From: Maxime Ripard <mripard@kernel.org>
To: "Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
"Thomas Zimmermann" <tzimmermann@suse.de>,
"David Airlie" <airlied@gmail.com>,
"Daniel Vetter" <daniel@ffwll.ch>,
"Jonathan Corbet" <corbet@lwn.net>,
"Sandy Huang" <hjc@rock-chips.com>,
"Heiko Stübner" <heiko@sntech.de>, "Chen-Yu Tsai" <wens@csie.org>,
"Jernej Skrabec" <jernej.skrabec@gmail.com>,
"Samuel Holland" <samuel@sholland.org>
Cc: "Hans Verkuil" <hverkuil@xs4all.nl>,
"Sebastian Wick" <sebastian.wick@redhat.com>,
"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
dri-devel@lists.freedesktop.org,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
linux-rockchip@lists.infradead.org, linux-sunxi@lists.linux.dev,
"Maxime Ripard" <mripard@kernel.org>,
"Dave Stevenson" <dave.stevenson@raspberrypi.com>
Subject: [PATCH v10 08/27] drm/connector: hdmi: Add HDMI compute clock helper
Date: Thu, 21 Mar 2024 16:29:04 +0100 [thread overview]
Message-ID: <20240321-kms-hdmi-connector-state-v10-8-e6c178361898@kernel.org> (raw)
In-Reply-To: <20240321-kms-hdmi-connector-state-v10-0-e6c178361898@kernel.org>
A lot of HDMI drivers have some variation of the formula to calculate
the TMDS character rate from a mode, but few of them actually take all
parameters into account.
Let's create a helper to provide that rate taking all parameters into
account.
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
drivers/gpu/drm/drm_connector.c | 71 +++++++++++++++++++++++++++++++++++++++++
include/drm/drm_connector.h | 5 +++
2 files changed, 76 insertions(+)
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index b629c8e990f4..8cc1332f11c2 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -2895,10 +2895,81 @@ void drm_connector_update_privacy_screen(const struct drm_connector_state *conne
/* The hw_state property value may have changed, update it. */
drm_connector_update_privacy_screen_properties(connector, false);
}
EXPORT_SYMBOL(drm_connector_update_privacy_screen);
+/**
+ * drm_connector_hdmi_compute_mode_clock() - Computes the TMDS Character Rate
+ * @mode: Display mode to compute the clock for
+ * @bpc: Bits per character
+ * @fmt: Output Pixel Format used
+ *
+ * Returns the TMDS Character Rate for a given mode, bpc count and output format.
+ *
+ * RETURNS:
+ * The TMDS Character Rate, in Hertz, or 0 on error.
+ */
+unsigned long long
+drm_connector_hdmi_compute_mode_clock(const struct drm_display_mode *mode,
+ unsigned int bpc,
+ enum hdmi_colorspace fmt)
+{
+ unsigned long long clock = mode->clock * 1000ULL;
+ unsigned int vic = drm_match_cea_mode(mode);
+
+ /*
+ * CTA-861-G Spec, section 5.4 - Color Coding and Quantization
+ * mandates that VIC 1 always uses 8 bpc.
+ */
+ if (vic == 1 && bpc != 8)
+ return 0;
+
+ /*
+ * HDMI 2.0 Spec, section 7.1 - YCbCr 4:2:0 Pixel Encoding
+ * specifies that YUV420 encoding is only available for those
+ * VICs.
+ */
+ if (fmt == HDMI_COLORSPACE_YUV420 &&
+ !(vic == 96 || vic == 97 || vic == 101 ||
+ vic == 102 || vic == 106 || vic == 107))
+ return 0;
+
+ if (fmt == HDMI_COLORSPACE_YUV422) {
+ /*
+ * HDMI 1.4b Spec, section 6.2.3 - Pixel Encoding Requirements
+ * specifies that YUV422 is 36-bit only.
+ */
+ if (bpc != 12)
+ return 0;
+
+ /*
+ * HDMI 1.0 Spec, section 6.5 - Pixel Encoding
+ * specifies that YUV422 requires two 12-bits components per
+ * pixel clock, which is equivalent in our calculation to three
+ * 8-bits components
+ */
+ bpc = 8;
+ }
+
+ /*
+ * HDMI 2.0 Spec, Section 7.1 - YCbCr 4:2:0 Pixel Encoding
+ * specifies that YUV420 encoding is carried at a TMDS Character Rate
+ * equal to half the pixel clock rate.
