Am Montag, 26. Mai 2014, 12:14:43 schrieb Thierry Reding:
> On Wed, May 21, 2014 at 01:42:56PM +0900, YoungJun Cho wrote:
> > This patch is based on videomode and display_timing relevant codes.
> > To support command mode panel, it does not need to guide its timing
> > information to the display controller like video mode panel,
> > but it requires signal timings to transfer video data.
> > So this patch adds cmdmode struct, cmdmode_display_timing struct and
> > the according helper functions to convert cmdmode_display_timing
> > to a generic cmdmode.
> > 
> > Signed-off-by: YoungJun Cho <yj44.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > Acked-by: Inki Dae <inki.dae-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > Acked-by: Kyungmin Park <kyungmin.park-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > ---
> > 
> >  drivers/video/Kconfig                     |    3 +
> >  drivers/video/Makefile                    |    2 +
> >  drivers/video/cmdmode.c                   |   42 ++++++
> >  drivers/video/cmdmode_display_timing.c    |   26 ++++
> >  drivers/video/of_cmdmode.c                |   55 ++++++++
> >  drivers/video/of_cmdmode_display_timing.c |  212
> >  +++++++++++++++++++++++++++++ include/video/cmdmode.h                  
> >  |   67 +++++++++
> >  include/video/cmdmode_display_timing.h    |   59 ++++++++
> >  include/video/of_cmdmode.h                |   19 +++
> >  include/video/of_cmdmode_display_timing.h |   26 ++++
> >  10 files changed, 511 insertions(+)
> >  create mode 100644 drivers/video/cmdmode.c
> >  create mode 100644 drivers/video/cmdmode_display_timing.c
> >  create mode 100644 drivers/video/of_cmdmode.c
> >  create mode 100644 drivers/video/of_cmdmode_display_timing.c
> >  create mode 100644 include/video/cmdmode.h
> >  create mode 100644 include/video/cmdmode_display_timing.h
> >  create mode 100644 include/video/of_cmdmode.h
> >  create mode 100644 include/video/of_cmdmode_display_timing.h
> 
> Cc'ing Heiko Stübner on this. Heiko, you seem to have done some work on
> i80 in the past[0] and I'm wondering if you could share any insights you
> may have here.
> 
> In particular I'd like your take on the approach taken in this patch to
> describe i80 parameters to a generic command-mode display timings
> structure. However it seems to me that these timings are really very i80
> specific and don't apply in general to command-mode displays.
> 
> As such I'm beginning to think that this should rather be a property of
> the attached display/panel rather than the interface that generates the
> signal.

OMG ... your digging in my ancient history :-D

I always got the impression, i80 is somehow related to the MIPI-DBI protocol 
[1].

Also the display I was working on (AUO-K190x epaper controller) used the 
command mode to also transfer the display region to update and had a 
completely dfferent command set [2].

In the end, I temporarily settled in adding a glue driver, driving the s3c2416 
i80 controller [3]. But someday I'd like to integrate this into a real 
solution, as the s3c2416 lcd-controller can do the i80 also in hardware, maybe 
speeding things up a little.

So I guess the transfer method itself is generic, but the commands used seem 
to differ. But I of course don't know if "regular" MIPI-DBI/i80 displays use a 
command set of commands for their timings.


