linux-kernel - [PATCH 5.13 194/266] drm/vc4: hdmi: Prevent clock unbalance

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Message-Id: <20210715182644.976995978@linuxfoundation.org>
Date:   Thu, 15 Jul 2021 20:39:09 +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, Maxime Ripard <maxime@...no.tech>,
        Dave Stevenson <dave.stevenson@...pberrypi.com>
Subject: [PATCH 5.13 194/266] drm/vc4: hdmi: Prevent clock unbalance

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

commit 5b006000423667ef0f55721fc93e477b31f22d28 upstream.

Since we fixed the hooks to disable the encoder at boot, we now have an
unbalanced clk_disable call at boot since we never enabled them in the
first place.

Let's mimic the state of the hardware and enable the clocks at boot if
the controller is enabled to get the use-count right.

Cc: <stable@...r.kernel.org> # v5.10+
Fixes: 09c438139b8f ("drm/vc4: hdmi: Implement finer-grained hooks")
Signed-off-by: Maxime Ripard <maxime@...no.tech>
Reviewed-by: Dave Stevenson <dave.stevenson@...pberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210507150515.257424-7-maxime@cerno.tech
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/vc4/vc4_hdmi.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -2012,6 +2012,14 @@ static int vc4_hdmi_bind(struct device *
 	if (vc4_hdmi->variant->reset)
 		vc4_hdmi->variant->reset(vc4_hdmi);
 
+	if ((of_device_is_compatible(dev->of_node, "brcm,bcm2711-hdmi0") ||
+	     of_device_is_compatible(dev->of_node, "brcm,bcm2711-hdmi1")) &&
+	    HDMI_READ(HDMI_VID_CTL) & VC4_HD_VID_CTL_ENABLE) {
+		clk_prepare_enable(vc4_hdmi->pixel_clock);
+		clk_prepare_enable(vc4_hdmi->hsm_clock);
+		clk_prepare_enable(vc4_hdmi->pixel_bvb_clock);
+	}
+
 	pm_runtime_enable(dev);
 
 	drm_simple_encoder_init(drm, encoder, DRM_MODE_ENCODER_TMDS);