1/*
2 * NXP PTN3460 DP/LVDS bridge driver
3 *
4 * Copyright (C) 2013 Google, Inc.
5 *
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 */
15
16#include <linux/delay.h>
17#include <linux/gpio.h>
18#include <linux/gpio/consumer.h>
19#include <linux/i2c.h>
20#include <linux/module.h>
21#include <linux/of.h>
22#include <linux/of_gpio.h>
23#include <linux/of_graph.h>
24
25#include <drm/drm_panel.h>
26
27#include "bridge/ptn3460.h"
28
29#include "drm_crtc.h"
30#include "drm_crtc_helper.h"
31#include "drm_edid.h"
32#include "drmP.h"
33
34#define PTN3460_EDID_ADDR			0x0
35#define PTN3460_EDID_EMULATION_ADDR		0x84
36#define PTN3460_EDID_ENABLE_EMULATION		0
37#define PTN3460_EDID_EMULATION_SELECTION	1
38#define PTN3460_EDID_SRAM_LOAD_ADDR		0x85
39
40struct ptn3460_bridge {
41	struct drm_connector connector;
42	struct i2c_client *client;
43	struct drm_bridge bridge;
44	struct edid *edid;
45	struct drm_panel *panel;
46	struct gpio_desc *gpio_pd_n;
47	struct gpio_desc *gpio_rst_n;
48	u32 edid_emulation;
49	bool enabled;
50};
51
52static inline struct ptn3460_bridge *
53		bridge_to_ptn3460(struct drm_bridge *bridge)
54{
55	return container_of(bridge, struct ptn3460_bridge, bridge);
56}
57
58static inline struct ptn3460_bridge *
59		connector_to_ptn3460(struct drm_connector *connector)
60{
61	return container_of(connector, struct ptn3460_bridge, connector);
62}
63
64static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
65		u8 *buf, int len)
66{
67	int ret;
68
69	ret = i2c_master_send(ptn_bridge->client, &addr, 1);
70	if (ret <= 0) {
71		DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
72		return ret;
73	}
74
75	ret = i2c_master_recv(ptn_bridge->client, buf, len);
76	if (ret <= 0) {
77		DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
78		return ret;
79	}
80
81	return 0;
82}
83
84static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
85		char val)
86{
87	int ret;
88	char buf[2];
89
90	buf[0] = addr;
91	buf[1] = val;
92
93	ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
94	if (ret <= 0) {
95		DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
96		return ret;
97	}
98
99	return 0;
100}
101
102static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
103{
104	int ret;
105	char val;
106
107	/* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
108	ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
109			ptn_bridge->edid_emulation);
110	if (ret) {
111		DRM_ERROR("Failed to transfer EDID to sram, ret=%d\n", ret);
112		return ret;
113	}
114
115	/* Enable EDID emulation and select the desired EDID */
116	val = 1 << PTN3460_EDID_ENABLE_EMULATION |
117		ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;
118
119	ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
120	if (ret) {
121		DRM_ERROR("Failed to write EDID value, ret=%d\n", ret);
122		return ret;
123	}
124
125	return 0;
126}
127
128static void ptn3460_pre_enable(struct drm_bridge *bridge)
129{
130	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
131	int ret;
132
133	if (ptn_bridge->enabled)
134		return;
135
136	gpiod_set_value(ptn_bridge->gpio_pd_n, 1);
137
138	gpiod_set_value(ptn_bridge->gpio_rst_n, 0);
139	usleep_range(10, 20);
140	gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
141
142	if (drm_panel_prepare(ptn_bridge->panel)) {
143		DRM_ERROR("failed to prepare panel\n");
144		return;
145	}
146
147	/*
148	 * There's a bug in the PTN chip where it falsely asserts hotplug before
149	 * it is fully functional. We're forced to wait for the maximum start up
150	 * time specified in the chip's datasheet to make sure we're really up.
