linux-kernel - [PATCH 08/15] drm/vc4: hdmi: Introduce a CEC clock

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Date:   Thu, 10 Dec 2020 14:46:41 +0100
From:   Maxime Ripard <maxime@...no.tech>
To:     Eric Anholt <eric@...olt.net>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Maxime Ripard <maxime@...no.tech>,
        Daniel Vetter <daniel.vetter@...el.com>,
        David Airlie <airlied@...ux.ie>
Cc:     Jason Cooper <jason@...edaemon.net>,
        bcm-kernel-feedback-list@...adcom.com,
        linux-arm-kernel@...ts.infradead.org,
        Marc Zyngier <maz@...nel.org>, linux-media@...r.kernel.org,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        linux-kernel@...r.kernel.org,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dave Stevenson <dave.stevenson@...pberrypi.com>,
        linux-rpi-kernel@...ts.infradead.org,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH 08/15] drm/vc4: hdmi: Introduce a CEC clock

While the BCM2835 had the CEC clock derived from the HSM clock, the
BCM2711 has a dedicated parent clock for it.

Let's introduce a separate clock for it so that we can handle both
cases.

Signed-off-by: Maxime Ripard <maxime@...no.tech>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 9 ++++++++-
 drivers/gpu/drm/vc4/vc4_hdmi.h | 1 +
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index b93ee3e26e2b..0debd22bc992 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -145,7 +145,7 @@ static void vc4_hdmi_cec_update_clk_div(struct vc4_hdmi *vc4_hdmi)
 	 * Set the clock divider: the hsm_clock rate and this divider
 	 * setting will give a 40 kHz CEC clock.
 	 */
-	clk_cnt = clk_get_rate(vc4_hdmi->hsm_clock) / CEC_CLOCK_FREQ;
+	clk_cnt = clk_get_rate(vc4_hdmi->cec_clock) / CEC_CLOCK_FREQ;
 	value |= clk_cnt << VC4_HDMI_CEC_DIV_CLK_CNT_SHIFT;
 	HDMI_WRITE(HDMI_CEC_CNTRL_1, value);
 }
@@ -1740,6 +1740,7 @@ static int vc4_hdmi_init_resources(struct vc4_hdmi *vc4_hdmi)
 		return PTR_ERR(vc4_hdmi->hsm_clock);
 	}
 	vc4_hdmi->audio_clock = vc4_hdmi->hsm_clock;
+	vc4_hdmi->cec_clock = vc4_hdmi->hsm_clock;
 
 	return 0;
 }
@@ -1833,6 +1834,12 @@ static int vc5_hdmi_init_resources(struct vc4_hdmi *vc4_hdmi)
 		return PTR_ERR(vc4_hdmi->audio_clock);
 	}
 
+	vc4_hdmi->cec_clock = devm_clk_get(dev, "cec");
+	if (IS_ERR(vc4_hdmi->cec_clock)) {
+		DRM_ERROR("Failed to get CEC clock\n");
+		return PTR_ERR(vc4_hdmi->cec_clock);
+	}
+
 	vc4_hdmi->reset = devm_reset_control_get(dev, NULL);
 	if (IS_ERR(vc4_hdmi->reset)) {
 		DRM_ERROR("Failed to get HDMI reset line\n");
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
index 720914761261..adc4bf33ff15 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.h
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
@@ -155,6 +155,7 @@ struct vc4_hdmi {
 	bool cec_tx_ok;
 	bool cec_irq_was_rx;
 
+	struct clk *cec_clock;
 	struct clk *pixel_clock;
 	struct clk *hsm_clock;
 	struct clk *audio_clock;
-- 
2.28.0