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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * apple-gmux.h - microcontroller built into dual GPU MacBook Pro & Mac Pro
4 * Copyright (C) 2015 Lukas Wunner <lukas@wunner.de>
5 */
6
7#ifndef LINUX_APPLE_GMUX_H
8#define LINUX_APPLE_GMUX_H
9
10#include <linux/acpi.h>
11#include <linux/io.h>
12#include <linux/pnp.h>
13
14#define GMUX_ACPI_HID "APP000B"
15
16/*
17 * gmux port offsets. Many of these are not yet used, but may be in the
18 * future, and it's useful to have them documented here anyhow.
19 */
20#define GMUX_PORT_VERSION_MAJOR 0x04
21#define GMUX_PORT_VERSION_MINOR 0x05
22#define GMUX_PORT_VERSION_RELEASE 0x06
23#define GMUX_PORT_SWITCH_DISPLAY 0x10
24#define GMUX_PORT_SWITCH_GET_DISPLAY 0x11
25#define GMUX_PORT_INTERRUPT_ENABLE 0x14
26#define GMUX_PORT_INTERRUPT_STATUS 0x16
27#define GMUX_PORT_SWITCH_DDC 0x28
28#define GMUX_PORT_SWITCH_EXTERNAL 0x40
29#define GMUX_PORT_SWITCH_GET_EXTERNAL 0x41
30#define GMUX_PORT_DISCRETE_POWER 0x50
31#define GMUX_PORT_MAX_BRIGHTNESS 0x70
32#define GMUX_PORT_BRIGHTNESS 0x74
33#define GMUX_PORT_VALUE 0xc2
34#define GMUX_PORT_READ 0xd0
35#define GMUX_PORT_WRITE 0xd4
36
37#define GMUX_MIN_IO_LEN (GMUX_PORT_BRIGHTNESS + 4)
38
39#if IS_ENABLED(CONFIG_APPLE_GMUX)
40static inline bool apple_gmux_is_indexed(unsigned long iostart)
41{
42 u16 val;
43
44 outb(0xaa, iostart + 0xcc);
45 outb(0x55, iostart + 0xcd);
46 outb(0x00, iostart + 0xce);
47
48 val = inb(iostart + 0xcc) | (inb(iostart + 0xcd) << 8);
49 if (val == 0x55aa)
50 return true;
51
52 return false;
53}
54
55/**
56 * apple_gmux_detect() - detect if gmux is built into the machine
57 *
58 * @pnp_dev: Device to probe or NULL to use the first matching device
59 * @indexed_ret: Returns (by reference) if the gmux is indexed or not
60 *
61 * Detect if a supported gmux device is present by actually probing it.
62 * This avoids the false positives returned on some models by
63 * apple_gmux_present().
64 *
65 * Return: %true if a supported gmux ACPI device is detected and the kernel
66 * was configured with CONFIG_APPLE_GMUX, %false otherwise.
67 */
68static inline bool apple_gmux_detect(struct pnp_dev *pnp_dev, bool *indexed_ret)
69{
70 u8 ver_major, ver_minor, ver_release;
71 struct device *dev = NULL;
72 struct acpi_device *adev;
73 struct resource *res;
74 bool indexed = false;
75 bool ret = false;
76
77 if (!pnp_dev) {
78 adev = acpi_dev_get_first_match_dev(GMUX_ACPI_HID, NULL, -1);
79 if (!adev)
80 return false;
81
82 dev = get_device(acpi_get_first_physical_node(adev));
83 acpi_dev_put(adev);
84 if (!dev)
85 return false;
86
87 pnp_dev = to_pnp_dev(dev);
88 }
89
90 res = pnp_get_resource(pnp_dev, IORESOURCE_IO, 0);
91 if (!res || resource_size(res) < GMUX_MIN_IO_LEN)
92 goto out;
93
94 /*
95 * Invalid version information may indicate either that the gmux
96 * device isn't present or that it's a new one that uses indexed io.
97 */
98 ver_major = inb(res->start + GMUX_PORT_VERSION_MAJOR);
99 ver_minor = inb(res->start + GMUX_PORT_VERSION_MINOR);
100 ver_release = inb(res->start + GMUX_PORT_VERSION_RELEASE);
101 if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
102 indexed = apple_gmux_is_indexed(res->start);
103 if (!indexed)
104 goto out;
105 }
106
107 if (indexed_ret)
108 *indexed_ret = indexed;
109
110 ret = true;
111out:
112 put_device(dev);
113 return ret;
114}
115
116/**
117 * apple_gmux_present() - check if gmux ACPI device is present
118 *
119 * Drivers may use this to activate quirks specific to dual GPU MacBook Pros
120 * and Mac Pros, e.g. for deferred probing, runtime pm and backlight.
121 *
122 * Return: %true if gmux ACPI device is present and the kernel was configured
123 * with CONFIG_APPLE_GMUX, %false otherwise.
124 */
125static inline bool apple_gmux_present(void)
126{
127 return acpi_dev_found(GMUX_ACPI_HID);
128}
129
130#else /* !CONFIG_APPLE_GMUX */
131
132static inline bool apple_gmux_present(void)
133{
134 return false;
135}
136
137static inline bool apple_gmux_detect(struct pnp_dev *pnp_dev, bool *indexed_ret)
138{
139 return false;
140}
141
142#endif /* !CONFIG_APPLE_GMUX */
143
144#endif /* LINUX_APPLE_GMUX_H */