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/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_edid.h>
19
20 struct display_connector {
21 struct drm_bridge bridge;
22
23 struct gpio_desc *hpd_gpio;
24 int hpd_irq;
25
26 struct regulator *supply;
27 struct gpio_desc *ddc_en;
28 };
29
30 static inline struct display_connector *
to_display_connector(struct drm_bridge * bridge)31 to_display_connector(struct drm_bridge *bridge)
32 {
33 return container_of(bridge, struct display_connector, bridge);
34 }
35
display_connector_attach(struct drm_bridge * bridge,enum drm_bridge_attach_flags flags)36 static int display_connector_attach(struct drm_bridge *bridge,
37 enum drm_bridge_attach_flags flags)
38 {
39 return flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR ? 0 : -EINVAL;
40 }
41
42 static enum drm_connector_status
display_connector_detect(struct drm_bridge * bridge)43 display_connector_detect(struct drm_bridge *bridge)
44 {
45 struct display_connector *conn = to_display_connector(bridge);
46
47 if (conn->hpd_gpio) {
48 if (gpiod_get_value_cansleep(conn->hpd_gpio))
49 return connector_status_connected;
50 else
51 return connector_status_disconnected;
52 }
53
54 if (conn->bridge.ddc && drm_probe_ddc(conn->bridge.ddc))
55 return connector_status_connected;
56
57 switch (conn->bridge.type) {
58 case DRM_MODE_CONNECTOR_DVIA:
59 case DRM_MODE_CONNECTOR_DVID:
60 case DRM_MODE_CONNECTOR_DVII:
61 case DRM_MODE_CONNECTOR_HDMIA:
62 case DRM_MODE_CONNECTOR_HDMIB:
63 /*
64 * For DVI and HDMI connectors a DDC probe failure indicates
65 * that no cable is connected.
66 */
67 return connector_status_disconnected;
68
69 case DRM_MODE_CONNECTOR_Composite:
70 case DRM_MODE_CONNECTOR_SVIDEO:
71 case DRM_MODE_CONNECTOR_VGA:
72 default:
73 /*
74 * Composite and S-Video connectors have no other detection
75 * mean than the HPD GPIO. For VGA connectors, even if we have
76 * an I2C bus, we can't assume that the cable is disconnected
77 * if drm_probe_ddc fails, as some cables don't wire the DDC
78 * pins.
79 */
80 return connector_status_unknown;
81 }
82 }
83
display_connector_edid_read(struct drm_bridge * bridge,struct drm_connector * connector)84 static const struct drm_edid *display_connector_edid_read(struct drm_bridge *bridge,
85 struct drm_connector *connector)
86 {
87 struct display_connector *conn = to_display_connector(bridge);
88
89 return drm_edid_read_ddc(connector, conn->bridge.ddc);
90 }
91
92 /*
93 * Since this bridge is tied to the connector, it acts like a passthrough,
94 * so concerning the output bus formats, either pass the bus formats from the
95 * previous bridge or return fallback data like done in the bridge function:
96 * drm_atomic_bridge_chain_select_bus_fmts().
97 * This supports negotiation if the bridge chain has all bits in place.
98 */
display_connector_get_output_bus_fmts(struct drm_bridge * bridge,struct drm_bridge_state * bridge_state,struct drm_crtc_state * crtc_state,struct drm_connector_state * conn_state,unsigned int * num_output_fmts)99 static u32 *display_connector_get_output_bus_fmts(struct drm_bridge *bridge,
100 struct drm_bridge_state *bridge_state,
101 struct drm_crtc_state *crtc_state,
102 struct drm_connector_state *conn_state,
103 unsigned int *num_output_fmts)
104 {
105 struct drm_bridge *prev_bridge = drm_bridge_get_prev_bridge(bridge);
106 struct drm_bridge_state *prev_bridge_state;
107
108 if (!prev_bridge || !prev_bridge->funcs->atomic_get_output_bus_fmts) {
109 struct drm_connector *conn = conn_state->connector;
110 u32 *out_bus_fmts;
111
112 *num_output_fmts = 1;
113 out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL);
114 if (!out_bus_fmts)
115 return NULL;
116
117 if (conn->display_info.num_bus_formats &&
118 conn->display_info.bus_formats)
119 out_bus_fmts[0] = conn->display_info.bus_formats[0];
120 else
121 out_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;
122
123 return out_bus_fmts;
124 }
125
126 prev_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
127 prev_bridge);
128
129 return prev_bridge->funcs->atomic_get_output_bus_fmts(prev_bridge, prev_bridge_state,
130 crtc_state, conn_state,
131 num_output_fmts);
132 }
133
134 /*
135 * Since this bridge is tied to the connector, it acts like a passthrough,
136 * so concerning the input bus formats, either pass the bus formats from the
137 * previous bridge or MEDIA_BUS_FMT_FIXED (like select_bus_fmt_recursive())
138 * when atomic_get_input_bus_fmts is not supported.
