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 ydepends on DISPLAY_TIMINGhelphelper to parse display timings from the devicetreeendmenu # 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
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