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
28struct 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
39static inline struct ptn3460_bridge *
40 bridge_to_ptn3460(struct drm_bridge *bridge)
41{
42 return container_of(bridge, struct ptn3460_bridge, bridge);
43}
44
45static inline struct ptn3460_bridge *
46 connector_to_ptn3460(struct drm_connector *connector)
47{
48 return container_of(connector, struct ptn3460_bridge, connector);
49}
50
51static 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(client: ptn_bridge->client, buf: &addr, count: 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(client: ptn_bridge->client, buf, count: 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
71static 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(client: 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
89static 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 val: 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
115static 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(desc: ptn_bridge->gpio_pd_n, value: 1);
124
125 gpiod_set_value(desc: ptn_bridge->gpio_rst_n, value: 0);
126 usleep_range(min: 10, max: 20);
127 gpiod_set_value(desc: ptn_bridge->gpio_rst_n, value: 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(msecs: 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
143static 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(desc: ptn_bridge->gpio_rst_n, value: 1);
153 gpiod_set_value(desc: ptn_bridge->gpio_pd_n, value: 0);
154}
155
156
157static const struct drm_edid *ptn3460_edid_read(struct drm_bridge *bridge,
158 struct drm_connector *connector)
159{
160 struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
161 const struct drm_edid *drm_edid = NULL;
162 bool power_off;
163 u8 *edid;
164 int ret;
165
166 power_off = !ptn_bridge->enabled;
167 ptn3460_pre_enable(bridge: &ptn_bridge->bridge);
168
169 edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
170 if (!edid) {
171 DRM_ERROR("Failed to allocate EDID\n");
172 goto out;
173 }
174
175 ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, buf: edid,
176 EDID_LENGTH);
177 if (ret) {
178 kfree(objp: edid);
179 goto out;
180 }
181
182 drm_edid = drm_edid_alloc(edid, EDID_LENGTH);
183
184out:
185 if (power_off)
186 ptn3460_disable(bridge: &ptn_bridge->bridge);
187
188 return drm_edid;
189}
190
191static int ptn3460_connector_get_modes(struct drm_connector *connector)
192{
193 struct ptn3460_bridge *ptn_bridge = connector_to_ptn3460(connector);
194 const struct drm_edid *drm_edid;
195 int num_modes;
196
197 drm_edid = ptn3460_edid_read(bridge: &ptn_bridge->bridge, connector);
198 drm_edid_connector_update(connector, edid: drm_edid);
199 num_modes = drm_edid_connector_add_modes(connector);
200 drm_edid_free(drm_edid);
201
202 return num_modes;
203}
204
205static const struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
206 .get_modes = ptn3460_connector_get_modes,
207};
208
209static const struct drm_connector_funcs ptn3460_connector_funcs = {
210 .fill_modes = drm_helper_probe_single_connector_modes,
211 .destroy = drm_connector_cleanup,
212 .reset = drm_atomic_helper_connector_reset,
213 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
214 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
215};
216
217static int ptn3460_bridge_attach(struct drm_bridge *bridge,
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: bridge->encoder, bridge: ptn_bridge->panel_bridge,
225 previous: bridge, flags: 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 if (!bridge->encoder) {
233 DRM_ERROR("Parent encoder object not found");
234 return -ENODEV;
235 }
236