151	 */
152	msleep(90);
153
154	ret = ptn3460_select_edid(ptn_bridge);
155	if (ret)
156		DRM_ERROR("Select EDID failed ret=%d\n", ret);
157
158	ptn_bridge->enabled = true;
159}
160
161static void ptn3460_enable(struct drm_bridge *bridge)
162{
163	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
164
165	if (drm_panel_enable(ptn_bridge->panel)) {
166		DRM_ERROR("failed to enable panel\n");
167		return;
168	}
169}
170
171static void ptn3460_disable(struct drm_bridge *bridge)
172{
173	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
174
175	if (!ptn_bridge->enabled)
176		return;
177
178	ptn_bridge->enabled = false;
179
180	if (drm_panel_disable(ptn_bridge->panel)) {
181		DRM_ERROR("failed to disable panel\n");
182		return;
183	}
184
185	gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
186	gpiod_set_value(ptn_bridge->gpio_pd_n, 0);
187}
188
189static void ptn3460_post_disable(struct drm_bridge *bridge)
190{
191	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
192
193	if (drm_panel_unprepare(ptn_bridge->panel)) {
194		DRM_ERROR("failed to unprepare panel\n");
195		return;
196	}
197}
198
199static int ptn3460_get_modes(struct drm_connector *connector)
200{
201	struct ptn3460_bridge *ptn_bridge;
202	u8 *edid;
203	int ret, num_modes = 0;
204	bool power_off;
205
206	ptn_bridge = connector_to_ptn3460(connector);
207
208	if (ptn_bridge->edid)
209		return drm_add_edid_modes(connector, ptn_bridge->edid);
210
211	power_off = !ptn_bridge->enabled;
212	ptn3460_pre_enable(&ptn_bridge->bridge);
213
214	edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
215	if (!edid) {
216		DRM_ERROR("Failed to allocate EDID\n");
217		return 0;
218	}
219
220	ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
221			EDID_LENGTH);
222	if (ret) {
223		kfree(edid);
224		goto out;
225	}
226
227	ptn_bridge->edid = (struct edid *)edid;
228	drm_mode_connector_update_edid_property(connector, ptn_bridge->edid);
229
230	num_modes = drm_add_edid_modes(connector, ptn_bridge->edid);
231
232out:
233	if (power_off)
234		ptn3460_disable(&ptn_bridge->bridge);
235
236	return num_modes;
237}
238
239static struct drm_encoder *ptn3460_best_encoder(struct drm_connector *connector)
240{
241	struct ptn3460_bridge *ptn_bridge = connector_to_ptn3460(connector);
242
243	return ptn_bridge->bridge.encoder;
244}
245
246static struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
247	.get_modes = ptn3460_get_modes,
248	.best_encoder = ptn3460_best_encoder,
249};
250
251static enum drm_connector_status ptn3460_detect(struct drm_connector *connector,
252		bool force)
253{
254	return connector_status_connected;
255}
256
257static void ptn3460_connector_destroy(struct drm_connector *connector)
258{
259	drm_connector_cleanup(connector);
260}
261
262static struct drm_connector_funcs ptn3460_connector_funcs = {
263	.dpms = drm_helper_connector_dpms,
264	.fill_modes = drm_helper_probe_single_connector_modes,
265	.detect = ptn3460_detect,
266	.destroy = ptn3460_connector_destroy,
267};
268
269static int ptn3460_bridge_attach(struct drm_bridge *bridge)
270{
271	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
272	int ret;
273
274	if (!bridge->encoder) {
275		DRM_ERROR("Parent encoder object not found");
276		return -ENODEV;
277	}
278
279	ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
280	ret = drm_connector_init(bridge->dev, &ptn_bridge->connector,
281			&ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
282	if (ret) {
283		DRM_ERROR("Failed to initialize connector with drm\n");
284		return ret;
285	}
286	drm_connector_helper_add(&ptn_bridge->connector,
287					&ptn3460_connector_helper_funcs);
