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
23struct simple_bridge_info {
24 const struct drm_bridge_timings *timings;
25 unsigned int connector_type;
26};
27
28struct 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
39static inline struct simple_bridge *
40drm_bridge_to_simple_bridge(struct drm_bridge *bridge)
41{
42 return container_of(bridge, struct simple_bridge, bridge);
43}
44
45static inline struct simple_bridge *
46drm_connector_to_simple_bridge(struct drm_connector *connector)
47{
48 return container_of(connector, struct simple_bridge, connector);
49}
50
51static 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(bridge: 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, edid: 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, hdisplay: 1920, vdisplay: 1200);
74 drm_set_preferred_mode(connector, hpref: 1024, vpref: 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
84static const struct drm_connector_helper_funcs simple_bridge_con_helper_funcs = {
85 .get_modes = simple_bridge_get_modes,
86};
87
88static enum drm_connector_status
89simple_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(bridge: sbridge->next_bridge);
94}
95
96static 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
105static 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(encoder: bridge->encoder, bridge: sbridge->next_bridge, previous: bridge,
112 flags: 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 if (!bridge->encoder) {
120 DRM_ERROR("Missing encoder\n");
121 return -ENODEV;
122 }
123
124 drm_connector_helper_add(connector: &sbridge->connector,
125 funcs: &simple_bridge_con_helper_funcs);
126 ret = drm_connector_init_with_ddc(dev: bridge->dev, connector: &sbridge->connector,
127 funcs: &simple_bridge_con_funcs,
128 connector_type: sbridge->info->connector_type,
129 ddc: sbridge->next_bridge->ddc);
130 if (ret) {
131 DRM_ERROR("Failed to initialize connector\n");
132 return ret;
133 }
134
135 drm_connector_attach_encoder(connector: &sbridge->connector, encoder: bridge->encoder);
136
137 return 0;
138}
139
140static void simple_bridge_enable(struct drm_bridge *bridge)
141{
142 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
143 int ret;
144
145 if (sbridge->vdd) {
146 ret = regulator_enable(regulator: sbridge->vdd);
147 if (ret)
148 DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
149 }
150
151 gpiod_set_value_cansleep(desc: sbridge->enable, value: 1);
152}
153
154static void simple_bridge_disable(struct drm_bridge *bridge)
155{
156 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
157
158 gpiod_set_value_cansleep(desc: sbridge->enable, value: 0);
159
160 if (sbridge->vdd)
161 regulator_disable(regulator: sbridge->vdd);
162}
163
164static const struct drm_bridge_funcs simple_bridge_bridge_funcs = {
165 .attach = simple_bridge_attach,
166 .enable = simple_bridge_enable,
167 .disable = simple_bridge_disable,
168};
169
170static int simple_bridge_probe(struct platform_device *pdev)
171{
172 struct simple_bridge *sbridge;
173 struct device_node *remote;
174
175 sbridge = devm_kzalloc(dev: &pdev->dev, size: sizeof(*sbridge), GFP_KERNEL);
176 if (!sbridge)
177 return -ENOMEM;
178 platform_set_drvdata(pdev, data: sbridge);
179
180 sbridge->info = of_device_get_match_data(dev: &pdev->dev);
181
182 /* Get the next bridge in the pipeline. */
183 remote = of_graph_get_remote_node(node: pdev->dev.of_node, port: 1, endpoint: -1);
184 if (!remote)
185 return -EINVAL;
186
187 sbridge->next_bridge = of_drm_find_bridge(np: remote);
188 of_node_put(node: remote);
189
190 if (!sbridge->next_bridge) {
191 dev_dbg(&pdev->dev, "Next bridge not found, deferring probe\n");
192 return -EPROBE_DEFER;
193 }
194
195 /* Get the regulator and GPIO resources. */
196 sbridge->vdd = devm_regulator_get_optional(dev: &pdev->dev, id: "vdd");
197 if (IS_ERR(ptr: sbridge->vdd)) {
198 int ret = PTR_ERR(ptr: sbridge->vdd);
199 if (ret == -EPROBE_DEFER)
200 return -EPROBE_DEFER;
201 sbridge->vdd = NULL;
202 dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret);
203 }
204
205 sbridge->enable = devm_gpiod_get_optional(dev: &pdev->dev, con_id: "enable",
206 flags: GPIOD_OUT_LOW);
207 if (IS_ERR(ptr: sbridge->enable))
208 return dev_err_probe(dev: &pdev->dev, err: PTR_ERR(ptr: sbridge->enable),
209 fmt: "Unable to retrieve enable GPIO\n");
210
211 /* Register the bridge. */
212 sbridge->bridge.funcs = &simple_bridge_bridge_funcs;
213 sbridge->bridge.of_node = pdev->dev.of_node;
214 sbridge->bridge.timings = sbridge->info->timings;
215
216 drm_bridge_add(bridge: &sbridge->bridge);
217
218 return 0;
219}
220
221static void simple_bridge_remove(struct platform_device *pdev)
222{
223 struct simple_bridge *sbridge = platform_get_drvdata(pdev);
224
225 drm_bridge_remove(bridge: &sbridge->bridge);
226}
227
228/*
229 * We assume the ADV7123 DAC is the "default" for historical reasons
230 * Information taken from the ADV7123 datasheet, revision D.
