| Message ID | 1351675689-26814-3-git-send-email-s.trumtrar@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 10/31/2012 03:28 AM, Steffen Trumtrar wrote: Patch description? The patch defines the DT binding as well, which isn't mentioned in the patch subject. > new file mode 100644 > index 0000000..04c94a3 > --- /dev/null > +++ b/Documentation/devicetree/bindings/video/display-timings.txt > +Usage in backend > +================ Everything before this point in the binding docs looks reasonable to me. Everything after this point is Linux-specific/internal implementation detail, and hence shouldn't be in the binding document. I only read the DT binding. -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Oct 31, 2012 at 10:28:02AM +0100, Steffen Trumtrar wrote: [...] > diff --git a/Documentation/devicetree/bindings/video/display-timings.txt b/Documentation/devicetree/bindings/video/display-timings.txt [...] > @@ -0,0 +1,139 @@ > +display-timings bindings > +================== > + > +display-timings-node > +------------ Maybe extend the underline to the length of the section and subsection titles respectively? > +struct display_timing > +=================== Same here. > +config OF_DISPLAY_TIMINGS > + def_bool y > + depends on DISPLAY_TIMING Maybe this should be called OF_DISPLAY_TIMING to match DISPLAY_TIMING, or rename DISPLAY_TIMING to DISPLAY_TIMINGS for the sake of consistency? > +/** > + * of_get_display_timing_list - parse all display_timing entries from a device_node > + * @np: device_node with the subnodes > + **/ > +struct display_timings *of_get_display_timing_list(struct device_node *np) Perhaps this would better be named of_get_display_timings() to match the return type? > + disp = kzalloc(sizeof(*disp), GFP_KERNEL); Shouldn't you be checking this for allocation failures? > + disp->timings = kzalloc(sizeof(struct display_timing *)*disp->num_timings, > + GFP_KERNEL); Same here. Thierry
Hello Steffen, On Wed, Oct 31, 2012 at 2:58 PM, Steffen Trumtrar <s.trumtrar@pengutronix.de> wrote: > Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de> > --- > .../devicetree/bindings/video/display-timings.txt | 139 +++++++++++++++ > drivers/of/Kconfig | 6 + > drivers/of/Makefile | 1 + > drivers/of/of_display_timings.c | 185 ++++++++++++++++++++ > include/linux/of_display_timings.h | 20 +++ > 5 files changed, 351 insertions(+) > create mode 100644 Documentation/devicetree/bindings/video/display-timings.txt > create mode 100644 drivers/of/of_display_timings.c > create mode 100644 include/linux/of_display_timings.h > > diff --git a/Documentation/devicetree/bindings/video/display-timings.txt b/Documentation/devicetree/bindings/video/display-timings.txt > new file mode 100644 > index 0000000..04c94a3 > --- /dev/null > +++ b/Documentation/devicetree/bindings/video/display-timings.txt > @@ -0,0 +1,139 @@ > +display-timings bindings > +================== > + > +display-timings-node > +------------ > + > +required properties: > + - none > + > +optional properties: > + - native-mode: the native mode for the display, in case multiple modes are > + provided. When omitted, assume the first node is the native. > + > +timings-subnode > +--------------- > + > +required properties: > + - hactive, vactive: Display resolution > + - hfront-porch, hback-porch, hsync-len: Horizontal Display timing parameters > + in pixels > + vfront-porch, vback-porch, vsync-len: Vertical display timing parameters in > + lines > + - clock-frequency: displayclock 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-inverted : pixelclock is inverted/non-inverted/ignored > + - interlaced (bool) > + - doublescan (bool) > + > +All the optional properties that are not bool follow the following logic: > + <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 datasheets for displays. > +If a display supports multiple signal timings, the native-mode can be specified. > + > +The parameters are defined as > + > +struct display_timing > +=================== > + > + +----------+---------------------------------------------+----------+-------+ > + | | ? | | | > + | | |vback_porch | | | > + | | ? | | | > + +----------###############################################----------+-------+ > + | # ? # | | > + | # | # | | > + | hback # | # hfront | hsync | > + | porch # | hactive # porch | len | > + |<-------->#<---------------+--------------------------->#<-------->|<----->| > + | # | # | | > + | # |vactive # | | > + | # | # | | > + | # ? # | | > + +----------###############################################----------+-------+ > + | | ? | | | > + | | |vfront_porch | | | > + | | ? | | | > + +----------+---------------------------------------------+----------+-------+ > + | | ? | | | > + | | |vsync_len | | | > + | | ? | | | > + +----------+---------------------------------------------+----------+-------+ > + > + > +Example: > + > + display-timings { > + native-mode = <&timing0>; > + timing0: 1920p24 { > + /* 1920x1080p24 */ > + clock = <52000000>; > + hactive = <1920>; > + vactive = <1080>; > + hfront-porch = <25>; > + hback-porch = <25>; > + hsync-len = <25>; > + vback-porch = <2>; > + vfront-porch = <2>; > + vsync-len = <2>; > + hsync-active = <1>; > + }; > + }; > + > +Every required property also supports the use of ranges, so the commonly used > +datasheet description with <min typ max>-tuples can be used. > + > +Example: > + > + timing1: timing { > + /* 1920x1080p24 */ > + clock = <148500000>; > + hactive = <1920>; > + vactive = <1080>; > + hsync-len = <0 44 60>; > + hfront-porch = <80 88 95>; > + hback-porch = <100 148 160>; > + vfront-porch = <0 4 6>; > + vback-porch = <0 36 50>; > + vsync-len = <0 5 6>; > + }; > + > + > +Usage in backend > +================ > + > +A backend driver may choose to use the display-timings directly and convert the timing > +ranges to a suitable mode. Or it may just use the conversion of the display timings > +to the required mode via the generic videomode struct. > + > + dtb > + | > + | of_get_display_timing_list > + ? > + struct display_timings > + | > + | videomode_from_timing > + ? > + --- struct videomode --- > + | | > + videomode_to_displaymode | | videomode_to_fb_videomode > + ? ? > + drm_display_mode fb_videomode > + > +The functions of_get_fb_videomode and of_get_display_mode are provided > +to conveniently get the respective mode representation from the devicetree. > + > +Conversion to videomode > +======================= > + > +As device drivers normally work with some kind of video mode, the timings can be > +converted (may be just a simple copying of the typical value) to a generic videomode > +structure which then can be converted to the according mode used by the backend. > diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig > index dfba3e6..781e773 100644 > --- a/drivers/of/Kconfig > +++ b/drivers/of/Kconfig > @@ -83,4 +83,10 @@ config OF_MTD > depends on MTD > def_bool y > > +config OF_DISPLAY_TIMINGS > + def_bool y > + depends on DISPLAY_TIMING > + help > + helper to parse display timings from the devicetree > + > endmenu # OF > diff --git a/drivers/of/Makefile b/drivers/of/Makefile > index e027f44..c8e9603 100644 > --- a/drivers/of/Makefile > +++ b/drivers/of/Makefile > @@ -11,3 +11,4 @@ obj-$(CONFIG_OF_MDIO) += of_mdio.o > obj-$(CONFIG_OF_PCI) += of_pci.o > obj-$(CONFIG_OF_PCI_IRQ) += of_pci_irq.o > obj-$(CONFIG_OF_MTD) += of_mtd.o > +obj-$(CONFIG_OF_DISPLAY_TIMINGS) += of_display_timings.o > diff --git a/drivers/of/of_display_timings.c b/drivers/of/of_display_timings.c > new file mode 100644 > index 0000000..388fe4c > --- /dev/null > +++ b/drivers/of/of_display_timings.c > @@ -0,0 +1,185 @@ > +/* > + * OF helpers for parsing display timings > + * > + * Copyright (c) 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>, Pengutronix > + * > + * based on of_videomode.c by Sascha Hauer <s.hauer@pengutronix.de> > + * > + * This file is released under the GPLv2 > + */ > +#include <linux/of.h> > +#include <linux/slab.h> > +#include <linux/export.h> > +#include <linux/of_display_timings.h> > + > +/** > + * parse_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 this > + **/ > +static int parse_property(struct device_node *np, char *name, > + struct timing_entry *result) > +{ > + struct property *prop; > + int length; > + int cells; > + int ret; > + > + prop = of_find_property(np, name, &length); > + if (!prop) { > + pr_err("%s: could not find property %s\n", __func__, name); > + return -EINVAL; > + } > + > + cells = length / sizeof(u32); > + if (cells == 1) { > + ret = of_property_read_u32_array(np, name, &result->typ, cells); As you are reading only one vaue, you can use of_property_read_u32 instead. > + result->min = result->typ; > + result->max = result->typ; > + } else if (cells == 3) { > + ret = of_property_read_u32_array(np, name, &result->min, cells); You are considering only min element, what about typ and max elements? > + } else { > + pr_err("%s: illegal timing specification in %s\n", __func__, name); > + return -EINVAL; > + } > + > + return ret; > +} > + > +/** > + * of_get_display_timing - parse display_timing entry from device_node > + * @np: device_node with the properties > + **/ > +struct display_timing *of_get_display_timing(struct device_node *np) > +{ > + struct display_timing *dt; > + int ret = 0; > + > + dt = kzalloc(sizeof(*dt), GFP_KERNEL); > + if (!dt) { > + pr_err("%s: could not allocate display_timing struct\n", __func__); > + return NULL; > + } > + > + ret |= parse_property(np, "hback-porch", &dt->hback_porch); > + ret |= parse_property(np, "hfront-porch", &dt->hfront_porch); > + ret |= parse_property(np, "hactive", &dt->hactive); > + ret |= parse_property(np, "hsync-len", &dt->hsync_len); > + ret |= parse_property(np, "vback-porch", &dt->vback_porch); > + ret |= parse_property(np, "vfront-porch", &dt->vfront_porch); > + ret |= parse_property(np, "vactive", &dt->vactive); > + ret |= parse_property(np, "vsync-len", &dt->vsync_len); > + ret |= parse_property(np, "clock-frequency", &dt->pixelclock); > + > + of_property_read_u32(np, "vsync-active", &dt->vsync_pol_active); > + of_property_read_u32(np, "hsync-active", &dt->hsync_pol_active); > + of_property_read_u32(np, "de-active", &dt->de_pol_active); > + of_property_read_u32(np, "pixelclk-inverted", &dt->pixelclk_pol); > + dt->interlaced = of_property_read_bool(np, "interlaced"); > + dt->doublescan = of_property_read_bool(np, "doublescan"); > + > + if (ret) { > + pr_err("%s: error reading timing properties\n", __func__); > + return NULL; > + } > + > + return dt; > +} > +EXPORT_SYMBOL_GPL(of_get_display_timing); > + > +/** > + * of_get_display_timing_list - parse all display_timing entries from a device_node > + * @np: device_node with the subnodes > + **/ > +struct display_timings *of_get_display_timing_list(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", __func__); > + return NULL; > + } > + > + timings_np = of_find_node_by_name(np, "display-timings"); > + if (!timings_np) { > + pr_err("%s: could not find display-timings node\n", __func__); > + return NULL; > + } > + > + disp = kzalloc(sizeof(*disp), GFP_KERNEL); > + > + 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 (!entry) { > + pr_err("%s: no timing specifications given\n", __func__); > + return NULL; > + } > + > + pr_info("%s: using %s as default timing\n", __func__, entry->name); > + > + native_mode = entry; > + > + disp->num_timings = of_get_child_count(timings_np); > + disp->timings = kzalloc(sizeof(struct display_timing *)*disp->num_timings, > + GFP_KERNEL); > + disp->num_timings = 0; > + disp->native_mode = 0; > + > + for_each_child_of_node(timings_np, entry) { > + struct display_timing *dt; > + > + dt = 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", __func__, disp->num_timings+1); > + return NULL; > + } > + > + if (native_mode == entry) > + disp->native_mode = disp->num_timings; > + > + disp->timings[disp->num_timings] = dt; > + disp->num_timings++; > + } > + of_node_put(timings_np); > + > + if (disp->num_timings > 0) > + pr_info("%s: got %d timings. Using timing #%d as default\n", __func__, > + disp->num_timings , disp->native_mode + 1); > + else { > + pr_err("%s: no valid timings specified\n", __func__); > + return NULL; > + } > + return disp; > +} > +EXPORT_SYMBOL_GPL(of_get_display_timing_list); > + > +/** > + * of_display_timings_exists - check if a display-timings node is provided > + * @np: device_node with the timing > + **/ > +int of_display_timings_exists(struct device_node *np) > +{ > + struct device_node *timings_np; > + struct device_node *default_np; > + > + if (!np) > + return -EINVAL; > + > + timings_np = of_parse_phandle(np, "display-timings", 0); > + if (!timings_np) > + return -EINVAL; > + > + return -EINVAL; Here it should return success instead of -EINVAL. And one query.. are the binding properties names and "display-timings" node structure template finalized..? Best Wishes, Leela Krishna Amudala. > +} > +EXPORT_SYMBOL_GPL(of_display_timings_exists); > diff --git a/include/linux/of_display_timings.h b/include/linux/of_display_timings.h > new file mode 100644 > index 0000000..e4e1f22 > --- /dev/null > +++ b/include/linux/of_display_timings.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_TIMINGS_H > +#define __LINUX_OF_DISPLAY_TIMINGS_H > + > +#include <linux/display_timing.h> > + > +#define OF_USE_NATIVE_MODE -1 > + > +struct display_timings *of_get_display_timing_list(struct device_node *np); > +struct display_timing *of_get_display_timing(struct device_node *np); > +int of_display_timings_exists(struct device_node *np); > + > +#endif > -- > 1.7.10.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Nov 01, 2012 at 09:15:10PM +0100, Thierry Reding wrote: > On Wed, Oct 31, 2012 at 10:28:02AM +0100, Steffen Trumtrar wrote: > [...] > > diff --git a/Documentation/devicetree/bindings/video/display-timings.txt b/Documentation/devicetree/bindings/video/display-timings.txt > [...] > > @@ -0,0 +1,139 @@ > > +display-timings bindings > > +================== > > + > > +display-timings-node > > +------------ > > Maybe extend the underline to the length of the section and subsection > titles respectively? > > > +struct display_timing > > +=================== > > Same here. > > > +config OF_DISPLAY_TIMINGS > > + def_bool y > > + depends on DISPLAY_TIMING > > Maybe this should be called OF_DISPLAY_TIMING to match DISPLAY_TIMING, > or rename DISPLAY_TIMING to DISPLAY_TIMINGS for the sake of consistency? > Yes, to all three above. > > +/** > > + * of_get_display_timing_list - parse all display_timing entries from a device_node > > + * @np: device_node with the subnodes > > + **/ > > +struct display_timings *of_get_display_timing_list(struct device_node *np) > > Perhaps this would better be named of_get_display_timings() to match the > return type? > Hm, I'm not really sure about that. I found it to error prone, to have a function of_get_display_timing and of_get_display_timings. That's why I chose of_get_display_timing_list. But you are correct, that it doesn't match the return value. Maybe I should just make the first function static and change the name as you suggested. > > + disp = kzalloc(sizeof(*disp), GFP_KERNEL); > > Shouldn't you be checking this for allocation failures? > > > + disp->timings = kzalloc(sizeof(struct display_timing *)*disp->num_timings, > > + GFP_KERNEL); > > Same here. > Yes, to both. Regards, Steffen
