1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2019 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
4  */
5 
6 #include <linux/gpio/consumer.h>
7 #include <linux/i2c.h>
8 #include <linux/interrupt.h>
9 #include <linux/media-bus-format.h>
10 #include <linux/module.h>
11 #include <linux/mutex.h>
12 #include <linux/of.h>
13 #include <linux/of_device.h>
14 #include <linux/platform_device.h>
15 #include <linux/regulator/consumer.h>
16 
17 #include <drm/drm_atomic_helper.h>
18 #include <drm/drm_bridge.h>
19 #include <drm/drm_edid.h>
20 
21 struct display_connector {
22 	struct drm_bridge	bridge;
23 
24 	struct gpio_desc	*hpd_gpio;
25 	int			hpd_irq;
26 
27 	struct regulator	*dp_pwr;
28 	struct gpio_desc	*ddc_en;
29 };
30 
31 static inline struct display_connector *
32 to_display_connector(struct drm_bridge *bridge)
33 {
34 	return container_of(bridge, struct display_connector, bridge);
35 }
36 
37 static int display_connector_attach(struct drm_bridge *bridge,
38 				    enum drm_bridge_attach_flags flags)
39 {
40 	return flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR ? 0 : -EINVAL;
41 }
42 
43 static enum drm_connector_status
44 display_connector_detect(struct drm_bridge *bridge)
45 {
46 	struct display_connector *conn = to_display_connector(bridge);
47 
48 	if (conn->hpd_gpio) {
49 		if (gpiod_get_value_cansleep(conn->hpd_gpio))
50 			return connector_status_connected;
51 		else
52 			return connector_status_disconnected;
53 	}
54 
55 	if (conn->bridge.ddc && drm_probe_ddc(conn->bridge.ddc))
56 		return connector_status_connected;
57 
58 	switch (conn->bridge.type) {
59 	case DRM_MODE_CONNECTOR_DVIA:
60 	case DRM_MODE_CONNECTOR_DVID:
61 	case DRM_MODE_CONNECTOR_DVII:
62 	case DRM_MODE_CONNECTOR_HDMIA:
63 	case DRM_MODE_CONNECTOR_HDMIB:
64 		/*
65 		 * For DVI and HDMI connectors a DDC probe failure indicates
66 		 * that no cable is connected.
67 		 */
68 		return connector_status_disconnected;
69 
70 	case DRM_MODE_CONNECTOR_Composite:
71 	case DRM_MODE_CONNECTOR_SVIDEO:
72 	case DRM_MODE_CONNECTOR_VGA:
73 	default:
74 		/*
75 		 * Composite and S-Video connectors have no other detection
76 		 * mean than the HPD GPIO. For VGA connectors, even if we have
77 		 * an I2C bus, we can't assume that the cable is disconnected
78 		 * if drm_probe_ddc fails, as some cables don't wire the DDC
79 		 * pins.
80 		 */
81 		return connector_status_unknown;
82 	}
83 }
84 
85 static struct edid *display_connector_get_edid(struct drm_bridge *bridge,
86 					       struct drm_connector *connector)
87 {
88 	struct display_connector *conn = to_display_connector(bridge);
89 
90 	return drm_get_edid(connector, conn->bridge.ddc);
91 }
92 
93 /*
94  * Since this bridge is tied to the connector, it acts like a passthrough,
95  * so concerning the output bus formats, either pass the bus formats from the
96  * previous bridge or return fallback data like done in the bridge function:
97  * drm_atomic_bridge_chain_select_bus_fmts().
98  * This supports negotiation if the bridge chain has all bits in place.
