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/module.h>
10 #include <linux/mutex.h>
11 #include <linux/of.h>
12 #include <linux/of_device.h>
13 #include <linux/platform_device.h>
14 #include <linux/regulator/consumer.h>
15
16 #include <drm/drm_bridge.h>
17 #include <drm/drm_edid.h>
18
19 struct display_connector {
20 struct drm_bridge bridge;
21
22 struct gpio_desc *hpd_gpio;
23 int hpd_irq;
24
25 struct regulator *dp_pwr;
26 };
27
28 static inline struct display_connector *
to_display_connector(struct drm_bridge * bridge)29 to_display_connector(struct drm_bridge *bridge)
30 {
31 return container_of(bridge, struct display_connector, bridge);
32 }
33
display_connector_attach(struct drm_bridge * bridge,enum drm_bridge_attach_flags flags)34 static int display_connector_attach(struct drm_bridge *bridge,
35 enum drm_bridge_attach_flags flags)
36 {
37 return flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR ? 0 : -EINVAL;
38 }
39
40 static enum drm_connector_status
display_connector_detect(struct drm_bridge * bridge)41 display_connector_detect(struct drm_bridge *bridge)
42 {
43 struct display_connector *conn = to_display_connector(bridge);
44
45 if (conn->hpd_gpio) {
46 if (gpiod_get_value_cansleep(conn->hpd_gpio))
47 return connector_status_connected;
48 else
49 return connector_status_disconnected;
50 }
51
52 if (conn->bridge.ddc && drm_probe_ddc(conn->bridge.ddc))
53 return connector_status_connected;
54
55 switch (conn->bridge.type) {
56 case DRM_MODE_CONNECTOR_DVIA:
57 case DRM_MODE_CONNECTOR_DVID:
58 case DRM_MODE_CONNECTOR_DVII:
59 case DRM_MODE_CONNECTOR_HDMIA:
60 case DRM_MODE_CONNECTOR_HDMIB:
61 /*
62 * For DVI and HDMI connectors a DDC probe failure indicates
63 * that no cable is connected.
64 */
65 return connector_status_disconnected;
66
67 case DRM_MODE_CONNECTOR_Composite:
68 case DRM_MODE_CONNECTOR_SVIDEO:
69 case DRM_MODE_CONNECTOR_VGA:
70 default:
71 /*
72 * Composite and S-Video connectors have no other detection
73 * mean than the HPD GPIO. For VGA connectors, even if we have
74 * an I2C bus, we can't assume that the cable is disconnected
75 * if drm_probe_ddc fails, as some cables don't wire the DDC
76 * pins.
77 */
78 return connector_status_unknown;
79 }
80 }
81
display_connector_get_edid(struct drm_bridge * bridge,struct drm_connector * connector)82 static struct edid *display_connector_get_edid(struct drm_bridge *bridge,
83 struct drm_connector *connector)
84 {
85 struct display_connector *conn = to_display_connector(bridge);
86
87 return drm_get_edid(connector, conn->bridge.ddc);
88 }
89
90 static const struct drm_bridge_funcs display_connector_bridge_funcs = {
91 .attach = display_connector_attach,
92 .detect = display_connector_detect,
93 .get_edid = display_connector_get_edid,
94 };
95
display_connector_hpd_irq(int irq,void * arg)96 static irqreturn_t display_connector_hpd_irq(int irq, void *arg)
97 {
98 struct display_connector *conn = arg;
99 struct drm_bridge *bridge = &conn->bridge;
100
101 drm_bridge_hpd_notify(bridge, display_connector_detect(bridge));
102
103 return IRQ_HANDLED;
104 }
105
display_connector_probe(struct platform_device * pdev)106 static int display_connector_probe(struct platform_device *pdev)
107 {
