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, connector);
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 struct drm_encoder *encoder,
107 enum drm_bridge_attach_flags flags)
108{
109 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
110 int ret;
111
112 ret = drm_bridge_attach(encoder, bridge: sbridge->next_bridge, previous: bridge,
113 flags: DRM_BRIDGE_ATTACH_NO_CONNECTOR);
114 if (ret < 0)
115 return ret;
116
117 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
118 return 0;
119
120 drm_connector_helper_add(connector: &sbridge->connector,
121 funcs: &simple_bridge_con_helper_funcs);
122 ret = drm_connector_init_with_ddc(dev: bridge->dev, connector: &sbridge->connector,
123 funcs: &simple_bridge_con_funcs,
124 connector_type: sbridge->info->connector_type,
125 ddc: sbridge->next_bridge->ddc);
126 if (ret) {
127 DRM_ERROR("Failed to initialize connector\n");
128 return ret;
129 }
130
131 drm_connector_attach_encoder(connector: &sbridge->connector, encoder);
132
133 return 0;
134}
135
136static void simple_bridge_enable(struct drm_bridge *bridge)
137{
138 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
139 int ret;
140
141 if (sbridge->vdd) {
142 ret = regulator_enable(regulator: sbridge->vdd);
143 if (ret)
144 DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
145 }
146
147 gpiod_set_value_cansleep(desc: sbridge->enable, value: 1);
148}
149
150static void simple_bridge_disable(struct drm_bridge *bridge)
151{
152 struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
153
154 gpiod_set_value_cansleep(desc: sbridge->enable, value: 0);
155
156 if (sbridge->vdd)
157 regulator_disable(regulator: sbridge->vdd);
158}
159
160static const struct drm_bridge_funcs simple_bridge_bridge_funcs = {
161 .attach = simple_bridge_attach,
162 .enable = simple_bridge_enable,
163 .disable = simple_bridge_disable,
164};
165
166static int simple_bridge_probe(struct platform_device *pdev)
167{
168 struct simple_bridge *sbridge;
169 struct device_node *remote;
170
171 sbridge = devm_drm_bridge_alloc(&pdev->dev, struct simple_bridge,
172 bridge, &simple_bridge_bridge_funcs);
173 if (IS_ERR(ptr: sbridge))
174 return PTR_ERR(ptr: sbridge);
175
176 sbridge->info = of_device_get_match_data(dev: &pdev->dev);
177
178 /* Get the next bridge in the pipeline. */
179 remote = of_graph_get_remote_node(node: pdev->dev.of_node, port: 1, endpoint: -1);
180 if (!remote)
181 return -EINVAL;
182
183 sbridge->next_bridge = of_drm_find_bridge(np: remote);
184 of_node_put(node: remote);
185
186 if (!sbridge->next_bridge) {
187 dev_dbg(&pdev->dev, "Next bridge not found, deferring probe\n");
188 return -EPROBE_DEFER;
189 }
190
191 /* Get the regulator and GPIO resources. */
192 sbridge->vdd = devm_regulator_get_optional(dev: &pdev->dev, id: "vdd");
193 if (IS_ERR(ptr: sbridge->vdd)) {
194 int ret = PTR_ERR(ptr: sbridge->vdd);
195 if (ret == -EPROBE_DEFER)
196 return -EPROBE_DEFER;
197 sbridge->vdd = NULL;
198 dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret);
199 }
200
201 sbridge->enable = devm_gpiod_get_optional(dev: &pdev->dev, con_id: "enable",
202 flags: GPIOD_OUT_LOW);
203 if (IS_ERR(ptr: sbridge->enable))
204 return dev_err_probe(dev: &pdev->dev, err: PTR_ERR(ptr: sbridge->enable),
205 fmt: "Unable to retrieve enable GPIO\n");
206
207 /* Register the bridge. */
208 sbridge->bridge.of_node = pdev->dev.of_node;
209 sbridge->bridge.timings = sbridge->info->timings;
210
211 return devm_drm_bridge_add(dev: &pdev->dev, bridge: &sbridge->bridge);
212}
213
214/*
215 * We assume the ADV7123 DAC is the "default" for historical reasons
216 * Information taken from the ADV7123 datasheet, revision D.