99  */
100 static u32 *display_connector_get_output_bus_fmts(struct drm_bridge *bridge,
101 					struct drm_bridge_state *bridge_state,
102 					struct drm_crtc_state *crtc_state,
103 					struct drm_connector_state *conn_state,
104 					unsigned int *num_output_fmts)
105 {
106 	struct drm_bridge *prev_bridge = drm_bridge_get_prev_bridge(bridge);
107 	struct drm_bridge_state *prev_bridge_state;
108 
109 	if (!prev_bridge || !prev_bridge->funcs->atomic_get_output_bus_fmts) {
110 		struct drm_connector *conn = conn_state->connector;
111 		u32 *out_bus_fmts;
112 
113 		*num_output_fmts = 1;
114 		out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL);
115 		if (!out_bus_fmts)
116 			return NULL;
117 
118 		if (conn->display_info.num_bus_formats &&
119 		    conn->display_info.bus_formats)
120 			out_bus_fmts[0] = conn->display_info.bus_formats[0];
121 		else
122 			out_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;
123 
124 		return out_bus_fmts;
125 	}
126 
127 	prev_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
128 							    prev_bridge);
129 
130 	return prev_bridge->funcs->atomic_get_output_bus_fmts(prev_bridge, prev_bridge_state,
131 							      crtc_state, conn_state,
132 							      num_output_fmts);
133 }
134 
135 /*
136  * Since this bridge is tied to the connector, it acts like a passthrough,
137  * so concerning the input bus formats, either pass the bus formats from the
138  * previous bridge or MEDIA_BUS_FMT_FIXED (like select_bus_fmt_recursive())
139  * when atomic_get_input_bus_fmts is not supported.
140  * This supports negotiation if the bridge chain has all bits in place.
141  */
142 static u32 *display_connector_get_input_bus_fmts(struct drm_bridge *bridge,
143 					struct drm_bridge_state *bridge_state,
144 					struct drm_crtc_state *crtc_state,
145 					struct drm_connector_state *conn_state,
146 					u32 output_fmt,
147 					unsigned int *num_input_fmts)
148 {
149 	struct drm_bridge *prev_bridge = drm_bridge_get_prev_bridge(bridge);
150 	struct drm_bridge_state *prev_bridge_state;
151 
152 	if (!prev_bridge || !prev_bridge->funcs->atomic_get_input_bus_fmts) {
153 		u32 *in_bus_fmts;
154 
155 		*num_input_fmts = 1;
156 		in_bus_fmts = kmalloc(sizeof(*in_bus_fmts), GFP_KERNEL);
157 		if (!in_bus_fmts)
158 			return NULL;
159 
160 		in_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;
161 
162 		return in_bus_fmts;
163 	}
164 
165 	prev_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
166 							    prev_bridge);
167 
168 	return prev_bridge->funcs->atomic_get_input_bus_fmts(prev_bridge, prev_bridge_state,
169 							     crtc_state, conn_state, output_fmt,
170 							     num_input_fmts);
171 }
172 
173 static const struct drm_bridge_funcs display_connector_bridge_funcs = {
174 	.attach = display_connector_attach,
175 	.detect = display_connector_detect,
176 	.get_edid = display_connector_get_edid,
177 	.atomic_get_output_bus_fmts = display_connector_get_output_bus_fmts,
178 	.atomic_get_input_bus_fmts = display_connector_get_input_bus_fmts,
179 	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
180 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
181 	.atomic_reset = drm_atomic_helper_bridge_reset,
182 };
183 
184 static irqreturn_t display_connector_hpd_irq(int irq, void *arg)
185 {
186 	struct display_connector *conn = arg;
187 	struct drm_bridge *bridge = &conn->bridge;
188 
189 	drm_bridge_hpd_notify(bridge, display_connector_detect(bridge));
190 
191 	return IRQ_HANDLED;
192 }
193 
194 static int display_connector_probe(struct platform_device *pdev)
195 {
196 	struct display_connector *conn;
