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 drm_connector_helper_add(&sbridge->connector, 120 &simple_bridge_con_helper_funcs); 121 ret = drm_connector_init_with_ddc(bridge->dev, &sbridge->connector, 122 &simple_bridge_con_funcs, 123 sbridge->info->connector_type, 124 sbridge->next_bridge->ddc); 125 if (ret) { 126 DRM_ERROR("Failed to initialize connector\n"); 127 return ret; 128 } 129 130 drm_connector_attach_encoder(&sbridge->connector, bridge->encoder); 131 132 return 0; 133 } 134 135 static void simple_bridge_enable(struct drm_bridge *bridge) 136 { 137 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); 138 int ret; 139 140 if (sbridge->vdd) { 141 ret = regulator_enable(sbridge->vdd); 142 if (ret) 143 DRM_ERROR("Failed to enable vdd regulator: %d\n", ret); 144 } 145 146 gpiod_set_value_cansleep(sbridge->enable, 1); 147 } 148 149 static void simple_bridge_disable(struct drm_bridge *bridge) 150 { 151 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); 152 153 gpiod_set_value_cansleep(sbridge->enable, 0); 154 155 if (sbridge->vdd) 156 regulator_disable(sbridge->vdd); 157 } 158 159 static const struct drm_bridge_funcs simple_bridge_bridge_funcs = { 160 .attach = simple_bridge_attach, 161 .enable = simple_bridge_enable, 162 .disable = simple_bridge_disable, 163 }; 164 165 static int simple_bridge_probe(struct platform_device *pdev) 166 { 167 struct simple_bridge *sbridge; 168 struct device_node *remote; 169 170 sbridge = devm_kzalloc(&pdev->dev, sizeof(*sbridge), GFP_KERNEL); 171 if (!sbridge) 172 return -ENOMEM; 173 174 sbridge->info = of_device_get_match_data(&pdev->dev); 175 176 /* Get the next bridge in the pipeline. */ 177 remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1); 178 if (!remote) 179 return -EINVAL; 180 181 sbridge->next_bridge = of_drm_find_bridge(remote); 182 of_node_put(remote); 183 184 if (!sbridge->next_bridge) { 185 dev_dbg(&pdev->dev, "Next bridge not found, deferring probe\n"); 186 return -EPROBE_DEFER; 187 } 188 189 /* Get the regulator and GPIO resources. */ 190 sbridge->vdd = devm_regulator_get_optional(&pdev->dev, "vdd"); 191 if (IS_ERR(sbridge->vdd)) { 192 int ret = PTR_ERR(sbridge->vdd); 193 if (ret == -EPROBE_DEFER) 194 return -EPROBE_DEFER; 195 sbridge->vdd = NULL; 196 dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret); 197 } 198 199 sbridge->enable = devm_gpiod_get_optional(&pdev->dev, "enable", 200 GPIOD_OUT_LOW); 201 if (IS_ERR(sbridge->enable)) 202 return dev_err_probe(&pdev->dev, PTR_ERR(sbridge->enable), 203 "Unable to retrieve enable GPIO\n"); 204 205 /* Register the bridge. */ 206 sbridge->bridge.funcs = &simple_bridge_bridge_funcs; 207 sbridge->bridge.of_node = pdev->dev.of_node; 208 sbridge->bridge.timings = sbridge->info->timings; 209 210 return devm_drm_bridge_add(&pdev->dev, &sbridge->bridge); 211 } 212 213 /* 214 * We assume the ADV7123 DAC is the "default" for historical reasons 215 * Information taken from the ADV7123 datasheet, revision D. 216 * NOTE: the ADV7123EP seems to have other timings and need a new timings 217 * set if used. 218 */ 219 static const struct drm_bridge_timings default_bridge_timings = { 220 /* Timing specifications, datasheet page 7 */ 221 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 222 .setup_time_ps = 500, 223 .hold_time_ps = 1500, 224 }; 225 226 /* 227 * Information taken from the THS8134, THS8134A, THS8134B datasheet named 228 * "SLVS205D", dated May 1990, revised March 2000. 229 */ 230 static const struct drm_bridge_timings ti_ths8134_bridge_timings = { 231 /* From timing diagram, datasheet page 9 */ 232 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 233 /* From datasheet, page 12 */ 234 .setup_time_ps = 3000, 235 /* I guess this means latched input */ 236 .hold_time_ps = 0, 237 }; 238 239 /* 240 * Information taken from the THS8135 datasheet named "SLAS343B", dated 241 * May 2001, revised April 2013. 242 */ 243 static const struct drm_bridge_timings ti_ths8135_bridge_timings = { 244 /* From timing diagram, datasheet page 14 */ 245 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, 246 /* From datasheet, page 16 */ 247 .setup_time_ps = 2000, 248 .hold_time_ps = 500, 249 }; 250 251 static const struct of_device_id simple_bridge_match[] = { 252 { 253 .compatible = "dumb-vga-dac", 254 .data = &(const struct simple_bridge_info) { 255 .connector_type = DRM_MODE_CONNECTOR_VGA, 256 }, 257 }, { 258 .compatible = "adi,adv7123", 259 .data = &(const struct simple_bridge_info) { 260 .timings = &default_bridge_timings, 261 .connector_type = DRM_MODE_CONNECTOR_VGA, 262 }, 263 }, { 264 .compatible = "ti,opa362", 265 .data = &(const struct simple_bridge_info) { 266 .connector_type = DRM_MODE_CONNECTOR_Composite, 267 }, 268 }, { 269 .compatible = "ti,ths8135", 270 .data = &(const struct simple_bridge_info) { 271 .timings = &ti_ths8135_bridge_timings, 272 .connector_type = DRM_MODE_CONNECTOR_VGA, 273 }, 274 }, { 275 .compatible = "ti,ths8134", 276 .data = &(const struct simple_bridge_info) { 277 .timings = &ti_ths8134_bridge_timings, 278 .connector_type = DRM_MODE_CONNECTOR_VGA, 279 }, 280 }, 281 {}, 282 }; 283 MODULE_DEVICE_TABLE(of, simple_bridge_match); 284 285 static struct platform_driver simple_bridge_driver = { 286 .probe = simple_bridge_probe, 287 .driver = { 288 .name = "simple-bridge", 289 .of_match_table = simple_bridge_match, 290 }, 291 }; 292 module_platform_driver(simple_bridge_driver); 293 294 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>"); 295 MODULE_DESCRIPTION("Simple DRM bridge driver"); 296 MODULE_LICENSE("GPL"); 297