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 struct display_timing *of_get_display_timing(struct device_node *np) 60 { 61 struct display_timing *dt; 62 u32 val = 0; 63 int ret = 0; 64 65 dt = kzalloc(sizeof(*dt), GFP_KERNEL); 66 if (!dt) { 67 pr_err("%s: could not allocate display_timing struct\n", 68 of_node_full_name(np)); 69 return NULL; 70 } 71 72 ret |= parse_timing_property(np, "hback-porch", &dt->hback_porch); 73 ret |= parse_timing_property(np, "hfront-porch", &dt->hfront_porch); 74 ret |= parse_timing_property(np, "hactive", &dt->hactive); 75 ret |= parse_timing_property(np, "hsync-len", &dt->hsync_len); 76 ret |= parse_timing_property(np, "vback-porch", &dt->vback_porch); 77 ret |= parse_timing_property(np, "vfront-porch", &dt->vfront_porch); 78 ret |= parse_timing_property(np, "vactive", &dt->vactive); 79 ret |= parse_timing_property(np, "vsync-len", &dt->vsync_len); 80 ret |= parse_timing_property(np, "clock-frequency", &dt->pixelclock); 81 82 dt->flags = 0; 83 if (!of_property_read_u32(np, "vsync-active", &val)) 84 dt->flags |= val ? DISPLAY_FLAGS_VSYNC_HIGH : 85 DISPLAY_FLAGS_VSYNC_LOW; 86 if (!of_property_read_u32(np, "hsync-active", &val)) 87 dt->flags |= val ? DISPLAY_FLAGS_HSYNC_HIGH : 88 DISPLAY_FLAGS_HSYNC_LOW; 89 if (!of_property_read_u32(np, "de-active", &val)) 90 dt->flags |= val ? DISPLAY_FLAGS_DE_HIGH : 91 DISPLAY_FLAGS_DE_LOW; 92 if (!of_property_read_u32(np, "pixelclk-active", &val)) 93 dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE : 94 DISPLAY_FLAGS_PIXDATA_NEGEDGE; 95 96 if (of_property_read_bool(np, "interlaced")) 97 dt->flags |= DISPLAY_FLAGS_INTERLACED; 98 if (of_property_read_bool(np, "doublescan")) 99 dt->flags |= DISPLAY_FLAGS_DOUBLESCAN; 100 101 if (ret) { 102 pr_err("%s: error reading timing properties\n", 103 of_node_full_name(np)); 104 kfree(dt); 105 return NULL; 106 } 107 108 return dt; 109 } 110 111 /** 112 * of_get_display_timings - parse all display_timing entries from a device_node 113 * @np: device_node with the subnodes 114 **/ 115 struct display_timings *of_get_display_timings(struct device_node *np) 116 { 117 struct device_node *timings_np; 118 struct device_node *entry; 119 struct device_node *native_mode; 120 struct display_timings *disp; 121 122 if (!np) { 123 pr_err("%s: no devicenode given\n", of_node_full_name(np)); 124 return NULL; 125 } 126 127 timings_np = of_find_node_by_name(np, "display-timings"); 128 if (!timings_np) { 129 pr_err("%s: could not find display-timings node\n", 130 of_node_full_name(np)); 131 return NULL; 132 } 133 134 disp = kzalloc(sizeof(*disp), GFP_KERNEL); 135 if (!disp) { 136 pr_err("%s: could not allocate struct disp'\n", 137 of_node_full_name(np)); 138 goto dispfail; 139 } 140 141 entry = of_parse_phandle(timings_np, "native-mode", 0); 142 /* assume first child as native mode if none provided */ 143 if (!entry) 144 entry = of_get_next_child(np, NULL); 145 /* if there is no child, it is useless to go on */ 146 if (!entry) { 147 pr_err("%s: no timing specifications given\n", 148 of_node_full_name(np)); 149 goto entryfail; 150 } 151 152 pr_debug("%s: using %s as default timing\n", 153 of_node_full_name(np), entry->name); 154 155 native_mode = entry; 156 157 disp->num_timings = of_get_child_count(timings_np); 158 if (disp->num_timings == 0) { 159 /* should never happen, as entry was already found above */ 160 pr_err("%s: no timings specified\n", of_node_full_name(np)); 161 goto entryfail; 162 } 163 164 disp->timings = kzalloc(sizeof(struct display_timing *) * 165 disp->num_timings, GFP_KERNEL); 166 if (!disp->timings) { 167 pr_err("%s: could not allocate timings array\n", 168 of_node_full_name(np)); 169 goto entryfail; 170 } 171 172 disp->num_timings = 0; 173 disp->native_mode = 0; 174 175 for_each_child_of_node(timings_np, entry) { 176 struct display_timing *dt; 177 178 dt = of_get_display_timing(entry); 179 if (!dt) { 180 /* 181 * to not encourage wrong devicetrees, fail in case of 182 * an error 183 */ 184 pr_err("%s: error in timing %d\n", 185 of_node_full_name(np), disp->num_timings + 1); 186 goto timingfail; 187 } 188 189 if (native_mode == entry) 190 disp->native_mode = disp->num_timings; 191 192 disp->timings[disp->num_timings] = dt; 193 disp->num_timings++; 194 } 195 of_node_put(timings_np); 196 /* 197 * native_mode points to the device_node returned by of_parse_phandle 198 * therefore call of_node_put on it 199 */ 200 of_node_put(native_mode); 201 202 pr_debug("%s: got %d timings. Using timing #%d as default\n", 203 of_node_full_name(np), disp->num_timings, 204 disp->native_mode + 1); 205 206 return disp; 207 208 timingfail: 209 if (native_mode) 210 of_node_put(native_mode); 211 display_timings_release(disp); 212 entryfail: 213 kfree(disp); 214 dispfail: 215 of_node_put(timings_np); 216 return NULL; 217 } 218 EXPORT_SYMBOL_GPL(of_get_display_timings); 219 220 /** 221 * of_display_timings_exist - check if a display-timings node is provided 222 * @np: device_node with the timing 223 **/ 224 int of_display_timings_exist(struct device_node *np) 225 { 226 struct device_node *timings_np; 227 228 if (!np) 229 return -EINVAL; 230 231 timings_np = of_parse_phandle(np, "display-timings", 0); 232 if (!timings_np) 233 return -EINVAL; 234 235 of_node_put(timings_np); 236 return 1; 237 } 238 EXPORT_SYMBOL_GPL(of_display_timings_exist); 239