1 // SPDX-License-Identifier: GPL-2.0-only
4 * Copyright (C) 2012 ARM Limited
7 #include <linux/delay.h>
8 #include <linux/notifier.h>
10 #include <linux/of_device.h>
11 #include <linux/platform_device.h>
12 #include <linux/reboot.h>
13 #include <linux/stat.h>
14 #include <linux/vexpress.h>
16 static void vexpress_reset_do(struct device
*dev
, const char *what
)
19 struct regmap
*reg
= dev_get_drvdata(dev
);
22 err
= regmap_write(reg
, 0, 0);
27 dev_emerg(dev
, "Unable to %s (%d)\n", what
, err
);
30 static struct device
*vexpress_power_off_device
;
31 static atomic_t vexpress_restart_nb_refcnt
= ATOMIC_INIT(0);
33 static void vexpress_power_off(void)
35 vexpress_reset_do(vexpress_power_off_device
, "power off");
38 static struct device
*vexpress_restart_device
;
40 static int vexpress_restart(struct notifier_block
*this, unsigned long mode
,
43 vexpress_reset_do(vexpress_restart_device
, "restart");
48 static struct notifier_block vexpress_restart_nb
= {
49 .notifier_call
= vexpress_restart
,
53 static ssize_t
vexpress_reset_active_show(struct device
*dev
,
54 struct device_attribute
*attr
, char *buf
)
56 return sprintf(buf
, "%d\n", vexpress_restart_device
== dev
);
59 static ssize_t
vexpress_reset_active_store(struct device
*dev
,
60 struct device_attribute
*attr
, const char *buf
, size_t count
)
63 int err
= kstrtol(buf
, 0, &value
);
66 vexpress_restart_device
= dev
;
68 return err
? err
: count
;
71 static DEVICE_ATTR(active
, S_IRUGO
| S_IWUSR
, vexpress_reset_active_show
,
72 vexpress_reset_active_store
);
75 enum vexpress_reset_func
{ FUNC_RESET
, FUNC_SHUTDOWN
, FUNC_REBOOT
};
77 static const struct of_device_id vexpress_reset_of_match
[] = {
79 .compatible
= "arm,vexpress-reset",
80 .data
= (void *)FUNC_RESET
,
82 .compatible
= "arm,vexpress-shutdown",
83 .data
= (void *)FUNC_SHUTDOWN
85 .compatible
= "arm,vexpress-reboot",
86 .data
= (void *)FUNC_REBOOT
91 static int _vexpress_register_restart_handler(struct device
*dev
)
95 vexpress_restart_device
= dev
;
96 if (atomic_inc_return(&vexpress_restart_nb_refcnt
) == 1) {
97 err
= register_restart_handler(&vexpress_restart_nb
);
99 dev_err(dev
, "cannot register restart handler (err=%d)\n", err
);
100 atomic_dec(&vexpress_restart_nb_refcnt
);
104 device_create_file(dev
, &dev_attr_active
);
109 static int vexpress_reset_probe(struct platform_device
*pdev
)
111 const struct of_device_id
*match
=
112 of_match_device(vexpress_reset_of_match
, &pdev
->dev
);
113 struct regmap
*regmap
;
119 regmap
= devm_regmap_init_vexpress_config(&pdev
->dev
);
121 return PTR_ERR(regmap
);
122 dev_set_drvdata(&pdev
->dev
, regmap
);
124 switch ((enum vexpress_reset_func
)match
->data
) {
126 vexpress_power_off_device
= &pdev
->dev
;
127 pm_power_off
= vexpress_power_off
;
130 if (!vexpress_restart_device
)
131 ret
= _vexpress_register_restart_handler(&pdev
->dev
);
134 ret
= _vexpress_register_restart_handler(&pdev
->dev
);
141 static struct platform_driver vexpress_reset_driver
= {
142 .probe
= vexpress_reset_probe
,
144 .name
= "vexpress-reset",
145 .of_match_table
= vexpress_reset_of_match
,
146 .suppress_bind_attrs
= true,
149 builtin_platform_driver(vexpress_reset_driver
);