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 *
drm_bridge_to_simple_bridge(struct drm_bridge * 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 *
drm_connector_to_simple_bridge(struct drm_connector * connector)44 drm_connector_to_simple_bridge(struct drm_connector *connector)
45 {
46 return container_of(connector, struct simple_bridge, connector);
47 }
48
simple_bridge_get_modes(struct drm_connector * connector)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
simple_bridge_connector_detect(struct drm_connector * connector,bool force)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
simple_bridge_attach(struct drm_bridge * bridge,enum drm_bridge_attach_flags flags)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
simple_bridge_enable(struct drm_bridge * bridge)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
simple_bridge_disable(struct drm_bridge * bridge)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
simple_bridge_probe(struct platform_device * pdev)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
simple_bridge_remove(struct platform_device * pdev)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