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_crtc.h>
 15#include <drm/drm_edid.h>
 16#include <drm/drm_of.h>
 17#include <drm/drm_panel.h>
 18#include <drm/drm_print.h>
 19#include <drm/drm_probe_helper.h>
 20
 21#define PTN3460_EDID_ADDR			0x0
 22#define PTN3460_EDID_EMULATION_ADDR		0x84
 23#define PTN3460_EDID_ENABLE_EMULATION		0
 24#define PTN3460_EDID_EMULATION_SELECTION	1
 25#define PTN3460_EDID_SRAM_LOAD_ADDR		0x85
 26
 27struct ptn3460_bridge {
 28	struct drm_connector connector;
 29	struct i2c_client *client;
 30	struct drm_bridge bridge;
 31	struct edid *edid;
 32	struct drm_panel *panel;
 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	if (drm_panel_prepare(ptn_bridge->panel)) {
130		DRM_ERROR("failed to prepare panel\n");
131		return;
132	}
133
134	/*
135	 * There's a bug in the PTN chip where it falsely asserts hotplug before
136	 * it is fully functional. We're forced to wait for the maximum start up
137	 * time specified in the chip's datasheet to make sure we're really up.
138	 */
139	msleep(90);
140
141	ret = ptn3460_select_edid(ptn_bridge);
142	if (ret)
143		DRM_ERROR("Select EDID failed ret=%d\n", ret);
144
145	ptn_bridge->enabled = true;
146}
147
148static void ptn3460_enable(struct drm_bridge *bridge)
149{
150	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
151
152	if (drm_panel_enable(ptn_bridge->panel)) {
153		DRM_ERROR("failed to enable panel\n");
154		return;
155	}
156}
157
158static void ptn3460_disable(struct drm_bridge *bridge)
159{
160	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
161
162	if (!ptn_bridge->enabled)
163		return;
164
165	ptn_bridge->enabled = false;
166
167	if (drm_panel_disable(ptn_bridge->panel)) {
168		DRM_ERROR("failed to disable panel\n");
169		return;
170	}
171
172	gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
173	gpiod_set_value(ptn_bridge->gpio_pd_n, 0);
174}
175
176static void ptn3460_post_disable(struct drm_bridge *bridge)
177{
178	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
179
180	if (drm_panel_unprepare(ptn_bridge->panel)) {
181		DRM_ERROR("failed to unprepare panel\n");
182		return;
183	}
184}
185
186static int ptn3460_get_modes(struct drm_connector *connector)
187{
188	struct ptn3460_bridge *ptn_bridge;
189	u8 *edid;
190	int ret, num_modes = 0;
191	bool power_off;
192
193	ptn_bridge = connector_to_ptn3460(connector);
194
195	if (ptn_bridge->edid)
196		return drm_add_edid_modes(connector, ptn_bridge->edid);
197
198	power_off = !ptn_bridge->enabled;
199	ptn3460_pre_enable(&ptn_bridge->bridge);
200
201	edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
202	if (!edid) {
203		DRM_ERROR("Failed to allocate EDID\n");
204		return 0;
205	}
206
207	ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
208			EDID_LENGTH);
209	if (ret) {
210		kfree(edid);
211		goto out;
212	}
213
214	ptn_bridge->edid = (struct edid *)edid;
215	drm_connector_update_edid_property(connector, ptn_bridge->edid);
216
217	num_modes = drm_add_edid_modes(connector, ptn_bridge->edid);
218
219out:
220	if (power_off)
221		ptn3460_disable(&ptn_bridge->bridge);
222
223	return num_modes;
224}
225
226static const struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
227	.get_modes = ptn3460_get_modes,
228};
229
230static const struct drm_connector_funcs ptn3460_connector_funcs = {
231	.fill_modes = drm_helper_probe_single_connector_modes,
232	.destroy = drm_connector_cleanup,
233	.reset = drm_atomic_helper_connector_reset,
234	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
235	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
236};
237
238static int ptn3460_bridge_attach(struct drm_bridge *bridge)
