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 edid *edid;
 33	struct drm_panel *panel;
 34	struct gpio_desc *gpio_pd_n;
 35	struct gpio_desc *gpio_rst_n;
 36	u32 edid_emulation;
 37	bool enabled;
 38};
 39
 40static inline struct ptn3460_bridge *
 41		bridge_to_ptn3460(struct drm_bridge *bridge)
 42{
 43	return container_of(bridge, struct ptn3460_bridge, bridge);
 44}
 45
 46static inline struct ptn3460_bridge *
 47		connector_to_ptn3460(struct drm_connector *connector)
 48{
 49	return container_of(connector, struct ptn3460_bridge, connector);
 50}
 51
 52static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
 53		u8 *buf, int len)
 54{
 55	int ret;
 56
 57	ret = i2c_master_send(ptn_bridge->client, &addr, 1);
 58	if (ret <= 0) {
 59		DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
 60		return ret;
 61	}
 62
 63	ret = i2c_master_recv(ptn_bridge->client, buf, len);
 64	if (ret <= 0) {
 65		DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
 66		return ret;
 67	}
 68
 69	return 0;
 70}
 71
 72static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
 73		char val)
 74{
 75	int ret;
 76	char buf[2];
 77
 78	buf[0] = addr;
 79	buf[1] = val;
 80
 81	ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
 82	if (ret <= 0) {
 83		DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
 84		return ret;
 85	}
 86
 87	return 0;
 88}
 89
 90static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
 91{
 92	int ret;
 93	char val;
 94
 95	/* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
 96	ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
 97			ptn_bridge->edid_emulation);
 98	if (ret) {
 99		DRM_ERROR("Failed to transfer EDID to sram, ret=%d\n", ret);
100		return ret;
101	}
102
103	/* Enable EDID emulation and select the desired EDID */
104	val = 1 << PTN3460_EDID_ENABLE_EMULATION |
105		ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;
106
107	ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
108	if (ret) {
109		DRM_ERROR("Failed to write EDID value, ret=%d\n", ret);
110		return ret;
111	}
112
113	return 0;
114}
115
116static void ptn3460_pre_enable(struct drm_bridge *bridge)
117{
118	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
119	int ret;
120
121	if (ptn_bridge->enabled)
122		return;
123
124	gpiod_set_value(ptn_bridge->gpio_pd_n, 1);
125
126	gpiod_set_value(ptn_bridge->gpio_rst_n, 0);
127	usleep_range(10, 20);
128	gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
129
130	if (drm_panel_prepare(ptn_bridge->panel)) {
131		DRM_ERROR("failed to prepare panel\n");
132		return;
133	}
134
135	/*
136	 * There's a bug in the PTN chip where it falsely asserts hotplug before
137	 * it is fully functional. We're forced to wait for the maximum start up
138	 * time specified in the chip's datasheet to make sure we're really up.
139	 */
140	msleep(90);
141
142	ret = ptn3460_select_edid(ptn_bridge);
143	if (ret)
144		DRM_ERROR("Select EDID failed ret=%d\n", ret);
145
146	ptn_bridge->enabled = true;
147}
148
149static void ptn3460_enable(struct drm_bridge *bridge)
150{
151	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
152
153	if (drm_panel_enable(ptn_bridge->panel)) {
154		DRM_ERROR("failed to enable panel\n");
155		return;
156	}
157}
158
159static void ptn3460_disable(struct drm_bridge *bridge)
160{
161	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
162
163	if (!ptn_bridge->enabled)
164		return;
165
166	ptn_bridge->enabled = false;
167
168	if (drm_panel_disable(ptn_bridge->panel)) {
169		DRM_ERROR("failed to disable panel\n");
170		return;
171	}
172
173	gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
174	gpiod_set_value(ptn_bridge->gpio_pd_n, 0);
175}
176
177static void ptn3460_post_disable(struct drm_bridge *bridge)
178{
179	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
180
181	if (drm_panel_unprepare(ptn_bridge->panel)) {
182		DRM_ERROR("failed to unprepare panel\n");
183		return;
184	}
185}
186
187static int ptn3460_get_modes(struct drm_connector *connector)
188{
189	struct ptn3460_bridge *ptn_bridge;
190	u8 *edid;
191	int ret, num_modes = 0;
192	bool power_off;
193
194	ptn_bridge = connector_to_ptn3460(connector);
195
196	if (ptn_bridge->edid)
197		return drm_add_edid_modes(connector, ptn_bridge->edid);
198
199	power_off = !ptn_bridge->enabled;
200	ptn3460_pre_enable(&ptn_bridge->bridge);
201
202	edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
203	if (!edid) {
204		DRM_ERROR("Failed to allocate EDID\n");
205		return 0;
206	}
207
208	ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
209			EDID_LENGTH);
210	if (ret) {
211		kfree(edid);
212		goto out;
213	}
214