Heiko


[1] https://www.mail-archive.com/linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org/msg29100.html
[2] 
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/video/fbdev/auo_k190x.h
[3] https://github.com/mmind/linux-es600/blob/topic/es600-devel/drivers/video/es600-epd.c

> > diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> > index c7b4f0f..7090ee5 100644
> > --- a/drivers/video/Kconfig
> > +++ b/drivers/video/Kconfig
> > @@ -38,6 +38,9 @@ config VGASTATE
> > 
> >  config VIDEOMODE_HELPERS
> >  
> >  	bool
> > 
> > +config CMDMODE_HELPERS
> > +	bool
> > +
> > 
> >  config HDMI
> >  
> >  	bool
> > 
> > diff --git a/drivers/video/Makefile b/drivers/video/Makefile
> > index 9ad3c17..619dd99 100644
> > --- a/drivers/video/Makefile
> > +++ b/drivers/video/Makefile
> > @@ -8,6 +8,8 @@ obj-y				  += backlight/
> > 
> >  obj-y				  += fbdev/
> >  
> >  obj-$(CONFIG_VIDEOMODE_HELPERS) += display_timing.o videomode.o
> > 
> > +obj-$(CONFIG_CMDMODE_HELPERS) += cmdmode_display_timing.o cmdmode.o
> > 
> >  ifeq ($(CONFIG_OF),y)
> >  obj-$(CONFIG_VIDEOMODE_HELPERS) += of_display_timing.o of_videomode.o
> > 
> > +obj-$(CONFIG_CMDMODE_HELPERS) += of_cmdmode_display_timing.o of_cmdmode.o
> > 
> >  endif
> > 
> > diff --git a/drivers/video/cmdmode.c b/drivers/video/cmdmode.c
> > new file mode 100644
> > index 0000000..3d3eeb8
> > --- /dev/null
> > +++ b/drivers/video/cmdmode.c
> > @@ -0,0 +1,42 @@
> > +/*
> > + * generic cmdmode display timing functions
> > + *
> > + * Copyright (c) 2014 YoungJun Cho <yj44.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#include <linux/errno.h>
> > +#include <linux/export.h>
> > +#include <video/cmdmode_display_timing.h>
> > +#include <video/cmdmode.h>
> > +
> > +void cmdmode_from_timing(const struct cmdmode_display_timing *cmdt,
> > +				struct cmdmode *cm)
> > +{
> > +	cm->pixelclock = cmdt->pixelclock;
> > +	cm->hactive = cmdt->hactive;
> > +	cm->vactive = cmdt->vactive;
> > +	cm->cs_setup = cmdt->cs_setup;
> > +	cm->wr_setup = cmdt->wr_setup;
> > +	cm->wr_active = cmdt->wr_active;
> > +	cm->wr_hold = cmdt->wr_hold;
> > +}
> > +EXPORT_SYMBOL_GPL(cmdmode_from_timing);
> > +
> > +int cmdmode_from_timings(const struct cmdmode_display_timings *cmdts,
> > +				struct cmdmode *cm, unsigned int index)
> > +{
> > +	struct cmdmode_display_timing *cmdt;
> > +
> > +	cmdt = cmdmode_display_timings_get(cmdts, index);
> > +	if (!cmdt)
> > +		return -EINVAL;
> > +
> > +	cmdmode_from_timing(cmdt, cm);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(cmdmode_from_timings);
> > diff --git a/drivers/video/cmdmode_display_timing.c
> > b/drivers/video/cmdmode_display_timing.c new file mode 100644
> > index 0000000..88bab08
> > --- /dev/null
> > +++ b/drivers/video/cmdmode_display_timing.c
> > @@ -0,0 +1,26 @@
> > +/*
> > + * generic cmdmode display timing functions
> > + *
> > + * Copyright (c) 2014 YoungJun Cho <yj44.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#include <linux/export.h>
> > +#include <linux/slab.h>
> > +#include <video/cmdmode_display_timing.h>
> > +
> > +void cmdmode_display_timings_release(struct cmdmode_display_timings
> > *cmdts) +{
> > +	if (cmdts->timings) {
> > +		unsigned int i;
> > +
> > +		for (i = 0; i < cmdts->num_timings; i++)
> > +			kfree(cmdts->timings[i]);
> > +		kfree(cmdts->timings);
> > +	}
> > +	kfree(cmdts);
> > +}
> > +EXPORT_SYMBOL_GPL(cmdmode_display_timings_release);
> > diff --git a/drivers/video/of_cmdmode.c b/drivers/video/of_cmdmode.c
> > new file mode 100644
> > index 0000000..d63294e
> > --- /dev/null
> > +++ b/drivers/video/of_cmdmode.c
> > @@ -0,0 +1,55 @@
> > +/*
> > + * generic cmdmode helper
> > + *
> > + * Copyright (c) 2014 YoungJun Cho <yj44.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +#include <linux/errno.h>
> > +#include <linux/export.h>
> > +#include <linux/of.h>
> > +#include <video/cmdmode_display_timing.h>
> > +#include <video/of_cmdmode_display_timing.h>
> > +#include <video/of_cmdmode.h>
> > +#include <video/cmdmode.h>
> > +
> > +/**
> > + * of_get_cmdmode - get the cmdmode #<index> from devicetree
> > + * @np - devicenode with the cmdmode_display_timings
> > + * @cm - set to return value
> > + * @index - index into list of cmdmode_display_timings
> > + *	    (Set this to OF_USE_CMDMODE_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 *cm. This function should only be used, if
> > + * only one cmdmode is to be retrieved. A driver that needs to work
> > + * with multiple/all cmdmodes should work with
> > + * of_get_cmdmode_display_timings instead.