Hi! On Fri, Nov 02, 2012 at 10:49:47PM +0530, Leela Krishna Amudala wrote: > Hello Steffen, > > On Wed, Oct 31, 2012 at 2:58 PM, Steffen Trumtrar > > +static int parse_property(struct device_node *np, char *name, > > + struct timing_entry *result) > > +{ > > + struct property *prop; > > + int length; > > + int cells; > > + int ret; > > + > > + prop = of_find_property(np, name, &length); > > + if (!prop) { > > + pr_err("%s: could not find property %s\n", __func__, name); > > + return -EINVAL; > > + } > > + > > + cells = length / sizeof(u32); > > + if (cells == 1) { > > + ret = of_property_read_u32_array(np, name, &result->typ, cells); > > As you are reading only one vaue, you can use of_property_read_u32 instead. > Yes, thats copypasta, no need for _array here. > > + result->min = result->typ; > > + result->max = result->typ; > > + } else if (cells == 3) { > > + ret = of_property_read_u32_array(np, name, &result->min, cells); > > You are considering only min element, what about typ and max elements? > I start at the address of result->min and read three u32-values, therefore all three (min,typ,max) are filled with values. > > + > > +/** > > + * of_display_timings_exists - check if a display-timings node is provided > > + * @np: device_node with the timing > > + **/ > > +int of_display_timings_exists(struct device_node *np) > > +{ > > + struct device_node *timings_np; > > + struct device_node *default_np; > > + > > + if (!np) > > + return -EINVAL; > > + > > + timings_np = of_parse_phandle(np, "display-timings", 0); > > + if (!timings_np) > > + return -EINVAL; > > + > > + return -EINVAL; > > Here it should return success instead of -EINVAL. > Yes. > And one query.. are the binding properties names and "display-timings" > node structure template finalized..? > I sure hope so. There actually is one error in the examples though. The property clock is called clock-frequency. I included it correctly at the top of display-timings.txt, but overlooked it in the examples. Regards, Steffen
diff --git a/Documentation/devicetree/bindings/video/display-timings.txt b/Documentation/devicetree/bindings/video/display-timings.txt new file mode 100644 index 0000000..04c94a3 --- /dev/null +++ b/Documentation/devicetree/bindings/video/display-timings.txt @@ -0,0 +1,139 @@ +display-timings bindings +================== + +display-timings-node +------------ + +required properties: + - none + +optional properties: + - native-mode: the native mode for the display, in case multiple modes are + provided. When omitted, assume the first node is the native. + +timings-subnode +--------------- + +required properties: + - hactive, vactive: Display resolution + - hfront-porch, hback-porch, hsync-len: Horizontal Display timing parameters + in pixels + vfront-porch, vback-porch, vsync-len: Vertical display timing parameters in + lines + - clock-frequency: displayclock 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-inverted : pixelclock is inverted/non-inverted/ignored + - interlaced (bool) + - doublescan (bool) + +All the optional properties that are not bool follow the following logic: + <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 datasheets for displays. +If a display supports multiple signal timings, the native-mode can be specified. + +The parameters are defined as + +struct display_timing +=================== + + +----------+---------------------------------------------+----------+-------+ + | | ? | | | + | | |vback_porch | | | + | | ? | | | + +----------###############################################----------+-------+ + | # ? # | | + | # | # | | + | hback # | # hfront | hsync | + | porch # | hactive # porch | len | + |<-------->#<---------------+--------------------------->#<-------->|<----->| + | # | # | | + | # |vactive # | | + | # | # | | + | # ? # | | + +----------###############################################----------+-------+ + | | ? | | | + | | |vfront_porch | | | + | | ? | | | + +----------+---------------------------------------------+----------+-------+ + | | ? | | | + | | |vsync_len | | | + | | ? | | | + +----------+---------------------------------------------+----------+-------+ + + +Example: + + display-timings { + native-mode = <&timing0>; + timing0: 1920p24 { + /* 1920x1080p24 */ + clock = <52000000>; + hactive = <1920>; + vactive = <1080>; + hfront-porch = <25>; + hback-porch = <25>; + hsync-len = <25>; + vback-porch = <2>; + vfront-porch = <2>; + vsync-len = <2>; + hsync-active = <1>; + }; + }; + +Every required property also supports the use of