tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2016 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of
7 * the License, or (at your option) any later version.
8 */
9
10#include <drm/drmP.h>
11#include <drm/drm_bridge.h>
12#include <drm/drm_panel.h>
13
14#include <linux/gpio/consumer.h>
15#include <linux/of_graph.h>
16
17struct lvds_encoder {
18 struct drm_bridge bridge;
19 struct drm_bridge *panel_bridge;
20 struct gpio_desc *powerdown_gpio;
21};
22
23static int lvds_encoder_attach(struct drm_bridge *bridge)
24{
25 struct lvds_encoder *lvds_encoder = container_of(bridge,
26 struct lvds_encoder,
27 bridge);
28
29 return drm_bridge_attach(bridge->encoder, lvds_encoder->panel_bridge,
30 bridge);
31}
32
33static void lvds_encoder_enable(struct drm_bridge *bridge)
34{
35 struct lvds_encoder *lvds_encoder = container_of(bridge,
36 struct lvds_encoder,
37 bridge);
38
39 if (lvds_encoder->powerdown_gpio)
40 gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 0);
41}
42
43static void lvds_encoder_disable(struct drm_bridge *bridge)
44{
45 struct lvds_encoder *lvds_encoder = container_of(bridge,
46 struct lvds_encoder,
47 bridge);
48
49 if (lvds_encoder->powerdown_gpio)
50 gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 1);
51}
52
53static struct drm_bridge_funcs funcs = {
54 .attach = lvds_encoder_attach,
55 .enable = lvds_encoder_enable,
56 .disable = lvds_encoder_disable,
57};
58
59static int lvds_encoder_probe(struct platform_device *pdev)
60{
61 struct device *dev = &pdev->dev;
62 struct device_node *port;
63 struct device_node *endpoint;
64 struct device_node *panel_node;
65 struct drm_panel *panel;
66 struct lvds_encoder *lvds_encoder;
67
68 lvds_encoder = devm_kzalloc(dev, sizeof(*lvds_encoder), GFP_KERNEL);
69 if (!lvds_encoder)
70 return -ENOMEM;
71
72 lvds_encoder->powerdown_gpio = devm_gpiod_get_optional(dev, "powerdown",
73 GPIOD_OUT_HIGH);
74 if (IS_ERR(lvds_encoder->powerdown_gpio)) {
75 int err = PTR_ERR(lvds_encoder->powerdown_gpio);
76
77 if (err != -EPROBE_DEFER)
78 dev_err(dev, "powerdown GPIO failure: %d\n", err);
79 return err;
80 }
81
82 /* Locate the panel DT node. */
83 port = of_graph_get_port_by_id(dev->of_node, 1);
84 if (!port) {
85 dev_dbg(dev, "port 1 not found\n");
86 return -ENXIO;
87 }
88
89 endpoint = of_get_child_by_name(port, "endpoint");
90 of_node_put(port);
91 if (!endpoint) {
92 dev_dbg(dev, "no endpoint for port 1\n");
93 return -ENXIO;
94 }
95
96 panel_node = of_graph_get_remote_port_parent(endpoint);
97 of_node_put(endpoint);
98 if (!panel_node) {
99 dev_dbg(dev, "no remote endpoint for port 1\n");
100 return -ENXIO;
101 }
102
103 panel = of_drm_find_panel(panel_node);
104 of_node_put(panel_node);
105 if (IS_ERR(panel)) {
106 dev_dbg(dev, "panel not found, deferring probe\n");
107 return PTR_ERR(panel);
108 }
109
110 lvds_encoder->panel_bridge =
111 devm_drm_panel_bridge_add(dev, panel, DRM_MODE_CONNECTOR_LVDS);
112 if (IS_ERR(lvds_encoder->panel_bridge))
113 return PTR_ERR(lvds_encoder->panel_bridge);
114
115 /* The panel_bridge bridge is attached to the panel's of_node,
116 * but we need a bridge attached to our of_node for our user
117 * to look up.
118 */
119 lvds_encoder->bridge.of_node = dev->of_node;
120 lvds_encoder->bridge.funcs = &funcs;
121 drm_bridge_add(&lvds_encoder->bridge);
122
123 platform_set_drvdata(pdev, lvds_encoder);
124
125 return 0;
126}
127
128static int lvds_encoder_remove(struct platform_device *pdev)
129{
130 struct lvds_encoder *lvds_encoder = platform_get_drvdata(pdev);
131
132 drm_bridge_remove(&lvds_encoder->bridge);
133
134 return 0;
135}
136
137static const struct of_device_id lvds_encoder_match[] = {
138 { .compatible = "lvds-encoder" },
139 { .compatible = "thine,thc63lvdm83d" },
140 {},
141};
142MODULE_DEVICE_TABLE(of, lvds_encoder_match);
143
144static struct platform_driver lvds_encoder_driver = {
145 .probe = lvds_encoder_probe,
146 .remove = lvds_encoder_remove,
147 .driver = {
148 .name = "lvds-encoder",
149 .of_match_table = lvds_encoder_match,
150 },
151};
152module_platform_driver(lvds_encoder_driver);
153
154MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
155MODULE_DESCRIPTION("Transparent parallel to LVDS encoder");
156MODULE_LICENSE("GPL");