1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * NXP PTN3460 DP/LVDS bridge driver
4 *
5 * Copyright (C) 2013 Google, Inc.
6 */
7
8 #include <linux/delay.h>
9 #include <linux/gpio/consumer.h>
10 #include <linux/i2c.h>
11 #include <linux/module.h>
12 #include <linux/of.h>
13 #include <drm/drm_atomic_helper.h>
14 #include <drm/drm_bridge.h>
15 #include <drm/drm_crtc.h>
16 #include <drm/drm_edid.h>
17 #include <drm/drm_of.h>
18 #include <drm/drm_panel.h>
19 #include <drm/drm_print.h>
20 #include <drm/drm_probe_helper.h>
21
22 #define PTN3460_EDID_ADDR 0x0
23 #define PTN3460_EDID_EMULATION_ADDR 0x84
24 #define PTN3460_EDID_ENABLE_EMULATION 0
25 #define PTN3460_EDID_EMULATION_SELECTION 1
26 #define PTN3460_EDID_SRAM_LOAD_ADDR 0x85
27
28 struct ptn3460_bridge {
29 struct drm_connector connector;
30 struct i2c_client *client;
31 struct drm_bridge bridge;
32 struct drm_bridge *panel_bridge;
33 struct gpio_desc *gpio_pd_n;
34 struct gpio_desc *gpio_rst_n;
35 u32 edid_emulation;
36 bool enabled;
37 };
38
39 static inline struct ptn3460_bridge *
bridge_to_ptn3460(struct drm_bridge * bridge)40 bridge_to_ptn3460(struct drm_bridge *bridge)
41 {
42 return container_of(bridge, struct ptn3460_bridge, bridge);
43 }
44
45 static inline struct ptn3460_bridge *
connector_to_ptn3460(struct drm_connector * connector)46 connector_to_ptn3460(struct drm_connector *connector)
47 {
48 return container_of(connector, struct ptn3460_bridge, connector);
49 }
50
ptn3460_read_bytes(struct ptn3460_bridge * ptn_bridge,char addr,u8 * buf,int len)51 static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
52 u8 *buf, int len)
53 {
54 int ret;
55
56 ret = i2c_master_send(ptn_bridge->client, &addr, 1);
57 if (ret < 0) {
58 DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
59 return ret;
60 }
61
62 ret = i2c_master_recv(ptn_bridge->client, buf, len);
63 if (ret < 0) {
64 DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
65 return ret;
66 }
67
68 return 0;
69 }
70
ptn3460_write_byte(struct ptn3460_bridge * ptn_bridge,char addr,char val)71 static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
72 char val)
73 {
74 int ret;
75 char buf[2];
76
77 buf[0] = addr;
78 buf[1] = val;
79
80 ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
81 if (ret < 0) {
82 DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
83 return ret;
84 }
85
86 return 0;
87 }
88
ptn3460_select_edid(struct ptn3460_bridge * ptn_bridge)89 static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
90 {
91 int ret;
92 char val;
93
94 /* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
95 ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
96 ptn_bridge->edid_emulation);
97 if (ret) {
98 DRM_ERROR("Failed to transfer EDID to sram, ret=%d\n", ret);
99 return ret;
100 }
101
102 /* Enable EDID emulation and select the desired EDID */
103 val = 1 << PTN3460_EDID_ENABLE_EMULATION |
104 ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;
105
106 ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
107 if (ret) {
108 DRM_ERROR("Failed to write EDID value, ret=%d\n", ret);
109 return ret;
110 }
111
112 return 0;
113 }
114
ptn3460_pre_enable(struct drm_bridge * bridge)115 static void ptn3460_pre_enable(struct drm_bridge *bridge)
116 {
117 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
118 int ret;
119
120 if (ptn_bridge->enabled)
121 return;
122
123 gpiod_set_value(ptn_bridge->gpio_pd_n, 1);
124
125 gpiod_set_value(ptn_bridge->gpio_rst_n, 0);
126 usleep_range(10, 20);
127 gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
128
129 /*
130 * There's a bug in the PTN chip where it falsely asserts hotplug before
131 * it is fully functional. We're forced to wait for the maximum start up
132 * time specified in the chip's datasheet to make sure we're really up.
