Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2025 NXP
4 * Based on panel-raspberrypi-touchscreen by Broadcom
5 */
6
7#include <linux/backlight.h>
8#include <linux/err.h>
9#include <linux/i2c.h>
10#include <linux/module.h>
11#include <linux/of.h>
12#include <linux/of_graph.h>
13#include <linux/regmap.h>
14
15#include <drm/drm_bridge.h>
16#include <drm/drm_mipi_dsi.h>
17#include <drm/drm_of.h>
18#include <drm/drm_panel.h>
19
20struct ws_bridge {
21 struct drm_bridge bridge;
22 struct drm_bridge *next_bridge;
23 struct backlight_device *backlight;
24 struct device *dev;
25 struct regmap *reg_map;
26};
27
28static const struct regmap_config ws_regmap_config = {
29 .reg_bits = 8,
30 .val_bits = 8,
31 .max_register = 0xff,
32};
33
34static struct ws_bridge *bridge_to_ws_bridge(struct drm_bridge *bridge)
35{
36 return container_of(bridge, struct ws_bridge, bridge);
37}
38
39static int ws_bridge_attach_dsi(struct ws_bridge *ws)
40{
41 const struct mipi_dsi_device_info info = {
42 .type = "ws-bridge",
43 .channel = 0,
44 .node = NULL,
45 };
46 struct device_node *dsi_host_node;
47 struct device *dev = ws->dev;
48 struct mipi_dsi_device *dsi;
49 struct mipi_dsi_host *host;
50 int ret;
51
52 dsi_host_node = of_graph_get_remote_node(dev->of_node, 0, 0);
53 if (!dsi_host_node) {
54 dev_err(dev, "Failed to get remote port\n");
55 return -ENODEV;
56 }
57 host = of_find_mipi_dsi_host_by_node(dsi_host_node);
58 of_node_put(dsi_host_node);
59 if (!host)
60 return dev_err_probe(dev, -EPROBE_DEFER, "Failed to find dsi_host\n");
61
62 dsi = devm_mipi_dsi_device_register_full(dev, host, &info);
63 if (IS_ERR(dsi))
64 return dev_err_probe(dev, PTR_ERR(dsi), "Failed to create dsi device\n");
65
66 dsi->mode_flags = MIPI_DSI_MODE_VIDEO_HSE | MIPI_DSI_MODE_VIDEO |
67 MIPI_DSI_CLOCK_NON_CONTINUOUS;
68 dsi->format = MIPI_DSI_FMT_RGB888;
69 dsi->lanes = 2;
70
71 ret = devm_mipi_dsi_attach(dev, dsi);
72 if (ret < 0)
73 return dev_err_probe(dev, ret, "Failed to attach dsi to host\n");
74
75 return 0;
76}
77
78static int ws_bridge_bridge_attach(struct drm_bridge *bridge,
79 struct drm_encoder *encoder,
80 enum drm_bridge_attach_flags flags)
81{
82 struct ws_bridge *ws = bridge_to_ws_bridge(bridge);
83 int ret;
84
85 ret = ws_bridge_attach_dsi(ws);
86 if (ret)
87 return ret;
88
89 return drm_bridge_attach(encoder, ws->next_bridge,
90 &ws->bridge, flags);
91}
92
93static void ws_bridge_bridge_enable(struct drm_bridge *bridge)
94{
95 struct ws_bridge *ws = bridge_to_ws_bridge(bridge);
96
97 regmap_write(ws->reg_map, 0xad, 0x01);
98 backlight_enable(ws->backlight);
99}
100
101static void ws_bridge_bridge_disable(struct drm_bridge *bridge)
102{
103 struct ws_bridge *ws = bridge_to_ws_bridge(bridge);
104
105 backlight_disable(ws->backlight);
106 regmap_write(ws->reg_map, 0xad, 0x00);
107}
108
109static const struct drm_bridge_funcs ws_bridge_bridge_funcs = {
110 .enable = ws_bridge_bridge_enable,
111 .disable = ws_bridge_bridge_disable,
112 .attach = ws_bridge_bridge_attach,
113};
114
115static int ws_bridge_bl_update_status(struct backlight_device *bl)
116{
117 struct ws_bridge *ws = bl_get_data(bl);
118
119 regmap_write(ws->reg_map, 0xab, 0xff - backlight_get_brightness(bl));
120 regmap_write(ws->reg_map, 0xaa, 0x01);
121
122 return 0;
123}
124
125static const struct backlight_ops ws_bridge_bl_ops = {
126 .update_status = ws_bridge_bl_update_status,
127};
128
129static struct backlight_device *ws_bridge_create_backlight(struct ws_bridge *ws)
130{
131 const struct backlight_properties props = {
132 .type = BACKLIGHT_RAW,
133 .brightness = 255,
134 .max_brightness = 255,
135 };
136 struct device *dev = ws->dev;
137
138 return devm_backlight_device_register(dev, dev_name(dev), dev, ws,
139 &ws_bridge_bl_ops, &props);
140}
141
142static int ws_bridge_probe(struct i2c_client *i2c)
143{
144 struct device *dev = &i2c->dev;
145 struct drm_panel *panel;
146 struct ws_bridge *ws;
147 int ret;
148
149 ws = devm_drm_bridge_alloc(dev, struct ws_bridge, bridge, &ws_bridge_bridge_funcs);
150 if (IS_ERR(ws))
151 return PTR_ERR(ws);
152
153 ws->dev = dev;
154
155 ws->reg_map = devm_regmap_init_i2c(i2c, &ws_regmap_config);
156 if (IS_ERR(ws->reg_map))
157 return dev_err_probe(dev, PTR_ERR(ws->reg_map), "Failed to allocate regmap\n");
158
159 ret = drm_of_find_panel_or_bridge(dev->of_node, 1, -1, &panel, NULL);
160 if (ret)
161 return dev_err_probe(dev, ret, "Failed to find remote panel\n");
162
163 ws->next_bridge = devm_drm_panel_bridge_add(dev, panel);
164 if (IS_ERR(ws->next_bridge))
165 return PTR_ERR(ws->next_bridge);
166
167 ws->backlight = ws_bridge_create_backlight(ws);
168 if (IS_ERR(ws->backlight)) {
169 ret = PTR_ERR(ws->backlight);
170 dev_err(dev, "Failed to create backlight: %d\n", ret);
171 return ret;
172 }
173
174 regmap_write(ws->reg_map, 0xc0, 0x01);
175 regmap_write(ws->reg_map, 0xc2, 0x01);
176 regmap_write(ws->reg_map, 0xac, 0x01);
177
178 ws->bridge.type = DRM_MODE_CONNECTOR_DPI;
179 ws->bridge.of_node = dev->of_node;
180 devm_drm_bridge_add(dev, &ws->bridge);
181
182 return 0;
183}
184
185static const struct of_device_id ws_bridge_of_ids[] = {
186 {.compatible = "waveshare,dsi2dpi",},
187 { }
188};
189
190MODULE_DEVICE_TABLE(of, ws_bridge_of_ids);
191
192static struct i2c_driver ws_bridge_driver = {
193 .driver = {
194 .name = "ws_dsi2dpi",
195 .of_match_table = ws_bridge_of_ids,
196 },
197 .probe = ws_bridge_probe,
198};
199module_i2c_driver(ws_bridge_driver);
200
201MODULE_AUTHOR("Joseph Guo <qijian.guo@nxp.com>");
202MODULE_DESCRIPTION("Waveshare DSI2DPI bridge driver");
203MODULE_LICENSE("GPL");