linux-kernel - [PATCH 5.19 01/72] drm/vc4: hdmi: Rework power up

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Date:   Fri,  2 Sep 2022 14:18:37 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Thomas Zimmermann <tzimmermann@...e.de>,
        Stefan Wahren <stefan.wahren@...e.com>,
        Maxime Ripard <maxime@...no.tech>,
        "Sudip Mukherjee (Codethink)" <sudipm.mukherjee@...il.com>
Subject: [PATCH 5.19 01/72] drm/vc4: hdmi: Rework power up

From: Maxime Ripard <maxime@...no.tech>

commit 258e483a4d5e97a6a8caa74381ddc1f395ac1c71 upstream.

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@...e.de>
Tested-by: Stefan Wahren <stefan.wahren@...e.com>
Signed-off-by: Maxime Ripard <maxime@...no.tech>
(cherry picked from commit 53565c28e6af2cef6bbf438c34250135e3564459)
Signed-off-by: Maxime Ripard <maxime@...no.tech>
Cc: "Sudip Mukherjee (Codethink)" <sudipm.mukherjee@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c |   15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -2992,17 +2992,15 @@ static int vc4_hdmi_bind(struct device *
 			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")) &&
@@ -3048,6 +3046,7 @@ 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);