1 /* 2 * OF helpers for parsing display timings 3 * 4 * Copyright (c) 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>, Pengutronix 5 * 6 * based on of_videomode.c by Sascha Hauer <s.hauer@pengutronix.de> 7 * 8 * This file is released under the GPLv2 9 */ 10 #include <linux/export.h> 11 #include <linux/of.h> 12 #include <linux/slab.h> 13 #include <video/display_timing.h> 14 #include <video/of_display_timing.h> 15 16 /** 17 * parse_timing_property - parse timing_entry from device_node 18 * @np: device_node with the property 19 * @name: name of the property 20 * @result: will be set to the return value 21 * 22 * DESCRIPTION: 23 * Every display_timing can be specified with either just the typical value or 24 * a range consisting of min/typ/max. This function helps handling this 25 **/ 26 static int parse_timing_property(const struct device_node *np, const char *name, 27 struct timing_entry *result) 28 { 29 struct property *prop; 30 int length, cells, ret; 31 32 prop = of_find_property(np, name, &length); 33 if (!prop) { 34 pr_err("%s: could not find property %s\n", 35 of_node_full_name(np), name); 36 return -EINVAL; 37 } 38 39 cells = length / sizeof(u32); 40 if (cells == 1) { 41 ret = of_property_read_u32(np, name, &result->typ); 42 result->min = result->typ; 43 result->max = result->typ; 44 } else if (cells == 3) { 45 ret = of_property_read_u32_array(np, name, &result->min, cells); 46 } else { 47 pr_err("%s: illegal timing specification in %s\n", 48 of_node_full_name(np), name); 49 return -EINVAL; 50 } 51 52 return ret; 53 } 54 55 /** 56 * of_parse_display_timing - parse display_timing entry from device_node 57 * @np: device_node with the properties 58 **/ 59 static int of_parse_display_timing(const struct device_node *np, 60 struct display_timing *dt) 61 { 62 u32 val = 0; 63 int ret = 0; 64 65 memset(dt, 0, sizeof(*dt)); 66 67 ret |= parse_timing_property(np, "hback-porch", &dt->hback_porch); 68 ret |= parse_timing_property(np, "hfront-porch", &dt->hfront_porch); 69 ret |= parse_timing_property(np, "hactive", &dt->hactive); 70 ret |= parse_timing_property(np, "hsync-len", &dt->hsync_len); 71 ret |= parse_timing_property(np, "vback-porch", &dt->vback_porch); 72 ret |= parse_timing_property(np, "vfront-porch", &dt->vfront_porch); 73 ret |= parse_timing_property(np, "vactive", &dt->vactive); 74 ret |= parse_timing_property(np, "vsync-len", &dt->vsync_len); 75 ret |= parse_timing_property(np, "clock-frequency", &dt->pixelclock); 76 77 dt->flags = 0; 78 if (!of_property_read_u32(np, "vsync-active", &val)) 79 dt->flags |= val ? DISPLAY_FLAGS_VSYNC_HIGH : 80 DISPLAY_FLAGS_VSYNC_LOW; 81 if (!of_property_read_u32(np, "hsync-active", &val)) 82 dt->flags |= val ? DISPLAY_FLAGS_HSYNC_HIGH : 83 DISPLAY_FLAGS_HSYNC_LOW; 84 if (!of_property_read_u32(np, "de-active", &val)) 85 dt->flags |= val ? DISPLAY_FLAGS_DE_HIGH : 86 DISPLAY_FLAGS_DE_LOW; 87 if (!of_property_read_u32(np, "pixelclk-active", &val)) 88 dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE : 89 DISPLAY_FLAGS_PIXDATA_NEGEDGE; 90 91 if (of_property_read_bool(np, "interlaced")) 92 dt->flags |= DISPLAY_FLAGS_INTERLACED; 93 if (of_property_read_bool(np, "doublescan")) 94 dt->flags |= DISPLAY_FLAGS_DOUBLESCAN; 95 if (of_property_read_bool(np, "doubleclk")) 96 dt->flags |= DISPLAY_FLAGS_DOUBLECLK; 97 98 if (ret) { 99 pr_err("%s: error reading timing properties\n", 100 of_node_full_name(np)); 101 return -EINVAL; 102 } 103 104 return 0; 105 } 106 107 /** 108 * of_get_display_timing - parse a display_timing entry 109 * @np: device_node with the timing subnode 110 * @name: name of the timing node 111 * @dt: display_timing struct to fill 112 **/ 113 int of_get_display_timing(struct device_node *np, const char *name, 114 struct display_timing *dt) 115 { 116 struct device_node *timing_np; 117 118 if (!np) 119 return -EINVAL; 120 121 timing_np = of_get_child_by_name(np, name); 122 if (!timing_np) { 123 pr_err("%s: could not find node '%s'\n", 124 of_node_full_name(np), name); 125 return -ENOENT; 126 } 127 128 return of_parse_display_timing(timing_np, dt); 129 } 130 EXPORT_SYMBOL_GPL(of_get_display_timing); 131 132 /** 133 * of_get_display_timings - parse all display_timing entries from a device_node 134 * @np: device_node with the subnodes 135 **/ 136 struct display_timings *of_get_display_timings(struct device_node *np) 137 { 138 struct device_node *timings_np; 139 struct device_node *entry; 140 struct device_node *native_mode; 141 struct display_timings *disp; 142 143 if (!np) 144 return NULL; 145 146 timings_np = of_get_child_by_name(np, "display-timings"); 147 if (!timings_np) { 148 pr_err("%s: could not find display-timings node\n", 149 of_node_full_name(np)); 150 return NULL; 151 } 152 153 disp = kzalloc(sizeof(*disp), GFP_KERNEL); 154 if (!disp) { 155 pr_err("%s: could not allocate struct disp'\n", 156 of_node_full_name(np)); 157 goto dispfail; 158 } 159 160 entry = of_parse_phandle(timings_np, "native-mode", 0); 161 /* assume first child as native mode if none provided */ 162 if (!entry) 163 entry = of_get_next_child(timings_np, NULL); 164 /* if there is no child, it is useless to go on */ 165 if (!entry) { 166 pr_err("%s: no timing specifications given\n", 167 of_node_full_name(np)); 168 goto entryfail; 169 } 170 171 pr_debug("%s: using %s as default timing\n", 172 of_node_full_name(np), entry->name); 173 174 native_mode = entry; 175 176 disp->num_timings = of_get_child_count(timings_np); 177 if (disp->num_timings == 0) { 178 /* should never happen, as entry was already found above */ 179 pr_err("%s: no timings specified\n", of_node_full_name(np)); 180 goto entryfail; 181 } 182 183 disp->timings = kzalloc(sizeof(struct display_timing *) * 184 disp->num_timings, GFP_KERNEL); 185 if (!disp->timings) { 186 pr_err("%s: could not allocate timings array\n", 187 of_node_full_name(np)); 188 goto entryfail; 189 } 190 191 disp->num_timings = 0; 192 disp->native_mode = 0; 193 194 for_each_child_of_node(timings_np, entry) { 195 struct display_timing *dt; 196 int r; 197 198 dt = kzalloc(sizeof(*dt), GFP_KERNEL); 199 if (!dt) { 200 pr_err("%s: could not allocate display_timing struct\n", 201 of_node_full_name(np)); 202 goto timingfail; 203 } 204 205 r = of_parse_display_timing(entry, dt); 206 if (r) { 207 /* 208 * to not encourage wrong devicetrees, fail in case of 209 * an error 210 */ 211 pr_err("%s: error in timing %d\n", 212 of_node_full_name(np), disp->num_timings + 1); 213 kfree(dt); 214 goto timingfail; 215 } 216 217 if (native_mode == entry) 218 disp->native_mode = disp->num_timings; 219 220 disp->timings[disp->num_timings] = dt; 221 disp->num_timings++; 222 } 223 of_node_put(timings_np); 224 /* 225 * native_mode points to the device_node returned by of_parse_phandle 226 * therefore call of_node_put on it 227 */ 228 of_node_put(native_mode); 229 230 pr_debug("%s: got %d timings. Using timing #%d as default\n", 231 of_node_full_name(np), disp->num_timings, 232 disp->native_mode + 1); 233 234 return disp; 235 236 timingfail: 237 of_node_put(native_mode); 238 display_timings_release(disp); 239 disp = NULL; 240 entryfail: 241 kfree(disp); 242 dispfail: 243 of_node_put(timings_np); 244 return NULL; 245 } 246 EXPORT_SYMBOL_GPL(of_get_display_timings); 247 248 /** 249 * of_display_timings_exist - check if a display-timings node is provided 250 * @np: device_node with the timing 251 **/ 252 int of_display_timings_exist(struct device_node *np) 253 { 254 struct device_node *timings_np; 255 256 if (!np) 257 return -EINVAL; 258 259 timings_np = of_parse_phandle(np, "display-timings", 0); 260 if (!timings_np) 261 return -EINVAL; 262 263 of_node_put(timings_np); 264 return 1; 265 } 266 EXPORT_SYMBOL_GPL(of_display_timings_exist); 267