From c2aa0b4586f6fe53390905603485a6f801f689a2 Mon Sep 17 00:00:00 2001
From: Emil Renner Berthing <kernel@esmil.dk>
Date: Mon, 3 May 2021 12:20:05 +0200
Subject: [PATCH 1/3] power: reset: Add TPS65086 restart driver

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
---
 drivers/mfd/tps65086.c                 |   1 +
 drivers/power/reset/Kconfig            |   6 ++
 drivers/power/reset/Makefile           |   1 +
 drivers/power/reset/tps65086-restart.c | 101 +++++++++++++++++++++++++
 4 files changed, 109 insertions(+)
 create mode 100644 drivers/power/reset/tps65086-restart.c

diff --git a/drivers/mfd/tps65086.c b/drivers/mfd/tps65086.c
index 341466ef20cc..e08823736fe9 100644
--- a/drivers/mfd/tps65086.c
+++ b/drivers/mfd/tps65086.c
@@ -24,6 +24,7 @@
 static const struct mfd_cell tps65086_cells[] = {
 	{ .name = "tps65086-regulator", },
 	{ .name = "tps65086-gpio", },
+	{ .name = "tps65086-restart", },
 };
 
 static const struct regmap_range tps65086_yes_ranges[] = {
diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index d55b3727e00e..fd212a6b1143 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -190,6 +190,12 @@ config POWER_RESET_ST
 	help
 	  Reset support for STMicroelectronics boards.
 
+config POWER_RESET_TPS65086
+	bool "TPS65086 restart driver"
+	depends on MFD_TPS65086
+	help
+	  Reset TPS65086 PMIC on restart.
+
 config POWER_RESET_VERSATILE
 	bool "ARM Versatile family reboot driver"
 	depends on ARM
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index c51eceba9ea3..d9bb7e2a6f80 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
 obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o
 obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o
 obj-$(CONFIG_POWER_RESET_ST) += st-poweroff.o
+obj-$(CONFIG_POWER_RESET_TPS65086) += tps65086-restart.o
 obj-$(CONFIG_POWER_RESET_VERSATILE) += arm-versatile-reboot.o
 obj-$(CONFIG_POWER_RESET_VEXPRESS) += vexpress-poweroff.o
 obj-$(CONFIG_POWER_RESET_XGENE) += xgene-reboot.o
diff --git a/drivers/power/reset/tps65086-restart.c b/drivers/power/reset/tps65086-restart.c
new file mode 100644
index 000000000000..8c47d534d08a
--- /dev/null
+++ b/drivers/power/reset/tps65086-restart.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Emil Renner Berthing
+ */
+
+#include <linux/reboot.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <linux/mfd/tps65086.h>
+
+struct tps65086_restart {
+	struct notifier_block handler;
+	struct tps65086 *tps;
+	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);
+	int ret;
+
+	ret = regmap_write(tps65086_restart->tps->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->tps = dev_get_drvdata(pdev->dev.parent);
+	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-restart", },
+	{ /* 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");
-- 
2.31.1

