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_print.h>
19 #include <drm/drm_probe_helper.h>
20
21 #define PTN3460_EDID_ADDR 0x0
22 #define PTN3460_EDID_EMULATION_ADDR 0x84
23 #define PTN3460_EDID_ENABLE_EMULATION 0
24 #define PTN3460_EDID_EMULATION_SELECTION 1
25 #define PTN3460_EDID_SRAM_LOAD_ADDR 0x85
26
27 struct ptn3460_bridge {
28 struct drm_connector connector;
29 struct i2c_client *client;
30 struct drm_bridge bridge;
31 struct drm_bridge *panel_bridge;
32 struct gpio_desc *gpio_pd_n;
33 struct gpio_desc *gpio_rst_n;
34 u32 edid_emulation;
35 bool enabled;
36 };
37
38 static inline struct ptn3460_bridge *
bridge_to_ptn3460(struct drm_bridge * bridge)39 bridge_to_ptn3460(struct drm_bridge *bridge)
40 {
41 return container_of(bridge, struct ptn3460_bridge, bridge);
42 }
43
44 static inline struct ptn3460_bridge *
connector_to_ptn3460(struct drm_connector * connector)45 connector_to_ptn3460(struct drm_connector *connector)
46 {
47 return container_of(connector, struct ptn3460_bridge, connector);
48 }
49
ptn3460_read_bytes(struct ptn3460_bridge * ptn_bridge,char addr,u8 * buf,int len)50 static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
51 u8 *buf, int len)
52 {
53 int ret;
54
55 ret = i2c_master_send(ptn_bridge->client, &addr, 1);
56 if (ret < 0) {
57 DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
58 return ret;
59 }
60
61 ret = i2c_master_recv(ptn_bridge->client, buf, len);
62 if (ret < 0) {
63 DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
64 return ret;
65 }
66
67 return 0;
68 }
69
ptn3460_write_byte(struct ptn3460_bridge * ptn_bridge,char addr,char val)70 static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
71 char val)
72 {
73 int ret;
74 char buf[2];
75
76 buf[0] = addr;
77 buf[1] = val;
78
79 ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
80 if (ret < 0) {
81 DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
82 return ret;
83 }
84
85 return 0;
86 }
87
ptn3460_select_edid(struct ptn3460_bridge * ptn_bridge)88 static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
89 {
90 int ret;
91 char val;
92
93 /* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
94 ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
95 ptn_bridge->edid_emulation);
96 if (ret) {
97 DRM_ERROR("Failed to transfer EDID to sram, ret=%d\n", ret);
98 return ret;
99 }
100
101 /* Enable EDID emulation and select the desired EDID */
102 val = 1 << PTN3460_EDID_ENABLE_EMULATION |
103 ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;
104
105 ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
106 if (ret) {
107 DRM_ERROR("Failed to write EDID value, ret=%d\n", ret);
108 return ret;
109 }
110
111 return 0;
112 }
113
ptn3460_pre_enable(struct drm_bridge * bridge)114 static void ptn3460_pre_enable(struct drm_bridge *bridge)
115 {
116 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
117 int ret;
118
119 if (ptn_bridge->enabled)
120 return;
121
122 gpiod_set_value(ptn_bridge->gpio_pd_n, 1);
123
124 gpiod_set_value(ptn_bridge->gpio_rst_n, 0);
125 usleep_range(10, 20);
126 gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
127
128 /*
129 * There's a bug in the PTN chip where it falsely asserts hotplug before
130 * it is fully functional. We're forced to wait for the maximum start up
131 * time specified in the chip's datasheet to make sure we're really up.
132 */
133 msleep(90);
134
135 ret = ptn3460_select_edid(ptn_bridge);
136 if (ret)
137 DRM_ERROR("Select EDID failed ret=%d\n", ret);
138
139 ptn_bridge->enabled = true;
140 }
141
ptn3460_disable(struct drm_bridge * bridge)142 static void ptn3460_disable(struct drm_bridge *bridge)
143 {
144 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
145
146 if (!ptn_bridge->enabled)
147 return;
148
149 ptn_bridge->enabled = false;
150
151 gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
152 gpiod_set_value(ptn_bridge->gpio_pd_n, 0);
153 }
154
155
ptn3460_edid_read(struct drm_bridge * bridge,struct drm_connector * connector)156 static const struct drm_edid *ptn3460_edid_read(struct drm_bridge *bridge,
157 struct drm_connector *connector)
158 {
159 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
160 const struct drm_edid *drm_edid = NULL;
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 goto out;
179 }
180
181 drm_edid = drm_edid_alloc(edid, EDID_LENGTH);
182
183 out:
184 if (power_off)
185 ptn3460_disable(&ptn_bridge->bridge);
186
187 return drm_edid;
188 }
189
ptn3460_connector_get_modes(struct drm_connector * connector)190 static int ptn3460_connector_get_modes(struct drm_connector *connector)
191 {
192 struct ptn3460_bridge *ptn_bridge = connector_to_ptn3460(connector);
193 const struct drm_edid *drm_edid;
194 int num_modes;
195
196 drm_edid = ptn3460_edid_read(&ptn_bridge->bridge, connector);
