linux/drivers/power/reset/tps65086-restart.c
Emil Renner Berthing 80698507e0 power: reset: Add TPS65086 restart driver
The only way to reset the BeagleV Starlight v0.9 board[1] properly is to
tell the PMIC to reset itself which will then assert the external reset
lines of the SoC, USB hub and ethernet phy.

This adds a driver to register a reset handler to do just that.

[1] https://github.com/beagleboard/beaglev-starlight

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2021-08-16 14:48:51 +02:00

99 lines
2.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2021 Emil Renner Berthing
*/
#include <linux/mfd/tps65086.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
struct tps65086_restart {
struct notifier_block handler;
struct device *dev;
};
static int tps65086_restart_notify(struct notifier_block *this,
unsigned long mode, void *cmd)
{
struct tps65086_restart *tps65086_restart =
container_of(this, struct tps65086_restart, handler);
struct tps65086 *tps65086 = dev_get_drvdata(tps65086_restart->dev->parent);
int ret;
ret = regmap_write(tps65086->regmap, TPS65086_FORCESHUTDN, 1);
if (ret) {
dev_err(tps65086_restart->dev, "%s: error writing to tps65086 pmic: %d\n",
__func__, ret);
return NOTIFY_DONE;
}
/* give it a little time */
mdelay(200);
WARN_ON(1);
return NOTIFY_DONE;
}
static int tps65086_restart_probe(struct platform_device *pdev)
{
struct tps65086_restart *tps65086_restart;
int ret;
tps65086_restart = devm_kzalloc(&pdev->dev, sizeof(*tps65086_restart), GFP_KERNEL);
if (!tps65086_restart)
return -ENOMEM;
platform_set_drvdata(pdev, tps65086_restart);
tps65086_restart->handler.notifier_call = tps65086_restart_notify;
tps65086_restart->handler.priority = 192;
tps65086_restart->dev = &pdev->dev;
ret = register_restart_handler(&tps65086_restart->handler);
if (ret) {
dev_err(&pdev->dev, "%s: cannot register restart handler: %d\n",
__func__, ret);
return -ENODEV;
}
return 0;
}
static int tps65086_restart_remove(struct platform_device *pdev)
{
struct tps65086_restart *tps65086_restart = platform_get_drvdata(pdev);
int ret;
ret = unregister_restart_handler(&tps65086_restart->handler);
if (ret) {
dev_err(&pdev->dev, "%s: cannot unregister restart handler: %d\n",
__func__, ret);
return -ENODEV;
}
return 0;
}
static const struct platform_device_id tps65086_restart_id_table[] = {
{ "tps65086-reset", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, tps65086_restart_id_table);
static struct platform_driver tps65086_restart_driver = {
.driver = {
.name = "tps65086-restart",
},
.probe = tps65086_restart_probe,
.remove = tps65086_restart_remove,
.id_table = tps65086_restart_id_table,
};
module_platform_driver(tps65086_restart_driver);
MODULE_AUTHOR("Emil Renner Berthing <kernel@esmil.dk>");
MODULE_DESCRIPTION("TPS65086 restart driver");
MODULE_LICENSE("GPL v2");