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 struct edid *edid;
55 int ret;
56
57 if (sbridge->next_bridge->ops & DRM_BRIDGE_OP_EDID) {
58 edid = drm_bridge_get_edid(bridge: 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, hdisplay: 1920, vdisplay: 1200);
72 drm_set_preferred_mode(connector, hpref: 1024, vpref: 768);
73 return ret;
74 }
75
76 drm_connector_update_edid_property(connector, edid);
77 ret = drm_add_edid_modes(connector, edid);
78 kfree(objp: edid);
79
80 return ret;
81}
82
83static const struct drm_connector_helper_funcs simple_bridge_con_helper_funcs = {
84 .get_modes = simple_bridge_get_modes,
85};
86
87static enum drm_connector_status
88simple_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(bridge: sbridge->next_bridge);
93}
94
95static 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
104static 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(encoder: bridge->encoder, bridge: sbridge->next_bridge, previous: bridge,
111 flags: 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(connector: &sbridge->connector,
124 funcs: &simple_bridge_con_helper_funcs);
125 ret = drm_connector_init_with_ddc(dev: bridge->dev, connector: &sbridge->connector,
126 funcs: &simple_bridge_con_funcs,
127 connector_type: sbridge->info->connector_type,
128 ddc: 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(connector: &sbridge->connector, encoder: bridge->encoder);
135
136 return 0;
137}
138
139static 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(regulator: sbridge->vdd);
146 if (ret)
147 DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
148 }
149
150 gpiod_set_value_cansleep(desc: sbridge->enable, value: 1);
151}
152
153static 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(desc: sbridge->enable, value: 0);
158
159 if (sbridge->vdd)
160 regulator_disable(regulator: sbridge->vdd);
161}
162
163static 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
169static int simple_bridge_probe(struct platform_device *pdev)
170{
171 struct simple_bridge *sbridge;
172 struct device_node *remote;
173
174 sbridge = devm_kzalloc(dev: &pdev->dev, size: sizeof(*sbridge), GFP_KERNEL);
175 if (!sbridge)
176 return -ENOMEM;
177 platform_set_drvdata(pdev, data: sbridge);
178
179 sbridge->info = of_device_get_match_data(dev: &pdev->dev);
180
181 /* Get the next bridge in the pipeline. */
182 remote = of_graph_get_remote_node(node: pdev->dev.of_node, port: 1, endpoint: -1);
183 if (!remote)
184 return -EINVAL;
185
186 sbridge->next_bridge = of_drm_find_bridge(np: remote);
187 of_node_put(node: 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(dev: &pdev->dev, id: "vdd");
196 if (IS_ERR(ptr: sbridge->vdd)) {
197 int ret = PTR_ERR(ptr: 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(dev: &pdev->dev, con_id: "enable",
205 flags: GPIOD_OUT_LOW);
206 if (IS_ERR(ptr: sbridge->enable))
207 return dev_err_probe(dev: &pdev->dev, err: PTR_ERR(ptr: sbridge->enable),
208 fmt: "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(bridge: &sbridge->bridge);
216
217 return 0;
218}
219
220static void simple_bridge_remove(struct platform_device *pdev)
221{
222 struct simple_bridge *sbridge = platform_get_drvdata(pdev);
223
224 drm_bridge_remove(bridge: &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 */
233static 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 */
244static 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 */
257static 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
265static 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};
297MODULE_DEVICE_TABLE(of, simple_bridge_match);
298
299static 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};
307module_platform_driver(simple_bridge_driver);
308
309MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
310MODULE_DESCRIPTION("Simple DRM bridge driver");
311MODULE_LICENSE("GPL");
312

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