nxp-ptn3460.c

  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_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 drm_bridge *panel_bridge;
 32	struct gpio_desc *gpio_pd_n;
 33	struct gpio_desc *gpio_rst_n;
 34	u32 edid_emulation;
 35	bool enabled;
 36};
 37
 38static inline struct ptn3460_bridge *
 39		bridge_to_ptn3460(struct drm_bridge *bridge)
 40{
 41	return container_of(bridge, struct ptn3460_bridge, bridge);
 42}
 43
 44static inline struct ptn3460_bridge *
 45		connector_to_ptn3460(struct drm_connector *connector)
 46{
 47	return container_of(connector, struct ptn3460_bridge, connector);
 48}
 49
 50static int ptn3460_read_bytes(struct ptn3460_bridge *ptn_bridge, char addr,
 51		u8 *buf, int len)
 52{
 53	int ret;
 54
 55	ret = i2c_master_send(ptn_bridge->client, &addr, 1);
 56	if (ret < 0) {
 57		DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
 58		return ret;
 59	}
 60
 61	ret = i2c_master_recv(ptn_bridge->client, buf, len);
 62	if (ret < 0) {
 63		DRM_ERROR("Failed to recv i2c data, ret=%d\n", ret);
 64		return ret;
 65	}
 66
 67	return 0;
 68}
 69
 70static int ptn3460_write_byte(struct ptn3460_bridge *ptn_bridge, char addr,
 71		char val)
 72{
 73	int ret;
 74	char buf[2];
 75
 76	buf[0] = addr;
 77	buf[1] = val;
 78
 79	ret = i2c_master_send(ptn_bridge->client, buf, ARRAY_SIZE(buf));
 80	if (ret < 0) {
 81		DRM_ERROR("Failed to send i2c command, ret=%d\n", ret);
 82		return ret;
 83	}
 84
 85	return 0;
 86}
 87
 88static int ptn3460_select_edid(struct ptn3460_bridge *ptn_bridge)
 89{
 90	int ret;
 91	char val;
 92
 93	/* Load the selected edid into SRAM (accessed at PTN3460_EDID_ADDR) */
 94	ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_SRAM_LOAD_ADDR,
 95			ptn_bridge->edid_emulation);
 96	if (ret) {
 97		DRM_ERROR("Failed to transfer EDID to sram, ret=%d\n", ret);
 98		return ret;
 99	}
100
101	/* Enable EDID emulation and select the desired EDID */
102	val = 1 << PTN3460_EDID_ENABLE_EMULATION |
103		ptn_bridge->edid_emulation << PTN3460_EDID_EMULATION_SELECTION;
104
105	ret = ptn3460_write_byte(ptn_bridge, PTN3460_EDID_EMULATION_ADDR, val);
106	if (ret) {
107		DRM_ERROR("Failed to write EDID value, ret=%d\n", ret);
108		return ret;
109	}
110
111	return 0;
112}
113
114static void ptn3460_pre_enable(struct drm_bridge *bridge)
115{
116	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
117	int ret;
118
119	if (ptn_bridge->enabled)
120		return;
121
122	gpiod_set_value(ptn_bridge->gpio_pd_n, 1);
123
124	gpiod_set_value(ptn_bridge->gpio_rst_n, 0);
125	usleep_range(10, 20);
126	gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
127
128	/*
129	 * There's a bug in the PTN chip where it falsely asserts hotplug before
130	 * it is fully functional. We're forced to wait for the maximum start up
131	 * time specified in the chip's datasheet to make sure we're really up.
