--- /dev/null
+display-timing 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.
+
+timing 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: 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 = drive pixel data on rising edge/
+ sample data on falling edge
+ - active low = drive pixel data on falling edge/
+ sample data on rising edge
+ - ignored = 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 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:
+
+ +----------+-------------------------------------+----------+-------+
+ | | ↑ | | |
+ | | |vback_porch | | |
+ | | ↓ | | |
+ +----------#######################################----------+-------+
+ | # ↑ # | |
+ | # | # | |
+ | hback # | # hfront | hsync |
+ | porch # | hactive # porch | len |
+ |<-------->#<-------+--------------------------->#<-------->|<----->|
+ | # | # | |
+ | # |vactive # | |
+ | # | # | |
+ | # ↓ # | |
+ +----------#######################################----------+-------+
+ | | ↑ | | |
+ | | |vfront_porch | | |
+ | | ↓ | | |
+ +----------+-------------------------------------+----------+-------+
+ | | ↑ | | |
+ | | |vsync_len | | |
+ | | ↓ | | |
+ +----------+-------------------------------------+----------+-------+
+
+Example:
+
+ display-timings {
+ native-mode = <&timing0>;
+ timing0: 1080p24 {
+ /* 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 minimum, typical and maximum values 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>;
+ };
--- /dev/null
+/*
+ * 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/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 this
+ **/
+static int parse_timing_property(struct device_node *np, const 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",
+ of_node_full_name(np), 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",
+ 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 = 0;
+ int ret = 0;
+
+ dt = 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 |= parse_timing_property(np, "hback-porch", &dt->hback_porch);
+ ret |= parse_timing_property(np, "hfront-porch", &dt->hfront_porch);
+ ret |= parse_timing_property(np, "hactive", &dt->hactive);
+ ret |= parse_timing_property(np, "hsync-len", &dt->hsync_len);
+ ret |= parse_timing_property(np, "vback-porch", &dt->vback_porch);
+ ret |= parse_timing_property(np, "vfront-porch", &dt->vfront_porch);
+ ret |= parse_timing_property(np, "vactive", &dt->vactive);
+ ret |= parse_timing_property(np, "vsync-len", &dt->vsync_len);
+ ret |= parse_timing_property(np, "clock-frequency", &dt->pixelclock);
+
+ dt->dmt_flags = 0;
+ dt->data_flags = 0;
+ if (!of_property_read_u32(np, "vsync-active", &val))
+ dt->dmt_flags |= val ? VESA_DMT_VSYNC_HIGH :
+ VESA_DMT_VSYNC_LOW;
+ if (!of_property_read_u32(np, "hsync-active", &val))
+ dt->dmt_flags |= val ? VESA_DMT_HSYNC_HIGH :
+ VESA_DMT_HSYNC_LOW;
+ if (!of_property_read_u32(np, "de-active", &val))
+ dt->data_flags |= val ? DISPLAY_FLAGS_DE_HIGH :
+ DISPLAY_FLAGS_DE_LOW;
+ if (!of_property_read_u32(np, "pixelclk-active", &val))
+ dt->data_flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE :
+ DISPLAY_FLAGS_PIXDATA_NEGEDGE;
+
+ if (of_property_read_bool(np, "interlaced"))
+ dt->data_flags |= DISPLAY_FLAGS_INTERLACED;
+ if (of_property_read_bool(np, "doublescan"))
+ dt->data_flags |= 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 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", of_node_full_name(np));
+ 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",
+ of_node_full_name(np));
+ return NULL;
+ }
+
+ disp = kzalloc(sizeof(*disp), GFP_KERNEL);
+ if (!disp) {
+ pr_err("%s: could not allocate struct disp'\n",
+ of_node_full_name(np));
+ goto dispfail;
+ }
+
+ 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;
+
+ disp->num_timings = of_get_child_count(timings_np);
+ if (disp->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;
+ }
+
+ disp->timings = 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 = 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",
+ of_node_full_name(np), disp->num_timings + 1);
+ goto timingfail;
+ }
+
+ if (native_mode == entry)
+ disp->native_mode = disp->num_timings;
+
+ disp->timings[disp->num_timings] = 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 provided
+ * @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 = 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);
--- /dev/null
+/*
+ * generic videomode helper
+ *
+ * Copyright (c) 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>, Pengutronix
+ *
+ * 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 = of_get_display_timings(np);
+ if (!disp) {
+ pr_err("%s: no timings specified\n", of_node_full_name(np));
+ return -EINVAL;
+ }
+
+ if (index == OF_USE_NATIVE_MODE)
+ index = disp->native_mode;
+
+ ret = videomode_from_timing(disp, vm, index);
+ if (ret)
+ return ret;
+
+ display_timings_release(disp);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(of_get_videomode);
projects / users / hch / xfs.git / commitdiff