197 drm_edid_connector_update(connector, drm_edid);
198 num_modes = drm_edid_connector_add_modes(connector);
199 drm_edid_free(drm_edid);
200
201 return num_modes;
202 }
203
204 static const struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
205 .get_modes = ptn3460_connector_get_modes,
206 };
207
208 static const struct drm_connector_funcs ptn3460_connector_funcs = {
209 .fill_modes = drm_helper_probe_single_connector_modes,
210 .destroy = drm_connector_cleanup,
211 .reset = drm_atomic_helper_connector_reset,
212 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
213 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
214 };
215
ptn3460_bridge_attach(struct drm_bridge * bridge,struct drm_encoder * encoder,enum drm_bridge_attach_flags flags)216 static int ptn3460_bridge_attach(struct drm_bridge *bridge,
217 struct drm_encoder *encoder,
218 enum drm_bridge_attach_flags flags)
219 {
220 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
221 int ret;
222
223 /* Let this driver create connector if requested */
224 ret = drm_bridge_attach(encoder, ptn_bridge->panel_bridge,
225 bridge, flags | DRM_BRIDGE_ATTACH_NO_CONNECTOR);
226 if (ret < 0)
227 return ret;
228
229 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
230 return 0;
231
232 ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
233 ret = drm_connector_init(bridge->dev, &ptn_bridge->connector,
234 &ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
235 if (ret) {
236 DRM_ERROR("Failed to initialize connector with drm\n");
237 return ret;
238 }
239 drm_connector_helper_add(&ptn_bridge->connector,
240 &ptn3460_connector_helper_funcs);
241 drm_connector_register(&ptn_bridge->connector);
242 drm_connector_attach_encoder(&ptn_bridge->connector,
243 encoder);
244
245 drm_helper_hpd_irq_event(ptn_bridge->connector.dev);
246
247 return ret;
248 }
249
250 static const struct drm_bridge_funcs ptn3460_bridge_funcs = {
251 .pre_enable = ptn3460_pre_enable,
252 .disable = ptn3460_disable,
253 .attach = ptn3460_bridge_attach,
254 .edid_read = ptn3460_edid_read,
255 };
256
ptn3460_probe(struct i2c_client * client)257 static int ptn3460_probe(struct i2c_client *client)
258 {
259 struct device *dev = &client->dev;
260 struct ptn3460_bridge *ptn_bridge;
261 struct drm_bridge *panel_bridge;
262 int ret;
263
264 ptn_bridge = devm_drm_bridge_alloc(dev, struct ptn3460_bridge, bridge,
265 &ptn3460_bridge_funcs);
266 if (IS_ERR(ptn_bridge))
267 return PTR_ERR(ptn_bridge);
268
269 panel_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
270 if (IS_ERR(panel_bridge))
271 return PTR_ERR(panel_bridge);
272
273 ptn_bridge->panel_bridge = panel_bridge;
274 ptn_bridge->client = client;
275
276 ptn_bridge->gpio_pd_n = devm_gpiod_get(&client->dev, "powerdown",
277 GPIOD_OUT_HIGH);
278 if (IS_ERR(ptn_bridge->gpio_pd_n)) {
279 ret = PTR_ERR(ptn_bridge->gpio_pd_n);
280 dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
281 return ret;
282 }
283
284 /*
285 * Request the reset pin low to avoid the bridge being
286 * initialized prematurely
287 */
288 ptn_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset",
289 GPIOD_OUT_LOW);
290 if (IS_ERR(ptn_bridge->gpio_rst_n)) {
291 ret = PTR_ERR(ptn_bridge->gpio_rst_n);
292 DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
293 return ret;
294 }
295
296 ret = of_property_read_u32(dev->of_node, "edid-emulation",
297 &ptn_bridge->edid_emulation);
298 if (ret) {
299 dev_err(dev, "Can't read EDID emulation value\n");
300 return ret;
301 }
302
303 ptn_bridge->bridge.ops = DRM_BRIDGE_OP_EDID;
304 ptn_bridge->bridge.type = DRM_MODE_CONNECTOR_LVDS;
305 ptn_bridge->bridge.of_node = dev->of_node;
306 drm_bridge_add(&ptn_bridge->bridge);
307
308 i2c_set_clientdata(client, ptn_bridge);
309
310 return 0;
311 }
312
ptn3460_remove(struct i2c_client * client)313 static void ptn3460_remove(struct i2c_client *client)
314 {
315 struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);
316
317 drm_bridge_remove(&ptn_bridge->bridge);
318 }
319
320 static const struct i2c_device_id ptn3460_i2c_table[] = {
321 { "ptn3460" },
322 {}
323 };
324 MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);
325
326 static const struct of_device_id ptn3460_match[] = {
327 { .compatible = "nxp,ptn3460" },
328 {},
329 };
330 MODULE_DEVICE_TABLE(of, ptn3460_match);
331
332 static struct i2c_driver ptn3460_driver = {
333 .id_table = ptn3460_i2c_table,
334 .probe = ptn3460_probe,
335 .remove = ptn3460_remove,
336 .driver = {
337 .name = "nxp,ptn3460",
338 .of_match_table = ptn3460_match,
339 },
340 };
341 module_i2c_driver(ptn3460_driver);
342
343 MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
344 MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
345 MODULE_LICENSE("GPL v2");
346