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From: Mika Kahola <mika.kahola@intel.com>
To: dri-devel@lists.freedesktop.org
Cc: daniel.vetter@ffwll.ch, intel-gfx@lists.freedesktop.org
Subject: [PATCH v8 04/12] drm: Helper to read max bits per component
Date: Wed, 17 Aug 2016 13:16:20 +0300	[thread overview]
Message-ID: <1471428989-30634-5-git-send-email-mika.kahola@intel.com> (raw)
In-Reply-To: <1471428989-30634-1-git-send-email-mika.kahola@intel.com>

Helper routine to read out maximum supported bits per
component for DisplayPort legay converters.

v2: Return early if detailed port cap info is not available.
    Replace if-else ladder with switch-case (Ville)

Reviewed-by: Jim Bride <jim.bride@linux.intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
---
 drivers/gpu/drm/drm_dp_helper.c | 42 +++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_dp_helper.h     |  2 ++
 2 files changed, 44 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 7497490..14e8ea0 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -472,6 +472,48 @@ int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
 }
 EXPORT_SYMBOL(drm_dp_downstream_max_clock);
 
+/**
+ * drm_dp_downstream_max_bpc() - extract branch device max
+ *                               bits per component
+ * @dpcd: DisplayPort configuration data
+ * @port_cap: port capabilities
+ *
+ * Returns max bpc on success or 0 if max bpc not defined
+ */
+int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
+			      const u8 port_cap[4])
+{
+	int type = port_cap[0] & DP_DS_PORT_TYPE_MASK;
+	bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] &
+		DP_DETAILED_CAP_INFO_AVAILABLE;
+	int bpc;
+
+	if (!detailed_cap_info)
+		return 0;
+
+	switch (type) {
+	case DP_DS_PORT_TYPE_VGA:
+	case DP_DS_PORT_TYPE_DVI:
+	case DP_DS_PORT_TYPE_HDMI:
+	case DP_DS_PORT_TYPE_DP_DUALMODE:
+		bpc = port_cap[2] & DP_DS_MAX_BPC_MASK;
+
+		switch (bpc) {
+		case DP_DS_8BPC:
+			return 8;
+		case DP_DS_10BPC:
+			return 10;
+		case DP_DS_12BPC:
+			return 12;
+		case DP_DS_16BPC:
+			return 16;
+		}
+	default:
+		return 0;
+	}
+}
+EXPORT_SYMBOL(drm_dp_downstream_max_bpc);
+
 /*
  * I2C-over-AUX implementation
  */
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 60dd9dc..f3d1424 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -817,6 +817,8 @@ int drm_dp_link_power_down(struct drm_dp_aux *aux, struct drm_dp_link *link);
 int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link);
 int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
 				const u8 port_cap[4]);
+int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
+			      const u8 port_cap[4]);
 
 void drm_dp_aux_init(struct drm_dp_aux *aux);
 int drm_dp_aux_register(struct drm_dp_aux *aux);
-- 
1.9.1

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  parent reply	other threads:[~2016-08-17 10:16 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-17 10:16 [PATCH v8 00/12] drm/i915: DP branch devices Mika Kahola
2016-08-17 10:16 ` [PATCH v8 01/12] drm: Add missing DP downstream port types Mika Kahola
2016-08-17 10:16 ` [PATCH v8 02/12] drm: Drop VGA from bpc definitions Mika Kahola
2016-08-17 10:16 ` [PATCH v8 03/12] drm: Helper to read max clock rate Mika Kahola
2016-08-17 10:16 ` Mika Kahola [this message]
2016-08-17 10:16 ` [PATCH v8 05/12] drm: Read DP branch device id Mika Kahola
2016-08-17 10:16 ` [PATCH v8 06/12] drm/i915: Cleanup DisplayPort AUX channel initialization Mika Kahola
2016-08-17 10:16 ` [PATCH v8 07/12] drm/i915: Read DP branch device HW revision Mika Kahola
2016-08-17 10:16 ` [PATCH v8 08/12] drm/i915: Read DP branch device SW revision Mika Kahola
2016-08-17 10:16 ` [PATCH v8 09/12] Check pixel rate for DP to VGA dongle Mika Kahola
2016-08-17 10:16 ` [PATCH v8 09/12] drm/i915: " Mika Kahola
2016-08-17 10:16 ` [PATCH v8 10/12] drm/i915: Update bits per component for display info Mika Kahola
2016-08-17 10:16 ` [PATCH v8 11/12] drm: Add DP branch device info on debugfs Mika Kahola
2016-08-17 10:16 ` [PATCH v8 12/12] drm/i915: Check TMDS clock DP to HDMI dongle Mika Kahola
  -- strict thread matches above, loose matches on Subject: below --
2016-08-17 10:49 [PATCH v8 00/12] drm/i915: DP branch devices Mika Kahola
2016-08-17 10:49 ` [PATCH v8 04/12] drm: Helper to read max bits per component Mika Kahola
2016-09-08 13:03   ` Ville Syrjälä

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