139 * This supports negotiation if the bridge chain has all bits in place.
140 */
display_connector_get_input_bus_fmts(struct drm_bridge * bridge,struct drm_bridge_state * bridge_state,struct drm_crtc_state * crtc_state,struct drm_connector_state * conn_state,u32 output_fmt,unsigned int * num_input_fmts)141 static u32 *display_connector_get_input_bus_fmts(struct drm_bridge *bridge,
142 struct drm_bridge_state *bridge_state,
143 struct drm_crtc_state *crtc_state,
144 struct drm_connector_state *conn_state,
145 u32 output_fmt,
146 unsigned int *num_input_fmts)
147 {
148 struct drm_bridge *prev_bridge = drm_bridge_get_prev_bridge(bridge);
149 struct drm_bridge_state *prev_bridge_state;
150
151 if (!prev_bridge || !prev_bridge->funcs->atomic_get_input_bus_fmts) {
152 u32 *in_bus_fmts;
153
154 *num_input_fmts = 1;
155 in_bus_fmts = kmalloc(sizeof(*in_bus_fmts), GFP_KERNEL);
156 if (!in_bus_fmts)
157 return NULL;
158
159 in_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;
160
161 return in_bus_fmts;
162 }
163
164 prev_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
165 prev_bridge);
166
167 return prev_bridge->funcs->atomic_get_input_bus_fmts(prev_bridge, prev_bridge_state,
168 crtc_state, conn_state, output_fmt,
169 num_input_fmts);
170 }
171
172 static const struct drm_bridge_funcs display_connector_bridge_funcs = {
173 .attach = display_connector_attach,
174 .detect = display_connector_detect,
175 .edid_read = display_connector_edid_read,
176 .atomic_get_output_bus_fmts = display_connector_get_output_bus_fmts,
177 .atomic_get_input_bus_fmts = display_connector_get_input_bus_fmts,
178 .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
179 .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
180 .atomic_reset = drm_atomic_helper_bridge_reset,
181 };
182
display_connector_hpd_irq(int irq,void * arg)183 static irqreturn_t display_connector_hpd_irq(int irq, void *arg)
184 {
185 struct display_connector *conn = arg;
186 struct drm_bridge *bridge = &conn->bridge;
187
188 drm_bridge_hpd_notify(bridge, display_connector_detect(bridge));
189
190 return IRQ_HANDLED;
191 }
192
display_connector_get_supply(struct platform_device * pdev,struct display_connector * conn,const char * name)193 static int display_connector_get_supply(struct platform_device *pdev,
194 struct display_connector *conn,
195 const char *name)
196 {
197 conn->supply = devm_regulator_get_optional(&pdev->dev, name);
198
199 if (conn->supply == ERR_PTR(-ENODEV))
200 conn->supply = NULL;
201
202 return PTR_ERR_OR_ZERO(conn->supply);
203 }
204
display_connector_probe(struct platform_device * pdev)205 static int display_connector_probe(struct platform_device *pdev)
206 {
207 struct display_connector *conn;
208 unsigned int type;
209 const char *label = NULL;
210 int ret;
211
212 conn = devm_kzalloc(&pdev->dev, sizeof(*conn), GFP_KERNEL);
213 if (!conn)
214 return -ENOMEM;
215
216 platform_set_drvdata(pdev, conn);
217
218 type = (uintptr_t)of_device_get_match_data(&pdev->dev);
219
220 /* Get the exact connector type. */
221 switch (type) {
222 case DRM_MODE_CONNECTOR_DVII: {
223 bool analog, digital;
224
225 analog = of_property_read_bool(pdev->dev.of_node, "analog");