288	drm_connector_register(&ptn_bridge->connector);
289	drm_mode_connector_attach_encoder(&ptn_bridge->connector,
290							bridge->encoder);
291
292	if (ptn_bridge->panel)
293		drm_panel_attach(ptn_bridge->panel, &ptn_bridge->connector);
294
295	drm_helper_hpd_irq_event(ptn_bridge->connector.dev);
296
297	return ret;
298}
299
300static struct drm_bridge_funcs ptn3460_bridge_funcs = {
301	.pre_enable = ptn3460_pre_enable,
302	.enable = ptn3460_enable,
303	.disable = ptn3460_disable,
304	.post_disable = ptn3460_post_disable,
305	.attach = ptn3460_bridge_attach,
306};
307
308static int ptn3460_probe(struct i2c_client *client,
309				const struct i2c_device_id *id)
310{
311	struct device *dev = &client->dev;
312	struct ptn3460_bridge *ptn_bridge;
313	struct device_node *endpoint, *panel_node;
314	int ret;
315
316	ptn_bridge = devm_kzalloc(dev, sizeof(*ptn_bridge), GFP_KERNEL);
317	if (!ptn_bridge) {
318		return -ENOMEM;
319	}
320
321	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
322	if (endpoint) {
323		panel_node = of_graph_get_remote_port_parent(endpoint);
324		if (panel_node) {
325			ptn_bridge->panel = of_drm_find_panel(panel_node);
326			of_node_put(panel_node);
327			if (!ptn_bridge->panel)
328				return -EPROBE_DEFER;
329		}
330	}
331
332	ptn_bridge->client = client;
333
334	ptn_bridge->gpio_pd_n = devm_gpiod_get(&client->dev, "powerdown");
335	if (IS_ERR(ptn_bridge->gpio_pd_n)) {
336		ret = PTR_ERR(ptn_bridge->gpio_pd_n);
337		dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
338		return ret;
339	}
340
341	ret = gpiod_direction_output(ptn_bridge->gpio_pd_n, 1);
342	if (ret) {
343		DRM_ERROR("cannot configure gpio_pd_n\n");
344		return ret;
345	}
346
347	ptn_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset");
348	if (IS_ERR(ptn_bridge->gpio_rst_n)) {
349		ret = PTR_ERR(ptn_bridge->gpio_rst_n);
350		DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
351		return ret;
352	}
353	/*
354	 * Request the reset pin low to avoid the bridge being
355	 * initialized prematurely
356	 */
357	ret = gpiod_direction_output(ptn_bridge->gpio_rst_n, 0);
358	if (ret) {
359		DRM_ERROR("cannot configure gpio_rst_n\n");
360		return ret;
361	}
362
363	ret = of_property_read_u32(dev->of_node, "edid-emulation",
364			&ptn_bridge->edid_emulation);
365	if (ret) {
366		dev_err(dev, "Can't read EDID emulation value\n");
367		return ret;
368	}
369
370	ptn_bridge->bridge.funcs = &ptn3460_bridge_funcs;
371	ptn_bridge->bridge.of_node = dev->of_node;
372	ret = drm_bridge_add(&ptn_bridge->bridge);
373	if (ret) {
374		DRM_ERROR("Failed to add bridge\n");
375		return ret;
376	}
377
378	i2c_set_clientdata(client, ptn_bridge);
379
380	return 0;
381}
382
383static int ptn3460_remove(struct i2c_client *client)
384{
385	struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);
386
387	drm_bridge_remove(&ptn_bridge->bridge);
388
389	return 0;
390}
391
392static const struct i2c_device_id ptn3460_i2c_table[] = {
393	{"nxp,ptn3460", 0},
394	{},
395};
396MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);
397
398static const struct of_device_id ptn3460_match[] = {
399	{ .compatible = "nxp,ptn3460" },
400	{},
401};
402MODULE_DEVICE_TABLE(of, ptn3460_match);
403
404static struct i2c_driver ptn3460_driver = {
405	.id_table	= ptn3460_i2c_table,
406	.probe		= ptn3460_probe,
407	.remove		= ptn3460_remove,
408	.driver		= {
409		.name	= "nxp,ptn3460",
410		.owner	= THIS_MODULE,
411		.of_match_table = ptn3460_match,
412	},
413};
414module_i2c_driver(ptn3460_driver);
415
416MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
417MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
418MODULE_LICENSE("GPL v2");
419