+ */
+ if (fmt == HDMI_COLORSPACE_YUV420)
+ clock = clock / 2;
+
+ if (mode->flags & DRM_MODE_FLAG_DBLCLK)
+ clock = clock * 2;
+
+ clock = clock * bpc;
+ do_div(clock, 8);
+
+ return clock;
+}
+EXPORT_SYMBOL(drm_connector_hdmi_compute_mode_clock);
+
int drm_connector_set_obj_prop(struct drm_mode_object *obj,
struct drm_property *property,
uint64_t value)
{
int ret = -EINVAL;
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 29883e6f8e50..a859ad7ee04b 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -36,10 +36,11 @@
struct drm_connector_helper_funcs;
struct drm_modeset_acquire_ctx;
struct drm_device;
struct drm_crtc;
+struct drm_display_mode;
struct drm_encoder;
struct drm_panel;
struct drm_property;
struct drm_property_blob;
struct drm_printer;
@@ -2092,10 +2093,14 @@ int drm_connector_attach_max_bpc_property(struct drm_connector *connector,
void drm_connector_create_privacy_screen_properties(struct drm_connector *conn);
void drm_connector_attach_privacy_screen_properties(struct drm_connector *conn);
void drm_connector_attach_privacy_screen_provider(
struct drm_connector *connector, struct drm_privacy_screen *priv);
void drm_connector_update_privacy_screen(const struct drm_connector_state *connector_state);
+unsigned long long
+drm_connector_hdmi_compute_mode_clock(const struct drm_display_mode *mode,
+ unsigned int bpc,
+ enum hdmi_colorspace fmt);
/**
* struct drm_tile_group - Tile group metadata
* @refcount: reference count
* @dev: DRM device
--
2.44.0
next prev parent reply other threads:[~2024-03-21 15:29 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-21 15:28 [PATCH v10 00/27] drm/connector: Create HDMI Connector infrastructure Maxime Ripard
2024-03-21 15:28 ` [PATCH v10 01/27] drm/connector: Introduce an HDMI connector initialization function Maxime Ripard
2024-03-21 15:28 ` [PATCH v10 02/27] drm/tests: connector: Add tests for drmm_connector_hdmi_init Maxime Ripard
2024-03-21 15:28 ` [PATCH v10 03/27] drm/connector: hdmi: Create an HDMI sub-state Maxime Ripard
2024-03-21 22:32 ` [v10,03/27] " Sui Jingfeng
2024-03-21 15:29 ` [PATCH v10 04/27] drm/connector: hdmi: Add output BPC to the connector state Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 05/27] drm/tests: Add output bpc tests Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 06/27] drm/connector: hdmi: Add support for output format Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 07/27] drm/tests: Add output formats tests Maxime Ripard
2024-03-21 15:29 ` Maxime Ripard [this message]
2024-03-21 15:29 ` [PATCH v10 09/27] drm/tests: Add HDMI TDMS character rate tests Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 10/27] drm/connector: hdmi: Calculate TMDS character rate Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 11/27] drm/tests: Add TDMS character rate connector state tests Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 12/27] drm/connector: hdmi: Add custom hook to filter TMDS character rate Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 13/27] drm/tests: Add HDMI connector rate filter hook tests Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 14/27] drm/connector: hdmi: Compute bpc and format automatically Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 15/27] drm/tests: Add HDMI connector bpc and format tests Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 16/27] drm/connector: hdmi: Add Broadcast RGB property Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 17/27] drm/tests: Add tests for " Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 18/27] drm/connector: hdmi: Add RGB Quantization Range to the connector state Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 19/27] drm/tests: Add RGB Quantization tests Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 20/27] drm/connector: hdmi: Add Infoframes generation Maxime Ripard
2024-03-21 21:53 ` [v10,20/27] " Sui Jingfeng
2024-03-22 9:22 ` Jani Nikula
2024-03-22 10:57 ` Maxime Ripard
2024-03-22 11:46 ` Jani Nikula
2024-03-22 11:28 ` Sui Jingfeng
2024-03-22 10:31 ` Maxime Ripard
2024-03-22 11:13 ` Sui Jingfeng
2024-03-22 12:31 ` Maxime Ripard
2024-03-22 14:30 ` Sui Jingfeng
2024-03-21 15:29 ` [PATCH v10 21/27] drm/tests: Add infoframes test Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 22/27] drm/connector: hdmi: Create Infoframe DebugFS entries Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 23/27] drm/vc4: hdmi: Switch to HDMI connector Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 24/27] drm/vc4: tests: Remove vc4_dummy_plane structure Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 25/27] drm/vc4: tests: Convert to plane creation helper Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 26/27] drm/rockchip: inno_hdmi: Switch to HDMI connector Maxime Ripard
2024-03-21 15:29 ` [PATCH v10 27/27] drm/sun4i: hdmi: " Maxime Ripard
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