239{
240	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
241	int ret;
242
243	if (!bridge->encoder) {
244		DRM_ERROR("Parent encoder object not found");
245		return -ENODEV;
246	}
247
248	ptn_bridge->connector.polled = DRM_CONNECTOR_POLL_HPD;
249	ret = drm_connector_init(bridge->dev, &ptn_bridge->connector,
250			&ptn3460_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
251	if (ret) {
252		DRM_ERROR("Failed to initialize connector with drm\n");
253		return ret;
254	}
255	drm_connector_helper_add(&ptn_bridge->connector,
256					&ptn3460_connector_helper_funcs);
257	drm_connector_register(&ptn_bridge->connector);
258	drm_connector_attach_encoder(&ptn_bridge->connector,
259							bridge->encoder);
260
261	if (ptn_bridge->panel)
262		drm_panel_attach(ptn_bridge->panel, &ptn_bridge->connector);
263
264	drm_helper_hpd_irq_event(ptn_bridge->connector.dev);
265
266	return ret;
267}
268
269static const struct drm_bridge_funcs ptn3460_bridge_funcs = {
270	.pre_enable = ptn3460_pre_enable,
271	.enable = ptn3460_enable,
272	.disable = ptn3460_disable,
273	.post_disable = ptn3460_post_disable,
274	.attach = ptn3460_bridge_attach,
275};
276
277static int ptn3460_probe(struct i2c_client *client,
278				const struct i2c_device_id *id)
279{
280	struct device *dev = &client->dev;
281	struct ptn3460_bridge *ptn_bridge;
282	int ret;
283
284	ptn_bridge = devm_kzalloc(dev, sizeof(*ptn_bridge), GFP_KERNEL);
285	if (!ptn_bridge) {
286		return -ENOMEM;
287	}
288
289	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &ptn_bridge->panel, NULL);
290	if (ret)
291		return ret;
292
293	ptn_bridge->client = client;
294
295	ptn_bridge->gpio_pd_n = devm_gpiod_get(&client->dev, "powerdown",
296					       GPIOD_OUT_HIGH);
297	if (IS_ERR(ptn_bridge->gpio_pd_n)) {
298		ret = PTR_ERR(ptn_bridge->gpio_pd_n);
299		dev_err(dev, "cannot get gpio_pd_n %d\n", ret);
300		return ret;
301	}
302
303	/*
304	 * Request the reset pin low to avoid the bridge being
305	 * initialized prematurely
306	 */
307	ptn_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset",
308						GPIOD_OUT_LOW);
309	if (IS_ERR(ptn_bridge->gpio_rst_n)) {
310		ret = PTR_ERR(ptn_bridge->gpio_rst_n);
311		DRM_ERROR("cannot get gpio_rst_n %d\n", ret);
312		return ret;
313	}
314
315	ret = of_property_read_u32(dev->of_node, "edid-emulation",
316			&ptn_bridge->edid_emulation);
317	if (ret) {
318		dev_err(dev, "Can't read EDID emulation value\n");
319		return ret;
320	}
321
322	ptn_bridge->bridge.funcs = &ptn3460_bridge_funcs;
323	ptn_bridge->bridge.of_node = dev->of_node;
324	drm_bridge_add(&ptn_bridge->bridge);
325
326	i2c_set_clientdata(client, ptn_bridge);
327
328	return 0;
329}
330
331static int ptn3460_remove(struct i2c_client *client)
332{
333	struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);
334
335	drm_bridge_remove(&ptn_bridge->bridge);
336
337	return 0;
338}
339
340static const struct i2c_device_id ptn3460_i2c_table[] = {
341	{"ptn3460", 0},
342	{},
343};
344MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);
345
346static const struct of_device_id ptn3460_match[] = {
347	{ .compatible = "nxp,ptn3460" },
348	{},
349};
350MODULE_DEVICE_TABLE(of, ptn3460_match);
351
352static struct i2c_driver ptn3460_driver = {
353	.id_table	= ptn3460_i2c_table,
354	.probe		= ptn3460_probe,
355	.remove		= ptn3460_remove,
356	.driver		= {
357		.name	= "nxp,ptn3460",
358		.of_match_table = ptn3460_match,
359	},
360};
361module_i2c_driver(ptn3460_driver);
362
363MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
364MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
365MODULE_LICENSE("GPL v2");