1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2015-2016 Free Electrons 4 * Copyright (C) 2015-2016 NextThing Co 5 * 6 * Maxime Ripard <maxime.ripard@free-electrons.com> 7 */ 8 9 #include <linux/gpio/consumer.h> 10 #include <linux/module.h> 11 #include <linux/of.h> 12 #include <linux/of_graph.h> 13 #include <linux/platform_device.h> 14 #include <linux/regulator/consumer.h> 15 16 #include <drm/drm_atomic_helper.h> 17 #include <drm/drm_bridge.h> 18 #include <drm/drm_crtc.h> 19 #include <drm/drm_edid.h> 20 #include <drm/drm_print.h> 21 #include <drm/drm_probe_helper.h> 22 23 struct simple_bridge_info { 24 const struct drm_bridge_timings *timings; 25 unsigned int connector_type; 26 }; 27 28 struct simple_bridge { 29 struct drm_bridge bridge; 30 struct drm_connector connector; 31 32 const struct simple_bridge_info *info; 33 34 struct drm_bridge *next_bridge; 35 struct regulator *vdd; 36 struct gpio_desc *enable; 37 }; 38 39 static inline struct simple_bridge * 40 drm_bridge_to_simple_bridge(struct drm_bridge *bridge) 41 { 42 return container_of(bridge, struct simple_bridge, bridge); 43 } 44 45 static inline struct simple_bridge * 46 drm_connector_to_simple_bridge(struct drm_connector *connector) 47 { 48 return container_of(connector, struct simple_bridge, connector); 49 } 50 51 static int simple_bridge_get_modes(struct drm_connector *connector) 52 { 53 struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector); 54 struct edid *edid; 55 int ret; 56 57 if (sbridge->next_bridge->ops & DRM_BRIDGE_OP_EDID) { 58 edid = drm_bridge_get_edid(sbridge->next_bridge, connector); 59 if (!edid) 60 DRM_INFO("EDID read failed. Fallback to standard modes\n"); 61 } else { 62 edid = NULL; 63 } 64 65 if (!edid) { 66 /* 67 * In case we cannot retrieve the EDIDs (missing or broken DDC 68 * bus from the next bridge), fallback on the XGA standards and 69 * prefer a mode pretty much anyone can handle. 70 */ 71 ret = drm_add_modes_noedid(connector, 1920, 1200); 72 drm_set_preferred_mode(connector, 1024, 768); 73 return ret; 74 } 75 76 drm_connector_update_edid_property(connector, edid); 77 ret = drm_add_edid_modes(connector, edid); 78 kfree(edid); 79 80 return ret; 81 } 82 83 static const struct drm_connector_helper_funcs simple_bridge_con_helper_funcs = { 84 .get_modes = simple_bridge_get_modes, 85 }; 86 87 static enum drm_connector_status 88 simple_bridge_connector_detect(struct drm_connector *connector, bool force) 89 { 90 struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector); 91 92 return drm_bridge_detect(sbridge->next_bridge); 93 } 94 95 static const struct drm_connector_funcs simple_bridge_con_funcs = { 96 .detect = simple_bridge_connector_detect, 97 .fill_modes = drm_helper_probe_single_connector_modes, 98 .destroy = drm_connector_cleanup, 99 .reset = drm_atomic_helper_connector_reset, 100 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, 101 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, 102 }; 103 104 static int simple_bridge_attach(struct drm_bridge *bridge, 105 enum drm_bridge_attach_flags flags) 106 { 107 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); 108 int ret; 109 110 ret = drm_bridge_attach(bridge->encoder, sbridge->next_bridge, bridge, 111 DRM_BRIDGE_ATTACH_NO_CONNECTOR); 112 if (ret < 0) 113 return ret; 114 115 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) 116 return 0; 117 118 if (!bridge->encoder) { 119 DRM_ERROR("Missing encoder\n"); 120 return -ENODEV; 121 } 122 123 drm_connector_helper_add(&sbridge->connector, 124 &simple_bridge_con_helper_funcs); 125 ret = drm_connector_init_with_ddc(bridge->dev, &sbridge->connector, 126 &simple_bridge_con_funcs, 127 sbridge->info->connector_type, 128 sbridge->next_bridge->ddc); 129 if (ret) { 130 DRM_ERROR("Failed to initialize connector\n"); 131 return ret; 132 } 133 134 drm_connector_attach_encoder(&sbridge->connector, bridge->encoder); 135 136 return 0; 137 } 138 139 static void simple_bridge_enable(struct drm_bridge *bridge) 140 { 141 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); 142 int ret; 143 144 if (sbridge->vdd) { 145 ret = regulator_enable(sbridge->vdd); 146 if (ret) 147 DRM_ERROR("Failed to enable vdd regulator: %d\n", ret); 148 } 149 150 gpiod_set_value_cansleep(sbridge->enable, 1); 151 } 152 153 static void simple_bridge_disable(struct drm_bridge *bridge) 154 { 155 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); 156 157 gpiod_set_value_cansleep(sbridge->enable, 0); 158 159 if (sbridge->vdd) 160 regulator_disable(sbridge->vdd); 161 } 162 163 static const struct drm_bridge_funcs simple_bridge_bridge_funcs = { 164 .attach = simple_bridge_attach, 165 .enable = simple_bridge_enable, 166 .disable = simple_bridge_disable, 167 }; 168 169 static int simple_bridge_probe(struct platform_device *pdev) 170 { 171 struct simple_bridge *sbridge; 172 struct device_node *remote; 173 174 sbridge = devm_kzalloc(&pdev->dev, sizeof(*sbridge), GFP_KERNEL); 175 if (!sbridge) 176 return -ENOMEM; 177 platform_set_drvdata(pdev, sbridge); 178 179 sbridge->info = of_device_get_match_data(&pdev->dev); 180 181 /* Get the next bridge in the pipeline. */ 182 remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1); 183 if (!remote) 184 return -EINVAL; 185 186 sbridge->next_bridge = of_drm_find_bridge(remote); 187 of_node_put(remote); 188 189 if (!sbridge->next_bridge) { 190 dev_dbg(&pdev->dev, "Next bridge not found, deferring probe\n"); 191 return -EPROBE_DEFER; 192 } 193 194 /* Get the regulator and GPIO resources. */ 195 sbridge->vdd = devm_regulator_get_optional(&pdev->dev, "vdd"); 196 if (IS_ERR(sbridge->vdd)) { 197 int ret = PTR_ERR(sbridge->vdd); 198 if (ret == -EPROBE_DEFER) 199 return -EPROBE_DEFER; 200 sbridge->vdd = NULL; 201 dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret); 202 } 203 204 sbridge->enable = devm_gpiod_get_optional(&pdev->dev, "enable", 205 GPIOD_OUT_LOW); 206 if (IS_ERR(sbridge->enable)) 207 return dev_err_probe(&pdev->dev, PTR_ERR(sbridge->enable), 208 "Unable to retrieve enable GPIO\n"); 209 210 /* Register the bridge. */ 211 sbridge->bridge.funcs = &simple_bridge_bridge_funcs; 212 sbridge->bridge.of_node = pdev->dev.of_node; 213 sbridge->bridge.timings = sbridge->info->timings; 214 215 drm_bridge_add(&sbridge->bridge); 216 217 return 0; 218 } 219 220 static void simple_bridge_remove(struct platform_device *pdev) 221 { 222 struct simple_bridge *sbridge = platform_get_drvdata(pdev); 223 224 drm_bridge_remove(&sbridge->bridge); 225 } 226 227 /* 228 * We assume the ADV7123 DAC is the "default" for historical reasons 229 * Information taken from the ADV7123 datasheet, revision D. 230 * NOTE: the ADV7123EP seems to have other timings and need a new timings 231 * set if used. 232 */ 233 static const struct drm_bridge_timings default_bridge_timings = { 234 /* Timing specifications, datasheet page 7 */ 235 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 236 .setup_time_ps = 500, 237 .hold_time_ps = 1500, 238 }; 239 240 /* 241 * Information taken from the THS8134, THS8134A, THS8134B datasheet named 242 * "SLVS205D", dated May 1990, revised March 2000. 243 */ 244 static const struct drm_bridge_timings ti_ths8134_bridge_timings = { 245 /* From timing diagram, datasheet page 9 */ 246 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 247 /* From datasheet, page 12 */ 248 .setup_time_ps = 3000, 249 /* I guess this means latched input */ 250 .hold_time_ps = 0, 251 }; 252 253 /* 254 * Information taken from the THS8135 datasheet named "SLAS343B", dated 255 * May 2001, revised April 2013. 256 */ 257 static const struct drm_bridge_timings ti_ths8135_bridge_timings = { 258 /* From timing diagram, datasheet page 14 */ 259 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 260 /* From datasheet, page 16 */ 261 .setup_time_ps = 2000, 262 .hold_time_ps = 500, 263 }; 264 265 static const struct of_device_id simple_bridge_match[] = { 266 { 267 .compatible = "dumb-vga-dac", 268 .data = &(const struct simple_bridge_info) { 269 .connector_type = DRM_MODE_CONNECTOR_VGA, 270 }, 271 }, { 272 .compatible = "adi,adv7123", 273 .data = &(const struct simple_bridge_info) { 274 .timings = &default_bridge_timings, 275 .connector_type = DRM_MODE_CONNECTOR_VGA, 276 }, 277 }, { 278 .compatible = "ti,opa362", 279 .data = &(const struct simple_bridge_info) { 280 .connector_type = DRM_MODE_CONNECTOR_Composite, 281 }, 282 }, { 283 .compatible = "ti,ths8135", 284 .data = &(const struct simple_bridge_info) { 285 .timings = &ti_ths8135_bridge_timings, 286 .connector_type = DRM_MODE_CONNECTOR_VGA, 287 }, 288 }, { 289 .compatible = "ti,ths8134", 290 .data = &(const struct simple_bridge_info) { 291 .timings = &ti_ths8134_bridge_timings, 292 .connector_type = DRM_MODE_CONNECTOR_VGA, 293 }, 294 }, 295 {}, 296 }; 297 MODULE_DEVICE_TABLE(of, simple_bridge_match); 298 299 static struct platform_driver simple_bridge_driver = { 300 .probe = simple_bridge_probe, 301 .remove_new = simple_bridge_remove, 302 .driver = { 303 .name = "simple-bridge", 304 .of_match_table = simple_bridge_match, 305 }, 306 }; 307 module_platform_driver(simple_bridge_driver); 308 309 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>"); 310 MODULE_DESCRIPTION("Simple DRM bridge driver"); 311 MODULE_LICENSE("GPL"); 312