215	ptn_bridge->edid = (struct edid *)edid;
216	drm_connector_update_edid_property(connector, ptn_bridge->edid);
217
218	num_modes = drm_add_edid_modes(connector, ptn_bridge->edid);
219
220out:
221	if (power_off)
222		ptn3460_disable(&ptn_bridge->bridge);
223
224	return num_modes;
225}
226
227static const struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
228	.get_modes = ptn3460_get_modes,
229};
230
231static const struct drm_connector_funcs ptn3460_connector_funcs = {
232	.fill_modes = drm_helper_probe_single_connector_modes,
233	.destroy = drm_connector_cleanup,
234	.reset = drm_atomic_helper_connector_reset,
235	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
236	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
237};
238
239static int ptn3460_bridge_attach(struct drm_bridge *bridge,
240				 enum drm_bridge_attach_flags flags)
241{
242	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
243	int ret;
244
245	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
246		DRM_ERROR("Fix bridge driver to make connector optional!");
247		return -EINVAL;
248	}
249
250	if (!bridge->encoder) {
251		DRM_ERROR("Parent encoder object not found");
252		return -ENODEV;
253	}
254
255	ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
256	ret = drm_connector_init(bridge->dev, &ptn_bridge->connector,
257			&ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
258	if (ret) {
259		DRM_ERROR("Failed to initialize connector with drm\n");
260		return ret;
261	}
262	drm_connector_helper_add(&ptn_bridge->connector,
263					&ptn3460_connector_helper_funcs);
264	drm_connector_register(&ptn_bridge->connector);
265	drm_connector_attach_encoder(&ptn_bridge->connector,
266							bridge->encoder);
267
268	if (ptn_bridge->panel)
269		drm_panel_attach(ptn_bridge->panel, &ptn_bridge->connector);
270
271	drm_helper_hpd_irq_event(ptn_bridge->connector.dev);
272
273	return ret;
274}
275
276static const struct drm_bridge_funcs ptn3460_bridge_funcs = {
277	.pre_enable = ptn3460_pre_enable,
278	.enable = ptn3460_enable,
279	.disable = ptn3460_disable,
280	.post_disable = ptn3460_post_disable,
281	.attach = ptn3460_bridge_attach,
282};
283
284static int ptn3460_probe(struct i2c_client *client,
285				const struct i2c_device_id *id)
286{
287	struct device *dev = &client->dev;
288	struct ptn3460_bridge *ptn_bridge;
289	int ret;
290
291	ptn_bridge = devm_kzalloc(dev, sizeof(*ptn_bridge), GFP_KERNEL);
292	if (!ptn_bridge) {
293		return -ENOMEM;
294	}
295
296	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &ptn_bridge->panel, NULL);
297	if (ret)
298		return ret;
299
300	ptn_bridge->client = client;
301
302	ptn_bridge->gpio_pd_n = devm_gpiod_get(&client->dev, "powerdown",
303					       GPIOD_OUT_HIGH);
304	if (IS_ERR(ptn_bridge->gpio_pd_n)) {
305		ret = PTR_ERR(ptn_bridge->gpio_pd_n);
306		dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
307		return ret;
308	}
309
310	/*
311	 * Request the reset pin low to avoid the bridge being
312	 * initialized prematurely
313	 */
314	ptn_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset",
315						GPIOD_OUT_LOW);
316	if (IS_ERR(ptn_bridge->gpio_rst_n)) {
317		ret = PTR_ERR(ptn_bridge->gpio_rst_n);
318		DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
319		return ret;
320	}
321
322	ret = of_property_read_u32(dev->of_node, "edid-emulation",
323			&ptn_bridge->edid_emulation);
324	if (ret) {
325		dev_err(dev, "Can't read EDID emulation value\n");
326		return ret;
327	}
328
329	ptn_bridge->bridge.funcs = &ptn3460_bridge_funcs;
330	ptn_bridge->bridge.of_node = dev->of_node;
331	drm_bridge_add(&ptn_bridge->bridge);
332
333	i2c_set_clientdata(client, ptn_bridge);
334
335	return 0;
336}
337
338static int ptn3460_remove(struct i2c_client *client)
339{
340	struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);
341
342	drm_bridge_remove(&ptn_bridge->bridge);
343
344	return 0;
345}
346
347static const struct i2c_device_id ptn3460_i2c_table[] = {
348	{"ptn3460", 0},
349	{},
350};
351MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);
352
353static const struct of_device_id ptn3460_match[] = {
354	{ .compatible = "nxp,ptn3460" },
355	{},
356};
357MODULE_DEVICE_TABLE(of, ptn3460_match);
358
359static struct i2c_driver ptn3460_driver = {
360	.id_table	= ptn3460_i2c_table,
361	.probe		= ptn3460_probe,
362	.remove		= ptn3460_remove,
363	.driver		= {
364		.name	= "nxp,ptn3460",
365		.of_match_table = ptn3460_match,
366	},
367};
368module_i2c_driver(ptn3460_driver);
369
370MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
371MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
372MODULE_LICENSE("GPL v2");