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 const struct drm_edid *drm_edid; 55 int ret; 56 57 if (sbridge->next_bridge->ops & DRM_BRIDGE_OP_EDID) { 58 drm_edid = drm_bridge_edid_read(sbridge->next_bridge, connector); 59 if (!drm_edid) 60 DRM_INFO("EDID read failed. Fallback to standard modes\n"); 61 } else { 62 drm_edid = NULL; 63 } 64 65 drm_edid_connector_update(connector, drm_edid); 66 67 if (!drm_edid) { 68 /* 69 * In case we cannot retrieve the EDIDs (missing or broken DDC 70 * bus from the next bridge), fallback on the XGA standards and 71 * prefer a mode pretty much anyone can handle. 72 */ 73 ret = drm_add_modes_noedid(connector, 1920, 1200); 74 drm_set_preferred_mode(connector, 1024, 768); 75 return ret; 76 } 77 78 ret = drm_edid_connector_add_modes(connector); 79 drm_edid_free(drm_edid); 80 81 return ret; 82 } 83 84 static const struct drm_connector_helper_funcs simple_bridge_con_helper_funcs = { 85 .get_modes = simple_bridge_get_modes, 86 }; 87 88 static enum drm_connector_status 89 simple_bridge_connector_detect(struct drm_connector *connector, bool force) 90 { 91 struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector); 92 93 return drm_bridge_detect(sbridge->next_bridge); 94 } 95 96 static const struct drm_connector_funcs simple_bridge_con_funcs = { 97 .detect = simple_bridge_connector_detect, 98 .fill_modes = drm_helper_probe_single_connector_modes, 99 .destroy = drm_connector_cleanup, 100 .reset = drm_atomic_helper_connector_reset, 101 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, 102 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, 103 }; 104 105 static int simple_bridge_attach(struct drm_bridge *bridge, 106 enum drm_bridge_attach_flags flags) 107 { 108 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); 109 int ret; 110 111 ret = drm_bridge_attach(bridge->encoder, sbridge->next_bridge, bridge, 112 DRM_BRIDGE_ATTACH_NO_CONNECTOR); 113 if (ret < 0) 114 return ret; 115 116 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) 117 return 0; 118 119 if (!bridge->encoder) { 120 DRM_ERROR("Missing encoder\n"); 121 return -ENODEV; 122 } 123 124 drm_connector_helper_add(&sbridge->connector, 125 &simple_bridge_con_helper_funcs); 126 ret = drm_connector_init_with_ddc(bridge->dev, &sbridge->connector, 127 &simple_bridge_con_funcs, 128 sbridge->info->connector_type, 129 sbridge->next_bridge->ddc); 130 if (ret) { 131 DRM_ERROR("Failed to initialize connector\n"); 132 return ret; 133 } 134 135 drm_connector_attach_encoder(&sbridge->connector, bridge->encoder); 136 137 return 0; 138 } 139 140 static void simple_bridge_enable(struct drm_bridge *bridge) 141 { 142 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); 143 int ret; 144 145 if (sbridge->vdd) { 146 ret = regulator_enable(sbridge->vdd); 147 if (ret) 148 DRM_ERROR("Failed to enable vdd regulator: %d\n", ret); 149 } 150 151 gpiod_set_value_cansleep(sbridge->enable, 1); 152 } 153 154 static void simple_bridge_disable(struct drm_bridge *bridge) 155 { 156 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); 157 158 gpiod_set_value_cansleep(sbridge->enable, 0); 159 160 if (sbridge->vdd) 161 regulator_disable(sbridge->vdd); 162 } 163 164 static const struct drm_bridge_funcs simple_bridge_bridge_funcs = { 165 .attach = simple_bridge_attach, 166 .enable = simple_bridge_enable, 167 .disable = simple_bridge_disable, 168 }; 169 170 static int simple_bridge_probe(struct platform_device *pdev) 171 { 172 struct simple_bridge *sbridge; 173 struct device_node *remote; 174 175 sbridge = devm_kzalloc(&pdev->dev, sizeof(*sbridge), GFP_KERNEL); 176 if (!sbridge) 177 return -ENOMEM; 178 platform_set_drvdata(pdev, sbridge); 179 180 sbridge->info = of_device_get_match_data(&pdev->dev); 181 182 /* Get the next bridge in the pipeline. */ 183 remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1); 184 if (!remote) 185 return -EINVAL; 186 187 sbridge->next_bridge = of_drm_find_bridge(remote); 188 