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
|
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* In some cases UART attached devices which require an in kernel driver,
* e.g. UART attached Bluetooth HCIs are described in the ACPI tables
* by an ACPI device with a broken or missing UartSerialBusV2() resource.
*
* This causes the kernel to create a /dev/ttyS# char-device for the UART
* instead of creating an in kernel serdev-controller + serdev-device pair
* for the in kernel driver.
*
* The quirk handling in acpi_quirk_skip_serdev_enumeration() makes the kernel
* create a serdev-controller device for these UARTs instead of a /dev/ttyS#.
*
* Instantiating the actual serdev-device to bind to is up to pdx86 code,
* this header provides a helper for getting the serdev-controller device.
*/
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/printk.h>
#include <linux/sprintf.h>
#include <linux/string.h>
static inline struct device *
get_serdev_controller(const char *serial_ctrl_hid,
const char *serial_ctrl_uid,
int serial_ctrl_port,
const char *serdev_ctrl_name)
{
struct device *ctrl_dev, *child;
struct acpi_device *ctrl_adev;
char name[32];
int i;
ctrl_adev = acpi_dev_get_first_match_dev(serial_ctrl_hid, serial_ctrl_uid, -1);
if (!ctrl_adev) {
pr_err("error could not get %s/%s serial-ctrl adev\n",
serial_ctrl_hid, serial_ctrl_uid);
return ERR_PTR(-ENODEV);
}
/* get_first_physical_node() returns a weak ref */
ctrl_dev = get_device(acpi_get_first_physical_node(ctrl_adev));
if (!ctrl_dev) {
pr_err("error could not get %s/%s serial-ctrl physical node\n",
serial_ctrl_hid, serial_ctrl_uid);
ctrl_dev = ERR_PTR(-ENODEV);
goto put_ctrl_adev;
}
/* Walk host -> uart-ctrl -> port -> serdev-ctrl */
for (i = 0; i < 3; i++) {
switch (i) {
case 0:
snprintf(name, sizeof(name), "%s:0", dev_name(ctrl_dev));
break;
case 1:
snprintf(name, sizeof(name), "%s.%d",
dev_name(ctrl_dev), serial_ctrl_port);
break;
case 2:
strscpy(name, serdev_ctrl_name, sizeof(name));
break;
}
child = device_find_child_by_name(ctrl_dev, name);
put_device(ctrl_dev);
if (!child) {
pr_err("error could not find '%s' device\n", name);
ctrl_dev = ERR_PTR(-ENODEV);
goto put_ctrl_adev;
}
ctrl_dev = child;
}
put_ctrl_adev:
acpi_dev_put(ctrl_adev);
return ctrl_dev;
}
|
