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(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_get_display_timing - parse display_timing entry from device_node 57 * @np: device_node with the properties 58 **/ 59 static int of_get_display_timing(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 96 if (ret) { 97 pr_err("%s: error reading timing properties\n", 98 of_node_full_name(np)); 99 return -EINVAL; 100 } 101 102 return 0; 103 } 104 105 /** 106 * of_get_display_timings - parse all display_timing entries from a device_node 107 * @np: device_node with the subnodes 108 **/ 109 struct display_timings *of_get_display_timings(struct device_node *np) 110 { 111 struct device_node *timings_np; 112 struct device_node *entry; 113 struct device_node *native_mode; 114 struct display_timings *disp; 115 116 if (!np) { 117 pr_err("%s: no devicenode given\n", of_node_full_name(np)); 118 return NULL; 119 } 120 121 timings_np = of_find_node_by_name(np, "display-timings"); 122 if (!timings_np) { 123 pr_err("%s: could not find display-timings node\n", 124 of_node_full_name(np)); 125 return NULL; 126 } 127 128 disp = kzalloc(sizeof(*disp), GFP_KERNEL); 129 if (!disp) { 130 pr_err("%s: could not allocate struct disp'\n", 131 of_node_full_name(np)); 132 goto dispfail; 133 } 134 135 entry = of_parse_phandle(timings_np, "native-mode", 0); 136 /* assume first child as native mode if none provided */ 137 if (!entry) 138 entry = of_get_next_child(np, NULL); 139 /* if there is no child, it is useless to go on */ 140 if (!entry) { 141 pr_err("%s: no timing specifications given\n", 142 of_node_full_name(np)); 143 goto entryfail; 144 } 145 146 pr_debug("%s: using %s as default timing\n", 147 of_node_full_name(np), entry->name); 148 149 native_mode = entry; 150 151 disp->num_timings = of_get_child_count(timings_np); 152 if (disp->num_timings == 0) { 153 /* should never happen, as entry was already found above */ 154 pr_err("%s: no timings specified\n", of_node_full_name(np)); 155 goto entryfail; 156 } 157 158 disp->timings = kzalloc(sizeof(struct display_timing *) * 159 disp->num_timings, GFP_KERNEL); 160 if (!disp->timings) { 161 pr_err("%s: could not allocate timings array\n", 162 of_node_full_name(np)); 163 goto entryfail; 164 } 165 166 disp->num_timings = 0; 167 disp->native_mode = 0; 168 169 for_each_child_of_node(timings_np, entry) { 170 struct display_timing *dt; 171 int r; 172 173 dt = kzalloc(sizeof(*dt), GFP_KERNEL); 174 if (!dt) { 175 pr_err("%s: could not allocate display_timing struct\n", 176 of_node_full_name(np)); 177 goto timingfail; 178 } 179 180 r = of_get_display_timing(entry, dt); 181 if (r) { 182 /* 183 * to not encourage wrong devicetrees, fail in case of 184 * an error 185 */ 186 pr_err("%s: error in timing %d\n", 187 of_node_full_name(np), disp->num_timings + 1); 188 goto timingfail; 189 } 190 191 if (native_mode == entry) 192 disp->native_mode = disp->num_timings; 193 194 disp->timings[disp->num_timings] = dt; 195 disp->num_timings++; 196 } 197 of_node_put(timings_np); 198 /* 199 * native_mode points to the device_node returned by of_parse_phandle 200 * therefore call of_node_put on it 201 */ 202 of_node_put(native_mode); 203 204 pr_debug("%s: got %d timings. Using timing #%d as default\n", 205 of_node_full_name(np), disp->num_timings, 206 disp->native_mode + 1); 207 208 return disp; 209 210 timingfail: 211 if (native_mode) 212 of_node_put(native_mode); 213 display_timings_release(disp); 214 entryfail: 215 kfree(disp); 216 dispfail: 217 of_node_put(timings_np); 218 return NULL; 219 } 220 EXPORT_SYMBOL_GPL(of_get_display_timings); 221 222 /** 223 * of_display_timings_exist - check if a display-timings node is provided 224 * @np: device_node with the timing 225 **/ 226 int of_display_timings_exist(struct device_node *np) 227 { 228 struct device_node *timings_np; 229 230 if (!np) 231 return -EINVAL; 232 233 timings_np = of_parse_phandle(np, "display-timings", 0); 234 if (!timings_np) 235 return -EINVAL; 236 237 of_node_put(timings_np); 238 return 1; 239 } 240 EXPORT_SYMBOL_GPL(of_display_timings_exist); 241