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 *
drm_bridge_to_simple_bridge(struct drm_bridge * 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 *
drm_connector_to_simple_bridge(struct drm_connector * connector)46 drm_connector_to_simple_bridge(struct drm_connector *connector)
47 {
48 return container_of(connector, struct simple_bridge, connector);
49 }
50
simple_bridge_get_modes(struct drm_connector * connector)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
simple_bridge_connector_detect(struct drm_connector * connector,bool force)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
simple_bridge_attach(struct drm_bridge * bridge,enum drm_bridge_attach_flags flags)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
simple_bridge_enable(struct drm_bridge * bridge)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
simple_bridge_disable(struct drm_bridge * bridge)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
simple_bridge_probe(struct platform_device * pdev)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
simple_bridge_remove(struct platform_device * pdev)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