simple-bridge.c

  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(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
 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(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, sbridge->next_bridge, bridge,
113				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(&sbridge->connector,
121				 &simple_bridge_con_helper_funcs);
122	ret = drm_connector_init_with_ddc(bridge->dev, &sbridge->connector,
123					  &simple_bridge_con_funcs,
124					  sbridge->info->connector_type,
125					  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(&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(sbridge->vdd);
143		if (ret)
144			DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
145	}
146
147	gpiod_set_value_cansleep(sbridge->enable, 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(sbridge->enable, 0);
155
156	if (sbridge->vdd)
157		regulator_disable(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(sbridge))
174		return PTR_ERR(sbridge);
175
176	sbridge->info = of_device_get_match_data(&pdev->dev);
177
178	/* Get the next bridge in the pipeline. */
179	remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1);
180	if (!remote)
181		return -EINVAL;
182
183	sbridge->next_bridge = of_drm_find_bridge(remote);
184	of_node_put(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(&pdev->dev, "vdd");
193	if (IS_ERR(sbridge->vdd)) {
194		int ret = PTR_ERR(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(&pdev->dev, "enable",
202						  GPIOD_OUT_LOW);
203	if (IS_ERR(sbridge->enable))
204		return dev_err_probe(&pdev->dev, PTR_ERR(sbridge->enable),
205				     "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(&pdev->dev, &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");