1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * OF helpers for parsing display timings
4 *
5 * Copyright (c) 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>, Pengutronix
6 *
7 * based on of_videomode.c by Sascha Hauer <s.hauer@pengutronix.de>
8 */
9#include <linux/export.h>
10#include <linux/of.h>
11#include <linux/slab.h>
12#include <video/display_timing.h>
13#include <video/of_display_timing.h>
14
15/**
16 * parse_timing_property - parse timing_entry from device_node
17 * @np: device_node with the property
18 * @name: name of the property
19 * @result: will be set to the return value
20 *
21 * DESCRIPTION:
22 * Every display_timing can be specified with either just the typical value or
23 * a range consisting of min/typ/max. This function helps handling this
24 **/
25static int parse_timing_property(const struct device_node *np, const char *name,
26			  struct timing_entry *result)
27{
28	struct property *prop;
29	int length, cells, ret;
30
31	prop = of_find_property(np, name, &length);
32	if (!prop) {
33		pr_err("%pOF: could not find property %s\n", np, name);
34		return -EINVAL;
35	}
36
37	cells = length / sizeof(u32);
38	if (cells == 1) {
39		ret = of_property_read_u32(np, name, &result->typ);
40		result->min = result->typ;
41		result->max = result->typ;
42	} else if (cells == 3) {
43		ret = of_property_read_u32_array(np, name, &result->min, cells);
44	} else {
45		pr_err("%pOF: illegal timing specification in %s\n", np, name);
46		return -EINVAL;
47	}
48
49	return ret;
50}
51
52/**
53 * of_parse_display_timing - parse display_timing entry from device_node
54 * @np: device_node with the properties
55 **/
56static int of_parse_display_timing(const struct device_node *np,
57		struct display_timing *dt)
58{
59	u32 val = 0;
60	int ret = 0;
61
62	memset(dt, 0, sizeof(*dt));
63
64	ret |= parse_timing_property(np, "hback-porch", &dt->hback_porch);
65	ret |= parse_timing_property(np, "hfront-porch", &dt->hfront_porch);
66	ret |= parse_timing_property(np, "hactive", &dt->hactive);
67	ret |= parse_timing_property(np, "hsync-len", &dt->hsync_len);
68	ret |= parse_timing_property(np, "vback-porch", &dt->vback_porch);
69	ret |= parse_timing_property(np, "vfront-porch", &dt->vfront_porch);
70	ret |= parse_timing_property(np, "vactive", &dt->vactive);
71	ret |= parse_timing_property(np, "vsync-len", &dt->vsync_len);
72	ret |= parse_timing_property(np, "clock-frequency", &dt->pixelclock);
73
74	dt->flags = 0;
75	if (!of_property_read_u32(np, "vsync-active", &val))
76		dt->flags |= val ? DISPLAY_FLAGS_VSYNC_HIGH :
77				DISPLAY_FLAGS_VSYNC_LOW;
78	if (!of_property_read_u32(np, "hsync-active", &val))
79		dt->flags |= val ? DISPLAY_FLAGS_HSYNC_HIGH :
80				DISPLAY_FLAGS_HSYNC_LOW;
81	if (!of_property_read_u32(np, "de-active", &val))
82		dt->flags |= val ? DISPLAY_FLAGS_DE_HIGH :
83				DISPLAY_FLAGS_DE_LOW;
84	if (!of_property_read_u32(np, "pixelclk-active", &val))
85		dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE :
86				DISPLAY_FLAGS_PIXDATA_NEGEDGE;
87
88	if (!of_property_read_u32(np, "syncclk-active", &val))
89		dt->flags |= val ? DISPLAY_FLAGS_SYNC_POSEDGE :
90				DISPLAY_FLAGS_SYNC_NEGEDGE;
91	else if (dt->flags & (DISPLAY_FLAGS_PIXDATA_POSEDGE |
92			      DISPLAY_FLAGS_PIXDATA_NEGEDGE))
93		dt->flags |= dt->flags & DISPLAY_FLAGS_PIXDATA_POSEDGE ?