108 struct display_connector *conn;
109 unsigned int type;
110 const char *label;
111 int ret;
112
113 conn = devm_kzalloc(&pdev->dev, sizeof(*conn), GFP_KERNEL);
114 if (!conn)
115 return -ENOMEM;
116
117 platform_set_drvdata(pdev, conn);
118
119 type = (uintptr_t)of_device_get_match_data(&pdev->dev);
120
121 /* Get the exact connector type. */
122 switch (type) {
123 case DRM_MODE_CONNECTOR_DVII: {
124 bool analog, digital;
125
126 analog = of_property_read_bool(pdev->dev.of_node, "analog");
127 digital = of_property_read_bool(pdev->dev.of_node, "digital");
128 if (analog && !digital) {
129 conn->bridge.type = DRM_MODE_CONNECTOR_DVIA;
130 } else if (!analog && digital) {
131 conn->bridge.type = DRM_MODE_CONNECTOR_DVID;
132 } else if (analog && digital) {
133 conn->bridge.type = DRM_MODE_CONNECTOR_DVII;
134 } else {
135 dev_err(&pdev->dev, "DVI connector with no type\n");
136 return -EINVAL;
137 }
138 break;
139 }
140
141 case DRM_MODE_CONNECTOR_HDMIA: {
142 const char *hdmi_type;
143
144 ret = of_property_read_string(pdev->dev.of_node, "type",
145 &hdmi_type);
146 if (ret < 0) {
147 dev_err(&pdev->dev, "HDMI connector with no type\n");
148 return -EINVAL;
149 }
150
151 if (!strcmp(hdmi_type, "a") || !strcmp(hdmi_type, "c") ||
152 !strcmp(hdmi_type, "d") || !strcmp(hdmi_type, "e")) {
153 conn->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
154 } else if (!strcmp(hdmi_type, "b")) {
155 conn->bridge.type = DRM_MODE_CONNECTOR_HDMIB;
156 } else {
157 dev_err(&pdev->dev,
158 "Unsupported HDMI connector type '%s'\n",
159 hdmi_type);
160 return -EINVAL;
161 }
162
163 break;
164 }
165
166 default:
167 conn->bridge.type = type;
168 break;
169 }
170
171 /* All the supported connector types support interlaced modes. */
172 conn->bridge.interlace_allowed = true;
173
174 /* Get the optional connector label. */
175 of_property_read_string(pdev->dev.of_node, "label", &label);
176
177 /*
178 * Get the HPD GPIO for DVI, HDMI and DP connectors. If the GPIO can provide
179 * edge interrupts, register an interrupt handler.
180 */
181 if (type == DRM_MODE_CONNECTOR_DVII ||
182 type == DRM_MODE_CONNECTOR_HDMIA ||
183 type == DRM_MODE_CONNECTOR_DisplayPort) {
184 conn->hpd_gpio = devm_gpiod_get_optional(&pdev->dev, "hpd",
185 GPIOD_IN);
186 if (IS_ERR(conn->hpd_gpio)) {
187 if (PTR_ERR(conn->hpd_gpio) != -EPROBE_DEFER)
188 dev_err(&pdev->dev,
189 "Unable to retrieve HPD GPIO\n");
190 return PTR_ERR(conn->hpd_gpio);
191 }
192
193 conn->hpd_irq = gpiod_to_irq(conn->hpd_gpio);
194 } else {
195 conn->hpd_irq = -EINVAL;
196 }
197
198 if (conn->hpd_irq >= 0) {
199 ret = devm_request_threaded_irq(&pdev->dev, conn->hpd_irq,
200 NULL, display_connector_hpd_irq,
201 IRQF_TRIGGER_RISING |
202 IRQF_TRIGGER_FALLING |
203 IRQF_ONESHOT,
204 "HPD", conn);
205 if (ret) {
206 dev_info(&pdev->dev,
207 "Failed to request HPD edge interrupt, falling back to polling\n");
208 conn->hpd_irq = -EINVAL;
209 }
210 }
211
212 /* Retrieve the DDC I2C adapter for DVI, HDMI and VGA connectors. */
213 if (type == DRM_MODE_CONNECTOR_DVII ||
214 type == DRM_MODE_CONNECTOR_HDMIA ||
215 type == DRM_MODE_CONNECTOR_VGA) {
216 struct device_node *phandle;
217
218 phandle = of_parse_phandle(pdev->dev.of_node, "ddc-i2c-bus", 0);