226 digital = of_property_read_bool(pdev->dev.of_node, "digital");
227 if (analog && !digital) {
228 conn->bridge.type = DRM_MODE_CONNECTOR_DVIA;
229 } else if (!analog && digital) {
230 conn->bridge.type = DRM_MODE_CONNECTOR_DVID;
231 } else if (analog && digital) {
232 conn->bridge.type = DRM_MODE_CONNECTOR_DVII;
233 } else {
234 dev_err(&pdev->dev, "DVI connector with no type\n");
235 return -EINVAL;
236 }
237 break;
238 }
239
240 case DRM_MODE_CONNECTOR_HDMIA: {
241 const char *hdmi_type;
242
243 ret = of_property_read_string(pdev->dev.of_node, "type",
244 &hdmi_type);
245 if (ret < 0) {
246 dev_err(&pdev->dev, "HDMI connector with no type\n");
247 return -EINVAL;
248 }
249
250 if (!strcmp(hdmi_type, "a") || !strcmp(hdmi_type, "c") ||
251 !strcmp(hdmi_type, "d") || !strcmp(hdmi_type, "e")) {
252 conn->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
253 } else if (!strcmp(hdmi_type, "b")) {
254 conn->bridge.type = DRM_MODE_CONNECTOR_HDMIB;
255 } else {
256 dev_err(&pdev->dev,
257 "Unsupported HDMI connector type '%s'\n",
258 hdmi_type);
259 return -EINVAL;
260 }
261
262 break;
263 }
264
265 default:
266 conn->bridge.type = type;
267 break;
268 }
269
270 /* All the supported connector types support interlaced modes. */
271 conn->bridge.interlace_allowed = true;
272
273 if (type == DRM_MODE_CONNECTOR_HDMIA ||
274 type == DRM_MODE_CONNECTOR_DisplayPort)
275 conn->bridge.ycbcr_420_allowed = true;
276
277 /* Get the optional connector label. */
278 of_property_read_string(pdev->dev.of_node, "label", &label);
279
280 /*
281 * Get the HPD GPIO for DVI, HDMI and DP connectors. If the GPIO can provide
282 * edge interrupts, register an interrupt handler.
283 */
284 if (type == DRM_MODE_CONNECTOR_DVII ||
285 type == DRM_MODE_CONNECTOR_HDMIA ||
286 type == DRM_MODE_CONNECTOR_DisplayPort) {
287 conn->hpd_gpio = devm_gpiod_get_optional(&pdev->dev, "hpd",
288 GPIOD_IN);
289 if (IS_ERR(conn->hpd_gpio))
290 return dev_err_probe(&pdev->dev, PTR_ERR(conn->hpd_gpio),
291 "Unable to retrieve HPD GPIO\n");
292
293 conn->hpd_irq = gpiod_to_irq(conn->hpd_gpio);
294 } else {
295 conn->hpd_irq = -EINVAL;
296 }
297
298 if (conn->hpd_irq >= 0) {
299 ret = devm_request_threaded_irq(&pdev->dev, conn->hpd_irq,
300 NULL, display_connector_hpd_irq,
301 IRQF_TRIGGER_RISING |
302 IRQF_TRIGGER_FALLING |
303 IRQF_ONESHOT,
304 "HPD", conn);
305 if (ret) {
306 dev_info(&pdev->dev,
307 "Failed to request HPD edge interrupt, falling back to polling\n");
308 conn->hpd_irq = -EINVAL;
309 }
310 }
311
312 /* Retrieve the DDC I2C adapter for DVI, HDMI and VGA connectors. */
313 if (type == DRM_MODE_CONNECTOR_DVII ||
314 type == DRM_MODE_CONNECTOR_HDMIA ||
315 type == DRM_MODE_CONNECTOR_VGA) {
316 struct device_node *phandle;
317
318 phandle = of_parse_phandle(pdev->dev.of_node, "ddc-i2c-bus", 0);
319 if (phandle) {
320 conn->bridge.ddc = of_get_i2c_adapter_by_node(phandle);
321 of_node_put(phandle);
322 if (!conn->bridge.ddc)
323 return -EPROBE_DEFER;
324 } else {
325 dev_dbg(&pdev->dev,
326 "No I2C bus specified, disabling EDID readout\n");
327 }
328 }
329
330 /* Get the DP PWR for DP connector. */
331 if (type == DRM_MODE_CONNECTOR_DisplayPort) {
