Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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os
linux
Merge tag 'backlight-next-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight
Pull backlight updates from Lee Jones:
"New Support & Features:
- Add a new driver for the Congatec Board Controller (CGBC)
backlight, providing brightness control via the board controller's
PWM interface
Improvements & Fixes:
- Resolve build failures in the Awinic AW99706 driver by switching to
the correct GPIO consumer header
- Extend the Qualcomm WLED driver to support the specific
over-voltage protection (OVP) values required for the PMI8994 and
PMI8950 variants
Device Tree Bindings Updates:
- Document the device-specific over-voltage protection (OVP)
millivolt ranges and default values for Qualcomm PMI8994 and
PMI8950 WLED controllers"
* tag 'backlight-next-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
backlight: qcom-wled: Change PM8950 WLED configurations
dt-bindings: backlight: qcom-wled: Document ovp values for PMI8950
backlight: qcom-wled: Support ovp values for PMI8994
dt-bindings: backlight: qcom-wled: Document ovp values for PMI8994
backlight: aw99706: Fix build errors caused by wrong gpio header
backlight: Add Congatec Board Controller (CGBC) backlight support
+255
-5
+22
-2
Documentation/devicetree/bindings/leds/backlight/qcom-wled.yaml
+22
-2
Documentation/devicetree/bindings/leds/backlight/qcom-wled.yaml
···
98
98
description: |
99
99
Over-voltage protection limit. This property is for WLED4 only.
100
100
$ref: /schemas/types.yaml#/definitions/uint32
101
-
enum: [ 18100, 19600, 29600, 31100 ]
102
-
default: 29600
101
+
minimum: 17800
102
+
maximum: 31100
103
103
104
104
qcom,num-strings:
105
105
description: |
···
238
238
max-brightness:
239
239
minimum: 0
240
240
maximum: 4095
241
+
242
+
- if:
243
+
properties:
244
+
compatible:
245
+
contains:
246
+
enum:
247
+
- qcom,pmi8950-wled
248
+
- qcom,pmi8994-wled
249
+
250
+
then:
251
+
properties:
252
+
qcom,ovp-millivolt:
253
+
enum: [ 17800, 19400, 29500, 31000 ]
254
+
default: 29500
255
+
256
+
else:
257
+
properties:
258
+
qcom,ovp-millivolt:
259
+
enum: [ 18100, 19600, 29600, 31100 ]
260
+
default: 29600
241
261
242
262
required:
243
263
- compatible
+11
drivers/video/backlight/Kconfig
+11
drivers/video/backlight/Kconfig
···
258
258
If you have a LCD backlight adjustable by PWM, say Y to enable
259
259
this driver.
260
260
261
+
config BACKLIGHT_CGBC
262
+
tristate "Congatec Board Controller (CGBC) backlight support"
263
+
depends on MFD_CGBC && X86
264
+
help
265
+
Say Y here to enable support for LCD backlight control on Congatec
266
+
x86-based boards via the CGBC (Congatec Board Controller).
267
+
268
+
This driver provides backlight brightness control through the Linux
269
+
backlight subsystem. It communicates with the board controller to
270
+
adjust LCD backlight using PWM signals.
271
+
261
272
config BACKLIGHT_DA903X
262
273
tristate "Backlight Driver for DA9030/DA9034 using WLED"
263
274
depends on PMIC_DA903X
+1
drivers/video/backlight/Makefile
+1
drivers/video/backlight/Makefile
···
27
27
obj-$(CONFIG_BACKLIGHT_AS3711) += as3711_bl.o
28
28
obj-$(CONFIG_BACKLIGHT_AW99706) += aw99706.o
29
29
obj-$(CONFIG_BACKLIGHT_BD6107) += bd6107.o
30
+
obj-$(CONFIG_BACKLIGHT_CGBC) += cgbc_bl.o
30
31
obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE) += backlight.o
31
32
obj-$(CONFIG_BACKLIGHT_DA903X) += da903x_bl.o
32
33
obj-$(CONFIG_BACKLIGHT_DA9052) += da9052_bl.o
+1
-1
drivers/video/backlight/aw99706.c
+1
-1
drivers/video/backlight/aw99706.c
+180
drivers/video/backlight/cgbc_bl.c
+180
drivers/video/backlight/cgbc_bl.c
···
1
+
// SPDX-License-Identifier: GPL-2.0-only
2
+
/*
3
+
* Congatec Board Controller (CGBC) Backlight Driver
4
+
*
5
+
* This driver provides backlight control for LCD displays connected to
6
+
* Congatec boards via the CGBC (Congatec Board Controller). It integrates
7
+
* with the Linux backlight subsystem and communicates with hardware through
8
+
* the cgbc-core module.