94				DISPLAY_FLAGS_SYNC_POSEDGE :
95				DISPLAY_FLAGS_SYNC_NEGEDGE;
96
97	if (of_property_read_bool(np, "interlaced"))
98		dt->flags |= DISPLAY_FLAGS_INTERLACED;
99	if (of_property_read_bool(np, "doublescan"))
100		dt->flags |= DISPLAY_FLAGS_DOUBLESCAN;
101	if (of_property_read_bool(np, "doubleclk"))
102		dt->flags |= DISPLAY_FLAGS_DOUBLECLK;
103
104	if (ret) {
105		pr_err("%pOF: error reading timing properties\n", np);
106		return -EINVAL;
107	}
108
109	return 0;
110}
111
112/**
113 * of_get_display_timing - parse a display_timing entry
114 * @np: device_node with the timing subnode
115 * @name: name of the timing node
116 * @dt: display_timing struct to fill
117 **/
118int of_get_display_timing(const struct device_node *np, const char *name,
119		struct display_timing *dt)
120{
121	struct device_node *timing_np;
122	int ret;
123
124	if (!np)
125		return -EINVAL;
126
127	timing_np = of_get_child_by_name(np, name);
128	if (!timing_np)
129		return -ENOENT;
130
131	ret = of_parse_display_timing(timing_np, dt);
132
133	of_node_put(timing_np);
134
135	return ret;
136}
137EXPORT_SYMBOL_GPL(of_get_display_timing);
138
139/**
140 * of_get_display_timings - parse all display_timing entries from a device_node
141 * @np: device_node with the subnodes
142 **/
143struct display_timings *of_get_display_timings(const struct device_node *np)
144{
145	struct device_node *timings_np;
146	struct device_node *entry;
147	struct device_node *native_mode;
148	struct display_timings *disp;
149
150	if (!np)
151		return NULL;
152
153	timings_np = of_get_child_by_name(np, "display-timings");
154	if (!timings_np) {
155		pr_err("%pOF: could not find display-timings node\n", np);
156		return NULL;
157	}
158
159	disp = kzalloc(sizeof(*disp), GFP_KERNEL);
160	if (!disp) {
161		pr_err("%pOF: could not allocate struct disp'\n", np);
162		goto dispfail;
163	}
164
165	entry = of_parse_phandle(timings_np, "native-mode", 0);
166	/* assume first child as native mode if none provided */
167	if (!entry)
168		entry = of_get_next_child(timings_np, NULL);
169	/* if there is no child, it is useless to go on */
170	if (!entry) {
171		pr_err("%pOF: no timing specifications given\n", np);
172		goto entryfail;
173	}
174
175	pr_debug("%pOF: using %pOFn as default timing\n", np, entry);
176
177	native_mode = entry;
178
179	disp->num_timings = of_get_child_count(timings_np);
180	if (disp->num_timings == 0) {
181		/* should never happen, as entry was already found above */
182		pr_err("%pOF: no timings specified\n", np);
183		goto entryfail;
184	}
185
186	disp->timings = kcalloc(disp->num_timings,
187				sizeof(struct display_timing *),
188				GFP_KERNEL);
189	if (!disp->timings) {
190		pr_err("%pOF: could not allocate timings array\n", np);
191		goto entryfail;
192	}
193
194	disp->num_timings = 0;
195	disp->native_mode = 0;
196
197	for_each_child_of_node(timings_np, entry) {
198		struct display_timing *dt;
199		int r;
200
201		dt = kzalloc(sizeof(*dt), GFP_KERNEL);
202		if (!dt) {
203			pr_err("%pOF: could not allocate display_timing struct\n",
204				np);
205			goto timingfail;
206		}
207
208		r = of_parse_display_timing(entry, dt);
209		if (r) {
210			/*
211			 * to not encourage wrong devicetrees, fail in case of
212			 * an error
213			 */
214			pr_err("%pOF: error in timing %d\n",
215				np, disp->num_timings + 1);
216			kfree(dt);
217			goto timingfail;
218		}
219
220		if (native_mode == entry)
221			disp->native_mode = disp->num_timings;
222
223		disp->timings[disp->num_timings] = dt;
224		disp->num_timings++;
225	}
226	of_node_put(timings_np);
227	/*
228	 * native_mode points to the device_node returned by of_parse_phandle
229	 * therefore call of_node_put on it
230	 */
231	of_node_put(native_mode);
232
233	pr_debug("%pOF: got %d timings. Using timing #%d as default\n",
234		np, disp->num_timings,
235		disp->native_mode + 1);
236
237	return disp;
238
239timingfail:
240	of_node_put(native_mode);
241	display_timings_release(disp);
242	disp = NULL;
243entryfail:
244	kfree(disp);
245dispfail:
246	of_node_put(timings_np);
247	return NULL;
248}
249EXPORT_SYMBOL_GPL(of_get_display_timings);
250