1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
|
From 7d9db46fa0eb27c0d6df7a3a6ae20da515a20e58 Mon Sep 17 00:00:00 2001
From: P33M <P33M@github.com>
Date: Wed, 21 Oct 2015 14:55:21 +0100
Subject: [PATCH 203/203] rpi_display: add backlight driver and overlay
Add a mailbox-driven backlight controller for the Raspberry Pi DSI
touchscreen display. Requires updated GPU firmware to recognise the
mailbox request.
Signed-off-by: Gordon Hollingworth <gordon@raspberrypi.org>
---
arch/arm/boot/dts/overlays/Makefile | 1 +
arch/arm/boot/dts/overlays/README | 6 ++
.../boot/dts/overlays/rpi-backlight-overlay.dts | 21 ++++
arch/arm/configs/bcm2709_defconfig | 1 +
arch/arm/configs/bcmrpi_defconfig | 1 +
drivers/video/backlight/Kconfig | 6 ++
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/rpi_backlight.c | 119 +++++++++++++++++++++
include/soc/bcm2835/raspberrypi-firmware.h | 1 +
9 files changed, 157 insertions(+)
create mode 100644 arch/arm/boot/dts/overlays/rpi-backlight-overlay.dts
create mode 100644 drivers/video/backlight/rpi_backlight.c
--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -40,6 +40,7 @@ dtb-$(RPI_DT_OVERLAYS) += pps-gpio-overl
dtb-$(RPI_DT_OVERLAYS) += pwm-overlay.dtb
dtb-$(RPI_DT_OVERLAYS) += pwm-2chan-overlay.dtb
dtb-$(RPI_DT_OVERLAYS) += raspidac3-overlay.dtb
+dtb-$(RPI_DT_OVERLAYS) += rpi-backlight-overlay.dtb
dtb-$(RPI_DT_OVERLAYS) += rpi-dac-overlay.dtb
dtb-$(RPI_DT_OVERLAYS) += rpi-display-overlay.dtb
dtb-$(RPI_DT_OVERLAYS) += rpi-ft5406-overlay.dtb
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -490,6 +490,12 @@ Load: dtoverlay=raspidac3
Params: <None>
+Name: rpi-backlight
+Info: Raspberry Pi official display backlight driver
+Load: dtoverlay=rpi-backlight
+Params: <None>
+
+
Name: rpi-dac
Info: Configures the RPi DAC audio card
Load: dtoverlay=rpi-dac
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/rpi-backlight-overlay.dts
@@ -0,0 +1,21 @@
+/*
+ * Devicetree overlay for mailbox-driven Raspberry Pi DSI Display
+ * backlight controller
+ */
+/dts-v1/;
+/plugin/;
+
+/ {
+ compatible = "brcm,bcm2708";
+
+ fragment@0 {
+ target-path = "/";
+ __overlay__ {
+ rpi_backlight: rpi_backlight {
+ compatible = "raspberrypi,rpi-backlight";
+ firmware = <&firmware>;
+ status = "okay";
+ };
+ };
+ };
+};
--- a/arch/arm/configs/bcm2709_defconfig
+++ b/arch/arm/configs/bcm2709_defconfig
@@ -806,6 +806,7 @@ CONFIG_FB_BCM2708=y
CONFIG_FB_SSD1307=m
CONFIG_FB_RPISENSE=m
# CONFIG_BACKLIGHT_GENERIC is not set
+CONFIG_BACKLIGHT_RPI=m
CONFIG_BACKLIGHT_GPIO=m
CONFIG_FRAMEBUFFER_CONSOLE=y
CONFIG_LOGO=y
--- a/arch/arm/configs/bcmrpi_defconfig
+++ b/arch/arm/configs/bcmrpi_defconfig
@@ -799,6 +799,7 @@ CONFIG_FB_BCM2708=y
CONFIG_FB_SSD1307=m
CONFIG_FB_RPISENSE=m
# CONFIG_BACKLIGHT_GENERIC is not set
+CONFIG_BACKLIGHT_RPI=m
CONFIG_BACKLIGHT_GPIO=m
CONFIG_FRAMEBUFFER_CONSOLE=y
CONFIG_LOGO=y
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -263,6 +263,12 @@ config BACKLIGHT_PWM
If you have a LCD backlight adjustable by PWM, say Y to enable
this driver.
+config BACKLIGHT_RPI
+ tristate "Raspberry Pi display firmware driven backlight"
+ help
+ If you have the Raspberry Pi DSI touchscreen display, say Y to
+ enable the mailbox-controlled backlight driver.
