linux-kernel - [PATCH 3/4] drm/vc4: use new helper to get ACR values

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Message-Id: <20250309-drm-hdmi-acr-v1-3-bb9c242f4d4b@linaro.org>
Date: Sun, 09 Mar 2025 10:13:58 +0200
From: Dmitry Baryshkov <lumag@...nel.org>
To: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Rob Clark <robdclark@...il.com>, Abhinav Kumar <quic_abhinavk@...cinc.com>, 
 Sean Paul <sean@...rly.run>, Marijn Suijten <marijn.suijten@...ainline.org>, 
 Dave Stevenson <dave.stevenson@...pberrypi.com>, 
 Maíra Canal <mcanal@...lia.com>, 
 Raspberry Pi Kernel Maintenance <kernel-list@...pberrypi.com>, 
 Andrzej Hajda <andrzej.hajda@...el.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 linux-arm-msm@...r.kernel.org, freedreno@...ts.freedesktop.org
Subject: [PATCH 3/4] drm/vc4: use new helper to get ACR values

From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>

Use drm_hdmi_acr_get_n_cts() helper instead of calculating N and CTS
values in the VC4 driver.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 10 +++-------
 drivers/gpu/drm/vc4/vc4_hdmi.h |  7 +++++++
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 37238a12baa58a06a5d6f40d1ab64abc7fac60d7..f24bcc2f3a2ac39aaea061b809940978341472f4 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1637,6 +1637,7 @@ static void vc4_hdmi_encoder_atomic_mode_set(struct drm_encoder *encoder,
 		      &crtc_state->adjusted_mode);
 	vc4_hdmi->output_bpc = conn_state->hdmi.output_bpc;
 	vc4_hdmi->output_format = conn_state->hdmi.output_format;
+	vc4_hdmi->tmds_char_rate = conn_state->hdmi.tmds_char_rate;
 	mutex_unlock(&vc4_hdmi->mutex);
 }
 
@@ -1829,17 +1830,12 @@ static void vc4_hdmi_audio_set_mai_clock(struct vc4_hdmi *vc4_hdmi,
 
 static void vc4_hdmi_set_n_cts(struct vc4_hdmi *vc4_hdmi, unsigned int samplerate)
 {
-	const struct drm_display_mode *mode = &vc4_hdmi->saved_adjusted_mode;
-	u32 n, cts;
-	u64 tmp;
+	unsigned int n, cts;
 
 	lockdep_assert_held(&vc4_hdmi->mutex);
 	lockdep_assert_held(&vc4_hdmi->hw_lock);
 
-	n = 128 * samplerate / 1000;
-	tmp = (u64)(mode->clock * 1000) * n;
-	do_div(tmp, 128 * samplerate);
-	cts = tmp;
+	drm_hdmi_acr_get_n_cts(vc4_hdmi->tmds_char_rate, samplerate, &n, &cts);
 
 	HDMI_WRITE(HDMI_CRP_CFG,
 		   VC4_HDMI_CRP_CFG_EXTERNAL_CTS_EN |
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
index e3d989ca302b72533c374dfa3fd0d5bd7fe64a82..0a775dbfe99d45521f3d0a2016555aefa81d7934 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.h
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
@@ -211,6 +211,13 @@ struct vc4_hdmi {
 	 * KMS hooks. Protected by @mutex.
 	 */
 	enum hdmi_colorspace output_format;
+
+	/**
+	 * @tmds_char_rate: Copy of
+	 * @drm_connector_state.hdmi.tmds_char_rate for use outside of
+	 * KMS hooks. Protected by @mutex.
+	 */
+	unsigned long long tmds_char_rate;
 };
 
 #define connector_to_vc4_hdmi(_connector)				\

-- 
2.39.5