linux-kernel - [PATCH AUTOSEL 5.19 06/33] drm/vc4: hdmi: Rework power up

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Message-Id: <20220830171825.580603-6-sashal@kernel.org>
Date:   Tue, 30 Aug 2022 13:17:57 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Maxime Ripard <maxime@...no.tech>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Stefan Wahren <stefan.wahren@...e.com>,
        Sasha Levin <sashal@...nel.org>, emma@...olt.net,
        mripard@...nel.org, airlied@...ux.ie, daniel@...ll.ch,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 5.19 06/33] drm/vc4: hdmi: Rework power up

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

[ Upstream commit 258e483a4d5e97a6a8caa74381ddc1f395ac1c71 ]

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>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index c5702f22fe1a8..199bc398817fa 100644
--- 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 *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")) &&
@@ -3048,6 +3046,7 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
 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);
-- 
2.35.1