217 * NOTE: the ADV7123EP seems to have other timings and need a new timings
218 * set if used.
219 */
220static const struct drm_bridge_timings default_bridge_timings = {
221 /* Timing specifications, datasheet page 7 */
222 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
223 .setup_time_ps = 500,
224 .hold_time_ps = 1500,
225};
226
227/*
228 * Information taken from the THS8134, THS8134A, THS8134B datasheet named
229 * "SLVS205D", dated May 1990, revised March 2000.
230 */
231static const struct drm_bridge_timings ti_ths8134_bridge_timings = {
232 /* From timing diagram, datasheet page 9 */
233 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
234 /* From datasheet, page 12 */
235 .setup_time_ps = 3000,
236 /* I guess this means latched input */
237 .hold_time_ps = 0,
238};
239
240/*
241 * Information taken from the THS8135 datasheet named "SLAS343B", dated
242 * May 2001, revised April 2013.
243 */
244static const struct drm_bridge_timings ti_ths8135_bridge_timings = {
245 /* From timing diagram, datasheet page 14 */
246 .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
247 /* From datasheet, page 16 */
248 .setup_time_ps = 2000,
249 .hold_time_ps = 500,
250};
251
252static const struct of_device_id simple_bridge_match[] = {
253 {
254 .compatible = "dumb-vga-dac",
255 .data = &(const struct simple_bridge_info) {
256 .connector_type = DRM_MODE_CONNECTOR_VGA,
257 },
258 }, {
259 .compatible = "adi,adv7123",
260 .data = &(const struct simple_bridge_info) {
261 .timings = &default_bridge_timings,
262 .connector_type = DRM_MODE_CONNECTOR_VGA,
263 },
264 }, {
265 .compatible = "asl-tek,cs5263",
266 .data = &(const struct simple_bridge_info) {
267 .connector_type = DRM_MODE_CONNECTOR_HDMIA,
268 },
269 }, {
270 .compatible = "parade,ps185hdm",
271 .data = &(const struct simple_bridge_info) {
272 .connector_type = DRM_MODE_CONNECTOR_HDMIA,
273 },
274 }, {
275 .compatible = "radxa,ra620",
276 .data = &(const struct simple_bridge_info) {
277 .connector_type = DRM_MODE_CONNECTOR_HDMIA,
278 },
279 }, {
280 .compatible = "realtek,rtd2171",
281 .data = &(const struct simple_bridge_info) {
282 .connector_type = DRM_MODE_CONNECTOR_HDMIA,
283 },
284 }, {
285 .compatible = "ti,opa362",
286 .data = &(const struct simple_bridge_info) {
287 .connector_type = DRM_MODE_CONNECTOR_Composite,
288 },
289 }, {
290 .compatible = "ti,ths8135",
291 .data = &(const struct simple_bridge_info) {
292 .timings = &ti_ths8135_bridge_timings,
293 .connector_type = DRM_MODE_CONNECTOR_VGA,
294 },
295 }, {
296 .compatible = "ti,ths8134",
297 .data = &(const struct simple_bridge_info) {
298 .timings = &ti_ths8134_bridge_timings,
299 .connector_type = DRM_MODE_CONNECTOR_VGA,
300 },
301 },
302 {},
303};
304MODULE_DEVICE_TABLE(of, simple_bridge_match);
305
306static struct platform_driver simple_bridge_driver = {
307 .probe = simple_bridge_probe,
308 .driver = {
309 .name = "simple-bridge",
310 .of_match_table = simple_bridge_match,
311 },
312};
313module_platform_driver(simple_bridge_driver);
314
315MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
316MODULE_DESCRIPTION("Simple DRM bridge driver");
317MODULE_LICENSE("GPL");
318

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