> > + **/
> > +int of_get_cmdmode(struct device_node *np, struct cmdmode *cm, int index)
> > +{
> > +	struct cmdmode_display_timings *cmdts;
> > +	int ret;
> > +
> > +	cmdts = of_get_cmdmode_display_timings(np);
> > +	if (!cmdts) {
> > +		pr_err("%s: no timings specified\n", of_node_full_name(np));
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (index == OF_USE_CMDMODE_NATIVE_MODE)
> > +		index = cmdts->native_mode;
> > +
> > +	ret = cmdmode_from_timings(cmdts, cm, index);
> > +	if (ret)
> > +		return ret;
> > +
> > +	cmdmode_display_timings_release(cmdts);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(of_get_cmdmode);
> > diff --git a/drivers/video/of_cmdmode_display_timing.c
> > b/drivers/video/of_cmdmode_display_timing.c new file mode 100644
> > index 0000000..fcf2b35
> > --- /dev/null
> > +++ b/drivers/video/of_cmdmode_display_timing.c
> > @@ -0,0 +1,212 @@
> > +/*
> > + * OF helpers for parsing cmdmode display timings
> > + *
> > + * Copyright (c) 2014 YoungJun Cho <yj44.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > + *
> > + * based on of_cmdmode.c
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +#include <linux/export.h>
> > +#include <linux/of.h>
> > +#include <linux/slab.h>
> > +#include <video/cmdmode_display_timing.h>
> > +#include <video/of_cmdmode_display_timing.h>
> > +
> > +/**
> > + * of_parse_cmdmode_display_timing - parse cmdmode_display_timing entry
> > + *					from device_node
> > + * @np: device_node with the properties
> > + **/
> > +static int of_parse_cmdmode_display_timing(const struct device_node *np,
> > +					struct cmdmode_display_timing *cmdt)
> > +{
> > +	int ret = 0;
> > +
> > +	memset(cmdt, 0, sizeof(*cmdt));
> > +
> > +	ret |= of_property_read_u32(np, "clock-frequency", &cmdt-
>pixelclock);
> > +	ret |= of_property_read_u32(np, "hactive", &cmdt->hactive);
> > +	ret |= of_property_read_u32(np, "vactive", &cmdt->vactive);
> > +	ret |= of_property_read_u32(np, "cs-setup", &cmdt->cs_setup);
> > +	ret |= of_property_read_u32(np, "wr-setup", &cmdt->wr_setup);
> > +	ret |= of_property_read_u32(np, "wr-active", &cmdt->wr_active);
> > +	ret |= of_property_read_u32(np, "wr-hold", &cmdt->wr_hold);
> > +
> > +	if (ret) {
> > +		pr_err("%s: error reading cmdmode timing properties\n",
> > +			of_node_full_name(np));
> > +		return -EINVAL;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +/**
> > + * of_get_cmdmode_display_timing - parse a cmdmode_display_timing entry
> > + * @np: device_node with the timing subnode
> > + * @name: name of the timing node
> > + * @cmdt: cmdmode_display_timing struct to fill
> > + **/
> > +int of_get_cmdmode_display_timing(struct device_node *np, const char
> > *name, +					struct cmdmode_display_timing *cmdt)
> > +{
> > +	struct device_node *timing_np;
> > +
> > +	if (!np) {
> > +		pr_err("%s: no devicenode given\n", of_node_full_name(np));
> > +		return -EINVAL;
> > +	}
> > +
> > +	timing_np = of_get_child_by_name(np, name);
> > +	if (!timing_np) {