231 * NOTE: the ADV7123EP seems to have other timings and need a new timings
232 * set if used.
233 */
234static const struct drm_bridge_timings default_bridge_timings = {
235 /* Timing specifications, datasheet page 7 */
236 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
237 .setup_time_ps = 500,
238 .hold_time_ps = 1500,
239};
240
241/*
242 * Information taken from the THS8134, THS8134A, THS8134B datasheet named
243 * "SLVS205D", dated May 1990, revised March 2000.
244 */
245static const struct drm_bridge_timings ti_ths8134_bridge_timings = {
246 /* From timing diagram, datasheet page 9 */
247 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
248 /* From datasheet, page 12 */
249 .setup_time_ps = 3000,
250 /* I guess this means latched input */
251 .hold_time_ps = 0,
252};
253
254/*
255 * Information taken from the THS8135 datasheet named "SLAS343B", dated
256 * May 2001, revised April 2013.
257 */
258static const struct drm_bridge_timings ti_ths8135_bridge_timings = {
259 /* From timing diagram, datasheet page 14 */
260 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
261 /* From datasheet, page 16 */
262 .setup_time_ps = 2000,
263 .hold_time_ps = 500,
264};
265
266static const struct of_device_id simple_bridge_match[] = {
267 {
268 .compatible = "dumb-vga-dac",
269 .data = &(const struct simple_bridge_info) {
270 .connector_type = DRM_MODE_CONNECTOR_VGA,
271 },
272 }, {
273 .compatible = "adi,adv7123",
274 .data = &(const struct simple_bridge_info) {
275 .timings = &default_bridge_timings,
276 .connector_type = DRM_MODE_CONNECTOR_VGA,
277 },
278 }, {
279 .compatible = "ti,opa362",
280 .data = &(const struct simple_bridge_info) {
281 .connector_type = DRM_MODE_CONNECTOR_Composite,
282 },
283 }, {
284 .compatible = "ti,ths8135",
285 .data = &(const struct simple_bridge_info) {
286 .timings = &ti_ths8135_bridge_timings,
287 .connector_type = DRM_MODE_CONNECTOR_VGA,
288 },
289 }, {
290 .compatible = "ti,ths8134",
291 .data = &(const struct simple_bridge_info) {
292 .timings = &ti_ths8134_bridge_timings,
293 .connector_type = DRM_MODE_CONNECTOR_VGA,
294 },
295 },
296 {},
297};
298MODULE_DEVICE_TABLE(of, simple_bridge_match);
299
300static struct platform_driver simple_bridge_driver = {
301 .probe = simple_bridge_probe,
302 .remove_new = simple_bridge_remove,
303 .driver = {
304 .name = "simple-bridge",
305 .of_match_table = simple_bridge_match,
306 },
307};
308module_platform_driver(simple_bridge_driver);
309
310MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
311MODULE_DESCRIPTION("Simple DRM bridge driver");
312MODULE_LICENSE("GPL");
313

source code of linux/drivers/gpu/drm/bridge/simple-bridge.c