From mboxrd@z Thu Jan  1 00:00:00 1970
From: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Subject: =?UTF-8?q?=5BPATCH=20v17=203/7=5D=20video=3A=20add=20of=20helper=20for=20display=20timings/videomode?=
Date: Fri, 25 Jan 2013 10:01:51 +0100
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To: devicetree-discuss@lists.ozlabs.org, Dave Airlie <airlied@linux.ie>
Cc: Steffen Trumtrar <s.trumtrar@pengutronix.de>, Philipp Zabel <p.zabel@pengutronix.de>, Rob Herring <robherring2@gmail.com>, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Laurent Pinchart <laurent.pinchart@ideasonboard.com>, Thierry Reding <thierry.reding@avionic-design.de>, Guennady Liakhovetski <g.liakhovetski@gmx.de>, linux-media@vger.kernel.org, Tomi Valkeinen <tomi.valkeinen@ti.com>, Stephen Warren <swarren@wwwdotorg.org>, Florian Tobias Schandinat <FlorianSchandinat@gmx.de>, Rob Clark <robdclark@gmail.com>, Leela Krishna Amudala <leelakrishna.a@gmail.com>, "Mohammed, Afzal" <afzal@ti.com>, kernel@pengutronix.de
List-Id: devicetree@vger.kernel.org

This adds support for reading display timings from DT into a struct
display_timings. The of_display_timing implementation supports multiple
subnodes. All children are read into an array, that can be queried.

If no native mode is specified, the first subnode will be used.

=46or cases where the graphics driver knows there can be only one
mode description or where the driver only supports one mode, a helper
function of_get_videomode is added, that gets a struct videomode from D=
T.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>
Tested-by: Thierry Reding <thierry.reding@avionic-design.de>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Afzal Mohammed <Afzal@ti.com>
Tested-by: Rob Clark <robclark@gmail.com>
Tested-by: Leela Krishna Amudala <leelakrishna.a@gmail.com>
---
 .../devicetree/bindings/video/display-timing.txt   |  109 +++++++++
 drivers/video/Kconfig                              |   15 ++
 drivers/video/Makefile                             |    2 +
 drivers/video/of_display_timing.c                  |  239 ++++++++++++=
++++++++
 drivers/video/of_videomode.c                       |   54 +++++
 include/video/of_display_timing.h                  |   20 ++
 include/video/of_videomode.h                       |   18 ++
 7 files changed, 457 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/video/display-tim=
ing.txt
 create mode 100644 drivers/video/of_display_timing.c
 create mode 100644 drivers/video/of_videomode.c
 create mode 100644 include/video/of_display_timing.h
 create mode 100644 include/video/of_videomode.h

diff --git a/Documentation/devicetree/bindings/video/display-timing.txt=
 b/Documentation/devicetree/bindings/video/display-timing.txt
new file mode 100644
index 0000000..1500385
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/display-timing.txt
@@ -0,0 +1,109 @@
+display-timing bindings
+=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
+
+display-timings node
+--------------------
+
+required properties:
+ - none
+
+optional properties:
+ - native-mode: The native mode for the display, in case multiple mode=
s are
+		provided. When omitted, assume the first node is the native.
+
+timing subnode
+--------------
+
+required properties:
+ - hactive, vactive: display resolution
+ - hfront-porch, hback-porch, hsync-len: horizontal display timing par=
ameters
+   in pixels
+   vfront-porch, vback-porch, vsync-len: vertical display timing param=
eters in
+   lines
+ - clock-frequency: display clock in Hz
+
+optional properties:
+ - hsync-active: hsync pulse is active low/high/ignored
+ - vsync-active: vsync pulse is active low/high/ignored
+ - de-active: data-enable pulse is active low/high/ignored
+ - pixelclk-active: with
+			- active high =3D drive pixel data on rising edge/
+					sample data on falling edge
+			- active low  =3D drive pixel data on falling edge/
+					sample data on rising edge
+			- ignored     =3D ignored
+ - interlaced (bool): boolean to enable interlaced mode
+ - doublescan (bool): boolean to enable doublescan mode
+
+All the optional properties that are not bool follow the following log=
ic:
+    <1>: high active
+    <0>: low active
+    omitted: not used on hardware
+
+There are different ways of describing the capabilities of a display. =
The
+devicetree representation corresponds to the one commonly found in dat=
asheets
+for displays. If a display supports multiple signal timings, the nativ=
e-mode
+can be specified.
