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 **/ 56 static int of_parse_display_timing(const struct device_node *np, 57 struct display_timing *dt) 58 { 59 u32 val = 0; 60 int ret = 0; 61 62 memset(dt, 0, sizeof(*dt)); 63 64 ret |= parse_timing_property(np, "hback-porch", &dt->hback_porch); 65 ret |= parse_timing_property(np, "hfront-porch", &dt->hfront_porch); 66 ret |= parse_timing_property(np, "hactive", &dt->hactive); 67 ret |= parse_timing_property(np, "hsync-len", &dt->hsync_len); 68 ret |= parse_timing_property(np, "vback-porch", &dt->vback_porch); 69 ret |= parse_timing_property(np, "vfront-porch", &dt->vfront_porch); 70 ret |= parse_timing_property(np, "vactive", &dt->vactive); 71 ret |= parse_timing_property(np, "vsync-len", &dt->vsync_len); 72 ret |= parse_timing_property(np, "clock-frequency", &dt->pixelclock); 73 74 dt->flags = 0; 75 if (!of_property_read_u32(np, "vsync-active", &val)) 76 dt->flags |= val ? DISPLAY_FLAGS_VSYNC_HIGH : 77 DISPLAY_FLAGS_VSYNC_LOW; 78 if (!of_property_read_u32(np, "hsync-active", &val)) 79 dt->flags |= val ? DISPLAY_FLAGS_HSYNC_HIGH : 80 DISPLAY_FLAGS_HSYNC_LOW; 81 if (!of_property_read_u32(np, "de-active", &val)) 82 dt->flags |= val ? DISPLAY_FLAGS_DE_HIGH : 83 DISPLAY_FLAGS_DE_LOW; 84 if (!of_property_read_u32(np, "pixelclk-active", &val)) 85 dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE : 86 DISPLAY_FLAGS_PIXDATA_NEGEDGE; 87 88 if (!of_property_read_u32(np, "syncclk-active", &val)) 89 dt->flags |= val ? DISPLAY_FLAGS_SYNC_POSEDGE : 90 DISPLAY_FLAGS_SYNC_NEGEDGE; 91 else if (dt->flags & (DISPLAY_FLAGS_PIXDATA_POSEDGE | 92 DISPLAY_FLAGS_PIXDATA_NEGEDGE)) 93 dt->flags |= dt->flags & DISPLAY_FLAGS_PIXDATA_POSEDGE ? 94 DISPLAY_FLAGS_SYNC_POSEDGE : 95 DISPLAY_FLAGS_SYNC_NEGEDGE; 96 97 if (of_property_read_bool(np, "interlaced")) 98 dt->flags |= DISPLAY_FLAGS_INTERLACED; 99 if (of_property_read_bool(np, "doublescan")) 100 dt->flags |= DISPLAY_FLAGS_DOUBLESCAN; 101 if (of_property_read_bool(np, "doubleclk")) 102 dt->flags |= DISPLAY_FLAGS_DOUBLECLK; 103 104 if (ret) { 105 pr_err("%pOF: error reading timing properties\n", np); 106 return -EINVAL; 107 } 108 109 return 0; 110 } 111 112 /** 113 * of_get_display_timing - parse a display_timing entry 114 * @np: device_node with the timing subnode 115 * @name: name of the timing node 116 * @dt: display_timing struct to fill 117 **/ 118 int of_get_display_timing(const struct device_node *np, const char *name, 119 struct display_timing *dt) 120 { 121 struct device_node *timing_np; 122 123 if (!np) 124 return -EINVAL; 125 126 timing_np = of_get_child_by_name(np, name); 127 if (!timing_np) { 128 pr_err("%pOF: could not find node '%s'\n", np, name); 129 return -ENOENT; 130 } 131 132 return of_parse_display_timing(timing_np, dt); 133 } 134 EXPORT_SYMBOL_GPL(of_get_display_timing); 135 136 /** 137 * of_get_display_timings - parse all display_timing entries from a device_node 138 * @np: device_node with the subnodes 139 **/ 140 struct display_timings *of_get_display_timings(const struct device_node *np) 141 { 142 struct device_node *timings_np; 143 struct device_node *entry; 144 struct device_node *native_mode; 145 struct display_timings *disp; 146 147 if (!np) 148 return NULL; 149 150 timings_np = of_get_child_by_name(np, "display-timings"); 151 if (!timings_np) { 152 pr_err("%pOF: could not find display-timings node\n", np); 153 return NULL; 154 } 155 156 disp = kzalloc(sizeof(*disp), GFP_KERNEL); 157 if (!disp) { 158 pr_err("%pOF: could not allocate struct disp'\n", np); 159 goto dispfail; 160 } 161 162 entry = of_parse_phandle(timings_np, "native-mode", 0); 163 /* assume first child as native mode if none provided */ 164 if (!entry) 165 entry = of_get_next_child(timings_np, NULL); 166 /* if there is no child, it is useless to go on */ 167 if (!entry) { 168 pr_err("%pOF: no timing specifications given\n", np); 169 goto entryfail; 170 } 171 172 pr_debug("%pOF: using %pOFn as default timing\n", np, entry); 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("%pOF: no timings specified\n", np); 180 goto entryfail; 181 } 182 183 disp->timings = kcalloc(disp->num_timings, 184 sizeof(struct display_timing *), 185 GFP_KERNEL); 186 if (!disp->timings) { 187 pr_err("%pOF: could not allocate timings array\n", 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("%pOF: could not allocate display_timing struct\n", 201 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("%pOF: error in timing %d\n", 212 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("%pOF: got %d timings. Using timing #%d as default\n", 231 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