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 <drm/drm_atomic_helper.h>
 24#include <drm/drm_crtc.h>
 25#include <drm/drm_crtc_helper.h>
 26#include <drm/drm_edid.h>
 27#include <drm/drm_of.h>
 28#include <drm/drm_panel.h>
 29#include <drm/drmP.h>
 30
 31#define PTN3460_EDID_ADDR			0x0
 32#define PTN3460_EDID_EMULATION_ADDR		0x84
 33#define PTN3460_EDID_ENABLE_EMULATION		0
 34#define PTN3460_EDID_EMULATION_SELECTION	1
 35#define PTN3460_EDID_SRAM_LOAD_ADDR		0x85
 36
 37struct ptn3460_bridge {
 38	struct drm_connector connector;
 39	struct i2c_client *client;
 40	struct drm_bridge bridge;
 41	struct edid *edid;
 42	struct drm_panel *panel;
 43	struct gpio_desc *gpio_pd_n;
 44	struct gpio_desc *gpio_rst_n;
 45	u32 edid_emulation;
 46	bool enabled;
 47};
 48
 49static inline struct ptn3460_bridge *
 50		bridge_to_ptn3460(struct drm_bridge *bridge)
 51{
 52	return container_of(bridge, struct ptn3460_bridge, bridge);
 53}
 54
 55static inline struct ptn3460_bridge *
 56		connector_to_ptn3460(struct drm_connector *connector)
 57{
 58	return container_of(connector, struct ptn3460_bridge, connector);
 59}
 60
 61static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
 62		u8 *buf, int len)
 63{
 64	int ret;
 65
 66	ret = i2c_master_send(ptn_bridge->client, &addr, 1);
 67	if (ret <= 0) {
 68		DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
 69		return ret;
 70	}
 71
 72	ret = i2c_master_recv(ptn_bridge->client, buf, len);
 73	if (ret <= 0) {
 74		DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
 75		return ret;
 76	}
 77
 78	return 0;
 79}
 80
 81static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
 82		char val)
 83{
 84	int ret;
 85	char buf[2];
 86
 87	buf[0] = addr;
 88	buf[1] = val;
 89
 90	ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
 91	if (ret <= 0) {
 92		DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
 93		return ret;
 94	}
 95
 96	return 0;
 97}
 98
 99static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
100{
101	int ret;
102	char val;
103
104	/* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
105	ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
106			ptn_bridge->edid_emulation);
107	if (ret) {
108		DRM_ERROR("Failed to transfer EDID to sram, ret=%d\n", ret);
109		return ret;
110	}
111
112	/* Enable EDID emulation and select the desired EDID */
113	val = 1 << PTN3460_EDID_ENABLE_EMULATION |
114		ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;
115
116	ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
117	if (ret) {
118		DRM_ERROR("Failed to write EDID value, ret=%d\n", ret);
119		return ret;
120	}
121
122	return 0;
123}
124
125static void ptn3460_pre_enable(struct drm_bridge *bridge)
126{
127	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
128	int ret;
129
130	if (ptn_bridge->enabled)
131		return;
132
133	gpiod_set_value(ptn_bridge->gpio_pd_n, 1);
134
135	gpiod_set_value(ptn_bridge->gpio_rst_n, 0);
136	usleep_range(10, 20);
137	gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
138
139	if (drm_panel_prepare(ptn_bridge->panel)) {
140		DRM_ERROR("failed to prepare panel\n");
141		return;
142	}
143
144	/*
145	 * There's a bug in the PTN chip where it falsely asserts hotplug before
146	 * it is fully functional. We're forced to wait for the maximum start up
147	 * time specified in the chip's datasheet to make sure we're really up.
148	 */
149	msleep(90);
150
151	ret = ptn3460_select_edid(ptn_bridge);
152	if (ret)
153		DRM_ERROR("Select EDID failed ret=%d\n", ret);
154
155	ptn_bridge->enabled = true;
156}
157
158static void ptn3460_enable(struct drm_bridge *bridge)
159{
160	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
161
162	if (drm_panel_enable(ptn_bridge->panel)) {
163		DRM_ERROR("failed to enable panel\n");
164		return;
165	}
166}
167
168static void ptn3460_disable(struct drm_bridge *bridge)
169{
170	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
171
172	if (!ptn_bridge->enabled)
173		return;
174
175	ptn_bridge->enabled = false;
176
177	if (drm_panel_disable(ptn_bridge->panel)) {
178		DRM_ERROR("failed to disable panel\n");
179		return;
180	}
181
182	gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
183	gpiod_set_value(ptn_bridge->gpio_pd_n, 0);
184}
185
186static void ptn3460_post_disable(struct drm_bridge *bridge)
187{
188	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
189
190	if (drm_panel_unprepare(ptn_bridge->panel)) {
191		DRM_ERROR("failed to unprepare panel\n");
192		return;
193	}
194}
195
196static int ptn3460_get_modes(struct drm_connector *connector)
197{
198	struct ptn3460_bridge *ptn_bridge;
199	u8 *edid;
200	int ret, num_modes = 0;
201	bool power_off;
202
203	ptn_bridge = connector_to_ptn3460(connector);
204
205	if (ptn_bridge->edid)
206		return drm_add_edid_modes(connector, ptn_bridge->edid);