+
+The parameters are defined as:
+
+  +----------+-------------------------------------+----------+-------=
+
+  |          |        =E2=86=91                            |          =
|       |
+  |          |        |vback_porch                 |          |       =
|
+  |          |        =E2=86=93                            |          =
|       |
+  +----------#######################################----------+-------=
+
+  |          #        =E2=86=91                            #          =
|       |
+  |          #        |                            #          |       =
|
+  |  hback   #        |                            #  hfront  | hsync =
|
+  |   porch  #        |       hactive              #  porch   |  len  =
|
+  |<-------->#<-------+--------------------------->#<-------->|<----->=
|
+  |          #        |                            #          |       =
|
+  |          #        |vactive                     #          |       =
|
+  |          #        |                            #          |       =
|
+  |          #        =E2=86=93                            #          =
|       |
+  +----------#######################################----------+-------=
+
+  |          |        =E2=86=91                            |          =
|       |
+  |          |        |vfront_porch                |          |       =
|
+  |          |        =E2=86=93                            |          =
|       |
+  +----------+-------------------------------------+----------+-------=
+
+  |          |        =E2=86=91                            |          =
|       |
+  |          |        |vsync_len                   |          |       =
|
+  |          |        =E2=86=93                            |          =
|       |
+  +----------+-------------------------------------+----------+-------=
+
+
+Example:
+
+	display-timings {
+		native-mode =3D <&timing0>;
+		timing0: 1080p24 {
+			/* 1920x1080p24 */
+			clock-frequency =3D <52000000>;
+			hactive =3D <1920>;
+			vactive =3D <1080>;
+			hfront-porch =3D <25>;
+			hback-porch =3D <25>;
+			hsync-len =3D <25>;
+			vback-porch =3D <2>;
+			vfront-porch =3D <2>;
+			vsync-len =3D <2>;
+			hsync-active =3D <1>;
+		};
+	};
+
+Every required property also supports the use of ranges, so the common=
ly used
+datasheet description with minimum, typical and maximum values can be =
used.
+
+Example:
+
+	timing1: timing {
+		/* 1920x1080p24 */
+		clock-frequency =3D <148500000>;
+		hactive =3D <1920>;
+		vactive =3D <1080>;
+		hsync-len =3D <0 44 60>;
+		hfront-porch =3D <80 88 95>;
+		hback-porch =3D <100 148 160>;
+		vfront-porch =3D <0 4 6>;
+		vback-porch =3D <0 36 50>;
+		vsync-len =3D <0 5 6>;
+	};
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 09a8f0d..807c7fa 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -39,6 +39,21 @@ config DISPLAY_TIMING
 config VIDEOMODE
        bool
=20
+config OF_DISPLAY_TIMING
+	bool "Enable device tree display timing support"
+	depends on OF
+	select DISPLAY_TIMING
+	help
+	  helper to parse display timings from the devicetree
+
+config OF_VIDEOMODE
+	bool "Enable device tree videomode support"
+	depends on OF
+	select VIDEOMODE
+	select OF_DISPLAY_TIMING
+	help
+	  helper to get videomodes from the devicetree
+
 menuconfig FB
 	tristate "Support for frame buffer devices"
 	---help---
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index e0dd820..f592f3b 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -169,4 +169,6 @@ obj-$(CONFIG_FB_VIRTUAL)          +=3D vfb.o
