xref: /openbmc/linux/arch/x86/platform/geode/alix.c (revision 60430301)
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