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 **/ 25 static 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 * @dt: display_timing that contains the result. I may be partially written in case of errors 56 **/ 57 static int of_parse_display_timing(const struct device_node *np, 58 struct display_timing *dt) 59 { 60 u32 val = 0; 61 int ret = 0; 62 63 memset(dt, 0, sizeof(*dt)); 64 65 ret |= parse_timing_property(np, "hback-porch", &dt->hback_porch); 66 ret |= parse_timing_property(np, "hfront-porch", &dt->hfront_porch); 67 ret |= parse_timing_property(np, "hactive", &dt->hactive); 68 ret |= parse_timing_property(np, "hsync-len", &dt->hsync_len); 69 ret |= parse_timing_property(np, "vback-porch", &dt->vback_porch); 70 ret |= parse_timing_property(np, "vfront-porch", &dt->vfront_porch); 71 ret |= parse_timing_property(np, "vactive", &dt->vactive); 72 ret |= parse_timing_property(np, "vsync-len", &dt->vsync_len); 73 ret |= parse_timing_property(np, "clock-frequency", &dt->pixelclock); 74 75 dt->flags = 0; 76 if (!of_property_read_u32(np, "vsync-active", &val)) 77 dt->flags |= val ? DISPLAY_FLAGS_VSYNC_HIGH : 78 DISPLAY_FLAGS_VSYNC_LOW; 79 if (!of_property_read_u32(np, "hsync-active", &val)) 80 dt->flags |= val ? DISPLAY_FLAGS_HSYNC_HIGH : 81 DISPLAY_FLAGS_HSYNC_LOW; 82 if (!of_property_read_u32(np, "de-active", &val)) 83 dt->flags |= val ? DISPLAY_FLAGS_DE_HIGH : 84 DISPLAY_FLAGS_DE_LOW; 85 if (!of_property_read_u32(np, "pixelclk-active", &val)) 86 dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE : 87 DISPLAY_FLAGS_PIXDATA_NEGEDGE; 88 89 if (!of_property_read_u32(np, "syncclk-active", &val)) 90 dt->flags |= val ? DISPLAY_FLAGS_SYNC_POSEDGE : 91 DISPLAY_FLAGS_SYNC_NEGEDGE; 92 else if (dt->flags & (DISPLAY_FLAGS_PIXDATA_POSEDGE | 93 DISPLAY_FLAGS_PIXDATA_NEGEDGE)) 94 dt->flags |= dt->flags & DISPLAY_FLAGS_PIXDATA_POSEDGE ? 95 DISPLAY_FLAGS_SYNC_POSEDGE : 96 DISPLAY_FLAGS_SYNC_NEGEDGE; 97 98 if (of_property_read_bool(np, "interlaced")) 99 dt->flags |= DISPLAY_FLAGS_INTERLACED; 100 if (of_property_read_bool(np, "doublescan")) 101 dt->flags |= DISPLAY_FLAGS_DOUBLESCAN; 102 if (of_property_read_bool(np, "doubleclk")) 103 dt->flags |= DISPLAY_FLAGS_DOUBLECLK; 104 105 if (ret) { 106 pr_err("%pOF: error reading timing properties\n", np); 107 return -EINVAL; 108 } 109 110 return 0; 111 } 112 113 /** 114 * of_get_display_timing - parse a display_timing entry 115 * @np: device_node with the timing subnode 116 * @name: name of the timing node 117 * @dt: display_timing struct to fill 118 **/ 119 int of_get_display_timing(const struct device_node *np, const char *name, 120 struct display_timing *dt) 121 { 122 struct device_node *timing_np; 123 int ret; 124 125 if (!np) 126 return -EINVAL; 127 128 timing_np = of_get_child_by_name(np, name); 129 if (!timing_np) 130 return -ENOENT; 131 132 ret = of_parse_display_timing(timing_np, dt); 133 134 of_node_put(timing_np); 135 136 return ret; 137 } 138 EXPORT_SYMBOL_GPL(of_get_display_timing); 139 140 /** 141 * of_get_display_timings - parse all display_timing entries from a device_node 142 * @np: device_node with the subnodes 143 **/ 144 struct display_timings *of_get_display_timings(const struct device_node *np) 145 { 146 struct device_node *timings_np; 147 struct device_node *entry; 148 struct device_node *native_mode; 149 struct display_timings *disp; 150 151 if (!np) 152 return NULL; 153 154 timings_np = of_get_child_by_name(np, "display-timings"); 155 if (!timings_np) { 156 pr_err("%pOF: could not find display-timings node\n", np); 157 return NULL; 158 } 159 160 disp = kzalloc(sizeof(*disp), GFP_KERNEL); 161 if (!disp) { 162 pr_err("%pOF: could not allocate struct disp'\n", np); 163 goto dispfail; 164 } 165 166 entry = of_parse_phandle(timings_np, "native-mode", 0); 167 /* assume first child as native mode if none provided */ 168 if (!entry) 169 entry = of_get_next_child(timings_np, NULL); 170 /* if there is no child, it is useless to go on */ 171 if (!entry) { 172 pr_err("%pOF: no timing specifications given\n", np); 173 goto entryfail; 174 } 175 176 pr_debug("%pOF: using %pOFn as default timing\n", np, entry); 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("%pOF: no timings specified\n", np); 184 goto entryfail; 185 } 186 187 disp->timings = kcalloc(disp->num_timings, 188 sizeof(struct display_timing *), 189 GFP_KERNEL); 190 if (!disp->timings) { 191 pr_err("%pOF: could not allocate timings array\n", 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("%pOF: could not allocate display_timing struct\n", 205 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("%pOF: error in timing %d\n", 216 np, disp->num_timings + 1); 217 kfree(dt); 218 goto timingfail; 219 } 220 221 if (native_mode == entry) 222 disp->native_mode = disp->num_timings; 223 224 disp->timings[disp->num_timings] = dt; 225 disp->num_timings++; 226 } 227 of_node_put(timings_np); 228 /* 229 * native_mode points to the device_node returned by of_parse_phandle 230 * therefore call of_node_put on it 231 */ 232 of_node_put(native_mode); 233 234 pr_debug("%pOF: got %d timings. Using timing #%d as default\n", 235 np, disp->num_timings, 236 disp->native_mode + 1); 237 238 return disp; 239 240 timingfail: 241 of_node_put(native_mode); 242 display_timings_release(disp); 243 disp = NULL; 244 entryfail: 245 kfree(disp); 246 dispfail: 247 of_node_put(timings_np); 248 return NULL; 249 } 250 EXPORT_SYMBOL_GPL(of_get_display_timings); 251