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 pr_err("%s: no devicenode given\n", of_node_full_name(np)); 120 return -EINVAL; 121 } 122 123 timing_np = of_get_child_by_name(np, name); 124 if (!timing_np) { 125 pr_err("%s: could not find node '%s'\n", 126 of_node_full_name(np), name); 127 return -ENOENT; 128 } 129 130 return of_parse_display_timing(timing_np, dt); 131 } 132 EXPORT_SYMBOL_GPL(of_get_display_timing); 133 134 /** 135 * of_get_display_timings - parse all display_timing entries from a device_node 136 * @np: device_node with the subnodes 137 **/ 138 struct display_timings *of_get_display_timings(struct device_node *np) 139 { 140 struct device_node *timings_np; 141 struct device_node *entry; 142 struct device_node *native_mode; 143 struct display_timings *disp; 144 145 if (!np) { 146 pr_err("%s: no device node given\n", of_node_full_name(np)); 147 return NULL; 148 } 149 150 timings_np = of_get_child_by_name(np, "display-timings"); 151 if (!timings_np) { 152 pr_err("%s: could not find display-timings node\n", 153 of_node_full_name(np)); 154 return NULL; 155 } 156 157 disp = kzalloc(sizeof(*disp), GFP_KERNEL); 158 if (!disp) { 159 pr_err("%s: could not allocate struct disp'\n", 160 of_node_full_name(np)); 161 goto dispfail; 162 } 163 164 entry = of_parse_phandle(timings_np, "native-mode", 0); 165 /* assume first child as native mode if none provided */ 166 if (!entry) 167 entry = of_get_next_child(np, NULL); 168 /* if there is no child, it is useless to go on */ 169 if (!entry) { 170 pr_err("%s: no timing specifications given\n", 171 of_node_full_name(np)); 172 goto entryfail; 173 } 174 175 pr_debug("%s: using %s as default timing\n", 176 of_node_full_name(np), entry->name); 177 178 native_mode = entry; 179 180 disp->num_timings = of_get_child_count(timings_np); 181 if (disp->num_timings == 0) { 182 /* should never happen, as entry was already found above */ 183 pr_err("%s: no timings specified\n", of_node_full_name(np)); 184 goto entryfail; 185 } 186 187 disp->timings = kzalloc(sizeof(struct display_timing *) * 188 disp->num_timings, GFP_KERNEL); 189 if (!disp->timings) { 190 pr_err("%s: could not allocate timings array\n", 191 of_node_full_name(np)); 192 goto entryfail; 193 } 194 195 disp->num_timings = 0; 196 disp->native_mode = 0; 197 198 for_each_child_of_node(timings_np, entry) { 199 struct display_timing *dt; 200 int r; 201 202 dt = kzalloc(sizeof(*dt), GFP_KERNEL); 203 if (!dt) { 204 pr_err("%s: could not allocate display_timing struct\n", 205 of_node_full_name(np)); 206 goto timingfail; 207 } 208 209 r = of_parse_display_timing(entry, dt); 210 if (r) { 211 /* 212 * to not encourage wrong devicetrees, fail in case of 213 * an error 214 */ 215 pr_err("%s: error in timing %d\n", 216 of_node_full_name(np), disp->num_timings + 1); 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("%s: got %d timings. Using timing #%d as default\n", 234 of_node_full_name(np), disp->num_timings, 235 disp->native_mode + 1); 236 237 return disp; 238 239 timingfail: 240 if (native_mode) 241 of_node_put(native_mode); 242 display_timings_release(disp); 243 entryfail: 244 kfree(disp); 245 dispfail: 246 of_node_put(timings_np); 247 return NULL; 248 } 249 EXPORT_SYMBOL_GPL(of_get_display_timings); 250 251 /** 252 * of_display_timings_exist - check if a display-timings node is provided 253 * @np: device_node with the timing 254 **/ 255 int of_display_timings_exist(struct device_node *np) 256 { 257 struct device_node *timings_np; 258 259 if (!np) 260 return -EINVAL; 261 262 timings_np = of_parse_phandle(np, "display-timings", 0); 263 if (!timings_np) 264 return -EINVAL; 265 266 of_node_put(timings_np); 267 return 1; 268 } 269 EXPORT_SYMBOL_GPL(of_display_timings_exist); 270