219 if (phandle) {
220 conn->bridge.ddc = of_get_i2c_adapter_by_node(phandle);
221 of_node_put(phandle);
222 if (!conn->bridge.ddc)
223 return -EPROBE_DEFER;
224 } else {
225 dev_dbg(&pdev->dev,
226 "No I2C bus specified, disabling EDID readout\n");
227 }
228 }
229
230 /* Get the DP PWR for DP connector. */
231 if (type == DRM_MODE_CONNECTOR_DisplayPort) {
232 int ret;
233
234 conn->dp_pwr = devm_regulator_get_optional(&pdev->dev, "dp-pwr");
235
236 if (IS_ERR(conn->dp_pwr)) {
237 ret = PTR_ERR(conn->dp_pwr);
238
239 switch (ret) {
240 case -ENODEV:
241 conn->dp_pwr = NULL;
242 break;
243
244 case -EPROBE_DEFER:
245 return -EPROBE_DEFER;
246
247 default:
248 dev_err(&pdev->dev, "failed to get DP PWR regulator: %d\n", ret);
249 return ret;
250 }
251 }
252
253 if (conn->dp_pwr) {
254 ret = regulator_enable(conn->dp_pwr);
255 if (ret) {
256 dev_err(&pdev->dev, "failed to enable DP PWR regulator: %d\n", ret);
257 return ret;
258 }
259 }
260 }
261
262 conn->bridge.funcs = &display_connector_bridge_funcs;
263 conn->bridge.of_node = pdev->dev.of_node;
264
265 if (conn->bridge.ddc)
266 conn->bridge.ops |= DRM_BRIDGE_OP_EDID
267 | DRM_BRIDGE_OP_DETECT;
268 if (conn->hpd_gpio)
269 conn->bridge.ops |= DRM_BRIDGE_OP_DETECT;
270 if (conn->hpd_irq >= 0)
271 conn->bridge.ops |= DRM_BRIDGE_OP_HPD;
272
273 dev_dbg(&pdev->dev,
274 "Found %s display connector '%s' %s DDC bus and %s HPD GPIO (ops 0x%x)\n",
275 drm_get_connector_type_name(conn->bridge.type),
276 label ? label : "<unlabelled>",
277 conn->bridge.ddc ? "with" : "without",
278 conn->hpd_gpio ? "with" : "without",
279 conn->bridge.ops);
280
281 drm_bridge_add(&conn->bridge);
282
283 return 0;
284 }
285
display_connector_remove(struct platform_device * pdev)286 static int display_connector_remove(struct platform_device *pdev)
287 {
288 struct display_connector *conn = platform_get_drvdata(pdev);
289
290 if (conn->dp_pwr)
291 regulator_disable(conn->dp_pwr);
292
293 drm_bridge_remove(&conn->bridge);
294
295 if (!IS_ERR(conn->bridge.ddc))
296 i2c_put_adapter(conn->bridge.ddc);
297
298 return 0;
299 }
300
301 static const struct of_device_id display_connector_match[] = {
302 {
303 .compatible = "composite-video-connector",
304 .data = (void *)DRM_MODE_CONNECTOR_Composite,
305 }, {
306 .compatible = "dvi-connector",
307 .data = (void *)DRM_MODE_CONNECTOR_DVII,
308 }, {
309 .compatible = "hdmi-connector",
310 .data = (void *)DRM_MODE_CONNECTOR_HDMIA,
311 }, {
312 .compatible = "svideo-connector",
313 .data = (void *)DRM_MODE_CONNECTOR_SVIDEO,
314 }, {
315 .compatible = "vga-connector",
316 .data = (void *)DRM_MODE_CONNECTOR_VGA,
317 }, {
318 .compatible = "dp-connector",
319 .data = (void *)DRM_MODE_CONNECTOR_DisplayPort,
320 },
321 {},
322 };
323 MODULE_DEVICE_TABLE(of, display_connector_match);
324
325 static struct platform_driver display_connector_driver = {
326 .probe = display_connector_probe,
327 .remove = display_connector_remove,
328 .driver = {
329 .name = "display-connector",
330 .of_match_table = display_connector_match,
331 },
332 };
333 module_platform_driver(display_connector_driver);
334
335 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
336 MODULE_DESCRIPTION("Display connector driver");
337 MODULE_LICENSE("GPL");
338