[PATCH v5 1/2] driver: reset: spacemit-p1: add driver for poweroff/reboot

Aurelien Jarno
2025-11-02T23:04:15Z

This driver implements poweroff/reboot support for the SpacemiT P1 PMIC
chip, which is commonly paired with the SpacemiT K1 SoC.

The SpacemiT P1 support is implemented as a MFD driver, so the access is
done directly through the regmap interface. Reboot or poweroff is
triggered by setting a specific bit in a control register, which is
automatically cleared by the hardware afterwards.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
---
v5:
- Change default to "MFD_SPACEMIT_P1"

drivers/power/reset/Kconfig | 9 +++
drivers/power/reset/Makefile | 1 +
drivers/power/reset/spacemit-p1-reboot.c | 88 ++++++++++++++++++++++++
3 files changed, 98 insertions(+)
create mode 100644 drivers/power/reset/spacemit-p1-reboot.c

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 8248895ca9038..f6c1bcbb57def 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -283,6 +283,15 @@ config POWER_RESET_KEYSTONE
help
Reboot support for the KEYSTONE SoCs.

+config POWER_RESET_SPACEMIT_P1
+ tristate "SpacemiT P1 poweroff and reset driver"
+ depends on ARCH_SPACEMIT || COMPILE_TEST
+ depends on MFD_SPACEMIT_P1
+ default MFD_SPACEMIT_P1
+ help
+ This driver supports power-off and reset operations for the SpacemiT
+ P1 PMIC.
+
config POWER_RESET_SYSCON
bool "Generic SYSCON regmap reset driver"
depends on OF
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index 51da87e05ce76..0e4ae6f6b5c55 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o
obj-$(CONFIG_POWER_RESET_REGULATOR) += regulator-poweroff.o
obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o
+obj-$(CONFIG_POWER_RESET_SPACEMIT_P1) += spacemit-p1-reboot.o
obj-$(CONFIG_POWER_RESET_ST) += st-poweroff.o
obj-$(CONFIG_POWER_RESET_TH1520_AON) += th1520-aon-reboot.o
obj-$(CONFIG_POWER_RESET_TORADEX_EC) += tdx-ec-poweroff.o
diff --git a/drivers/power/reset/spacemit-p1-reboot.c b/drivers/power/reset/spacemit-p1-reboot.c
new file mode 100644
index 0000000000000..9ec3d1fff8f3d
--- /dev/null
+++ b/drivers/power/reset/spacemit-p1-reboot.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025 by Aurelien Jarno
+ */
+
+#include <linux/bits.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reboot.h>
+
+/* Power Control Register 2 */
+#define PWR_CTRL2 0x7e
+#define PWR_CTRL2_SHUTDOWN BIT(2) /* Shutdown request */
+#define PWR_CTRL2_RST BIT(1) /* Reset request */
+
+static int spacemit_p1_pwroff_handler(struct sys_off_data *data)
+{
+ struct regmap *regmap = data->cb_data;
+ int ret;
+
+ /* Put the PMIC into shutdown state */
+ ret = regmap_set_bits(regmap, PWR_CTRL2, PWR_CTRL2_SHUTDOWN);
+ if (ret) {
+ dev_err(data->dev, "shutdown failed: %d\n", ret);
+ return notifier_from_errno(ret);
+ }
+
+ return NOTIFY_DONE;
+}
+
+static int spacemit_p1_restart_handler(struct sys_off_data *data)
+{
+ struct regmap *regmap = data->cb_data;
+ int ret;
+
+ /* Put the PMIC into reset state */
+ ret = regmap_set_bits(regmap, PWR_CTRL2, PWR_CTRL2_RST);
+ if (ret) {
+ dev_err(data->dev, "restart failed: %d\n", ret);
+ return notifier_from_errno(ret);
+ }
+
+ return NOTIFY_DONE;
+}
+
+static int spacemit_p1_reboot_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct regmap *regmap;
+ int ret;
+
+ regmap = dev_get_regmap(dev->parent, NULL);
+ if (!regmap)
+ return -ENODEV;
+
+ ret = devm_register_power_off_handler(dev, &spacemit_p1_pwroff_handler,
+ regmap);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Failed to register power off handler\n");
+
+ ret = devm_register_restart_handler(dev, spacemit_p1_restart_handler,
+ regmap);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Failed to register restart handler\n");
+
+ return 0;
+}
+
+static const struct platform_device_id spacemit_p1_reboot_id_table[] = {
+ { "spacemit-p1-reboot", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(platform, spacemit_p1_reboot_id_table);
+
+static struct platform_driver spacemit_p1_reboot_driver = {
+ .driver = {
+ .name = "spacemit-p1-reboot",
+ },
+ .probe = spacemit_p1_reboot_probe,
+ .id_table = spacemit_p1_reboot_id_table,
+};
+module_platform_driver(spacemit_p1_reboot_driver);
+
+MODULE_DESCRIPTION("SpacemiT P1 reboot/poweroff driver");
+MODULE_LICENSE("GPL");
--
2.47.2