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
 21struct simple_bridge_info {
 22	const struct drm_bridge_timings *timings;
 23	unsigned int connector_type;
 24};
 25
 26struct 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
 37static inline struct simple_bridge *
 38drm_bridge_to_simple_bridge(struct drm_bridge *bridge)
 39{
 40	return container_of(bridge, struct simple_bridge, bridge);
 41}
 42
 43static inline struct simple_bridge *
 44drm_connector_to_simple_bridge(struct drm_connector *connector)
 45{
 46	return container_of(connector, struct simple_bridge, connector);
 47}
 48
 49static 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
 81static const struct drm_connector_helper_funcs simple_bridge_con_helper_funcs = {
 82	.get_modes	= simple_bridge_get_modes,
 83};
 84
 85static enum drm_connector_status
 86simple_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
 93static 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
102static 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
137static 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
151static 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
161static 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
167static 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
220static 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 */
235static 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 */
246static 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 */
259static 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
267static 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};
299MODULE_DEVICE_TABLE(of, simple_bridge_match);
300
301static 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};
309module_platform_driver(simple_bridge_driver);
310
311MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
312MODULE_DESCRIPTION("Simple DRM bridge driver");
313MODULE_LICENSE("GPL");