// 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
  ", 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
  ", 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_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
  ", 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
  ", np);

  		return NULL;
  	}
  
  	disp = kzalloc(sizeof(*disp), GFP_KERNEL);
  	if (!disp) {

  		pr_err("%pOF: could not allocate struct disp'
  ", 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
  ", np);

  		goto entryfail;
  	}

  	pr_debug("%pOF: using %pOFn as default timing
  ", 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
  ", 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
  ", 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("%pOF: could not allocate display_timing struct
  ",
  				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
  ",
  				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
  ",
  		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);