 #video output switch sysfs driver
 obj-$(CONFIG_VIDEO_OUTPUT_CONTROL) +=3D output.o
 obj-$(CONFIG_DISPLAY_TIMING) +=3D display_timing.o
+obj-$(CONFIG_OF_DISPLAY_TIMING) +=3D of_display_timing.o
 obj-$(CONFIG_VIDEOMODE) +=3D videomode.o
+obj-$(CONFIG_OF_VIDEOMODE) +=3D of_videomode.o
diff --git a/drivers/video/of_display_timing.c b/drivers/video/of_displ=
ay_timing.c
new file mode 100644
index 0000000..13ecd98
--- /dev/null
+++ b/drivers/video/of_display_timing.c
@@ -0,0 +1,239 @@
+/*
+ * OF helpers for parsing display timings
+ *
+ * Copyright (c) 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>, Pe=
ngutronix
+ *
+ * based on of_videomode.c by Sascha Hauer <s.hauer@pengutronix.de>
+ *
+ * This file is released under the GPLv2
+ */
+#include <linux/export.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <video/display_timing.h>
+#include <video/of_display_timing.h>
+
+/**
+ * parse_timing_property - parse timing_entry from device_node
+ * @np: device_node with the property
+ * @name: name of the property
+ * @result: will be set to the return value
+ *
+ * DESCRIPTION:
+ * Every display_timing can be specified with either just the typical =
value or
+ * a range consisting of min/typ/max. This function helps handling thi=
s
+ **/
+static int parse_timing_property(struct device_node *np, const char *n=
ame,
+			  struct timing_entry *result)
+{
+	struct property *prop;
+	int length, cells, ret;
+
+	prop =3D of_find_property(np, name, &length);
+	if (!prop) {
+		pr_err("%s: could not find property %s\n",
+			of_node_full_name(np), name);
+		return -EINVAL;
+	}
+
+	cells =3D length / sizeof(u32);
+	if (cells =3D=3D 1) {
+		ret =3D of_property_read_u32(np, name, &result->typ);
+		result->min =3D result->typ;
+		result->max =3D result->typ;
+	} else if (cells =3D=3D 3) {
+		ret =3D of_property_read_u32_array(np, name, &result->min, cells);
+	} else {
+		pr_err("%s: illegal timing specification in %s\n",
+			of_node_full_name(np), name);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+/**
+ * of_get_display_timing - parse display_timing entry from device_node
+ * @np: device_node with the properties
+ **/
+static struct display_timing *of_get_display_timing(struct device_node=
 *np)
+{
+	struct display_timing *dt;
+	u32 val =3D 0;
+	int ret =3D 0;
+
+	dt =3D kzalloc(sizeof(*dt), GFP_KERNEL);
+	if (!dt) {
+		pr_err("%s: could not allocate display_timing struct\n",
+			of_node_full_name(np));
+		return NULL;
+	}
+
+	ret |=3D parse_timing_property(np, "hback-porch", &dt->hback_porch);
+	ret |=3D parse_timing_property(np, "hfront-porch", &dt->hfront_porch)=
;
+	ret |=3D parse_timing_property(np, "hactive", &dt->hactive);
+	ret |=3D parse_timing_property(np, "hsync-len", &dt->hsync_len);
+	ret |=3D parse_timing_property(np, "vback-porch", &dt->vback_porch);
+	ret |=3D parse_timing_property(np, "vfront-porch", &dt->vfront_porch)=
;
+	ret |=3D parse_timing_property(np, "vactive", &dt->vactive);
+	ret |=3D parse_timing_property(np, "vsync-len", &dt->vsync_len);
+	ret |=3D parse_timing_property(np, "clock-frequency", &dt->pixelclock=
);
+
+	dt->dmt_flags =3D 0;
+	dt->data_flags =3D 0;
+	if (!of_property_read_u32(np, "vsync-active", &val))
+		dt->dmt_flags |=3D val ? VESA_DMT_VSYNC_HIGH :
+				VESA_DMT_VSYNC_LOW;
+	if (!of_property_read_u32(np, "hsync-active", &val))