ranges, so the commonly used +datasheet description with <min typ max>-tuples can be used. + +Example: + + timing1: timing { + /* 1920x1080p24 */ + clock = <148500000>; + hactive = <1920>; + vactive = <1080>; + hsync-len = <0 44 60>; + hfront-porch = <80 88 95>; + hback-porch = <100 148 160>; + vfront-porch = <0 4 6>; + vback-porch = <0 36 50>; + vsync-len = <0 5 6>; + }; + + +Usage in backend +================ + +A backend driver may choose to use the display-timings directly and convert the timing +ranges to a suitable mode. Or it may just use the conversion of the display timings +to the required mode via the generic videomode struct. + + dtb + | + | of_get_display_timing_list + ? + struct display_timings + | + | videomode_from_timing + ? + --- struct videomode --- + | | + videomode_to_displaymode | | videomode_to_fb_videomode + ? ? + drm_display_mode fb_videomode + +The functions of_get_fb_videomode and of_get_display_mode are provided +to conveniently get the respective mode representation from the devicetree. + +Conversion to videomode +======================= + +As device drivers normally work with some kind of video mode, the timings can be +converted (may be just a simple copying of the typical value) to a generic videomode +structure which then can be converted to the according mode used by the backend. diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig index dfba3e6..781e773 100644 --- a/drivers/of/Kconfig +++ b/drivers/of/Kconfig @@ -83,4 +83,10 @@ config OF_MTD depends on MTD def_bool y +config OF_DISPLAY_TIMINGS + def_bool y + depends on DISPLAY_TIMING + help + helper to parse display timings from the devicetree + endmenu # OF diff --git a/drivers/of/Makefile b/drivers/of/Makefile index e027f44..c8e9603 100644 --- a/drivers/of/Makefile +++ b/drivers/of/Makefile @@ -11,3 +11,4 @@ obj-$(CONFIG_OF_MDIO) += of_mdio.o obj-$(CONFIG_OF_PCI) += of_pci.o obj-$(CONFIG_OF_PCI_IRQ) += of_pci_irq.o obj-$(CONFIG_OF_MTD) += of_mtd.o +obj-$(CONFIG_OF_DISPLAY_TIMINGS) += of_display_timings.o diff --git a/drivers/of/of_display_timings.c b/drivers/of/of_display_timings.c new file mode 100644 index 0000000..388fe4c --- /dev/null +++ b/drivers/of/of_display_timings.c @@ -0,0 +1,185 @@ +/* + * OF helpers for parsing display timings + * + * Copyright (c) 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>, Pengutronix + * + * based on of_videomode.c by Sascha Hauer <s.hauer@pengutronix.de> + * + * This file is released under the GPLv2 + */ +#include <linux/of.h> +#include <linux/slab.h> +#include <linux/export.h> +#include <linux/of_display_timings.h> + +/** + * parse_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 this + **/ +static int parse_property(struct device_node *np, char *name, + struct timing_entry *result) +{ + struct property *prop; + int length; + int cells; + int ret; + + prop = of_find_property(np, name, &length); + if (!prop) { + pr_err("%s: could not find property %s\n", __func__, name); + return -EINVAL; + } + + cells = length / sizeof(u32); + if (cells == 1) { + ret = of_property_read_u32_array(np, name, &result->typ, cells); + result->min = result->typ; + result->max = result->typ; + } else if (cells == 3) { + ret = of_property_read_u32_array(np, name, &result->min, cells); + } else { + pr_err("%s: illegal timing specification in %s\n", __func__, name); + return -EINVAL; + } + + return ret; +} + +/** + * of_get_display_timing - parse display_timing entry from device_node + * @np: device_node with the properties + **/ +struct display_timing *of_get_display_timing(struct device_node *np) +{ + struct display_timing *dt; + int ret = 0; + + dt = kzalloc(sizeof(*dt), GFP_KERNEL); + if (!dt) { + pr_err("%s: could not allocate display_timing struct\n", __func__); + return NULL; + } + + ret |= parse_property(np, "hback-porch", &dt->hback_porch); + ret |= parse_property(np, "hfront-porch", &dt->hfront_porch); + ret |= parse_property(np, "hactive", &dt->hactive); + ret |= parse_property(np, "hsync-len", &dt->hsync_len); + ret |= parse_property(np, "vback-porch", &dt->vback_porch); + ret |= parse_property(np, "vfront-porch", &dt->vfront_porch); + ret |= parse_property(np, "vactive", &dt->vactive); + ret |= parse_property(np, "vsync-len", &dt->vsync_len); + ret |= parse_property(np, "clock-frequency", &dt->pixelclock); + + of_property_read_u32(np, "vsync-active", &dt->vsync_pol_active); + of_property_read_u32(np, "hsync-active", &dt->hsync_pol_active); + of_property_read_u32(np, "de-active", &dt->de_pol_active); + of_property_read_u32(np, "pixelclk-inverted", &dt->pixelclk_pol); + dt->interlaced = of_property_read_bool(np, "interlaced"); + dt->doublescan = of_property_read_bool(np, "doublescan"); + + if (ret) { + pr_err("%s: error reading timing properties\n", __func__); + return NULL; + } + + return dt; +} +EXPORT_SYMBOL_GPL(of_get_display_timing); + +/** + * of_get_display_timing_list - parse all display_timing entries from a device_node + * @np: device_node with the subnodes + **/ +struct display_timings *of_get_display_timing_list(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", __func__); + return NULL; + } + + timings_np = of_find_node_by_name(np, "display-timings"); + if (!timings_np) { + pr_err("%s: could not find display-timings node\n", __func__); + return NULL; + } + + disp = kzalloc(sizeof(*disp), GFP_KERNEL); + + 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 (!entry) { + pr_err("%s: no timing specifications given\n", __func__); + return NULL; + } + + pr_info("%s: using %s as default timing\n", __func__, entry->name); + + native_mode = entry; + + disp->num_timings = of_get_child_count(timings_np); + disp->timings = kzalloc(sizeof(struct display_timing *)*disp->num_timings, + GFP_KERNEL); + disp->num_timings = 0; + disp->native_mode = 0; + + for_each_child_of_node(timings_np, entry) { + struct display_timing *dt; + + dt = 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", __func__, disp->num_timings+1); + return NULL; + } + + if (native_mode == entry) + disp->native_mode = disp->num_timings; + + disp->timings[disp->num_timings] = dt; + disp->num_timings++; + } + of_node_put(timings_np); + + if (disp->num_timings > 0) + pr_info("%s: got %d timings. Using timing #%d as default\n", __func__, + disp->num_timings , disp->native_mode + 1); + else { + pr_err("%s: no valid timings specified\n", __func__); + return NULL; + } + return disp; +} +EXPORT_SYMBOL_GPL(of_get_display_timing_list); + +/** + * of_display_timings_exists - check if a display-timings node is provided + * @np: device_node with the timing + **/ +int of_display_timings_exists(struct device_node *np) +{ + struct device_node *timings_np; + struct device_node *default_np; + + if (!np) + return -EINVAL; + + timings_np = of_parse_phandle(np, "display-timings", 0); + if (!timings_np) + return -EINVAL; + + return -EINVAL; +} +EXPORT_SYMBOL_GPL(of_display_timings_exists); diff --git a/include/linux/of_display_timings.h b/include/linux/of_display_timings.h new file mode 100644 index 0000000..e4e1f22 --- /dev/null +++ b/include/linux/of_display_timings.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_TIMINGS_H +#define __LINUX_OF_DISPLAY_TIMINGS_H + +#include <linux/display_timing.h> + +#define OF_USE_NATIVE_MODE -1 + +struct display_timings *of_get_display_timing_list(struct device_node *np); +struct display_timing *of_get_display_timing(struct device_node *np); +int of_display_timings_exists(struct device_node *np); + +#endif
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de> --- .../devicetree/bindings/video/display-timings.txt | 139 +++++++++++++++ drivers/of/Kconfig | 6 + drivers/of/Makefile | 1 + drivers/of/of_display_timings.c | 185 ++++++++++++++++++++ include/linux/of_display_timings.h | 20 +++ 5 files changed, 351 insertions(+) create mode 100644 Documentation/devicetree/bindings/video/display-timings.txt create mode 100644 drivers/of/of_display_timings.c create mode 100644 include/linux/of_display_timings.h