of_node_put(remote); 189 190 if (!sbridge->next_bridge) { 191 dev_dbg(&pdev->dev, "Next bridge not found, deferring probe\n"); 192 return -EPROBE_DEFER; 193 } 194 195 /* Get the regulator and GPIO resources. */ 196 sbridge->vdd = devm_regulator_get_optional(&pdev->dev, "vdd"); 197 if (IS_ERR(sbridge->vdd)) { 198 int ret = PTR_ERR(sbridge->vdd); 199 if (ret == -EPROBE_DEFER) 200 return -EPROBE_DEFER; 201 sbridge->vdd = NULL; 202 dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret); 203 } 204 205 sbridge->enable = devm_gpiod_get_optional(&pdev->dev, "enable", 206 GPIOD_OUT_LOW); 207 if (IS_ERR(sbridge->enable)) 208 return dev_err_probe(&pdev->dev, PTR_ERR(sbridge->enable), 209 "Unable to retrieve enable GPIO\n"); 210 211 /* Register the bridge. */ 212 sbridge->bridge.funcs = &simple_bridge_bridge_funcs; 213 sbridge->bridge.of_node = pdev->dev.of_node; 214 sbridge->bridge.timings = sbridge->info->timings; 215 216 drm_bridge_add(&sbridge->bridge); 217 218 return 0; 219 } 220 221 static void simple_bridge_remove(struct platform_device *pdev) 222 { 223 struct simple_bridge *sbridge = platform_get_drvdata(pdev); 224 225 drm_bridge_remove(&sbridge->bridge); 226 } 227 228 /* 229 * We assume the ADV7123 DAC is the "default" for historical reasons 230 * Information taken from the ADV7123 datasheet, revision D. 231 * NOTE: the ADV7123EP seems to have other timings and need a new timings 232 * set if used. 233 */ 234 static const struct drm_bridge_timings default_bridge_timings = { 235 /* Timing specifications, datasheet page 7 */ 236 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 237 .setup_time_ps = 500, 238 .hold_time_ps = 1500, 239 }; 240 241 /* 242 * Information taken from the THS8134, THS8134A, THS8134B datasheet named 243 * "SLVS205D", dated May 1990, revised March 2000. 244 */ 245 static const struct drm_bridge_timings ti_ths8134_bridge_timings = { 246 /* From timing diagram, datasheet page 9 */ 247 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 248 /* From datasheet, page 12 */ 249 .setup_time_ps = 3000, 250 /* I guess this means latched input */ 251 .hold_time_ps = 0, 252 }; 253 254 /* 255 * Information taken from the THS8135 datasheet named "SLAS343B", dated 256 * May 2001, revised April 2013. 257 */ 258 static const struct drm_bridge_timings ti_ths8135_bridge_timings = { 259 /* From timing diagram, datasheet page 14 */ 260 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 261 /* From datasheet, page 16 */ 262 .setup_time_ps = 2000, 263 .hold_time_ps = 500, 264 }; 265 266 static const struct of_device_id simple_bridge_match[] = { 267 { 268 .compatible = "dumb-vga-dac", 269 .data = &(const struct simple_bridge_info) { 270 .connector_type = DRM_MODE_CONNECTOR_VGA, 271 }, 272 }, { 273 .compatible = "adi,adv7123", 274 .data = &(const struct simple_bridge_info) { 275 .timings = &default_bridge_timings, 276 .connector_type = DRM_MODE_CONNECTOR_VGA, 277 }, 278 }, { 279 .compatible = "ti,opa362", 280 .data = &(const struct simple_bridge_info) { 281 .connector_type = DRM_MODE_CONNECTOR_Composite, 282 }, 283 }, { 284 .compatible = "ti,ths8135", 285 .data = &(const struct simple_bridge_info) { 286 .timings = &ti_ths8135_bridge_timings, 287 .connector_type = DRM_MODE_CONNECTOR_VGA, 288 }, 289 }, { 290 .compatible = "ti,ths8134", 291 .data = &(const struct simple_bridge_info) { 292 .timings = &ti_ths8134_bridge_timings, 293 .connector_type = DRM_MODE_CONNECTOR_VGA, 294 }, 295 }, 296 {}, 297 }; 298 MODULE_DEVICE_TABLE(of, simple_bridge_match); 299 300 static struct platform_driver simple_bridge_driver = { 301 .probe = simple_bridge_probe, 302 .remove_new = simple_bridge_remove, 303 .driver = { 304 .name = "simple-bridge", 305 .of_match_table = simple_bridge_match, 306 }, 307 }; 308 module_platform_driver(simple_bridge_driver); 309 310 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>"); 311 MODULE_DESCRIPTION("Simple DRM bridge driver"); 312 MODULE_LICENSE("GPL"); 313