From 9065b87f35018a4e993e7dfb8a8ec29474785f76 Mon Sep 17 00:00:00 2001
From: Primoz Fiser <primoz.fiser@norik.com>
Date: Thu, 28 Aug 2025 13:24:04 +0200
Subject: [PATCH] power: pmic: pca9450: Add support for system reset

The family of PCA9450 PMICs have the ability to perform system resets.
Restarting via PMIC is preferred method of restarting the system as all
the peripherals are brought to a know state after a power-cycle. The
PCA9450 features a cold restart procedure which is initiated by an I2C
command 0x14 to the SW_RST register.

Support in Linux for restarting via PCA9450 PMIC has been added by
Linux commit 6157e62b07d9 ("regulator: pca9450: Add restart handler").

Now add support for it also in the U-Boot via sysreset framework.

Signed-off-by: Primoz Fiser <primoz.fiser@norik.com>
Reviewed-by: Paul Geurts <paul.geurts@prodrive-technologies.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/power/pmic/pca9450.c | 44 ++++++++++++++++++++++++++++++++++++
 include/power/pca9450.h      |  2 ++
 2 files changed, 46 insertions(+)

diff --git a/drivers/power/pmic/pca9450.c b/drivers/power/pmic/pca9450.c
index 0e3d14abf15..8b98c2239e1 100644
--- a/drivers/power/pmic/pca9450.c
+++ b/drivers/power/pmic/pca9450.c
@@ -6,13 +6,17 @@
 #include <fdtdec.h>
 #include <errno.h>
 #include <dm.h>
+#include <dm/device_compat.h>
+#include <dm/lists.h>
 #include <i2c.h>
 #include <log.h>
 #include <asm/global_data.h>
+#include <linux/delay.h>
 #include <linux/printk.h>
 #include <power/pmic.h>
 #include <power/regulator.h>
 #include <power/pca9450.h>
+#include <sysreset.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -79,6 +83,15 @@ static int pca9450_bind(struct udevice *dev)
 static int pca9450_probe(struct udevice *dev)
 {
 	unsigned int reset_ctrl;
+	int ret;
+
+	if (CONFIG_IS_ENABLED(SYSRESET)) {
+		ret = device_bind_driver_to_node(dev, "pca9450_sysreset",
+						 "pca9450_sysreset",
+						 dev_ofnode(dev), NULL);
+		if (ret)
+			return ret;
+	}
 
 	if (ofnode_read_bool(dev_ofnode(dev), "nxp,wdog_b-warm-reset"))
 		reset_ctrl = PCA9450_PMIC_RESET_WDOG_B_CFG_WARM;
@@ -112,3 +125,34 @@ U_BOOT_DRIVER(pmic_pca9450) = {
 	.probe = pca9450_probe,
 	.ops = &pca9450_ops,
 };
+
+#ifdef CONFIG_SYSRESET
+static int pca9450_sysreset_request(struct udevice *dev, enum sysreset_t type)
+{
+	u8 cmd = PCA9450_SW_RST_COLD_RST;
+
+	if (type != SYSRESET_COLD)
+		return -EPROTONOSUPPORT;
+
+	if (pmic_write(dev->parent, PCA9450_SW_RST, &cmd, 1)) {
+		dev_err(dev, "reset command failed\n");
+	} else {
+		/* tRESTART is 250ms, delay 300ms just to be sure */
+		mdelay(300);
+		/* Should not get here, warn if we do */
+		dev_warn(dev, "didn't respond to reset command\n");
+	}
+
+	return -EINPROGRESS;
+}
+
+static struct sysreset_ops pca9450_sysreset_ops = {
+	.request	= pca9450_sysreset_request,
+};
+
+U_BOOT_DRIVER(pca9450_sysreset) = {
+	.name		= "pca9450_sysreset",
+	.id		= UCLASS_SYSRESET,
+	.ops		= &pca9450_sysreset_ops,
+};
+#endif /* CONFIG_SYSRESET */
diff --git a/include/power/pca9450.h b/include/power/pca9450.h
index e5ab09fb8c8..9119ef793b1 100644
--- a/include/power/pca9450.h
+++ b/include/power/pca9450.h
@@ -75,4 +75,6 @@ enum {
 #define PCA9450_PMIC_RESET_WDOG_B_CFG_WARM		0x40
 #define PCA9450_PMIC_RESET_WDOG_B_CFG_COLD_LDO12	0x80
 
+#define PCA9450_SW_RST_COLD_RST		0x14
+
 #endif
-- 
2.47.3