1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * THC63LVD1024 LVDS to parallel data DRM bridge driver.
  4 *
  5 * Copyright (C) 2018 Jacopo Mondi <jacopo+renesas@jmondi.org>
  6 */
  7
  8#include <linux/gpio/consumer.h>
  9#include <linux/module.h>
 10#include <linux/of.h>
 11#include <linux/of_graph.h>
 12#include <linux/platform_device.h>
 13#include <linux/regulator/consumer.h>
 14#include <linux/slab.h>
 15
 16#include <drm/drm_bridge.h>
 17#include <drm/drm_panel.h>
 18
 19enum thc63_ports {
 20	THC63_LVDS_IN0,
 21	THC63_LVDS_IN1,
 22	THC63_RGB_OUT0,
 23	THC63_RGB_OUT1,
 24};
 25
 26struct thc63_dev {
 27	struct device *dev;
 28
 29	struct regulator *vcc;
 30
 31	struct gpio_desc *pdwn;
 32	struct gpio_desc *oe;
 33
 34	struct drm_bridge bridge;
 35	struct drm_bridge *next;
 36
 37	struct drm_bridge_timings timings;
 38};
 39
 40static inline struct thc63_dev *to_thc63(struct drm_bridge *bridge)
 41{
 42	return container_of(bridge, struct thc63_dev, bridge);
 43}
 44
 45static int thc63_attach(struct drm_bridge *bridge,
 46			enum drm_bridge_attach_flags flags)
 47{
 48	struct thc63_dev *thc63 = to_thc63(bridge);
 49
 50	return drm_bridge_attach(bridge->encoder, thc63->next, bridge, flags);
 51}
 52
 53static enum drm_mode_status thc63_mode_valid(struct drm_bridge *bridge,
 54					const struct drm_display_info *info,
 55					const struct drm_display_mode *mode)
 56{
 57	struct thc63_dev *thc63 = to_thc63(bridge);
 58	unsigned int min_freq;
 59	unsigned int max_freq;
 60
 61	/*
 62	 * The THC63LVD1024 pixel rate range is 8 to 135 MHz in all modes but
 63	 * dual-in, single-out where it is 40 to 150 MHz. As dual-in, dual-out
 64	 * isn't supported by the driver yet, simply derive the limits from the
 65	 * input mode.
 66	 */
 67	if (thc63->timings.dual_link) {
 68		min_freq = 40000;
 69		max_freq = 150000;
 70	} else {
 71		min_freq = 8000;
 72		max_freq = 135000;
 73	}
 74
 75	if (mode->clock < min_freq)
 76		return MODE_CLOCK_LOW;
 77
 78	if (mode->clock > max_freq)
 79		return MODE_CLOCK_HIGH;
 80
 81	return MODE_OK;
 82}
 83
 84static void thc63_enable(struct drm_bridge *bridge)
 85{
 86	struct thc63_dev *thc63 = to_thc63(bridge);
 87	int ret;
 88
 89	ret = regulator_enable(thc63->vcc);
 90	if (ret) {
 91		dev_err(thc63->dev,
 92			"Failed to enable regulator \"vcc\": %d\n", ret);
 93		return;
 94	}
 95
 96	gpiod_set_value(thc63->pdwn, 0);
 97	gpiod_set_value(thc63->oe, 1);
 98}
 99
100static void thc63_disable(struct drm_bridge *bridge)
101{
102	struct thc63_dev *thc63 = to_thc63(bridge);
103	int ret;
104
105	gpiod_set_value(thc63->oe, 0);
106	gpiod_set_value(thc63->pdwn, 1);
107
108	ret = regulator_disable(thc63->vcc);
109	if (ret)
110		dev_err(thc63->dev,
111			"Failed to disable regulator \"vcc\": %d\n", ret);
112}
113
114static const struct drm_bridge_funcs thc63_bridge_func = {
115	.attach	= thc63_attach,
116	.mode_valid = thc63_mode_valid,
117	.enable = thc63_enable,
118	.disable = thc63_disable,
119};
120
121static int thc63_parse_dt(struct thc63_dev *thc63)
122{
123	struct device_node *endpoint;
124	struct device_node *remote;
125
126	endpoint = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
127						 THC63_RGB_OUT0, -1);
128	if (!endpoint) {
129		dev_err(thc63->dev, "Missing endpoint in port@%u\n",
130			THC63_RGB_OUT0);
131		return -ENODEV;