197 	unsigned int type;
198 	const char *label = NULL;
199 	int ret;
200 
201 	conn = devm_kzalloc(&pdev->dev, sizeof(*conn), GFP_KERNEL);
202 	if (!conn)
203 		return -ENOMEM;
204 
205 	platform_set_drvdata(pdev, conn);
206 
207 	type = (uintptr_t)of_device_get_match_data(&pdev->dev);
208 
209 	/* Get the exact connector type. */
210 	switch (type) {
211 	case DRM_MODE_CONNECTOR_DVII: {
212 		bool analog, digital;
213 
214 		analog = of_property_read_bool(pdev->dev.of_node, "analog");
215 		digital = of_property_read_bool(pdev->dev.of_node, "digital");
216 		if (analog && !digital) {
217 			conn->bridge.type = DRM_MODE_CONNECTOR_DVIA;
218 		} else if (!analog && digital) {
219 			conn->bridge.type = DRM_MODE_CONNECTOR_DVID;
220 		} else if (analog && digital) {
221 			conn->bridge.type = DRM_MODE_CONNECTOR_DVII;
222 		} else {
223 			dev_err(&pdev->dev, "DVI connector with no type\n");
224 			return -EINVAL;
225 		}
226 		break;
227 	}
228 
229 	case DRM_MODE_CONNECTOR_HDMIA: {
230 		const char *hdmi_type;
231 
232 		ret = of_property_read_string(pdev->dev.of_node, "type",
233 					      &hdmi_type);
234 		if (ret < 0) {
235 			dev_err(&pdev->dev, "HDMI connector with no type\n");
236 			return -EINVAL;
237 		}
238 
239 		if (!strcmp(hdmi_type, "a") || !strcmp(hdmi_type, "c") ||
240 		    !strcmp(hdmi_type, "d") || !strcmp(hdmi_type, "e")) {
241 			conn->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
242 		} else if (!strcmp(hdmi_type, "b")) {
243 			conn->bridge.type = DRM_MODE_CONNECTOR_HDMIB;
244 		} else {
245 			dev_err(&pdev->dev,
246 				"Unsupported HDMI connector type '%s'\n",
247 				hdmi_type);
248 			return -EINVAL;
249 		}
250 
251 		break;
252 	}
253 
254 	default:
255 		conn->bridge.type = type;
256 		break;
257 	}
258 
259 	/* All the supported connector types support interlaced modes. */
260 	conn->bridge.interlace_allowed = true;
261 
262 	/* Get the optional connector label. */
263 	of_property_read_string(pdev->dev.of_node, "label", &label);
264 
265 	/*
266 	 * Get the HPD GPIO for DVI, HDMI and DP connectors. If the GPIO can provide
267 	 * edge interrupts, register an interrupt handler.
268 	 */
269 	if (type == DRM_MODE_CONNECTOR_DVII ||
270 	    type == DRM_MODE_CONNECTOR_HDMIA ||
271 	    type == DRM_MODE_CONNECTOR_DisplayPort) {
272 		conn->hpd_gpio = devm_gpiod_get_optional(&pdev->dev, "hpd",
273 							 GPIOD_IN);
274 		if (IS_ERR(conn->hpd_gpio)) {
275 			if (PTR_ERR(conn->hpd_gpio) != -EPROBE_DEFER)
276 				dev_err(&pdev->dev,
277 					"Unable to retrieve HPD GPIO\n");
278 			return PTR_ERR(conn->hpd_gpio);
279 		}
280 
281 		conn->hpd_irq = gpiod_to_irq(conn->hpd_gpio);
282 	} else {
283 		conn->hpd_irq = -EINVAL;
284 	}
285 
286 	if (conn->hpd_irq >= 0) {
287 		ret = devm_request_threaded_irq(&pdev->dev, conn->hpd_irq,
288 						NULL, display_connector_hpd_irq,
289 						IRQF_TRIGGER_RISING |
290 						IRQF_TRIGGER_FALLING |
291 						IRQF_ONESHOT,
292 						"HPD", conn);
293 		if (ret) {
294 			dev_info(&pdev->dev,
295 				 "Failed to request HPD edge interrupt, falling back to polling\n");
296 			conn->hpd_irq = -EINVAL;
297 		}
298 	}
299 
300 	/* Retrieve the DDC I2C adapter for DVI, HDMI and VGA connectors. */
301 	if (type == DRM_MODE_CONNECTOR_DVII ||
302 	    type == DRM_MODE_CONNECTOR_HDMIA ||
303 	    type == DRM_MODE_CONNECTOR_VGA) {
304 		struct device_node *phandle;
305 
306 		phandle = of_parse_phandle(pdev->dev.of_node, "ddc-i2c-bus", 0);
307 		if (phandle) {
308 			conn->bridge.ddc = of_get_i2c_adapter_by_node(phandle);
309 			of_node_put(phandle);
310 			if (!conn->bridge.ddc)
