1 files changed, 250 insertions, 0 deletions
diff --git a/drivers/video/of_display_timing.c b/drivers/video/of_display_timing.c
new file mode 100644
index 0000000000..bebd371c6b
--- /dev/null
+++ b/drivers/video/of_display_timing.c
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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>
+ */
+#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("%pOF: could not find property %s\n", 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("%pOF: illegal timing specification in %s\n", np, name);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+/**
+ * of_parse_display_timing - parse display_timing entry from device_node
+ * @np: device_node with the properties
+ * @dt: display_timing that contains the result. I may be partially written in case of errors
+ **/
+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_u32(np, "syncclk-active", &val))
+		dt->flags |= val ? DISPLAY_FLAGS_SYNC_POSEDGE :
+				DISPLAY_FLAGS_SYNC_NEGEDGE;
+	else if (dt->flags & (DISPLAY_FLAGS_PIXDATA_POSEDGE |
+			      DISPLAY_FLAGS_PIXDATA_NEGEDGE))
+		dt->flags |= dt->flags & DISPLAY_FLAGS_PIXDATA_POSEDGE ?
+				DISPLAY_FLAGS_SYNC_POSEDGE :
+				DISPLAY_FLAGS_SYNC_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("%pOF: error reading timing properties\n", 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(const struct device_node *np, const char *name,
+		struct display_timing *dt)
+{
+	struct device_node *timing_np;
+	int ret;
+
+	if (!np)
+		return -EINVAL;
+
+	timing_np = of_get_child_by_name(np, name);
+	if (!timing_np)
+		return -ENOENT;
+
+	ret = of_parse_display_timing(timing_np, dt);
+
+	of_node_put(timing_np);
+
+	return ret;
+}
+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(const 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("%pOF: could not find display-timings node\n", np);
+		return NULL;
+	}
+
+	disp = kzalloc(sizeof(*disp), GFP_KERNEL);
+	if (!disp) {
+		pr_err("%pOF: could not allocate struct disp'\n", 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("%pOF: no timing specifications given\n", np);
+		goto entryfail;
+	}
+
+	pr_debug("%pOF: using %pOFn as default timing\n", np, entry);
+
+	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("%pOF: no timings specified\n", np);
+		goto entryfail;
+	}
+
+	disp->timings = kcalloc(disp->num_timings,
+				sizeof(struct display_timing *),
+				GFP_KERNEL);
+	if (!disp->timings) {
+		pr_err("%pOF: could not allocate timings array\n", 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 = kmalloc(sizeof(*dt), GFP_KERNEL);
+		if (!dt) {
+			pr_err("%pOF: could not allocate display_timing struct\n",
+				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("%pOF: error in timing %d\n",
+				np, disp->num_timings + 1);
+			kfree(dt);
+			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("%pOF: got %d timings. Using timing #%d as default\n",
+		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);