237 ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
238 ret = drm_connector_init(dev: bridge->dev, connector: &ptn_bridge->connector,
239 funcs: &ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
240 if (ret) {
241 DRM_ERROR("Failed to initialize connector with drm\n");
242 return ret;
243 }
244 drm_connector_helper_add(connector: &ptn_bridge->connector,
245 funcs: &ptn3460_connector_helper_funcs);
246 drm_connector_register(connector: &ptn_bridge->connector);
247 drm_connector_attach_encoder(connector: &ptn_bridge->connector,
248 encoder: bridge->encoder);
249
250 drm_helper_hpd_irq_event(dev: ptn_bridge->connector.dev);
251
252 return ret;
253}
254
255static const struct drm_bridge_funcs ptn3460_bridge_funcs = {
256 .pre_enable = ptn3460_pre_enable,
257 .disable = ptn3460_disable,
258 .attach = ptn3460_bridge_attach,
259 .edid_read = ptn3460_edid_read,
260};
261
262static int ptn3460_probe(struct i2c_client *client)
263{
264 struct device *dev = &client->dev;
265 struct ptn3460_bridge *ptn_bridge;
266 struct drm_bridge *panel_bridge;
267 int ret;
268
269 ptn_bridge = devm_kzalloc(dev, size: sizeof(*ptn_bridge), GFP_KERNEL);
270 if (!ptn_bridge) {
271 return -ENOMEM;
272 }
273
274 panel_bridge = devm_drm_of_get_bridge(dev, node: dev->of_node, port: 0, endpoint: 0);
275 if (IS_ERR(ptr: panel_bridge))
276 return PTR_ERR(ptr: panel_bridge);
277
278 ptn_bridge->panel_bridge = panel_bridge;
279 ptn_bridge->client = client;
280
281 ptn_bridge->gpio_pd_n = devm_gpiod_get(dev: &client->dev, con_id: "powerdown",
282 flags: GPIOD_OUT_HIGH);
283 if (IS_ERR(ptr: ptn_bridge->gpio_pd_n)) {
284 ret = PTR_ERR(ptr: ptn_bridge->gpio_pd_n);
285 dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
286 return ret;
287 }
288
289 /*
290 * Request the reset pin low to avoid the bridge being
291 * initialized prematurely
292 */
293 ptn_bridge->gpio_rst_n = devm_gpiod_get(dev: &client->dev, con_id: "reset",
294 flags: GPIOD_OUT_LOW);
295 if (IS_ERR(ptr: ptn_bridge->gpio_rst_n)) {
296 ret = PTR_ERR(ptr: ptn_bridge->gpio_rst_n);
297 DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
298 return ret;
299 }
300
301 ret = of_property_read_u32(np: dev->of_node, propname: "edid-emulation",
302 out_value: &ptn_bridge->edid_emulation);
303 if (ret) {
304 dev_err(dev, "Can't read EDID emulation value\n");
305 return ret;
306 }
307
308 ptn_bridge->bridge.funcs = &ptn3460_bridge_funcs;
309 ptn_bridge->bridge.ops = DRM_BRIDGE_OP_EDID;
310 ptn_bridge->bridge.type = DRM_MODE_CONNECTOR_LVDS;
311 ptn_bridge->bridge.of_node = dev->of_node;
312 drm_bridge_add(bridge: &ptn_bridge->bridge);
313
314 i2c_set_clientdata(client, data: ptn_bridge);
315
316 return 0;
317}
318
319static void ptn3460_remove(struct i2c_client *client)
320{
321 struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);
322
323 drm_bridge_remove(bridge: &ptn_bridge->bridge);
324}
325
326static const struct i2c_device_id ptn3460_i2c_table[] = {
327 {"ptn3460", 0},
328 {},
329};
330MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);
331
332static const struct of_device_id ptn3460_match[] = {
333 { .compatible = "nxp,ptn3460" },
334 {},
335};
336MODULE_DEVICE_TABLE(of, ptn3460_match);
337
338static struct i2c_driver ptn3460_driver = {
339 .id_table = ptn3460_i2c_table,
340 .probe = ptn3460_probe,
341 .remove = ptn3460_remove,
342 .driver = {
343 .name = "nxp,ptn3460",
344 .of_match_table = ptn3460_match,
345 },
346};
347module_i2c_driver(ptn3460_driver);
348
349MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
350MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
351MODULE_LICENSE("GPL v2");
352

source code of linux/drivers/gpu/drm/bridge/nxp-ptn3460.c