Hello Steffen,
On Mon, Nov 12, 2012 at 7:37 PM, Steffen Trumtrar s.trumtrar@pengutronix.de wrote:
This adds support for reading display timings from DT or/and convert one of those timings to a videomode. The of_display_timing implementation supports multiple children where each property can have up to 3 values. All children are read into an array, that can be queried. of_get_videomode converts exactly one of that timings to a struct videomode.
Signed-off-by: Steffen Trumtrar s.trumtrar@pengutronix.de Signed-off-by: Philipp Zabel p.zabel@pengutronix.de
.../devicetree/bindings/video/display-timings.txt | 107 +++++++++++ drivers/video/Kconfig | 13 ++ drivers/video/Makefile | 2 + drivers/video/of_display_timing.c | 186 ++++++++++++++++++++ drivers/video/of_videomode.c | 47 +++++ include/linux/of_display_timings.h | 19 ++ include/linux/of_videomode.h | 15 ++ 7 files changed, 389 insertions(+) create mode 100644 Documentation/devicetree/bindings/video/display-timings.txt create mode 100644 drivers/video/of_display_timing.c create mode 100644 drivers/video/of_videomode.c create mode 100644 include/linux/of_display_timings.h create mode 100644 include/linux/of_videomode.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..e22e2fd --- /dev/null +++ b/Documentation/devicetree/bindings/video/display-timings.txt @@ -0,0 +1,107 @@ +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-frequency = <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-frequency = <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>;};diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig index 2a23b18..a324457 100644 --- a/drivers/video/Kconfig +++ b/drivers/video/Kconfig @@ -39,6 +39,19 @@ config DISPLAY_TIMING config VIDEOMODE bool
+config OF_DISPLAY_TIMING
def_bool yselect DISPLAY_TIMINGhelphelper to parse display timings from the devicetree+config OF_VIDEOMODE
def_bool yselect VIDEOMODEselect OF_DISPLAY_TIMINGhelphelper to get videomodes from the devicetreemenuconfig FB tristate "Support for frame buffer devices" ---help--- diff --git a/drivers/video/Makefile b/drivers/video/Makefile index fc30439..b936b00 100644 --- a/drivers/video/Makefile +++ b/drivers/video/Makefile @@ -168,4 +168,6 @@ obj-$(CONFIG_FB_VIRTUAL) += vfb.o #video output switch sysfs driver obj-$(CONFIG_VIDEO_OUTPUT_CONTROL) += output.o obj-$(CONFIG_DISPLAY_TIMING) += display_timing.o +obj-$(CONFIG_OF_DISPLAY_TIMING) += of_display_timing.o obj-$(CONFIG_VIDEOMODE) += videomode.o +obj-$(CONFIG_OF_VIDEOMODE) += of_videomode.o diff --git a/drivers/video/of_display_timing.c b/drivers/video/of_display_timing.c new file mode 100644 index 0000000..0bd30cc --- /dev/null +++ b/drivers/video/of_display_timing.c @@ -0,0 +1,186 @@ +/*
- 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, cells, 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(np, name, &result->typ);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
- **/
+static 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;+}
+/**
- of_get_display_timings - parse all display_timing entries from a device_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", __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);if (!disp)return -ENOMEM;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);if (!disp->timings)return -ENOMEM;
Could you please check return values here ^^^ and above "disp = kzalloc(sizeof(*disp), GFP_KERNEL);" ? May be it's better to return NULL instead of -ENOMEM and put error message?