9
+
*
10
+
* Copyright (C) 2025 Novatron Oy
11
+
*
12
+
* Author: Petri Karhula <petri.karhula@novatron.fi>
13
+
*/
14
+
15
+
#include <linux/backlight.h>
16
+
#include <linux/bitfield.h>
17
+
#include <linux/bits.h>
18
+
#include <linux/mfd/cgbc.h>
19
+
#include <linux/module.h>
20
+
#include <linux/platform_device.h>
21
+
22
+
#define BLT_PWM_DUTY_MASK GENMASK(6, 0)
23
+
24
+
/* CGBC command for PWM brightness control*/
25
+
#define CGBC_CMD_BLT0_PWM 0x75
26
+
27
+
#define CGBC_BL_MAX_BRIGHTNESS 100
28
+
29
+
/**
30
+
* CGBC backlight driver data
31
+
* @dev: Pointer to the platform device
32
+
* @cgbc: Pointer to the parent CGBC device data
33
+
* @current_brightness: Current brightness level (0-100)
34
+
*/
35
+
struct cgbc_bl_data {
36
+
struct device *dev;
37
+
struct cgbc_device_data *cgbc;
38
+
unsigned int current_brightness;
39
+
};
40
+
41
+
static int cgbc_bl_read_brightness(struct cgbc_bl_data *bl_data)
42
+
{
43
+
u8 cmd_buf[4] = { CGBC_CMD_BLT0_PWM };
44
+
u8 reply_buf[3];
45
+
int ret;
46
+
47
+
ret = cgbc_command(bl_data->cgbc, cmd_buf, sizeof(cmd_buf),
48
+
reply_buf, sizeof(reply_buf), NULL);
49
+
if (ret < 0)
50
+
return ret;
51
+
52
+
/*
53
+
* Get only PWM duty factor percentage,
54
+
* ignore polarity inversion bit (bit 7)
55
+
*/
56
+
bl_data->current_brightness = FIELD_GET(BLT_PWM_DUTY_MASK, reply_buf[0]);
57
+
58
+
return 0;
59
+
}
60
+
61
+
static int cgbc_bl_update_status(struct backlight_device *bl)
62
+
{
63
+
struct cgbc_bl_data *bl_data = bl_get_data(bl);
64
+
u8 cmd_buf[4] = { CGBC_CMD_BLT0_PWM };
65
+
u8 reply_buf[3];
66
+
u8 brightness;
67
+
int ret;
68
+
69
+
brightness = backlight_get_brightness(bl);
70
+
71
+
if (brightness != bl_data->current_brightness) {
72
+
/* Read the current values */
73
+
ret = cgbc_command(bl_data->cgbc, cmd_buf, sizeof(cmd_buf), reply_buf,
74
+
sizeof(reply_buf), NULL);
75
+
if (ret < 0) {
76
+
dev_err(bl_data->dev, "Failed to read PWM settings: %d\n", ret);
77
+
return ret;
78
+
}
79
+
80
+
/*
81
+
* Prepare command buffer for writing new settings. Only 2nd byte is changed
82
+
* to set new brightness (PWM duty cycle %). Other values (polarity, frequency)
83
+
* are preserved from the read values.
84
+
*/
85
+
cmd_buf[1] = (reply_buf[0] & ~BLT_PWM_DUTY_MASK) |
86
+
FIELD_PREP(BLT_PWM_DUTY_MASK, brightness);
87
+
cmd_buf[2] = reply_buf[1];
88
+
cmd_buf[3] = reply_buf[2];
89
+
90
+
ret = cgbc_command(bl_data->cgbc, cmd_buf, sizeof(cmd_buf), reply_buf,
91
+
sizeof(reply_buf), NULL);
92
+
if (ret < 0) {
93
+
dev_err(bl_data->dev, "Failed to set brightness: %d\n", ret);
94
+
return ret;
95
+
}
96
+
97
+
bl_data->current_brightness = reply_buf[0] & BLT_PWM_DUTY_MASK;
98
+
99
+
/* Verify the setting was applied correctly */
100
+
if (bl_data->current_brightness != brightness) {
101
+
dev_err(bl_data->dev,
102
+
"Brightness setting verification failed (got %u, expected %u)\n",
103
+
bl_data->current_brightness, (unsigned int)brightness);
104
+
return -EIO;
105
+
}
106
+
}
107
+
108
+
return 0;
109
+
}
110
+
111
+
static int cgbc_bl_get_brightness(struct backlight_device *bl)
112
+
{
113
+
struct cgbc_bl_data *bl_data = bl_get_data(bl);
114
+
int ret;
115
+
116
+
ret = cgbc_bl_read_brightness(bl_data);
117
+
if (ret < 0) {
118
+
dev_err(bl_data->dev, "Failed to read brightness: %d\n", ret);
119
+
return ret;
120
+
}
121
+
122
+
return bl_data->current_brightness;
123
+
}
124
+
125
+
static const struct backlight_ops cgbc_bl_ops = {
126
+
.options = BL_CORE_SUSPENDRESUME,
127
+
.update_status = cgbc_bl_update_status,
128
+