> > +		pr_err("%s: could not find node '%s'\n",
> > +			of_node_full_name(np), name);
> > +		return -ENOENT;
> > +	}
> > +
> > +	return of_parse_cmdmode_display_timing(timing_np, cmdt);
> > +}
> > +EXPORT_SYMBOL_GPL(of_get_cmdmode_display_timing);
> > +
> > +/**
> > + * of_get_cmdmode_display_timings - parse all cmdmode_display_timing
> > + * entries from a device_node
> > + * @np: device_node with the subnodes
> > + **/
> > +struct cmdmode_display_timings*
> > +of_get_cmdmode_display_timings(struct device_node *np)
> > +{
> > +	struct device_node *timings_np;
> > +	struct device_node *entry;
> > +	struct device_node *native_mode;
> > +	struct cmdmode_display_timings *cmdts;
> > +
> > +	if (!np) {
> > +		pr_err("%s: no device node given\n", of_node_full_name(np));
> > +		return NULL;
> > +	}
> > +
> > +	timings_np = of_get_child_by_name(np, "cmdmode-display-timings");
> > +	if (!timings_np) {
> > +		pr_err("%s: could not find cmdmode-display-timings node\n",
> > +			of_node_full_name(np));
> > +		return NULL;
> > +	}
> > +
> > +	cmdts = kzalloc(sizeof(*cmdts), GFP_KERNEL);
> > +	if (!cmdts) {
> > +		pr_err("%s: could not allocate struct cmdts'\n",
> > +			of_node_full_name(np));
> > +		goto cmdtsfail;
> > +	}
> > +
> > +	entry = of_parse_phandle(timings_np, "native-mode", 0);
> > +	/* assume first child as native mode if none provided */
> > +	if (!entry)
> > +		entry = 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 = entry;
> > +
> > +	cmdts->num_timings = of_get_child_count(timings_np);
> > +	if (cmdts->num_timings == 0) {
> > +		/* should never happen, as entry was already found above */
> > +		pr_err("%s: no timings specified\n", of_node_full_name(np));
> > +		goto entryfail;
> > +	}
> > +
> > +	cmdts->timings = kzalloc(sizeof(struct cmdmode_display_timing *) *
> > +				cmdts->num_timings, GFP_KERNEL);
> > +	if (!cmdts->timings) {
> > +		pr_err("%s: could not allocate timings array\n",
> > +			of_node_full_name(np));
> > +		goto entryfail;
> > +	}
> > +
> > +	cmdts->num_timings = 0;
> > +	cmdts->native_mode = 0;
> > +
> > +	for_each_child_of_node(timings_np, entry) {
> > +		struct cmdmode_display_timing *cmdt;
> > +		int r;
> > +
> > +		cmdt = kzalloc(sizeof(*cmdt), GFP_KERNEL);
> > +		if (!cmdt) {
> > +			pr_err("%s: could not allocate cmdmode_display_timing\n"
> > +				, of_node_full_name(np));
> > +			goto timingfail;
> > +		}
> > +
> > +		r = of_parse_cmdmode_display_timing(entry, cmdt);
> > +		if (r) {
> > +			/*
> > +			 * to not encourage wrong devicetrees, fail in case of
> > +			 * an error
> > +			 */
> > +			pr_err("%s: error in timing %d\n",
> > +				of_node_full_name(np), cmdts->num_timings + 1);
> > +			goto timingfail;
> > +		}
> > +
> > +		if (native_mode == entry)
> > +			cmdts->native_mode = cmdts->num_timings;
> > +
> > +		cmdts->timings[cmdts->num_timings] = cmdt;
> > +		cmdts->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), cmdts->num_timings,
> > +		cmdts->native_mode + 1);
