From c1bf9e8c50baa237b514715dcb9c8fd367694c93 Mon Sep 17 00:00:00 2001
From: Jason Wu <jason.wu.misc@gmail.com>
Date: Sun, 10 Apr 2016 13:14:13 +1000
Subject: [PATCH 1/3] drm: xilinx: Add encoder for Digilent boards

Add the dglnt_encoder driver that enables DRM support for the VGA and
HDMI output ports found on many Digilent boards.

Upstream-Status: Pending

Signed-off-by: Sam Bobrowicz <sbobrowicz@digilentinc.com>
Signed-off-by: Jason Wu <jason.wu.misc@gmail.com>
---
 .../bindings/drm/xilinx/dglnt_encoder.txt          |  23 +++
 drivers/gpu/drm/xilinx/Kconfig                     |   6 +
 drivers/gpu/drm/xilinx/Makefile                    |   1 +
 drivers/gpu/drm/xilinx/dglnt_encoder.c             | 217 +++++++++++++++++++++
 4 files changed, 247 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/drm/xilinx/dglnt_encoder.txt
 create mode 100644 drivers/gpu/drm/xilinx/dglnt_encoder.c

diff --git a/Documentation/devicetree/bindings/drm/xilinx/dglnt_encoder.txt b/Documentation/devicetree/bindings/drm/xilinx/dglnt_encoder.txt
new file mode 100644
index 0000000000..242b24e482
--- /dev/null
+++ b/Documentation/devicetree/bindings/drm/xilinx/dglnt_encoder.txt
@@ -0,0 +1,23 @@
+Device-Tree bindings for Digilent DRM Encoder Slave
+
+This driver provides support for VGA and HDMI outputs on Digilent FPGA boards.
+The VGA or HDMI port must be connected to a Xilinx display pipeline via an
+axi2vid IP core.
+
+Required properties:
+ - compatible: Should be "digilent,drm-encoder".
+
+Optional properties:
+ - dglnt,edid-i2c: The I2C device connected to the DDC bus on the video
+                   connector. This is used to obtain the supported resolutions
+                   of an attached monitor. If not defined, then a default
+                   set of resolutions is used and the display will initialize
+                   to 720p. Note most VGA connectors on Digilent boards do
+                   not have the DDC bus routed out.
+
+Example:
+
+	encoder_0: digilent_encoder {
+		compatible = "digilent,drm-encoder";
+		dglnt,edid-i2c = <&i2c1>;
+	};
diff --git a/drivers/gpu/drm/xilinx/Kconfig b/drivers/gpu/drm/xilinx/Kconfig
index 12b548c2a9..c3e2562e53 100644
--- a/drivers/gpu/drm/xilinx/Kconfig
+++ b/drivers/gpu/drm/xilinx/Kconfig
@@ -57,3 +57,9 @@ config DRM_XILINX_SDI
 	depends on DRM_XILINX
 	help
 	  DRM driver for Xilinx Display Port Subsystem.
+
+config DRM_DIGILENT_ENCODER
+   tristate "Digilent VGA/HDMI DRM Encoder Driver"
+   depends on DRM_XILINX
+   help
+     DRM slave encoder for Video-out on Digilent boards.
diff --git a/drivers/gpu/drm/xilinx/Makefile b/drivers/gpu/drm/xilinx/Makefile
index 19bc1541ca..c2717e40ea 100644
--- a/drivers/gpu/drm/xilinx/Makefile
+++ b/drivers/gpu/drm/xilinx/Makefile
@@ -7,6 +7,7 @@ xilinx_drm-y := xilinx_drm_crtc.o xilinx_drm_connector.o xilinx_drm_drv.o \
 		xilinx_drm_plane.o
 xilinx_drm-y += xilinx_cresample.o xilinx_osd.o xilinx_rgb2yuv.o xilinx_vtc.o
 