132	}
133
134	remote = of_graph_get_remote_port_parent(endpoint);
135	of_node_put(endpoint);
136	if (!remote) {
137		dev_err(thc63->dev, "Endpoint in port@%u unconnected\n",
138			THC63_RGB_OUT0);
139		return -ENODEV;
140	}
141
142	if (!of_device_is_available(remote)) {
143		dev_err(thc63->dev, "port@%u remote endpoint is disabled\n",
144			THC63_RGB_OUT0);
145		of_node_put(remote);
146		return -ENODEV;
147	}
148
149	thc63->next = of_drm_find_bridge(remote);
150	of_node_put(remote);
151	if (!thc63->next)
152		return -EPROBE_DEFER;
153
154	endpoint = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
155						 THC63_LVDS_IN1, -1);
156	if (endpoint) {
157		remote = of_graph_get_remote_port_parent(endpoint);
158		of_node_put(endpoint);
159
160		if (remote) {
161			if (of_device_is_available(remote))
162				thc63->timings.dual_link = true;
163			of_node_put(remote);
164		}
165	}
166
167	dev_dbg(thc63->dev, "operating in %s-link mode\n",
168		thc63->timings.dual_link ? "dual" : "single");
169
170	return 0;
171}
172
173static int thc63_gpio_init(struct thc63_dev *thc63)
174{
175	thc63->oe = devm_gpiod_get_optional(thc63->dev, "oe", GPIOD_OUT_LOW);
176	if (IS_ERR(thc63->oe)) {
177		dev_err(thc63->dev, "Unable to get \"oe-gpios\": %ld\n",
178			PTR_ERR(thc63->oe));
179		return PTR_ERR(thc63->oe);
180	}
181
182	thc63->pdwn = devm_gpiod_get_optional(thc63->dev, "powerdown",
183					      GPIOD_OUT_HIGH);
184	if (IS_ERR(thc63->pdwn)) {
185		dev_err(thc63->dev, "Unable to get \"powerdown-gpios\": %ld\n",
186			PTR_ERR(thc63->pdwn));
187		return PTR_ERR(thc63->pdwn);
188	}
189
190	return 0;
191}
192
193static int thc63_probe(struct platform_device *pdev)
194{
195	struct thc63_dev *thc63;
196	int ret;
197
198	thc63 = devm_kzalloc(&pdev->dev, sizeof(*thc63), GFP_KERNEL);
199	if (!thc63)
200		return -ENOMEM;
201
202	thc63->dev = &pdev->dev;
203	platform_set_drvdata(pdev, thc63);
204
205	thc63->vcc = devm_regulator_get(thc63->dev, "vcc");
206	if (IS_ERR(thc63->vcc)) {
207		if (PTR_ERR(thc63->vcc) == -EPROBE_DEFER)
208			return -EPROBE_DEFER;
209
210		dev_err(thc63->dev, "Unable to get \"vcc\" supply: %ld\n",
211			PTR_ERR(thc63->vcc));
212		return PTR_ERR(thc63->vcc);
213	}
214
215	ret = thc63_gpio_init(thc63);
216	if (ret)
217		return ret;
218
219	ret = thc63_parse_dt(thc63);
220	if (ret)
221		return ret;
222
223	thc63->bridge.driver_private = thc63;
224	thc63->bridge.of_node = pdev->dev.of_node;
225	thc63->bridge.funcs = &thc63_bridge_func;
226	thc63->bridge.timings = &thc63->timings;
227
228	drm_bridge_add(&thc63->bridge);
229
230	return 0;
231}
232
233static void thc63_remove(struct platform_device *pdev)
234{
235	struct thc63_dev *thc63 = platform_get_drvdata(pdev);
236
237	drm_bridge_remove(&thc63->bridge);
238}
239
240static const struct of_device_id thc63_match[] = {
241	{ .compatible = "thine,thc63lvd1024", },
242	{ },
243};
244MODULE_DEVICE_TABLE(of, thc63_match);
245
246static struct platform_driver thc63_driver = {
247	.probe	= thc63_probe,
248	.remove_new = thc63_remove,
249	.driver	= {
250		.name		= "thc63lvd1024",
251		.of_match_table	= thc63_match,
252	},
253};
254module_platform_driver(thc63_driver);
255
256MODULE_AUTHOR("Jacopo Mondi <jacopo@jmondi.org>");
257MODULE_DESCRIPTION("Thine THC63LVD1024 LVDS decoder DRM bridge driver");
258MODULE_LICENSE("GPL v2");