tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2016 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
4 */
5
6#include <linux/gpio/consumer.h>
7#include <linux/module.h>
8#include <linux/of.h>
9#include <linux/of_graph.h>
10#include <linux/platform_device.h>
11
12#include <drm/drm_bridge.h>
13#include <drm/drm_panel.h>
14
15struct lvds_encoder {
16 struct drm_bridge bridge;
17 struct drm_bridge *panel_bridge;
18 struct gpio_desc *powerdown_gpio;
19};
20
21static int lvds_encoder_attach(struct drm_bridge *bridge)
22{
23 struct lvds_encoder *lvds_encoder = container_of(bridge,
24 struct lvds_encoder,
25 bridge);
26
27 return drm_bridge_attach(bridge->encoder, lvds_encoder->panel_bridge,
28 bridge);
29}
30
31static void lvds_encoder_enable(struct drm_bridge *bridge)
32{
33 struct lvds_encoder *lvds_encoder = container_of(bridge,
34 struct lvds_encoder,
35 bridge);
36
37 if (lvds_encoder->powerdown_gpio)
38 gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 0);
39}
40
41static void lvds_encoder_disable(struct drm_bridge *bridge)
42{
43 struct lvds_encoder *lvds_encoder = container_of(bridge,
44 struct lvds_encoder,
45 bridge);
46
47 if (lvds_encoder->powerdown_gpio)
48 gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 1);
49}
50
51static struct drm_bridge_funcs funcs = {
52 .attach = lvds_encoder_attach,
53 .enable = lvds_encoder_enable,
54 .disable = lvds_encoder_disable,
55};
56
57static int lvds_encoder_probe(struct platform_device *pdev)
58{
59 struct device *dev = &pdev->dev;
60 struct device_node *port;
61 struct device_node *endpoint;
62 struct device_node *panel_node;
63 struct drm_panel *panel;
64 struct lvds_encoder *lvds_encoder;
65
66 lvds_encoder = devm_kzalloc(dev, sizeof(*lvds_encoder), GFP_KERNEL);
67 if (!lvds_encoder)
68 return -ENOMEM;
69
70 lvds_encoder->powerdown_gpio = devm_gpiod_get_optional(dev, "powerdown",
71 GPIOD_OUT_HIGH);
72 if (IS_ERR(lvds_encoder->powerdown_gpio)) {
73 int err = PTR_ERR(lvds_encoder->powerdown_gpio);
74
75 if (err != -EPROBE_DEFER)
76 dev_err(dev, "powerdown GPIO failure: %d\n", err);
77 return err;
78 }
79
80 /* Locate the panel DT node. */
81 port = of_graph_get_port_by_id(dev->of_node, 1);
82 if (!port) {
83 dev_dbg(dev, "port 1 not found\n");
84 return -ENXIO;
85 }
86
87 endpoint = of_get_child_by_name(port, "endpoint");
88 of_node_put(port);
89 if (!endpoint) {
90 dev_dbg(dev, "no endpoint for port 1\n");
91 return -ENXIO;
92 }
93
94 panel_node = of_graph_get_remote_port_parent(endpoint);
95 of_node_put(endpoint);
96 if (!panel_node) {
97 dev_dbg(dev, "no remote endpoint for port 1\n");
98 return -ENXIO;
99 }
100
101 panel = of_drm_find_panel(panel_node);
102 of_node_put(panel_node);
103 if (IS_ERR(panel)) {
104 dev_dbg(dev, "panel not found, deferring probe\n");
105 return PTR_ERR(panel);
106 }
107
108 lvds_encoder->panel_bridge =
109 devm_drm_panel_bridge_add(dev, panel, DRM_MODE_CONNECTOR_LVDS);
110 if (IS_ERR(lvds_encoder->panel_bridge))
111 return PTR_ERR(lvds_encoder->panel_bridge);
112
113 /* The panel_bridge bridge is attached to the panel's of_node,
114 * but we need a bridge attached to our of_node for our user
115 * to look up.
116 */
117 lvds_encoder->bridge.of_node = dev->of_node;
118 lvds_encoder->bridge.funcs = &funcs;
119 drm_bridge_add(&lvds_encoder->bridge);
120
121 platform_set_drvdata(pdev, lvds_encoder);
122
123 return 0;
124}
125
126static int lvds_encoder_remove(struct platform_device *pdev)
127{
128 struct lvds_encoder *lvds_encoder = platform_get_drvdata(pdev);
129
130 drm_bridge_remove(&lvds_encoder->bridge);
131
132 return 0;
133}
134
135static const struct of_device_id lvds_encoder_match[] = {
136 { .compatible = "lvds-encoder" },
137 { .compatible = "thine,thc63lvdm83d" },
138 {},
139};
140MODULE_DEVICE_TABLE(of, lvds_encoder_match);
141
142static struct platform_driver lvds_encoder_driver = {
143 .probe = lvds_encoder_probe,
144 .remove = lvds_encoder_remove,
145 .driver = {
146 .name = "lvds-encoder",
147 .of_match_table = lvds_encoder_match,
148 },
149};
150module_platform_driver(lvds_encoder_driver);
151
152MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
153MODULE_DESCRIPTION("Transparent parallel to LVDS encoder");
154MODULE_LICENSE("GPL");