On 08/09/16 20:52, Martin Blumenstingl wrote:
On Thu, Sep 8, 2016 at 9:35 PM, Kevin Hilman <khilman@xxxxxxxxxxxx> wrote:+ phy = devm_phy_create(&pdev->dev, NULL, &phy_meson_usb2_ops); + if (IS_ERR(phy)) { + dev_err(&pdev->dev, "failed to create PHY\n"); + return PTR_ERR(phy); + } + + if (usb_reset_refcnt++ == 0) { + ret = device_reset(&pdev->dev); + if (ret) { + dev_err(&phy->dev, "Failed to reset USB PHY\n"); + return ret; + } + }The ref count + reset here looks like something that could/should be handled in a runtime PM callback.Unfortunately that doesn't work (as Jerome found out) because both PHYs are sharing the same reset line. So if the second PHY would call device_reset then it would also reset the first PHY! There's a comment above the declaration of usb_reset_refcnt which tries to explain this: "The PHYs are sharing a common reset line -> we are only allowed to reset once for all PHYs." Maybe I should move this comment to the "if (usb_reset_refcnt++ == 0) {" line to make it easier to see?
pm-runtime has refcounting in it. When one of the nodes turns on, the pm-runtime will call your driver to say there is a user when this first use turns up. If all the sub-phys turn off and drop their refcount then the driver is called to say there are no more users and you can go to sleep. So, in phy_meson_usb2_power_on() you could do: pm_runtime_get_sync(pdev); and in phy_meson_usb2_power_off pm_runtime_put(pdev); https://www.kernel.org/doc/Documentation/power/runtime_pm.txt -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
