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