drm/vc4: hdmi: Rework power up

The current code tries to handle the case where CONFIG_PM isn't selected
by first calling our runtime_resume implementation and then properly
report the power state to the runtime_pm core.

This allows to have a functionning device even if pm_runtime_get_*
functions are nops.

However, the device power state if CONFIG_PM is enabled is
RPM_SUSPENDED, and thus our vc4_hdmi_write() and vc4_hdmi_read() calls
in the runtime_pm hooks will now report a warning since the device might
not be properly powered.

Even more so, we need CONFIG_PM enabled since the previous RaspberryPi
have a power domain that needs to be powered up for the HDMI controller
to be usable.

The previous patch has created a dependency on CONFIG_PM, now we can
just assume it's there and only call pm_runtime_resume_and_get() to make
sure our device is powered in bind.

Link: https://lore.kernel.org/r/20220629123510.1915022-39-maxime@cerno.tech
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 4a2e244..e77bdc3 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -2971,17 +2971,15 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
                        vc4_hdmi->disable_4kp60 = true;
        }
 
+       pm_runtime_enable(dev);
+
        /*
-        * We need to have the device powered up at this point to call
-        * our reset hook and for the CEC init.
+        *  We need to have the device powered up at this point to call
+        *  our reset hook and for the CEC init.
         */
-       ret = vc4_hdmi_runtime_resume(dev);
+       ret = pm_runtime_resume_and_get(dev);
        if (ret)
-               goto err_put_ddc;
-
-       pm_runtime_get_noresume(dev);
-       pm_runtime_set_active(dev);
-       pm_runtime_enable(dev);
+               goto err_disable_runtime_pm;
 
        if ((of_device_is_compatible(dev->of_node, "brcm,bcm2711-hdmi0") ||
             of_device_is_compatible(dev->of_node, "brcm,bcm2711-hdmi1")) &&
@@ -3027,6 +3025,7 @@ err_destroy_conn:
 err_destroy_encoder:
        drm_encoder_cleanup(encoder);
        pm_runtime_put_sync(dev);
+err_disable_runtime_pm:
        pm_runtime_disable(dev);
 err_put_ddc:
        put_device(&vc4_hdmi->ddc->dev);