332 int ret;
333
334 ret = display_connector_get_supply(pdev, conn, "dp-pwr");
335 if (ret < 0)
336 return dev_err_probe(&pdev->dev, ret, "failed to get DP PWR regulator\n");
337 }
338
339 /* enable DDC */
340 if (type == DRM_MODE_CONNECTOR_HDMIA) {
341 int ret;
342
343 conn->ddc_en = devm_gpiod_get_optional(&pdev->dev, "ddc-en",
344 GPIOD_OUT_HIGH);
345
346 if (IS_ERR(conn->ddc_en)) {
347 dev_err(&pdev->dev, "Couldn't get ddc-en gpio\n");
348 return PTR_ERR(conn->ddc_en);
349 }
350
351 ret = display_connector_get_supply(pdev, conn, "hdmi-pwr");
352 if (ret < 0)
353 return dev_err_probe(&pdev->dev, ret, "failed to get HDMI +5V Power regulator\n");
354 }
355
356 if (conn->supply) {
357 ret = regulator_enable(conn->supply);
358 if (ret) {
359 dev_err(&pdev->dev, "failed to enable PWR regulator: %d\n", ret);
360 return ret;
361 }
362 }
363
364 conn->bridge.funcs = &display_connector_bridge_funcs;
365 conn->bridge.of_node = pdev->dev.of_node;
366
367 if (conn->bridge.ddc)
368 conn->bridge.ops |= DRM_BRIDGE_OP_EDID
369 | DRM_BRIDGE_OP_DETECT;
370 if (conn->hpd_gpio)
371 conn->bridge.ops |= DRM_BRIDGE_OP_DETECT;
372 if (conn->hpd_irq >= 0)
373 conn->bridge.ops |= DRM_BRIDGE_OP_HPD;
374
375 dev_dbg(&pdev->dev,
376 "Found %s display connector '%s' %s DDC bus and %s HPD GPIO (ops 0x%x)\n",
377 drm_get_connector_type_name(conn->bridge.type),
378 label ? label : "<unlabelled>",
379 conn->bridge.ddc ? "with" : "without",
380 conn->hpd_gpio ? "with" : "without",
381 conn->bridge.ops);
382
383 drm_bridge_add(&conn->bridge);
384
385 return 0;
386 }
387
display_connector_remove(struct platform_device * pdev)388 static void display_connector_remove(struct platform_device *pdev)
389 {
390 struct display_connector *conn = platform_get_drvdata(pdev);
391
392 if (conn->ddc_en)
393 gpiod_set_value(conn->ddc_en, 0);
394
395 if (conn->supply)
396 regulator_disable(conn->supply);
397
398 drm_bridge_remove(&conn->bridge);
399
400 if (!IS_ERR(conn->bridge.ddc))
401 i2c_put_adapter(conn->bridge.ddc);
402 }
403
404 static const struct of_device_id display_connector_match[] = {
405 {
406 .compatible = "composite-video-connector",
407 .data = (void *)DRM_MODE_CONNECTOR_Composite,
408 }, {
409 .compatible = "dvi-connector",
410 .data = (void *)DRM_MODE_CONNECTOR_DVII,
411 }, {
412 .compatible = "hdmi-connector",
413 .data = (void *)DRM_MODE_CONNECTOR_HDMIA,
414 }, {
415 .compatible = "svideo-connector",
416 .data = (void *)DRM_MODE_CONNECTOR_SVIDEO,
417 }, {
418 .compatible = "vga-connector",
419 .data = (void *)DRM_MODE_CONNECTOR_VGA,
420 }, {
421 .compatible = "dp-connector",
422 .data = (void *)DRM_MODE_CONNECTOR_DisplayPort,
423 },
424 {},
425 };
426 MODULE_DEVICE_TABLE(of, display_connector_match);
427
428 static struct platform_driver display_connector_driver = {
429 .probe = display_connector_probe,
430 .remove = display_connector_remove,
431 .driver = {
432 .name = "display-connector",
433 .of_match_table = display_connector_match,
434 },
435 };
436 module_platform_driver(display_connector_driver);
437
438 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
439 MODULE_DESCRIPTION("Display connector driver");
440 MODULE_LICENSE("GPL");
441