+
config BACKLIGHT_DA903X
tristate "Backlight Driver for DA9030/DA9034 using WLED"
depends on PMIC_DA903X
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -49,6 +49,7 @@ obj-$(CONFIG_BACKLIGHT_OT200) += ot200_
obj-$(CONFIG_BACKLIGHT_PANDORA) += pandora_bl.o
obj-$(CONFIG_BACKLIGHT_PCF50633) += pcf50633-backlight.o
obj-$(CONFIG_BACKLIGHT_PWM) += pwm_bl.o
+obj-$(CONFIG_BACKLIGHT_RPI) += rpi_backlight.o
obj-$(CONFIG_BACKLIGHT_SAHARA) += kb3886_bl.o
obj-$(CONFIG_BACKLIGHT_SKY81452) += sky81452-backlight.o
obj-$(CONFIG_BACKLIGHT_TOSA) += tosa_bl.o
--- /dev/null
+++ b/drivers/video/backlight/rpi_backlight.c
@@ -0,0 +1,119 @@
+/*
+ * rpi_bl.c - Backlight controller through VPU
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/backlight.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <linux/gpio.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+struct rpi_backlight {
+ struct device *dev;
+ struct device *fbdev;
+ struct rpi_firmware *fw;
+};
+
+static int rpi_backlight_update_status(struct backlight_device *bl)
+{
+ struct rpi_backlight *gbl = bl_get_data(bl);
+ int brightness = bl->props.brightness;
+ int ret;
+
+ if (bl->props.power != FB_BLANK_UNBLANK ||
+ bl->props.fb_blank != FB_BLANK_UNBLANK ||
+ bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
+ brightness = 0;
+
+ ret = rpi_firmware_property(gbl->fw,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_BACKLIGHT,
+ &brightness, sizeof(brightness));
+ if (ret) {
+ dev_err(gbl->dev, "Failed to set brightness\n");
+ return ret;
+ }
+
+ if (brightness < 0) {
+ dev_err(gbl->dev, "Backlight change failed\n");
+ return -EAGAIN;
+ }
+
+ return 0;
+}
+
+static const struct backlight_ops rpi_backlight_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .update_status = rpi_backlight_update_status,
+};
+
+static int rpi_backlight_probe(struct platform_device *pdev)
+{
+ struct backlight_properties props;
+ struct backlight_device *bl;
+ struct rpi_backlight *gbl;
+ struct device_node *fw_node;
+
+ gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
+ if (gbl == NULL)
+ return -ENOMEM;
+
+ gbl->dev = &pdev->dev;
+
+ fw_node = of_parse_phandle(pdev->dev.of_node, "firmware", 0);
+ if (!fw_node) {
+ dev_err(&pdev->dev, "Missing firmware node\n");
+ return -ENOENT;
+ }
+
+ gbl->fw = rpi_firmware_get(fw_node);
+ if (!gbl->fw)
+ return -EPROBE_DEFER;
+
+ memset(&props, 0, sizeof(props));
+ props.type = BACKLIGHT_RAW;
+ props.max_brightness = 255;
+ bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
+ &pdev->dev, gbl, &rpi_backlight_ops,
+ &props);
+ if (IS_ERR(bl)) {
+ dev_err(&pdev->dev, "failed to register backlight\n");
+ return PTR_ERR(bl);
+ }
+
+ bl->props.brightness = 255;
+ backlight_update_status(bl);
+
+ platform_set_drvdata(pdev, bl);
+ return 0;
+}
+
+static const struct of_device_id rpi_backlight_of_match[] = {
+ { .compatible = "raspberrypi,rpi-backlight" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rpi_backlight_of_match);
+
+static struct platform_driver rpi_backlight_driver = {
+ .driver = {
+ .name = "rpi-backlight",
+ .of_match_table = of_match_ptr(rpi_backlight_of_match),
+ },
+ .probe = rpi_backlight_probe,
+};
+
+module_platform_driver(rpi_backlight_driver);
+
+MODULE_AUTHOR("Gordon Hollingworth <gordon@raspberrypi.org>");
+MODULE_DESCRIPTION("Raspberry Pi mailbox based Backlight Driver");
+MODULE_LICENSE("GPL");
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -109,6 +109,7 @@ enum rpi_firmware_property_tag {
RPI_FIRMWARE_FRAMEBUFFER_SET_OVERSCAN = 0x0004800a,
RPI_FIRMWARE_FRAMEBUFFER_SET_PALETTE = 0x0004800b,
RPI_FIRMWARE_FRAMEBUFFER_SET_VSYNC = 0x0004800e,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_BACKLIGHT = 0x0004800f,
RPI_FIRMWARE_VCHIQ_INIT = 0x00048010,
|
