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_device.h> 12 #include <linux/of_graph.h> 13 #include <linux/regulator/consumer.h> 14 15 #include <drm/drm_atomic_helper.h> 16 #include <drm/drm_bridge.h> 17 #include <drm/drm_crtc.h> 18 #include <drm/drm_print.h> 19 #include <drm/drm_probe_helper.h> 20 21 struct simple_bridge_info { 22 const struct drm_bridge_timings *timings; 23 unsigned int connector_type; 24 }; 25 26 struct simple_bridge { 27 struct drm_bridge bridge; 28 struct drm_connector connector; 29 30 const struct simple_bridge_info *info; 31 32 struct drm_bridge *next_bridge; 33 struct regulator *vdd; 34 struct gpio_desc *enable; 35 }; 36 37 static inline struct simple_bridge * 38 drm_bridge_to_simple_bridge(struct drm_bridge *bridge) 39 { 40 return container_of(bridge, struct simple_bridge, bridge); 41 } 42 43 static inline struct simple_bridge * 44 drm_connector_to_simple_bridge(struct drm_connector *connector) 45 { 46 return container_of(connector, struct simple_bridge, connector); 47 } 48 49 static int simple_bridge_get_modes(struct drm_connector *connector) 50 { 51 struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector); 52 struct edid *edid; 53 int ret; 54 55 if (sbridge->next_bridge->ops & DRM_BRIDGE_OP_EDID) { 56 edid = drm_bridge_get_edid(sbridge->next_bridge, connector); 57 if (!edid) 58 DRM_INFO("EDID read failed. Fallback to standard modes\n"); 59 } else { 60 edid = NULL; 61 } 62 63 if (!edid) { 64 /* 65 * In case we cannot retrieve the EDIDs (missing or broken DDC 66 * bus from the next bridge), fallback on the XGA standards and 67 * prefer a mode pretty much anyone can handle. 68 */ 69 ret = drm_add_modes_noedid(connector, 1920, 1200); 70 drm_set_preferred_mode(connector, 1024, 768); 71 return ret; 72 } 73 74 drm_connector_update_edid_property(connector, edid); 75 ret = drm_add_edid_modes(connector, edid); 76 kfree(edid); 77 78 return ret; 79 } 80 81 static const struct drm_connector_helper_funcs simple_bridge_con_helper_funcs = { 82 .get_modes = simple_bridge_get_modes, 83 }; 84 85 static enum drm_connector_status 86 simple_bridge_connector_detect(struct drm_connector *connector, bool force) 87 { 88 struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector); 89 90 return drm_bridge_detect(sbridge->next_bridge); 91 } 92 93 static const struct drm_connector_funcs simple_bridge_con_funcs = { 94 .detect = simple_bridge_connector_detect, 95 .fill_modes = drm_helper_probe_single_connector_modes, 96 .destroy = drm_connector_cleanup, 97 .reset = drm_atomic_helper_connector_reset, 98 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, 99 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, 100 }; 101 102 static int simple_bridge_attach(struct drm_bridge *bridge, 103 enum drm_bridge_attach_flags flags) 104 { 105 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); 106 int ret; 107 108 ret = drm_bridge_attach(bridge->encoder, sbridge->next_bridge, bridge, 109 DRM_BRIDGE_ATTACH_NO_CONNECTOR); 110 if (ret < 0) 111 return ret; 112 113 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) 114 return 0; 115 116 if (!bridge->encoder) { 117 DRM_ERROR("Missing encoder\n"); 118 return -ENODEV; 119 } 120 121 drm_connector_helper_add(&sbridge->connector, 122 &simple_bridge_con_helper_funcs); 123 ret = drm_connector_init_with_ddc(bridge->dev, &sbridge->connector, 124 &simple_bridge_con_funcs, 125 sbridge->info->connector_type, 126 sbridge->next_bridge->ddc); 127 if (ret) { 128 DRM_ERROR("Failed to initialize connector\n"); 129 return ret; 130 } 131 132 drm_connector_attach_encoder(&sbridge->connector, bridge->encoder); 133 134 return 0; 135 } 136 137 static void simple_bridge_enable(struct drm_bridge *bridge) 138 { 139 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); 140 int ret; 141 142 if (sbridge->vdd) { 143 ret = regulator_enable(sbridge->vdd); 144 if (ret) 145 DRM_ERROR("Failed to enable vdd regulator: %d\n", ret); 146 } 147 148 gpiod_set_value_cansleep(sbridge->enable, 1); 149 } 150 151 static void simple_bridge_disable(struct drm_bridge *bridge) 152 { 153 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); 154 155 gpiod_set_value_cansleep(sbridge->enable, 0); 156 157 if (sbridge->vdd) 158 regulator_disable(sbridge->vdd); 159 } 160 161 static const struct drm_bridge_funcs simple_bridge_bridge_funcs = { 162 .attach = simple_bridge_attach, 163 .enable = simple_bridge_enable, 164 .disable = simple_bridge_disable, 165 }; 166 167 static int simple_bridge_probe(struct platform_device *pdev) 168 { 169 struct simple_bridge *sbridge; 170 struct device_node *remote; 171 172 sbridge = devm_kzalloc(&pdev->dev, sizeof(*sbridge), GFP_KERNEL); 173 if (!sbridge) 174 return -ENOMEM; 175 platform_set_drvdata(pdev, sbridge); 176 177 sbridge->info = of_device_get_match_data(&pdev->dev); 178 179 /* Get the next bridge in the pipeline. */ 180 remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1); 181 if (!remote) 182 return -EINVAL; 183 184 sbridge->next_bridge = of_drm_find_bridge(remote); 185 of_node_put(remote); 186 187 if (!sbridge->next_bridge) { 188 dev_dbg(&pdev->dev, "Next bridge not found, deferring probe\n"); 189 return -EPROBE_DEFER; 190 } 191 192 /* Get the regulator and GPIO resources. */ 193 sbridge->vdd = devm_regulator_get_optional(&pdev->dev, "vdd"); 194 if (IS_ERR(sbridge->vdd)) { 195 int ret = PTR_ERR(sbridge->vdd); 196 if (ret == -EPROBE_DEFER) 197 return -EPROBE_DEFER; 198 sbridge->vdd = NULL; 199 dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret); 200 } 201 202 sbridge->enable = devm_gpiod_get_optional(&pdev->dev, "enable", 203 GPIOD_OUT_LOW); 204 if (IS_ERR(sbridge->enable)) { 205 if (PTR_ERR(sbridge->enable) != -EPROBE_DEFER) 206 dev_err(&pdev->dev, "Unable to retrieve enable GPIO\n"); 207 return PTR_ERR(sbridge->enable); 208 } 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 int 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 return 0; 227 } 228 229 /* 230 * We assume the ADV7123 DAC is the "default" for historical reasons 231 * Information taken from the ADV7123 datasheet, revision D. 232 * NOTE: the ADV7123EP seems to have other timings and need a new timings 233 * set if used. 234 */ 235 static const struct drm_bridge_timings default_bridge_timings = { 236 /* Timing specifications, datasheet page 7 */ 237 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 238 .setup_time_ps = 500, 239 .hold_time_ps = 1500, 240 }; 241 242 /* 243 * Information taken from the THS8134, THS8134A, THS8134B datasheet named 244 * "SLVS205D", dated May 1990, revised March 2000. 245 */ 246 static const struct drm_bridge_timings ti_ths8134_bridge_timings = { 247 /* From timing diagram, datasheet page 9 */ 248 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 249 /* From datasheet, page 12 */ 250 .setup_time_ps = 3000, 251 /* I guess this means latched input */ 252 .hold_time_ps = 0, 253 }; 254 255 /* 256 * Information taken from the THS8135 datasheet named "SLAS343B", dated 257 * May 2001, revised April 2013. 258 */ 259 static const struct drm_bridge_timings ti_ths8135_bridge_timings = { 260 /* From timing diagram, datasheet page 14 */ 261 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 262 /* From datasheet, page 16 */ 263 .setup_time_ps = 2000, 264 .hold_time_ps = 500, 265 }; 266 267 static const struct of_device_id simple_bridge_match[] = { 268 { 269 .compatible = "dumb-vga-dac", 270 .data = &(const struct simple_bridge_info) { 271 .connector_type = DRM_MODE_CONNECTOR_VGA, 272 }, 273 }, { 274 .compatible = "adi,adv7123", 275 .data = &(const struct simple_bridge_info) { 276 .timings = &default_bridge_timings, 277 .connector_type = DRM_MODE_CONNECTOR_VGA, 278 }, 279 }, { 280 .compatible = "ti,opa362", 281 .data = &(const struct simple_bridge_info) { 282 .connector_type = DRM_MODE_CONNECTOR_Composite, 283 }, 284 }, { 285 .compatible = "ti,ths8135", 286 .data = &(const struct simple_bridge_info) { 287 .timings = &ti_ths8135_bridge_timings, 288 .connector_type = DRM_MODE_CONNECTOR_VGA, 289 }, 290 }, { 291 .compatible = "ti,ths8134", 292 .data = &(const struct simple_bridge_info) { 293 .timings = &ti_ths8134_bridge_timings, 294 .connector_type = DRM_MODE_CONNECTOR_VGA, 295 }, 296 }, 297 {}, 298 }; 299 MODULE_DEVICE_TABLE(of, simple_bridge_match); 300 301 static struct platform_driver simple_bridge_driver = { 302 .probe = simple_bridge_probe, 303 .remove = simple_bridge_remove, 304 .driver = { 305 .name = "simple-bridge", 306 .of_match_table = simple_bridge_match, 307 }, 308 }; 309 module_platform_driver(simple_bridge_driver); 310 311 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>"); 312 MODULE_DESCRIPTION("Simple DRM bridge driver"); 313 MODULE_LICENSE("GPL"); 314