--- /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(const 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_parse_display_timing - parse display_timing entry from device_node
+ * @np: device_node with the properties
+ **/
+static int of_parse_display_timing(const struct device_node *np,
+ struct display_timing *dt)
+{
+ u32 val = 0;
+ int ret = 0;
+
+ memset(dt, 0, sizeof(*dt));
+
+ 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->flags = 0;
+ if (!of_property_read_u32(np, "vsync-active", &val))
+ dt->flags |= val ? DISPLAY_FLAGS_VSYNC_HIGH :
+ DISPLAY_FLAGS_VSYNC_LOW;
+ if (!of_property_read_u32(np, "hsync-active", &val))
+ dt->flags |= val ? DISPLAY_FLAGS_HSYNC_HIGH :
+ DISPLAY_FLAGS_HSYNC_LOW;
+ if (!of_property_read_u32(np, "de-active", &val))
+ dt->flags |= val ? DISPLAY_FLAGS_DE_HIGH :
+ DISPLAY_FLAGS_DE_LOW;
+ if (!of_property_read_u32(np, "pixelclk-active", &val))
+ dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE :
+ DISPLAY_FLAGS_PIXDATA_NEGEDGE;
+
+ if (of_property_read_bool(np, "interlaced"))
+ dt->flags |= DISPLAY_FLAGS_INTERLACED;
+ if (of_property_read_bool(np, "doublescan"))
+ dt->flags |= DISPLAY_FLAGS_DOUBLESCAN;
+ if (of_property_read_bool(np, "doubleclk"))
+ dt->flags |= DISPLAY_FLAGS_DOUBLECLK;
+
+ if (ret) {
+ pr_err("%s: error reading timing properties\n",
+ of_node_full_name(np));
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/**
+ * of_get_display_timing - parse a display_timing entry
+ * @np: device_node with the timing subnode
+ * @name: name of the timing node
+ * @dt: display_timing struct to fill
+ **/
+int of_get_display_timing(struct device_node *np, const char *name,
+ struct display_timing *dt)
+{
+ struct device_node *timing_np;
+
+ if (!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_display_timing(timing_np, dt);
+}
+EXPORT_SYMBOL_GPL(of_get_display_timing);
+
+/**
+ * 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)
+ return NULL;
+
+ timings_np = of_get_child_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(timings_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;
+ int r;
+
+ dt = kzalloc(sizeof(*dt), GFP_KERNEL);
+ if (!dt) {
+ pr_err("%s: could not allocate display_timing struct\n",
+ of_node_full_name(np));
+ goto timingfail;
+ }
+
+ r = of_parse_display_timing(entry, dt);
+ 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), 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:
+ of_node_put(native_mode);
+ display_timings_release(disp);
+ disp = NULL;
+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);
Code Review / kvmfornfv.git / blobdiff