> > +
> > +	return cmdts;
> > +
> > +timingfail:
> > +	if (native_mode)
> > +		of_node_put(native_mode);
> > +	cmdmode_display_timings_release(cmdts);
> > +entryfail:
> > +	kfree(cmdts);
> > +cmdtsfail:
> > +	of_node_put(timings_np);
> > +	return NULL;
> > +}
> > +EXPORT_SYMBOL_GPL(of_get_cmdmode_display_timings);
> > +
> > +/**
> > + * of_cmdmode_display_timings_exist - check if a display-timings node is
> > + * provided
> > + * @np: device_node with the timing
> > + **/
> > +int of_cmdmode_display_timings_exist(struct device_node *np)
> > +{
> > +	struct device_node *timings_np;
> > +
> > +	if (!np)
> > +		return -EINVAL;
> > +
> > +	timings_np = of_parse_phandle(np, "cmdmode-display-timings", 0);
> > +	if (!timings_np)
> > +		return -EINVAL;
> > +
> > +	of_node_put(timings_np);
> > +	return 1;
> > +}
> > +EXPORT_SYMBOL_GPL(of_cmdmode_display_timings_exist);
> > diff --git a/include/video/cmdmode.h b/include/video/cmdmode.h
> > new file mode 100644
> > index 0000000..61ee71e
> > --- /dev/null
> > +++ b/include/video/cmdmode.h
> > @@ -0,0 +1,67 @@
> > +/*
> > + * generic cmdmode description
> > + *
> > + * Copyright 2014 YoungJun Cho <yj44.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#ifndef __LINUX_CMDMODE_H
> > +#define __LINUX_CMDMODE_H
> > +
> > +#include <linux/types.h>
> > +#include <video/cmdmode_display_timing.h>
> > +
> > +/*
> > + * Subsystem independent description of a cmdmode.
> > + * Can be generated from struct cmdmode_display_timing.
> > + * @pixelclock: display clock in Hz
> > + * @hactive: horizontal active video
> > + * @vactive: vertical active video
> > + * @cs_setup: clock cycles for the active period of address signal is
> > enabled + *		until chip select is enabled
> > + * @wr_setup: clock cycles for the active period of CS signal is enabled
> > until + *		write signal is enabled
> > + * @wr_active: clock cycles for the active period of CS is enabled
> > + * @wr_hold: clock cycles for the active period of CS is disabled until
> > write + *		signal is disabled
> > + */
> > +struct cmdmode {
> > +	unsigned long pixelclock;
> > +
> > +	u32 hactive;
> > +	u32 vactive;
> > +
> > +	u32 cs_setup;
> > +	u32 wr_setup;
> > +	u32 wr_active;
> > +	u32 wr_hold;
> > +};
> > +
> > +/**
> > + * cmdmode_from_timing - convert display timing to cmdmode
> > + * @cmdt: cmdmode_display_timing structure
> > + * @cm: return value
> > + *
> > + * DESCRIPTION:
> > + * This function converts a struct cmdmode_display_timing to a struct
> > cmdmode. + */
> > +void cmdmode_from_timing(const struct cmdmode_display_timing *cmdt,
> > +				struct cmdmode *cm);
> > +
> > +/**
> > + * cmdmode_from_timings - convert one display timings entry to cmdmode
> > + * @disp: structure with all possible timing entries
> > + * @cm: return value
> > + * @index: index into the list of display timings in devicetree
> > + *
> > + * DESCRIPTION:
> > + * This function converts one struct cmdmode_display_timing entry to a
> > + * struct cmdmode.
