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_edid.h>
 19#include <drm/drm_print.h>
 20#include <drm/drm_probe_helper.h>
 21
 22struct simple_bridge_info {
 23	const struct drm_bridge_timings *timings;
 24	unsigned int connector_type;
 25};
 26
 27struct simple_bridge {
 28	struct drm_bridge	bridge;
 29	struct drm_connector	connector;
 30
 31	const struct simple_bridge_info *info;
 32
 33	struct drm_bridge	*next_bridge;
 34	struct regulator	*vdd;
 35	struct gpio_desc	*enable;
 36};
 37
 38static inline struct simple_bridge *
 39drm_bridge_to_simple_bridge(struct drm_bridge *bridge)
 40{
 41	return container_of(bridge, struct simple_bridge, bridge);
 42}
 43
 44static inline struct simple_bridge *
 45drm_connector_to_simple_bridge(struct drm_connector *connector)
 46{
 47	return container_of(connector, struct simple_bridge, connector);
 48}
 49
 50static int simple_bridge_get_modes(struct drm_connector *connector)
 51{
 52	struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector);
 53	struct edid *edid;
 54	int ret;
 55
 56	if (sbridge->next_bridge->ops & DRM_BRIDGE_OP_EDID) {
 57		edid = drm_bridge_get_edid(sbridge->next_bridge, connector);
 58		if (!edid)
 59			DRM_INFO("EDID read failed. Fallback to standard modes\n");
 60	} else {
 61		edid = NULL;
 62	}
 63
 64	if (!edid) {
 65		/*
 66		 * In case we cannot retrieve the EDIDs (missing or broken DDC
 67		 * bus from the next bridge), fallback on the XGA standards and
 68		 * prefer a mode pretty much anyone can handle.
 69		 */
 70		ret = drm_add_modes_noedid(connector, 1920, 1200);
 71		drm_set_preferred_mode(connector, 1024, 768);
 72		return ret;
 73	}
 74
 75	drm_connector_update_edid_property(connector, edid);
 76	ret = drm_add_edid_modes(connector, edid);
 77	kfree(edid);
 78
 79	return ret;
 80}
 81
 82static const struct drm_connector_helper_funcs simple_bridge_con_helper_funcs = {
 83	.get_modes	= simple_bridge_get_modes,
 84};
 85
 86static enum drm_connector_status
 87simple_bridge_connector_detect(struct drm_connector *connector, bool force)
 88{
 89	struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector);
 90
 91	return drm_bridge_detect(sbridge->next_bridge);
 92}
 93
 94static const struct drm_connector_funcs simple_bridge_con_funcs = {
 95	.detect			= simple_bridge_connector_detect,
 96	.fill_modes		= drm_helper_probe_single_connector_modes,
 97	.destroy		= drm_connector_cleanup,
 98	.reset			= drm_atomic_helper_connector_reset,
 99	.atomic_duplicate_state	= drm_atomic_helper_connector_duplicate_state,
100	.atomic_destroy_state	= drm_atomic_helper_connector_destroy_state,
101};
102
103static int simple_bridge_attach(struct drm_bridge *bridge,
104				enum drm_bridge_attach_flags flags)
105{
106	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
107	int ret;
108
109	ret = drm_bridge_attach(bridge->encoder, sbridge->next_bridge, bridge,
110				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
111	if (ret < 0)
112		return ret;
113
114	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
115		return 0;
116
117	if (!bridge->encoder) {
118		DRM_ERROR("Missing encoder\n");
119		return -ENODEV;
120	}
121
122	drm_connector_helper_add(&sbridge->connector,
123				 &simple_bridge_con_helper_funcs);
124	ret = drm_connector_init_with_ddc(bridge->dev, &sbridge->connector,
125					  &simple_bridge_con_funcs,
126					  sbridge->info->connector_type,
127					  sbridge->next_bridge->ddc);
128	if (ret) {
129		DRM_ERROR("Failed to initialize connector\n");
130		return ret;
131	}
132
133	drm_connector_attach_encoder(&sbridge->connector, bridge->encoder);
134
135	return 0;
136}
137
138static void simple_bridge_enable(struct drm_bridge *bridge)
139{
140	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
141	int ret;
142
143	if (sbridge->vdd) {
144		ret = regulator_enable(sbridge->vdd);
145		if (ret)
146			DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
147	}
148
149	gpiod_set_value_cansleep(sbridge->enable, 1);
150}
151
152static void simple_bridge_disable(struct drm_bridge *bridge)
153{
154	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
155
156	gpiod_set_value_cansleep(sbridge->enable, 0);
157
158	if (sbridge->vdd)
159		regulator_disable(sbridge->vdd);
160}
161
162static const struct drm_bridge_funcs simple_bridge_bridge_funcs = {
163	.attach		= simple_bridge_attach,
164	.enable		= simple_bridge_enable,
165	.disable	= simple_bridge_disable,
166};
167