133 */
134 msleep(90);
135
136 ret = ptn3460_select_edid(ptn_bridge);
137 if (ret)
138 DRM_ERROR("Select EDID failed ret=%d\n", ret);
139
140 ptn_bridge->enabled = true;
141 }
142
ptn3460_disable(struct drm_bridge * bridge)143 static void ptn3460_disable(struct drm_bridge *bridge)
144 {
145 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
146
147 if (!ptn_bridge->enabled)
148 return;
149
150 ptn_bridge->enabled = false;
151
152 gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
153 gpiod_set_value(ptn_bridge->gpio_pd_n, 0);
154 }
155
156
ptn3460_get_edid(struct drm_bridge * bridge,struct drm_connector * connector)157 static struct edid *ptn3460_get_edid(struct drm_bridge *bridge,
158 struct drm_connector *connector)
159 {
160 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
161 bool power_off;
162 u8 *edid;
163 int ret;
164
165 power_off = !ptn_bridge->enabled;
166 ptn3460_pre_enable(&ptn_bridge->bridge);
167
168 edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
169 if (!edid) {
170 DRM_ERROR("Failed to allocate EDID\n");
171 goto out;
172 }
173
174 ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
175 EDID_LENGTH);
176 if (ret) {
177 kfree(edid);
178 edid = NULL;
179 goto out;
180 }
181
182 out:
183 if (power_off)
184 ptn3460_disable(&ptn_bridge->bridge);
185
186 return (struct edid *)edid;
187 }
188
ptn3460_connector_get_modes(struct drm_connector * connector)189 static int ptn3460_connector_get_modes(struct drm_connector *connector)
190 {
191 struct ptn3460_bridge *ptn_bridge = connector_to_ptn3460(connector);
192 struct edid *edid;
193 int num_modes;
194
195 edid = ptn3460_get_edid(&ptn_bridge->bridge, connector);
196 drm_connector_update_edid_property(connector, edid);
197 num_modes = drm_add_edid_modes(connector, edid);
198 kfree(edid);
199
200 return num_modes;
201 }
202
203 static const struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
204 .get_modes = ptn3460_connector_get_modes,
205 };
206
207 static const struct drm_connector_funcs ptn3460_connector_funcs = {
208 .fill_modes = drm_helper_probe_single_connector_modes,
209 .destroy = drm_connector_cleanup,
210 .reset = drm_atomic_helper_connector_reset,
211 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
212 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
213 };
214
ptn3460_bridge_attach(struct drm_bridge * bridge,enum drm_bridge_attach_flags flags)215 static int ptn3460_bridge_attach(struct drm_bridge *bridge,
216 enum drm_bridge_attach_flags flags)
217 {
218 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
219 int ret;
220
221 /* Let this driver create connector if requested */
222 ret = drm_bridge_attach(bridge->encoder, ptn_bridge->panel_bridge,
223 bridge, flags | DRM_BRIDGE_ATTACH_NO_CONNECTOR);
224 if (ret < 0)
225 return ret;
226
227 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
228 return 0;
229
230 if (!bridge->encoder) {
231 DRM_ERROR("Parent encoder object not found");
232 return -ENODEV;
233 }
234
235 ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
236 ret = drm_connector_init(bridge->dev, &ptn_bridge->connector,
237 &ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
238 if (ret) {
239 DRM_ERROR("Failed to initialize connector with drm\n");
240 return ret;
241 }
242 drm_connector_helper_add(&ptn_bridge->connector,
243 &ptn3460_connector_helper_funcs);
244 drm_connector_register(&ptn_bridge->connector);
245 drm_connector_attach_encoder(&ptn_bridge->connector,
246 bridge->encoder);
247
248 drm_helper_hpd_irq_event(ptn_bridge->connector.dev);
249
250 return ret;
251 }
252
253 static const struct drm_bridge_funcs ptn3460_bridge_funcs = {
254 .pre_enable = ptn3460_pre_enable,
255 .disable = ptn3460_disable,
256 .attach = ptn3460_bridge_attach,
257 .get_edid = ptn3460_get_edid,
258 };
259
ptn3460_probe(struct i2c_client * client)260 static int ptn3460_probe(struct i2c_client *client)
261 {
262 struct device *dev = &client->dev;
263 struct ptn3460_bridge *ptn_bridge;
264 struct drm_bridge *panel_bridge;
265 int ret;
266
267 ptn_bridge = devm_kzalloc(dev, sizeof(*ptn_bridge), GFP_KERNEL);
268 if (!ptn_bridge) {
269 return -ENOMEM;
270 }
271
272 panel_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
273 if (IS_ERR(panel_bridge))
274 return PTR_ERR(panel_bridge);
275
276 ptn_bridge->panel_bridge = panel_bridge;
277 ptn_bridge->client = client;
278
279 ptn_bridge->gpio_pd_n = devm_gpiod_get(&client->dev, "powerdown",
280 GPIOD_OUT_HIGH);
281 if (IS_ERR(ptn_bridge->gpio_pd_n)) {
282 ret = PTR_ERR(ptn_bridge->gpio_pd_n);
283 dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
284 return ret;
285 }
286
287 /*
288 * Request the reset pin low to avoid the bridge being
289 * initialized prematurely
290 */
291 ptn_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset",
292 GPIOD_OUT_LOW);
293 if (IS_ERR(ptn_bridge->gpio_rst_n)) {
294 ret = PTR_ERR(ptn_bridge->gpio_rst_n);
295 DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
296 return ret;
297 }
298
299 ret = of_property_read_u32(dev->of_node, "edid-emulation",
300 &ptn_bridge->edid_emulation);
301 if (ret) {
302 dev_err(dev, "Can't read EDID emulation value\n");
303 return ret;
304 }
305
306 ptn_bridge->bridge.funcs = &ptn3460_bridge_funcs;
307 ptn_bridge->bridge.ops = DRM_BRIDGE_OP_EDID;
308 ptn_bridge->bridge.type = DRM_MODE_CONNECTOR_LVDS;
309 ptn_bridge->bridge.of_node = dev->of_node;
310 drm_bridge_add(&ptn_bridge->bridge);
311
312 i2c_set_clientdata(client, ptn_bridge);
313
314 return 0;
315 }
316
ptn3460_remove(struct i2c_client * client)317 static void ptn3460_remove(struct i2c_client *client)
318 {
319 struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);
320
321 drm_bridge_remove(&ptn_bridge->bridge);
322 }
323
324 static const struct i2c_device_id ptn3460_i2c_table[] = {
325 {"ptn3460", 0},
326 {},
327 };
328 MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);
329
330 static const struct of_device_id ptn3460_match[] = {
331 { .compatible = "nxp,ptn3460" },
332 {},
333 };
334 MODULE_DEVICE_TABLE(of, ptn3460_match);
335
336 static struct i2c_driver ptn3460_driver = {
337 .id_table = ptn3460_i2c_table,
338 .probe = ptn3460_probe,
339 .remove = ptn3460_remove,
340 .driver = {
341 .name = "nxp,ptn3460",
342 .of_match_table = ptn3460_match,
343 },
344 };
345 module_i2c_driver(ptn3460_driver);
346
347 MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
348 MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
349 MODULE_LICENSE("GPL v2");
350