> > + */
> > +int cmdmode_from_timings(const struct cmdmode_display_timings *cmdts,
> > +				struct cmdmode *cm, unsigned int index);
> > +
> > +#endif /* __LINUX_CMDMODE_H */
> > diff --git a/include/video/cmdmode_display_timing.h
> > b/include/video/cmdmode_display_timing.h new file mode 100644
> > index 0000000..5005660
> > --- /dev/null
> > +++ b/include/video/cmdmode_display_timing.h
> > @@ -0,0 +1,59 @@
> > +/*
> > + * description of cmdmode display timings
> > + *
> > + * Copyright 2014 YoungJun Cho <yj44.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#ifndef __LINUX_CMDMODE_DISPLAY_TIMING_H
> > +#define __LINUX_CMDMODE_DISPLAY_TIMING_H
> > +
> > +#include <linux/types.h>
> > +
> > +/*
> > + * Single "mode" entry. This describes one set of signal timings a
> > display can + * have in one setting. This struct can later be converted
> > to struct cmdmode + * (see include/video/cmdmode.h).
> > + */
> > +struct cmdmode_display_timing {
> > +	u32	pixelclock;
> > +
> > +	u32	hactive;
> > +	u32	vactive;
> > +
> > +	u32	cs_setup;
> > +	u32	wr_setup;
> > +	u32	wr_active;
> > +	u32	wr_hold;
> > +};
> > +
> > +/*
> > + * This describes all timing settings a display provides.
> > + * The native_mode is the default setting for this display.
> > + * Drivers that can handle multiple cmdmodes should work with this struct
> > + * and convert each entry to the desired end result.
> > + */
> > +struct cmdmode_display_timings {
> > +	unsigned int num_timings;
> > +	unsigned int native_mode;
> > +
> > +	struct cmdmode_display_timing **timings;
> > +};
> > +
> > +/* get one entry from struct cmdmode_display_timings */
> > +static inline struct cmdmode_display_timing*
> > +cmdmode_display_timings_get(const struct cmdmode_display_timings *cmdts,
> > +				unsigned int index)
> > +{
> > +	if (cmdts->num_timings > index)
> > +		return cmdts->timings[index];
> > +	else
> > +		return NULL;
> > +}
> > +
> > +void cmdmode_display_timings_release(struct cmdmode_display_timings
> > *cmdts); +
> > +#endif /* __LINUX_CMDDMODE_DISPLAY_TIMING_H */
> > diff --git a/include/video/of_cmdmode.h b/include/video/of_cmdmode.h
> > new file mode 100644
> > index 0000000..fb7c6c7
> > --- /dev/null
> > +++ b/include/video/of_cmdmode.h
> > @@ -0,0 +1,19 @@
> > +/*
> > + * Copyright 2014 YoungJun Cho <yj44.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > + *
> > + * cmdmode of-helpers
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#ifndef __LINUX_OF_CMDMODE_H
> > +#define __LINUX_OF_CMDMODE_H
> > +
> > +struct device_node;
> > +struct cmdmode;
> > +
> > +int of_get_cmdmode(struct device_node *np, struct cmdmode *cm, int
> > index);
> > +
> > +#endif /* __LINUX_OF_CMDMODE_H */
> > diff --git a/include/video/of_cmdmode_display_timing.h
> > b/include/video/of_cmdmode_display_timing.h new file mode 100644
> > index 0000000..6be91ba
> > --- /dev/null
> > +++ b/include/video/of_cmdmode_display_timing.h
> > @@ -0,0 +1,26 @@
> > +/*
> > + * Copyright 2014 YoungJun Cho <yj44.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > + *
> > + * cmdmode display timings of helpers
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#ifndef __LINUX_OF_CMDMODE_DISPLAY_TIMING_H
> > +#define __LINUX_OF_CMDMODE_DISPLAY_TIMING_H
> > +
> > +struct device_node;
> > +struct cmdmode_display_timing;
> > +struct cmdmode_display_timings;
> > +
> > +#define OF_USE_CMDMODE_NATIVE_MODE -1
> > +
> > +int of_get_cmdmode_display_timing(struct device_node *np, const char
> > *name, +					struct cmdmode_display_timing *cmdt);
> > +struct cmdmode_display_timings*
> > +	of_get_cmdmode_display_timings(struct device_node *np);
> > +int of_cmdmode_display_timings_exist(struct device_node *np);
> > +
> > +#endif /* __LINUX_OF_CMDMODE_DISPLAY_TIMING_H */