132	 */
133	msleep(90);
134
135	ret = ptn3460_select_edid(ptn_bridge);
136	if (ret)
137		DRM_ERROR("Select EDID failed ret=%d\n", ret);
138
139	ptn_bridge->enabled = true;
140}
141
142static void ptn3460_disable(struct drm_bridge *bridge)
143{
144	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
145
146	if (!ptn_bridge->enabled)
147		return;
148
149	ptn_bridge->enabled = false;
150
151	gpiod_set_value(ptn_bridge->gpio_rst_n, 1);
152	gpiod_set_value(ptn_bridge->gpio_pd_n, 0);
153}
154
155
156static const struct drm_edid *ptn3460_edid_read(struct drm_bridge *bridge,
157						struct drm_connector *connector)
158{
159	struct ptn3460_bridge *ptn_bridge = bridge_to_ptn3460(bridge);
160	const struct drm_edid *drm_edid = NULL;
161	bool power_off;
162	u8 *edid;
163	int ret;
164
165	power_off = !ptn_bridge->enabled;
166	ptn3460_pre_enable(&ptn_bridge->bridge);
167
168	edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
169	if (!edid) {
170		DRM_ERROR("Failed to allocate EDID\n");
171		goto out;
172	}
173
174	ret = ptn3460_read_bytes(ptn_bridge, PTN3460_EDID_ADDR, edid,
175				 EDID_LENGTH);
176	if (ret) {
177		kfree(edid);
178		goto out;
179	}
180
181	drm_edid = drm_edid_alloc(edid, EDID_LENGTH);
182
183out:
184	if (power_off)
185		ptn3460_disable(&ptn_bridge->bridge);
186
187	return drm_edid;
188}
189
190static int ptn3460_connector_get_modes(struct drm_connector *connector)
191{
192	struct ptn3460_bridge *ptn_bridge = connector_to_ptn3460(connector);
193	const struct drm_edid *drm_edid;
194	int num_modes;
195
196	drm_edid = ptn3460_edid_read(&ptn_bridge->bridge, connector);
197	drm_edid_connector_update(connector, drm_edid);
198	num_modes = drm_edid_connector_add_modes(connector);
199	drm_edid_free(drm_edid);
200
201	return num_modes;
202}
203
204static const struct drm_connector_helper_funcs ptn3460_connector_helper_funcs = {
205	.get_modes = ptn3460_connector_get_modes,
206};
207
208static const struct drm_connector_funcs ptn3460_connector_funcs = {
209	.fill_modes = drm_helper_probe_single_connector_modes,
210	.destroy = drm_connector_cleanup,
211	.reset = drm_atomic_helper_connector_reset,
212	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
213	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
214};
215
216static int ptn3460_bridge_attach(struct drm_bridge *bridge,
217				 struct drm_encoder *encoder,
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(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							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_drm_bridge_alloc(dev, struct ptn3460_bridge, bridge,
265					   &ptn3460_bridge_funcs);
266	if (IS_ERR(ptn_bridge))
267		return PTR_ERR(ptn_bridge);
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.ops = DRM_BRIDGE_OP_EDID;
304	ptn_bridge->bridge.type = DRM_MODE_CONNECTOR_LVDS;
305	ptn_bridge->bridge.of_node = dev->of_node;
306	drm_bridge_add(&ptn_bridge->bridge);
307
308	i2c_set_clientdata(client, ptn_bridge);
309
310	return 0;
311}
312
313static void ptn3460_remove(struct i2c_client *client)
314{
315	struct ptn3460_bridge *ptn_bridge = i2c_get_clientdata(client);
316
317	drm_bridge_remove(&ptn_bridge->bridge);
318}
319
320static const struct i2c_device_id ptn3460_i2c_table[] = {
321	{ "ptn3460" },
322	{}
323};
324MODULE_DEVICE_TABLE(i2c, ptn3460_i2c_table);
325
326static const struct of_device_id ptn3460_match[] = {
327	{ .compatible = "nxp,ptn3460" },
328	{},
329};
330MODULE_DEVICE_TABLE(of, ptn3460_match);
331
332static struct i2c_driver ptn3460_driver = {
333	.id_table	= ptn3460_i2c_table,
334	.probe		= ptn3460_probe,
335	.remove		= ptn3460_remove,
336	.driver		= {
337		.name	= "nxp,ptn3460",
338		.of_match_table = ptn3460_match,
339	},
340};
341module_i2c_driver(ptn3460_driver);
342
343MODULE_AUTHOR("Sean Paul <seanpaul@chromium.org>");
344MODULE_DESCRIPTION("NXP ptn3460 eDP-LVDS converter driver");
345MODULE_LICENSE("GPL v2");