all phys though. > > > > I have been told that another option is to poll the TX_PHY_LOCK bit in the > > phy_stat0 register. That would be a simpler solution that doesn't require > > I2C access. Could you confirm (or disconfirm) this ? > > Yes (In our implementation we have TX_PHY_LOCK wired up to > TX_READY that comes from phy. But if using a custom phy or an > unusual implementation then this may not hold).
Thank you for the information. I've submitted a v4 that poll the TX_PHY_LOCK bit. With the patch series applied the vendor PHY handling code already delegates PHY power control to the glue code, there's thus no issue there. For platforms using a Synopsys PHY, all the ones we have to support today have TX_READY wired to the PHY lock signal so we should be good as well there. If that doesn't remain true in the future we'll fix it. > >>>> HPD and RXSENSE should work in power down mode by enabling enhpdrxsense > >>>> bit in phy_conf0 BUT to enter power down you must disable TX_PWRON, > >>>> enhpdrxsense and enable PDDQ and PHY_RESET. Only after doing this (and > >>>> consequently entering power down mode) you can enable again > >>>> enhpdrxsense. > >>> > >>> Thanks, I'll give it a try. -- Regards, Laurent Pinchart