207
208	power_off = !ptn_bridge->enabled;
209	ptn3460_pre_enable(&ptn_bridge->bridge);
210
211	edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
212	if (!edid) {
213		DRM_ERROR("Failed to allocate EDID\n");
214		return 0;
215	}
216
217	ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
218			EDID_LENGTH);
219	if (ret) {
220		kfree(edid);
221		goto out;
222	}
223
224	ptn_bridge->edid = (struct edid *)edid;
225	drm_mode_connector_update_edid_property(connector, ptn_bridge->edid);
226
227	num_modes = drm_add_edid_modes(connector, ptn_bridge->edid);
228
229out:
230	if (power_off)
231		ptn3460_disable(&ptn_bridge->bridge);
232
233	return num_modes;
234}
235
236static const struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
237	.get_modes = ptn3460_get_modes,
238};
239
240static const struct drm_connector_funcs ptn3460_connector_funcs = {
241	.fill_modes = drm_helper_probe_single_connector_modes,
242	.destroy = drm_connector_cleanup,
243	.reset = drm_atomic_helper_connector_reset,
244	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
245	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
246};
247
248static int ptn3460_bridge_attach(struct drm_bridge *bridge)
249{
250	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
251	int ret;
252
253	if (!bridge->encoder) {
254		DRM_ERROR("Parent encoder object not found");
255		return -ENODEV;
256	}
257
258	ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
259	ret = drm_connector_init(bridge->dev, &ptn_bridge->connector,
260			&ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
261	if (ret) {
262		DRM_ERROR("Failed to initialize connector with drm\n");
263		return ret;
264	}
265	drm_connector_helper_add(&ptn_bridge->connector,
266					&ptn3460_connector_helper_funcs);
267	drm_connector_register(&ptn_bridge->connector);
268	drm_mode_connector_attach_encoder(&ptn_bridge->connector,
269							bridge->encoder);
270
271	if (ptn_bridge->panel)
272		drm_panel_attach(ptn_bridge->panel, &ptn_bridge->connector);
273
274	drm_helper_hpd_irq_event(ptn_bridge->connector.dev);
275
276	return ret;
277}
278
279static const struct drm_bridge_funcs ptn3460_bridge_funcs = {
280	.pre_enable = ptn3460_pre_enable,
281	.enable = ptn3460_enable,
282	.disable = ptn3460_disable,
283	.post_disable = ptn3460_post_disable,
284	.attach = ptn3460_bridge_attach,
285};
286
287static int ptn3460_probe(struct i2c_client *client,
288				const struct i2c_device_id *id)
289{
290	struct device *dev = &client->dev;
291	struct ptn3460_bridge *ptn_bridge;
292	int ret;
293
294	ptn_bridge = devm_kzalloc(dev, sizeof(*ptn_bridge), GFP_KERNEL);
295	if (!ptn_bridge) {
296		return -ENOMEM;
297	}
298
299	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &ptn_bridge->panel, NULL);
300	if (ret)
301		return ret;
302
303	ptn_bridge->client = client;
304
305	ptn_bridge->gpio_pd_n = devm_gpiod_get(&client->dev, "powerdown",
306					       GPIOD_OUT_HIGH);
307	if (IS_ERR(ptn_bridge->gpio_pd_n)) {
308		ret = PTR_ERR(ptn_bridge->gpio_pd_n);
309		dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
310		return ret;
311	}
312
313	/*
314	 * Request the reset pin low to avoid the bridge being
315	 * initialized prematurely
316	 */
317	ptn_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset",
318						GPIOD_OUT_LOW);
319	if (IS_ERR(ptn_bridge->gpio_rst_n)) {
320		ret = PTR_ERR(ptn_bridge->gpio_rst_n);
321		DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
322		return ret;
323	}
324
325	ret = of_property_read_u32(dev->of_node, "edid-emulation",
326			&ptn_bridge->edid_emulation);
327	if (ret) {
328		dev_err(dev, "Can't read EDID emulation value\n");
329		return ret;
330	}
331
332	ptn_bridge->bridge.funcs = &ptn3460_bridge_funcs;
333	ptn_bridge->bridge.of_node = dev->of_node;
334	drm_bridge_add(&ptn_bridge->bridge);
335
336	i2c_set_clientdata(client, ptn_bridge);
337
338	return 0;
339}
340
341static int ptn3460_remove(struct i2c_client *client)
342{
343	struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);
344
345	drm_bridge_remove(&ptn_bridge->bridge);
346
347	return 0;
348}
349
350static const struct i2c_device_id ptn3460_i2c_table[] = {
351	{"ptn3460", 0},
352	{},
353};
354MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);
355
356static const struct of_device_id ptn3460_match[] = {
357	{ .compatible = "nxp,ptn3460" },
358	{},
359};
360MODULE_DEVICE_TABLE(of, ptn3460_match);
361
362static struct i2c_driver ptn3460_driver = {
363	.id_table	= ptn3460_i2c_table,
364	.probe		= ptn3460_probe,
365	.remove		= ptn3460_remove,
366	.driver		= {
367		.name	= "nxp,ptn3460",
368		.of_match_table = ptn3460_match,
369	},
370};
371module_i2c_driver(ptn3460_driver);
372
373MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
374MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
375MODULE_LICENSE("GPL v2");