.get_brightness = cgbc_bl_get_brightness,
129
+
};
130
+
131
+
static int cgbc_bl_probe(struct platform_device *pdev)
132
+
{
133
+
struct cgbc_device_data *cgbc = dev_get_drvdata(pdev->dev.parent);
134
+
struct backlight_properties props = { };
135
+
struct backlight_device *bl_dev;
136
+
struct cgbc_bl_data *bl_data;
137
+
int ret;
138
+
139
+
bl_data = devm_kzalloc(&pdev->dev, sizeof(*bl_data), GFP_KERNEL);
140
+
if (!bl_data)
141
+
return -ENOMEM;
142
+
143
+
bl_data->dev = &pdev->dev;
144
+
bl_data->cgbc = cgbc;
145
+
146
+
ret = cgbc_bl_read_brightness(bl_data);
147
+
if (ret < 0)
148
+
return dev_err_probe(&pdev->dev, ret,
149
+
"Failed to read initial brightness\n");
150
+
151
+
props.type = BACKLIGHT_PLATFORM;
152
+
props.max_brightness = CGBC_BL_MAX_BRIGHTNESS;
153
+
props.brightness = bl_data->current_brightness;
154
+
props.scale = BACKLIGHT_SCALE_LINEAR;
155
+
156
+
bl_dev = devm_backlight_device_register(&pdev->dev, "cgbc-backlight",
157
+
&pdev->dev, bl_data,
158
+
&cgbc_bl_ops, &props);
159
+
if (IS_ERR(bl_dev))
160
+
return dev_err_probe(&pdev->dev, PTR_ERR(bl_dev),
161
+
"Failed to register backlight device\n");
162
+
163
+
platform_set_drvdata(pdev, bl_data);
164
+
165
+
return 0;
166
+
}
167
+
168
+
static struct platform_driver cgbc_bl_driver = {
169
+
.driver = {
170
+
.name = "cgbc-backlight",
171
+
},
172
+
.probe = cgbc_bl_probe,
173
+
};
174
+
175
+
module_platform_driver(cgbc_bl_driver);
176
+
177
+
MODULE_AUTHOR("Petri Karhula <petri.karhula@novatron.fi>");
178
+
MODULE_DESCRIPTION("Congatec Board Controller (CGBC) Backlight Driver");
179
+
MODULE_LICENSE("GPL");
180
+
MODULE_ALIAS("platform:cgbc-backlight");
+40
-2
drivers/video/backlight/qcom-wled.c
+40
-2
drivers/video/backlight/qcom-wled.c
···
1244
1244
.size = ARRAY_SIZE(wled4_ovp_values),
1245
1245
};
1246
1246
1247
+
static const u32 pmi8994_wled_ovp_values[] = {
1248
+
31000, 29500, 19400, 17800,
1249
+
};
1250
+
1251
+
static const struct wled_var_cfg pmi8994_wled_ovp_cfg = {
1252
+
.values = pmi8994_wled_ovp_values,
1253
+
.size = ARRAY_SIZE(pmi8994_wled_ovp_values),
1254
+
};
1255
+
1247
1256
static inline u32 wled5_ovp_values_fn(u32 idx)
1248
1257
{
1249
1258
/*
···
1366
1357
},
1367
1358
};
1368
1359
1360
+
const struct wled_u32_opts pmi8994_wled_opts[] = {
1361
+
{
1362
+
.name = "qcom,current-boost-limit",
1363
+
.val_ptr = &cfg->boost_i_limit,
1364
+
.cfg = &wled4_boost_i_limit_cfg,
1365
+
},
1366
+
{
1367
+
.name = "qcom,current-limit-microamp",
1368
+
.val_ptr = &cfg->string_i_limit,
1369
+
.cfg = &wled4_string_i_limit_cfg,
1370
+
},
1371
+
{
1372
+
.name = "qcom,ovp-millivolt",
1373
+
.val_ptr = &cfg->ovp,
1374
+
.cfg = &pmi8994_wled_ovp_cfg,
1375
+
},
1376
+
{
1377
+
.name = "qcom,switching-freq",
1378
+
.val_ptr = &cfg->switch_freq,
1379
+
.cfg = &wled3_switch_freq_cfg,
1380
+
},
1381
+
};
1382
+
1369
1383
const struct wled_u32_opts wled5_opts[] = {
1370
1384
{
1371
1385
.name = "qcom,current-boost-limit",
···
1455
1423
break;
1456
1424
1457
1425
case 4:
1458
-
u32_opts = wled4_opts;
1459
-
size = ARRAY_SIZE(wled4_opts);
1426
+
if (of_device_is_compatible(dev->of_node, "qcom,pmi8950-wled") ||
1427
+
of_device_is_compatible(dev->of_node, "qcom,pmi8994-wled")) {
1428
+
u32_opts = pmi8994_wled_opts;
1429
+
size = ARRAY_SIZE(pmi8994_wled_opts);
1430
+
} else {
1431
+
u32_opts = wled4_opts;
1432
+
size = ARRAY_SIZE(wled4_opts);
1433
+
}
1460
1434
*cfg = wled4_config_defaults;
1461
1435
wled->wled_set_brightness = wled4_set_brightness;
1462
1436
wled->wled_sync_toggle = wled3_sync_toggle;