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(ptn_bridge->client, &addr, 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(ptn_bridge->client, buf, 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(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			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(ptn_bridge->gpio_pd_n, 1);
124
125	gpiod_set_value(ptn_bridge->gpio_rst_n, 0);
126	usleep_range(10, 20);
127	gpiod_set_value(ptn_bridge->gpio_rst_n, 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(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(ptn_bridge->gpio_rst_n, 1);
153	gpiod_set_value(ptn_bridge->gpio_pd_n, 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(&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, edid,
176				 EDID_LENGTH);
177	if (ret) {
178		kfree(edid);
179		goto out;
180	}
181
182	drm_edid = drm_edid_alloc(edid, EDID_LENGTH);
183
184out:
185	if (power_off)
186		ptn3460_disable(&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(&ptn_bridge->bridge, connector);
198	drm_edid_connector_update(connector, 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(bridge->encoder, ptn_bridge->panel_bridge,
225				bridge, 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	ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
233	ret = drm_connector_init(bridge->dev, &ptn_bridge->connector,
234			&ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
235	if (ret) {
236		DRM_ERROR("Failed to initialize connector with drm\n");
237		return ret;
238	}
239	drm_connector_helper_add(&ptn_bridge->connector,
240					&ptn3460_connector_helper_funcs);
241	drm_connector_register(&ptn_bridge->connector);
242	drm_connector_attach_encoder(&ptn_bridge->connector,
243							bridge->encoder);
244
245	drm_helper_hpd_irq_event(ptn_bridge->connector.dev);
246
247	return ret;
248}
249
250static const struct drm_bridge_funcs ptn3460_bridge_funcs = {
251	.pre_enable = ptn3460_pre_enable,
252	.disable = ptn3460_disable,
253	.attach = ptn3460_bridge_attach,
254	.edid_read = ptn3460_edid_read,
255};
256
257static int ptn3460_probe(struct i2c_client *client)
258{
259	struct device *dev = &client->dev;
260	struct ptn3460_bridge *ptn_bridge;
261	struct drm_bridge *panel_bridge;
262	int ret;
263
264	ptn_bridge = devm_kzalloc(dev, sizeof(*ptn_bridge), GFP_KERNEL);
265	if (!ptn_bridge) {
266		return -ENOMEM;
267	}
268
269	panel_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
270	if (IS_ERR(panel_bridge))
271		return PTR_ERR(panel_bridge);
272
273	ptn_bridge->panel_bridge = panel_bridge;
274	ptn_bridge->client = client;
275
276	ptn_bridge->gpio_pd_n = devm_gpiod_get(&client->dev, "powerdown",
277					       GPIOD_OUT_HIGH);
278	if (IS_ERR(ptn_bridge->gpio_pd_n)) {
279		ret = PTR_ERR(ptn_bridge->gpio_pd_n);
280		dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
281		return ret;
282	}
283
284	/*
285	 * Request the reset pin low to avoid the bridge being
286	 * initialized prematurely
287	 */
288	ptn_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset",
289						GPIOD_OUT_LOW);
290	if (IS_ERR(ptn_bridge->gpio_rst_n)) {
291		ret = PTR_ERR(ptn_bridge->gpio_rst_n);
292		DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
293		return ret;
294	}
295
296	ret = of_property_read_u32(dev->of_node, "edid-emulation",
297			&ptn_bridge->edid_emulation);
298	if (ret) {
299		dev_err(dev, "Can't read EDID emulation value\n");
300		return ret;
301	}
302
303	ptn_bridge->bridge.funcs = &ptn3460_bridge_funcs;
304	ptn_bridge->bridge.ops = DRM_BRIDGE_OP_EDID;
305	ptn_bridge->bridge.type = DRM_MODE_CONNECTOR_LVDS;
306	ptn_bridge->bridge.of_node = dev->of_node;
307	drm_bridge_add(&ptn_bridge->bridge);
308
309	i2c_set_clientdata(client, ptn_bridge);
310
311	return 0;
312}
313
314static void ptn3460_remove(struct i2c_client *client)
315{
316	struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);
317
318	drm_bridge_remove(&ptn_bridge->bridge);
319}
320
321static const struct i2c_device_id ptn3460_i2c_table[] = {
322	{"ptn3460", 0},
323	{},
324};
325MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);
326
327static const struct of_device_id ptn3460_match[] = {
328	{ .compatible = "nxp,ptn3460" },
329	{},
330};
331MODULE_DEVICE_TABLE(of, ptn3460_match);
332
333static struct i2c_driver ptn3460_driver = {
334	.id_table	= ptn3460_i2c_table,
335	.probe		= ptn3460_probe,
336	.remove		= ptn3460_remove,
337	.driver		= {
338		.name	= "nxp,ptn3460",
339		.of_match_table = ptn3460_match,
340	},
341};
342module_i2c_driver(ptn3460_driver);
343
344MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
345MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
346MODULE_LICENSE("GPL v2");