+		dt->dmt_flags |=3D val ? VESA_DMT_HSYNC_HIGH :
+				VESA_DMT_HSYNC_LOW;
+	if (!of_property_read_u32(np, "de-active", &val))
+		dt->data_flags |=3D val ? DISPLAY_FLAGS_DE_HIGH :
+				DISPLAY_FLAGS_DE_LOW;
+	if (!of_property_read_u32(np, "pixelclk-active", &val))
+		dt->data_flags |=3D val ? DISPLAY_FLAGS_PIXDATA_POSEDGE :
+				DISPLAY_FLAGS_PIXDATA_NEGEDGE;
+
+	if (of_property_read_bool(np, "interlaced"))
+		dt->data_flags |=3D DISPLAY_FLAGS_INTERLACED;
+	if (of_property_read_bool(np, "doublescan"))
+		dt->data_flags |=3D DISPLAY_FLAGS_DOUBLESCAN;
+
+	if (ret) {
+		pr_err("%s: error reading timing properties\n",
+			of_node_full_name(np));
+		kfree(dt);
+		return NULL;
+	}
+
+	return dt;
+}
+
+/**
+ * of_get_display_timings - parse all display_timing entries from a de=
vice_node
+ * @np: device_node with the subnodes
+ **/
+struct display_timings *of_get_display_timings(struct device_node *np)
+{
+	struct device_node *timings_np;
+	struct device_node *entry;
+	struct device_node *native_mode;
+	struct display_timings *disp;
+
+	if (!np) {
+		pr_err("%s: no devicenode given\n", of_node_full_name(np));
+		return NULL;
+	}
+
+	timings_np =3D of_find_node_by_name(np, "display-timings");
+	if (!timings_np) {
+		pr_err("%s: could not find display-timings node\n",
+			of_node_full_name(np));
+		return NULL;
+	}
+
+	disp =3D kzalloc(sizeof(*disp), GFP_KERNEL);
+	if (!disp) {
+		pr_err("%s: could not allocate struct disp'\n",
+			of_node_full_name(np));
+		goto dispfail;
+	}
+
+	entry =3D of_parse_phandle(timings_np, "native-mode", 0);
+	/* assume first child as native mode if none provided */
+	if (!entry)
+		entry =3D of_get_next_child(np, NULL);
+	/* if there is no child, it is useless to go on */
+	if (!entry) {
+		pr_err("%s: no timing specifications given\n",
+			of_node_full_name(np));
+		goto entryfail;
+	}
+
+	pr_debug("%s: using %s as default timing\n",
+		of_node_full_name(np), entry->name);
+
+	native_mode =3D entry;
+
+	disp->num_timings =3D of_get_child_count(timings_np);
+	if (disp->num_timings =3D=3D 0) {
+		/* should never happen, as entry was already found above */
+		pr_err("%s: no timings specified\n", of_node_full_name(np));
+		goto entryfail;
+	}
+
+	disp->timings =3D kzalloc(sizeof(struct display_timing *) *
+				disp->num_timings, GFP_KERNEL);
+	if (!disp->timings) {
+		pr_err("%s: could not allocate timings array\n",
+			of_node_full_name(np));
+		goto entryfail;
+	}
+
+	disp->num_timings =3D 0;
+	disp->native_mode =3D 0;
+
+	for_each_child_of_node(timings_np, entry) {
+		struct display_timing *dt;
+
+		dt =3D of_get_display_timing(entry);
+		if (!dt) {
+			/*
+			 * to not encourage wrong devicetrees, fail in case of
+			 * an error
+			 */
+			pr_err("%s: error in timing %d\n",
+				of_node_full_name(np), disp->num_timings + 1);
+			goto timingfail;
+		}
+
+		if (native_mode =3D=3D entry)
+			disp->native_mode =3D disp->num_timings;
+
+		disp->timings[disp->num_timings] =3D dt;
+		disp->num_timings++;
+	}
+	of_node_put(timings_np);
+	/*
+	 * native_mode points to the device_node returned by of_parse_phandle
+	 * therefore call of_node_put on it
+	 */
+	of_node_put(native_mode);
+
+	pr_debug("%s: got %d timings. Using timing #%d as default\n",
+		of_node_full_name(np), disp->num_timings,
+		disp->native_mode + 1);
+
+	return disp;
+
+timingfail:
+	if (native_mode)
+		of_node_put(native_mode);
+	display_timings_release(disp);
+entryfail:
+	kfree(disp);
+dispfail:
+	of_node_put(timings_np);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(of_get_display_timings);
+
+/**
+ * of_display_timings_exist - check if a display-timings node is provi=
ded
+ * @np: device_node with the timing
+ **/
+int of_display_timings_exist(struct device_node *np)
+{
+	struct device_node *timings_np;
+
+	if (!np)
+		return -EINVAL;
+
+	timings_np =3D of_parse_phandle(np, "display-timings", 0);
+	if (!timings_np)
+		return -EINVAL;
+
+	of_node_put(timings_np);
+	return 1;
+}
+EXPORT_SYMBOL_GPL(of_display_timings_exist);
diff --git a/drivers/video/of_videomode.c b/drivers/video/of_videomode.=
c
new file mode 100644
index 0000000..5b8066c
--- /dev/null
+++ b/drivers/video/of_videomode.c
@@ -0,0 +1,54 @@
+/*
+ * generic videomode helper
+ *
+ * Copyright (c) 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>, Pe=
ngutronix
+ *
+ * This file is released under the GPLv2
+ */
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/of.h>
+#include <video/display_timing.h>
+#include <video/of_display_timing.h>
+#include <video/of_videomode.h>
+#include <video/videomode.h>
+
+/**
+ * of_get_videomode - get the videomode #<index> from devicetree
+ * @np - devicenode with the display_timings
+ * @vm - set to return value
+ * @index - index into list of display_timings
+ *	    (Set this to OF_USE_NATIVE_MODE to use whatever mode is
+ *	     specified as native mode in the DT.)
+ *
+ * DESCRIPTION:
+ * Get a list of all display timings and put the one
+ * specified by index into *vm. This function should only be used, if
+ * only one videomode is to be retrieved. A driver that needs to work
+ * with multiple/all videomodes should work with
+ * of_get_display_timings instead.
+ **/
+int of_get_videomode(struct device_node *np, struct videomode *vm,
+		     int index)
+{
+	struct display_timings *disp;
+	int ret;
+
+	disp =3D of_get_display_timings(np);
+	if (!disp) {
+		pr_err("%s: no timings specified\n", of_node_full_name(np));
+		return -EINVAL;
+	}
+
+	if (index =3D=3D OF_USE_NATIVE_MODE)
+		index =3D disp->native_mode;
+
+	ret =3D videomode_from_timing(disp, vm, index);
+	if (ret)
+		return ret;
+
+	display_timings_release(disp);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_get_videomode);
diff --git a/include/video/of_display_timing.h b/include/video/of_displ=
ay_timing.h
new file mode 100644
index 0000000..8016eb7
--- /dev/null
+++ b/include/video/of_display_timing.h
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>
+ *
+ * display timings of helpers
+ *
+ * This file is released under the GPLv2
+ */
+
+#ifndef __LINUX_OF_DISPLAY_TIMING_H
+#define __LINUX_OF_DISPLAY_TIMING_H
+
+struct device_node;
+struct display_timings;
+
+#define OF_USE_NATIVE_MODE -1
+
+struct display_timings *of_get_display_timings(struct device_node *np)=
;
+int of_display_timings_exist(struct device_node *np);
+
+#endif
diff --git a/include/video/of_videomode.h b/include/video/of_videomode.=
h
new file mode 100644
index 0000000..a07efcc
--- /dev/null
+++ b/include/video/of_videomode.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>
+ *
+ * videomode of-helpers
+ *
+ * This file is released under the GPLv2
+ */
+
+#ifndef __LINUX_OF_VIDEOMODE_H
+#define __LINUX_OF_VIDEOMODE_H
+
+struct device_node;
+struct videomode;
+
+int of_get_videomode(struct device_node *np, struct videomode *vm,
+		     int index);
+
+#endif /* __LINUX_OF_VIDEOMODE_H */
--=20
1.7.10.4