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 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
simple_bridge_connector_detect(struct drm_connector * connector,bool force)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
simple_bridge_attach(struct drm_bridge * bridge,enum drm_bridge_attach_flags flags)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
simple_bridge_enable(struct drm_bridge * bridge)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
simple_bridge_disable(struct drm_bridge * bridge)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
simple_bridge_probe(struct platform_device * pdev)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