+obj-$(CONFIG_DRM_DIGILENT_ENCODER) += dglnt_encoder.o
 obj-$(CONFIG_DRM_XILINX) += xilinx_drm.o
 obj-$(CONFIG_DRM_XILINX_DP) += xilinx_drm_dp.o
 obj-$(CONFIG_DRM_XILINX_DP_SUB) += xilinx_drm_dp_sub.o
diff --git a/drivers/gpu/drm/xilinx/dglnt_encoder.c b/drivers/gpu/drm/xilinx/dglnt_encoder.c
new file mode 100644
index 0000000000..26a23986f9
--- /dev/null
+++ b/drivers/gpu/drm/xilinx/dglnt_encoder.c
@@ -0,0 +1,217 @@
+/*
+ * dglnt_encoder.c - DRM slave encoder for Video-out on Digilent boards
+ *
+ * Copyright (C) 2015 Digilent
+ * Author: Sam Bobrowicz <sbobrowicz@digilentinc.com>
+ *
+ * Based on udl_encoder.c and udl_connector.c, Copyright (C) 2012 Red Hat.
+ * Also based on xilinx_drm_dp.c, Copyright (C) 2014 Xilinx, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <drm/drmP.h>
+#include <drm/drm_edid.h>
+#include <drm/drm_encoder_slave.h>
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#define DGLNT_ENC_MAX_FREQ 150000
+#define DGLNT_ENC_MAX_H 1920
+#define DGLNT_ENC_MAX_V 1080
+#define DGLNT_ENC_PREF_H 1280
+#define DGLNT_ENC_PREF_V 720
+
+struct dglnt_encoder {
+	struct drm_encoder *encoder;
+	struct i2c_adapter *i2c_bus;
+	bool i2c_present;
+};
+
+static inline struct dglnt_encoder *to_dglnt_encoder(
+					struct drm_encoder *encoder)
+{
+	return to_encoder_slave(encoder)->slave_priv;
+}
+
+static bool dglnt_mode_fixup(struct drm_encoder *encoder,
+				const struct drm_display_mode *mode,
+				struct drm_display_mode *adjusted_mode)
+{
+	return true;
+}
+
+static void dglnt_encoder_mode_set(struct drm_encoder *encoder,
+				struct drm_display_mode *mode,
+				struct drm_display_mode *adjusted_mode)
+{
+}
+
+static void
+dglnt_encoder_dpms(struct drm_encoder *encoder, int mode)
+{
+}
+
+static void dglnt_encoder_save(struct drm_encoder *encoder)
+{
+}
+
+static void dglnt_encoder_restore(struct drm_encoder *encoder)
+{
+}
+
+static int dglnt_encoder_mode_valid(struct drm_encoder *encoder,
+				struct drm_display_mode *mode)
+{
+	if (mode &&
+		!(mode->flags & ((DRM_MODE_FLAG_INTERLACE |
+			DRM_MODE_FLAG_DBLCLK) | DRM_MODE_FLAG_3D_MASK)) &&
+		(mode->clock <= DGLNT_ENC_MAX_FREQ) &&
+		(mode->hdisplay <= DGLNT_ENC_MAX_H) &&
+		(mode->vdisplay <= DGLNT_ENC_MAX_V))
+		return MODE_OK;
+	return MODE_BAD;
+}
+
+static int dglnt_encoder_get_modes(struct drm_encoder *encoder,
+				struct drm_connector *connector)
+{
+	struct dglnt_encoder *dglnt = to_dglnt_encoder(encoder);
+	struct edid *edid;
+	int num_modes = 0;
+
+	if (dglnt->i2c_present) {
+		edid = drm_get_edid(connector, dglnt->i2c_bus);
+		drm_mode_connector_update_edid_property(connector, edid);
+		if (edid) {
+			num_modes = drm_add_edid_modes(connector, edid);
+			kfree(edid);
+		}
+	} else {
+		num_modes = drm_add_modes_noedid(connector, DGLNT_ENC_MAX_H,
+						DGLNT_ENC_MAX_V);
+		drm_set_preferred_mode(connector, DGLNT_ENC_PREF_H,
+					DGLNT_ENC_PREF_V);
+	}
