1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * System Specific setup for PCEngines ALIX.
4 * At the moment this means setup of GPIO control of LEDs
5 * on Alix.2/3/6 boards.
6 *
7 * Copyright (C) 2008 Constantin Baranov <const@mimas.ru>
8 * Copyright (C) 2011 Ed Wildgoose <kernel@wildgooses.com>
9 * and Philip Prindeville <philipp@redfish-solutions.com>
10 *
11 * TODO: There are large similarities with leds-net5501.c
12 * by Alessandro Zummo <a.zummo@towertech.it>
13 * In the future leds-net5501.c should be migrated over to platform
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/io.h>
19 #include <linux/string.h>
20 #include <linux/moduleparam.h>
21 #include <linux/leds.h>
22 #include <linux/platform_device.h>
23 #include <linux/input.h>
24 #include <linux/gpio_keys.h>
25 #include <linux/gpio/machine.h>
26 #include <linux/dmi.h>
27
28 #include <asm/geode.h>
29
30 #define BIOS_SIGNATURE_TINYBIOS 0xf0000
31 #define BIOS_SIGNATURE_COREBOOT 0x500
32 #define BIOS_REGION_SIZE 0x10000
33
34 /*
35 * This driver is not modular, but to keep back compatibility
36 * with existing use cases, continuing with module_param is
37 * the easiest way forward.
38 */
39 static bool force = 0;
40 module_param(force, bool, 0444);
41 /* FIXME: Award bios is not automatically detected as Alix platform */
42 MODULE_PARM_DESC(force, "Force detection as ALIX.2/ALIX.3 platform");
43
44 static struct gpio_keys_button alix_gpio_buttons[] = {
45 {
46 .code = KEY_RESTART,
47 .gpio = 24,
48 .active_low = 1,
49 .desc = "Reset button",
50 .type = EV_KEY,
51 .wakeup = 0,
52 .debounce_interval = 100,
53 .can_disable = 0,
54 }
55 };
56 static struct gpio_keys_platform_data alix_buttons_data = {
57 .buttons = alix_gpio_buttons,
58 .nbuttons = ARRAY_SIZE(alix_gpio_buttons),
59 .poll_interval = 20,
60 };
61
62 static struct platform_device alix_buttons_dev = {
63 .name = "gpio-keys-polled",
64 .id = 1,
65 .dev = {
66 .platform_data = &alix_buttons_data,
67 }
68 };
69
70 static struct gpio_led alix_leds[] = {
71 {
72 .name = "alix:1",
73 .default_trigger = "default-on",
74 },
75 {
76 .name = "alix:2",
77 .default_trigger = "default-off",
78 },
79 {
80 .name = "alix:3",
81 .default_trigger = "default-off",
82 },
83 };
84
85 static struct gpio_led_platform_data alix_leds_data = {
86 .num_leds = ARRAY_SIZE(alix_leds),
87 .leds = alix_leds,
88 };
89
90 static struct gpiod_lookup_table alix_leds_gpio_table = {
91 .dev_id = "leds-gpio",
92 .table = {
93 /* The Geode GPIOs should be on the CS5535 companion chip */
94 GPIO_LOOKUP_IDX("cs5535-gpio", 6, NULL, 0, GPIO_ACTIVE_LOW),
95 GPIO_LOOKUP_IDX("cs5535-gpio", 25, NULL, 1, GPIO_ACTIVE_LOW),
96 GPIO_LOOKUP_IDX("cs5535-gpio", 27, NULL, 2, GPIO_ACTIVE_LOW),
97 { }
98 },
99 };
100
101 static struct platform_device alix_leds_dev = {
102 .name = "leds-gpio",
103 .id = -1,
104 .dev.platform_data = &alix_leds_data,
105 };
106
107 static struct platform_device *alix_devs[] __initdata = {
108 &alix_buttons_dev,
109 &alix_leds_dev,
110 };
111
register_alix(void)112 static void __init register_alix(void)
113 {
114 /* Setup LED control through leds-gpio driver */
115 gpiod_add_lookup_table(&alix_leds_gpio_table);
116 platform_add_devices(alix_devs, ARRAY_SIZE(alix_devs));
117 }
118
alix_present(unsigned long bios_phys,const char * alix_sig,size_t alix_sig_len)119 static bool __init alix_present(unsigned long bios_phys,
120 const char *alix_sig,
121 size_t alix_sig_len)
122 {
123 const size_t bios_len = BIOS_REGION_SIZE;
124 const char *bios_virt;
125 const char *scan_end;
126 const char *p;
127 char name[64];
128
129 if (force) {
130 printk(KERN_NOTICE "%s: forced to skip BIOS test, "
131 "assume system is ALIX.2/ALIX.3\n",
132 KBUILD_MODNAME);
133 return true;
134 }
135
136 bios_virt = phys_to_virt(bios_phys);
137 scan_end = bios_virt + bios_len - (alix_sig_len + 2);
138 for (p = bios_virt; p < scan_end; p++) {
139 const char *tail;
140 char *a;
141
142 if (memcmp(p, alix_sig, alix_sig_len) != 0)
143 continue;
144
145 memcpy(name, p, sizeof(name));
146
147 /* remove the first \0 character from string */
148 a = strchr(name, '\0');
149 if (a)
150 *a = ' ';
151
152 /* cut the string at a newline */
153 a = strchr(name, '\r');
154 if (a)
155 *a = '\0';
156
157 tail = p + alix_sig_len;
158 if ((tail[0] == '2' || tail[0] == '3' || tail[0] == '6')) {
159 printk(KERN_INFO
160 "%s: system is recognized as \"%s\"\n",
161 KBUILD_MODNAME, name);
162 return true;
163 }
164 }
165
166 return false;
167 }
168
alix_present_dmi(void)169 static bool __init alix_present_dmi(void)
170 {
171 const char *vendor, *product;
172
173 vendor = dmi_get_system_info(DMI_SYS_VENDOR);
174 if (!vendor || strcmp(vendor, "PC Engines"))
175 return false;
176
177 product = dmi_get_system_info(DMI_PRODUCT_NAME);
178 if (!product || (strcmp(product, "ALIX.2D") && strcmp(product, "ALIX.6")))
179 return false;
180
181 printk(KERN_INFO "%s: system is recognized as \"%s %s\"\n",
182 KBUILD_MODNAME, vendor, product);
183
184 return true;
185 }
186
alix_init(void)187 static int __init alix_init(void)
188 {
189 const char tinybios_sig[] = "PC Engines ALIX.";
190 const char coreboot_sig[] = "PC Engines\0ALIX.";
191
192 if (!is_geode())
193 return 0;
194
195 if (alix_present(BIOS_SIGNATURE_TINYBIOS, tinybios_sig, sizeof(tinybios_sig) - 1) ||
196 alix_present(BIOS_SIGNATURE_COREBOOT, coreboot_sig, sizeof(coreboot_sig) - 1) ||
197 alix_present_dmi())
198 register_alix();
199
200 return 0;
201 }
202 device_initcall(alix_init);
203