311 				return -EPROBE_DEFER;
312 		} else {
313 			dev_dbg(&pdev->dev,
314 				"No I2C bus specified, disabling EDID readout\n");
315 		}
316 	}
317 
318 	/* Get the DP PWR for DP connector. */
319 	if (type == DRM_MODE_CONNECTOR_DisplayPort) {
320 		int ret;
321 
322 		conn->dp_pwr = devm_regulator_get_optional(&pdev->dev, "dp-pwr");
323 
324 		if (IS_ERR(conn->dp_pwr)) {
325 			ret = PTR_ERR(conn->dp_pwr);
326 
327 			switch (ret) {
328 			case -ENODEV:
329 				conn->dp_pwr = NULL;
330 				break;
331 
332 			case -EPROBE_DEFER:
333 				return -EPROBE_DEFER;
334 
335 			default:
336 				dev_err(&pdev->dev, "failed to get DP PWR regulator: %d\n", ret);
337 				return ret;
338 			}
339 		}
340 
341 		if (conn->dp_pwr) {
342 			ret = regulator_enable(conn->dp_pwr);
343 			if (ret) {
344 				dev_err(&pdev->dev, "failed to enable DP PWR regulator: %d\n", ret);
345 				return ret;
346 			}
347 		}
348 	}
349 
350 	/* enable DDC */
351 	if (type == DRM_MODE_CONNECTOR_HDMIA) {
352 		conn->ddc_en = devm_gpiod_get_optional(&pdev->dev, "ddc-en",
353 						       GPIOD_OUT_HIGH);
354 
355 		if (IS_ERR(conn->ddc_en)) {
356 			dev_err(&pdev->dev, "Couldn't get ddc-en gpio\n");
357 			return PTR_ERR(conn->ddc_en);
358 		}
359 	}
360 
361 	conn->bridge.funcs = &display_connector_bridge_funcs;
362 	conn->bridge.of_node = pdev->dev.of_node;
363 
364 	if (conn->bridge.ddc)
365 		conn->bridge.ops |= DRM_BRIDGE_OP_EDID
366 				 |  DRM_BRIDGE_OP_DETECT;
367 	if (conn->hpd_gpio)
368 		conn->bridge.ops |= DRM_BRIDGE_OP_DETECT;
369 	if (conn->hpd_irq >= 0)
370 		conn->bridge.ops |= DRM_BRIDGE_OP_HPD;
371 
372 	dev_dbg(&pdev->dev,
373 		"Found %s display connector '%s' %s DDC bus and %s HPD GPIO (ops 0x%x)\n",
374 		drm_get_connector_type_name(conn->bridge.type),
375 		label ? label : "<unlabelled>",
376 		conn->bridge.ddc ? "with" : "without",
377 		conn->hpd_gpio ? "with" : "without",
378 		conn->bridge.ops);
379 
380 	drm_bridge_add(&conn->bridge);
381 
382 	return 0;
383 }
384 
385 static int display_connector_remove(struct platform_device *pdev)
386 {
387 	struct display_connector *conn = platform_get_drvdata(pdev);
388 
389 	if (conn->ddc_en)
390 		gpiod_set_value(conn->ddc_en, 0);
391 
392 	if (conn->dp_pwr)
393 		regulator_disable(conn->dp_pwr);
394 
395 	drm_bridge_remove(&conn->bridge);
396 
397 	if (!IS_ERR(conn->bridge.ddc))
398 		i2c_put_adapter(conn->bridge.ddc);
399 
400 	return 0;
401 }
402 
403 static const struct of_device_id display_connector_match[] = {
404 	{
405 		.compatible = "composite-video-connector",
406 		.data = (void *)DRM_MODE_CONNECTOR_Composite,
407 	}, {
408 		.compatible = "dvi-connector",
409 		.data = (void *)DRM_MODE_CONNECTOR_DVII,
410 	}, {
411 		.compatible = "hdmi-connector",
412 		.data = (void *)DRM_MODE_CONNECTOR_HDMIA,
413 	}, {
414 		.compatible = "svideo-connector",
415 		.data = (void *)DRM_MODE_CONNECTOR_SVIDEO,
416 	}, {
417 		.compatible = "vga-connector",
418 		.data = (void *)DRM_MODE_CONNECTOR_VGA,
419 	}, {
420 		.compatible = "dp-connector",
421 		.data = (void *)DRM_MODE_CONNECTOR_DisplayPort,
422 	},
423 	{},
424 };
425 MODULE_DEVICE_TABLE(of, display_connector_match);
426 
427 static struct platform_driver display_connector_driver = {
428 	.probe	= display_connector_probe,
429 	.remove	= display_connector_remove,
430 	.driver		= {
431 		.name		= "display-connector",
432 		.of_match_table	= display_connector_match,
433 	},
434 };
435 module_platform_driver(display_connector_driver);
436 
437 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
438 MODULE_DESCRIPTION("Display connector driver");
439 MODULE_LICENSE("GPL");
440