+	return num_modes;
+}
+
+static enum drm_connector_status dglnt_encoder_detect(
+					struct drm_encoder *encoder,
+					struct drm_connector *connector)
+{
+	struct dglnt_encoder *dglnt = to_dglnt_encoder(encoder);
+
+	if (dglnt->i2c_present) {
+		if (drm_probe_ddc(dglnt->i2c_bus))
+			return connector_status_connected;
+		return connector_status_disconnected;
+	} else
+		return connector_status_unknown;
+}
+
+static struct drm_encoder_slave_funcs dglnt_encoder_slave_funcs = {
+	.dpms			= dglnt_encoder_dpms,
+	.save			= dglnt_encoder_save,
+	.restore		= dglnt_encoder_restore,
+	.mode_fixup		= dglnt_mode_fixup,
+	.mode_valid		= dglnt_encoder_mode_valid,
+	.mode_set		= dglnt_encoder_mode_set,
+	.detect			= dglnt_encoder_detect,
+	.get_modes		= dglnt_encoder_get_modes,
+};
+
+static int dglnt_encoder_encoder_init(struct platform_device *pdev,
+				struct drm_device *dev,
+				struct drm_encoder_slave *encoder)
+{
+	struct dglnt_encoder *dglnt = platform_get_drvdata(pdev);
+	struct device_node *sub_node;
+
+	encoder->slave_priv = dglnt;
+	encoder->slave_funcs = &dglnt_encoder_slave_funcs;
+
+	dglnt->encoder = &encoder->base;
+
+	/* get i2c adapter for edid */
+	dglnt->i2c_present = false;
+	sub_node = of_parse_phandle(pdev->dev.of_node, "dglnt,edid-i2c", 0);
+	if (sub_node) {
+		dglnt->i2c_bus = of_find_i2c_adapter_by_node(sub_node);
+		if (!dglnt->i2c_bus)
+			DRM_INFO("failed to get the edid i2c adapter, using default modes\n");
+		else
+			dglnt->i2c_present = true;
+		of_node_put(sub_node);
+	}
+
+	return 0;
+}
+
+static int dglnt_encoder_probe(struct platform_device *pdev)
+{
+	struct dglnt_encoder *dglnt;
+
+	dglnt = devm_kzalloc(&pdev->dev, sizeof(*dglnt), GFP_KERNEL);
+	if (!dglnt)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, dglnt);
+
+	return 0;
+}
+
+static int dglnt_encoder_remove(struct platform_device *pdev)
+{
+	return 0;
+}
+
+static const struct of_device_id dglnt_encoder_of_match[] = {
+	{ .compatible = "digilent,drm-encoder", },
+	{ /* end of table */ },
+};
+MODULE_DEVICE_TABLE(of, dglnt_encoder_of_match);
+
+static struct drm_platform_encoder_driver dglnt_encoder_driver = {
+	.platform_driver = {
+		.probe			= dglnt_encoder_probe,
+		.remove			= dglnt_encoder_remove,
+		.driver			= {
+			.owner		= THIS_MODULE,
+			.name		= "dglnt-drm-enc",
+			.of_match_table	= dglnt_encoder_of_match,
+		},
+	},
+
+	.encoder_init = dglnt_encoder_encoder_init,
+};
+
+static int __init dglnt_encoder_init(void)
+{
+	return platform_driver_register(&dglnt_encoder_driver.platform_driver);
+}
+
+static void __exit dglnt_encoder_exit(void)
+{
+	platform_driver_unregister(&dglnt_encoder_driver.platform_driver);
+}
+
+module_init(dglnt_encoder_init);
+module_exit(dglnt_encoder_exit);
+
+MODULE_AUTHOR("Digilent, Inc.");
+MODULE_DESCRIPTION("DRM slave encoder for Video-out on Digilent boards");
+MODULE_LICENSE("GPL v2");
-- 
2.14.2