168static int simple_bridge_probe(struct platform_device *pdev)
169{
170	struct simple_bridge *sbridge;
171	struct device_node *remote;
172
173	sbridge = devm_kzalloc(&pdev->dev, sizeof(*sbridge), GFP_KERNEL);
174	if (!sbridge)
175		return -ENOMEM;
176	platform_set_drvdata(pdev, sbridge);
177
178	sbridge->info = of_device_get_match_data(&pdev->dev);
179
180	/* Get the next bridge in the pipeline. */
181	remote = of_graph_get_remote_node(pdev->dev.of_node, 1, -1);
182	if (!remote)
183		return -EINVAL;
184
185	sbridge->next_bridge = of_drm_find_bridge(remote);
186	of_node_put(remote);
187
188	if (!sbridge->next_bridge) {
189		dev_dbg(&pdev->dev, "Next bridge not found, deferring probe\n");
190		return -EPROBE_DEFER;
191	}
192
193	/* Get the regulator and GPIO resources. */
194	sbridge->vdd = devm_regulator_get_optional(&pdev->dev, "vdd");
195	if (IS_ERR(sbridge->vdd)) {
196		int ret = PTR_ERR(sbridge->vdd);
197		if (ret == -EPROBE_DEFER)
198			return -EPROBE_DEFER;
199		sbridge->vdd = NULL;
200		dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret);
201	}
202
203	sbridge->enable = devm_gpiod_get_optional(&pdev->dev, "enable",
204						  GPIOD_OUT_LOW);
205	if (IS_ERR(sbridge->enable)) {
206		if (PTR_ERR(sbridge->enable) != -EPROBE_DEFER)
207			dev_err(&pdev->dev, "Unable to retrieve enable GPIO\n");
208		return PTR_ERR(sbridge->enable);
209	}
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(&sbridge->bridge);
217
218	return 0;
219}
220
221static int simple_bridge_remove(struct platform_device *pdev)
222{
223	struct simple_bridge *sbridge = platform_get_drvdata(pdev);
224
225	drm_bridge_remove(&sbridge->bridge);
226
227	return 0;
228}
229
230/*
231 * We assume the ADV7123 DAC is the "default" for historical reasons
232 * Information taken from the ADV7123 datasheet, revision D.
233 * NOTE: the ADV7123EP seems to have other timings and need a new timings
234 * set if used.
235 */
236static const struct drm_bridge_timings default_bridge_timings = {
237	/* Timing specifications, datasheet page 7 */
238	.input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
239	.setup_time_ps = 500,
240	.hold_time_ps = 1500,
241};
242
243/*
244 * Information taken from the THS8134, THS8134A, THS8134B datasheet named
245 * "SLVS205D", dated May 1990, revised March 2000.
246 */
247static const struct drm_bridge_timings ti_ths8134_bridge_timings = {
248	/* From timing diagram, datasheet page 9 */
249	.input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
250	/* From datasheet, page 12 */
251	.setup_time_ps = 3000,
252	/* I guess this means latched input */
253	.hold_time_ps = 0,
254};
255
256/*
257 * Information taken from the THS8135 datasheet named "SLAS343B", dated
258 * May 2001, revised April 2013.
259 */
260static const struct drm_bridge_timings ti_ths8135_bridge_timings = {
261	/* From timing diagram, datasheet page 14 */
262	.input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE,
263	/* From datasheet, page 16 */
264	.setup_time_ps = 2000,
265	.hold_time_ps = 500,
266};
267
268static const struct of_device_id simple_bridge_match[] = {
269	{
270		.compatible = "dumb-vga-dac",
271		.data = &(const struct simple_bridge_info) {
272			.connector_type = DRM_MODE_CONNECTOR_VGA,
273		},
274	}, {
275		.compatible = "adi,adv7123",
276		.data = &(const struct simple_bridge_info) {
277			.timings = &default_bridge_timings,
278			.connector_type = DRM_MODE_CONNECTOR_VGA,
279		},
280	}, {
281		.compatible = "ti,opa362",
282		.data = &(const struct simple_bridge_info) {
283			.connector_type = DRM_MODE_CONNECTOR_Composite,
284		},
285	}, {
286		.compatible = "ti,ths8135",
287		.data = &(const struct simple_bridge_info) {
288			.timings = &ti_ths8135_bridge_timings,
289			.connector_type = DRM_MODE_CONNECTOR_VGA,
290		},
291	}, {
292		.compatible = "ti,ths8134",
293		.data = &(const struct simple_bridge_info) {
294			.timings = &ti_ths8134_bridge_timings,
295			.connector_type = DRM_MODE_CONNECTOR_VGA,
296		},
297	},
298	{},
299};
300MODULE_DEVICE_TABLE(of, simple_bridge_match);
301
302static struct platform_driver simple_bridge_driver = {
303	.probe	= simple_bridge_probe,
304	.remove	= simple_bridge_remove,
305	.driver		= {
306		.name		= "simple-bridge",
307		.of_match_table	= simple_bridge_match,
308	},
309};
310module_platform_driver(simple_bridge_driver);
311
312MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
313MODULE_DESCRIPTION("Simple DRM bridge driver");
314MODULE_LICENSE("GPL");