lib: utils/reset: add SpacemiT P1 PMIC support

The SpacemiT P1 is a PMIC commonly found with SpacemiT CPU like K1. Add
a reset driver for it.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Link: https://lore.kernel.org/r/20260419150857.2705843-3-aurelien@aurel32.net
Signed-off-by: Anup Patel <anup@brainfault.org>

lib/utils/reset/Kconfig

@@ -33,6 +33,10 @@ config FDT_RESET_SG2042_HWMON_MCU
 	bool "Sophgo SG2042 hwmon MCU FDT reset driver"
 	default n
 
+config FDT_RESET_SPACEMIT_P1
+	bool "SpacemiT P1 reset driver"
+	default n
+
 config FDT_RESET_SUNXI_WDT
 	bool "Sunxi WDT FDT reset driver"
 	default n

lib/utils/reset/fdt_reset_spacemit_p1.c

@@ -0,0 +1,112 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2026 Aurelien Jarno
+ * Authors:
+ *   Aurelien Jarno <aurelien@aurel32.net>
+ */
+
+#include <libfdt.h>
+#include <platform_override.h>
+#include <sbi/sbi_bitops.h>
+#include <sbi/sbi_console.h>
+#include <sbi/sbi_system.h>
+#include <sbi_utils/fdt/fdt_driver.h>
+#include <sbi_utils/i2c/fdt_i2c.h>
+
+/* SpacemiT P1 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 struct i2c_adapter *p1_adapter = NULL;
+static uint32_t p1_reg = 0;
+
+static int p1_system_reset_check(uint32_t type, uint32_t reason)
+{
+	switch (type) {
+	case SBI_SRST_RESET_TYPE_SHUTDOWN:
+		return 1;
+	case SBI_SRST_RESET_TYPE_COLD_REBOOT:
+	case SBI_SRST_RESET_TYPE_WARM_REBOOT:
+		return 255;
+	}
+
+	return 0;
+}
+
+static void p1_ops(uint32_t type)
+{
+	uint8_t byte;
+	int rc;
+
+	rc = i2c_adapter_reg_read(p1_adapter, p1_reg, PWR_CTRL2, &byte);
+	if (rc) {
+		sbi_printf("%s: cannot read P1 Power Control Register 2\n", __func__);
+		return;
+	}
+
+	if (type == SBI_SRST_RESET_TYPE_SHUTDOWN)
+		byte |= PWR_CTRL2_SHUTDOWN;
+	else
+		byte |= PWR_CTRL2_RST;
+
+	rc = i2c_adapter_reg_write(p1_adapter, p1_reg, PWR_CTRL2, byte);
+	if (rc)
+		sbi_printf("%s: cannot write P1 Power Control Register 2\n", __func__);
+}
+
+static void p1_system_reset(uint32_t type, uint32_t reason)
+{
+	switch (type) {
+	case SBI_SRST_RESET_TYPE_SHUTDOWN:
+	case SBI_SRST_RESET_TYPE_COLD_REBOOT:
+	case SBI_SRST_RESET_TYPE_WARM_REBOOT:
+		p1_ops(type);
+		break;
+	}
+}
+
+static struct sbi_system_reset_device p1_reset = {
+	.name = "spacemit-p1-reset",
+	.system_reset_check = p1_system_reset_check,
+	.system_reset = p1_system_reset
+};
+
+static int p1_reset_init(const void *fdt, int nodeoff,
+			 const struct fdt_match *match)
+{
+	int rc, i2c_bus;
+	uint64_t addr;
+
+	/* we are spacemit,p1 node */
+	rc = fdt_get_node_addr_size(fdt, nodeoff, 0, &addr, NULL);
+	if (rc)
+		return rc;
+
+	p1_reg = addr;
+
+	/* find i2c bus parent node */
+	i2c_bus = fdt_parent_offset(fdt, nodeoff);
+	if (i2c_bus < 0)
+		return i2c_bus;
+
+	/* i2c adapter get */
+	rc = fdt_i2c_adapter_get(fdt, i2c_bus, &p1_adapter);
+	if (rc)
+		return rc;
+
+	sbi_system_reset_add_device(&p1_reset);
+
+	return 0;
+}
+
+static const struct fdt_match p1_reset_match[] = {
+	{ .compatible = "spacemit,p1", .data = (void *)true },
+	{ },
+};
+
+const struct fdt_driver fdt_reset_spacemit_p1 = {
+	.match_table = p1_reset_match,
+	.init = p1_reset_init,
+};

lib/utils/reset/objects.mk

@@ -20,6 +20,9 @@ libsbiutils-objs-$(CONFIG_FDT_RESET_HTIF) += reset/fdt_reset_htif.o
 carray-fdt_early_drivers-$(CONFIG_FDT_RESET_SG2042_HWMON_MCU) += fdt_reset_sg2042_mcu
 libsbiutils-objs-$(CONFIG_FDT_RESET_SG2042_HWMON_MCU) += reset/fdt_reset_sg2042_hwmon_mcu.o
 
+carray-fdt_early_drivers-$(CONFIG_FDT_RESET_SPACEMIT_P1) += fdt_reset_spacemit_p1
+libsbiutils-objs-$(CONFIG_FDT_RESET_SPACEMIT_P1) += reset/fdt_reset_spacemit_p1.o
+
 carray-fdt_early_drivers-$(CONFIG_FDT_RESET_SUNXI_WDT) += fdt_reset_sunxi_wdt
 libsbiutils-objs-$(CONFIG_FDT_RESET_SUNXI_WDT) += reset/fdt_reset_sunxi_wdt.o