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path: root/drivers/power/reset/vexpress-poweroff.c
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Diffstat (limited to 'drivers/power/reset/vexpress-poweroff.c')
-rw-r--r--drivers/power/reset/vexpress-poweroff.c149
1 files changed, 149 insertions, 0 deletions
diff --git a/drivers/power/reset/vexpress-poweroff.c b/drivers/power/reset/vexpress-poweroff.c
new file mode 100644
index 0000000000..17064d7b19
--- /dev/null
+++ b/drivers/power/reset/vexpress-poweroff.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Copyright (C) 2012 ARM Limited
+ */
+
+#include <linux/delay.h>
+#include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/stat.h>
+#include <linux/vexpress.h>
+
+static void vexpress_reset_do(struct device *dev, const char *what)
+{
+ int err = -ENOENT;
+ struct regmap *reg = dev_get_drvdata(dev);
+
+ if (reg) {
+ err = regmap_write(reg, 0, 0);
+ if (!err)
+ mdelay(1000);
+ }
+
+ dev_emerg(dev, "Unable to %s (%d)\n", what, err);
+}
+
+static struct device *vexpress_power_off_device;
+static atomic_t vexpress_restart_nb_refcnt = ATOMIC_INIT(0);
+
+static void vexpress_power_off(void)
+{
+ vexpress_reset_do(vexpress_power_off_device, "power off");
+}
+
+static struct device *vexpress_restart_device;
+
+static int vexpress_restart(struct notifier_block *this, unsigned long mode,
+ void *cmd)
+{
+ vexpress_reset_do(vexpress_restart_device, "restart");
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block vexpress_restart_nb = {
+ .notifier_call = vexpress_restart,
+ .priority = 128,
+};
+
+static ssize_t vexpress_reset_active_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", vexpress_restart_device == dev);
+}
+
+static ssize_t vexpress_reset_active_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ long value;
+ int err = kstrtol(buf, 0, &value);
+
+ if (!err && value)
+ vexpress_restart_device = dev;
+
+ return err ? err : count;
+}
+
+static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
+ vexpress_reset_active_store);
+
+
+enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
+
+static const struct of_device_id vexpress_reset_of_match[] = {
+ {
+ .compatible = "arm,vexpress-reset",
+ .data = (void *)FUNC_RESET,
+ }, {
+ .compatible = "arm,vexpress-shutdown",
+ .data = (void *)FUNC_SHUTDOWN
+ }, {
+ .compatible = "arm,vexpress-reboot",
+ .data = (void *)FUNC_REBOOT
+ },
+ {}
+};
+
+static int _vexpress_register_restart_handler(struct device *dev)
+{
+ int err;
+
+ vexpress_restart_device = dev;
+ if (atomic_inc_return(&vexpress_restart_nb_refcnt) == 1) {
+ err = register_restart_handler(&vexpress_restart_nb);
+ if (err) {
+ dev_err(dev, "cannot register restart handler (err=%d)\n", err);
+ atomic_dec(&vexpress_restart_nb_refcnt);
+ return err;
+ }
+ }
+ device_create_file(dev, &dev_attr_active);
+
+ return 0;
+}
+
+static int vexpress_reset_probe(struct platform_device *pdev)
+{
+ const struct of_device_id *match =
+ of_match_device(vexpress_reset_of_match, &pdev->dev);
+ struct regmap *regmap;
+ int ret = 0;
+
+ if (!match)
+ return -EINVAL;
+
+ regmap = devm_regmap_init_vexpress_config(&pdev->dev);
+ if (IS_ERR(regmap))
+ return PTR_ERR(regmap);
+ dev_set_drvdata(&pdev->dev, regmap);
+
+ switch ((uintptr_t)match->data) {
+ case FUNC_SHUTDOWN:
+ vexpress_power_off_device = &pdev->dev;
+ pm_power_off = vexpress_power_off;
+ break;
+ case FUNC_RESET:
+ if (!vexpress_restart_device)
+ ret = _vexpress_register_restart_handler(&pdev->dev);
+ break;
+ case FUNC_REBOOT:
+ ret = _vexpress_register_restart_handler(&pdev->dev);
+ break;
+ }
+
+ return ret;
+}
+
+static struct platform_driver vexpress_reset_driver = {
+ .probe = vexpress_reset_probe,
+ .driver = {
+ .name = "vexpress-reset",
+ .of_match_table = vexpress_reset_of_match,
+ .suppress_bind_attrs = true,
+ },
+};
+builtin_platform_driver(vexpress_reset_driver);