sysreset: implement MAX9807 sysreset functions

MAX8907 PMIC has embedded poweroff function used by some device to initiane
device power off. Implement it as optional sysreset driver guarded by
kconfig option and system-power-controller device tree property.

Tested-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>

drivers/power/pmic/max8907.c

@@ -45,7 +45,19 @@ static int max8907_read(struct udevice *dev, uint reg, uint8_t *buff, int len)
 static int max8907_bind(struct udevice *dev)
 {
 	ofnode regulators_node;
-	int children;
+	int children, ret;
+
+	if (IS_ENABLED(CONFIG_SYSRESET_MAX8907) &&
+	    dev_read_bool(dev, "maxim,system-power-controller")) {
+		ret = device_bind_driver_to_node(dev, MAX8907_RST_DRIVER,
+						 "sysreset", dev_ofnode(dev),
+						 NULL);
+		if (ret) {
+			log_debug("%s: cannot bind SYSRESET (ret = %d)\n",
+				  __func__, ret);
+			return ret;
+		}
+	}
 
 	regulators_node = dev_read_subnode(dev, "regulators");
 	if (!ofnode_valid(regulators_node)) {

drivers/sysreset/Kconfig

@@ -131,6 +131,13 @@ config SYSRESET_MAX77663
 	help
 	  Enable system power management functions found in MAX77663 PMIC.
 
+config SYSRESET_MAX8907
+	bool "Enable support for MAX8907 PMIC System Reset"
+	depends on DM_PMIC_MAX8907
+	select SYSRESET_CMD_POWEROFF if CMD_POWEROFF
+	help
+	  Enable system power management functions found in MAX8907 PMIC.
+
 config SYSRESET_MICROBLAZE
 	bool "Enable support for Microblaze soft reset"
 	depends on MICROBLAZE

drivers/sysreset/Makefile

@@ -11,6 +11,7 @@ obj-$(CONFIG_SYSRESET_CV1800B) += sysreset_cv1800b.o
 obj-$(CONFIG_$(PHASE_)POWEROFF_GPIO) += poweroff_gpio.o
 obj-$(CONFIG_$(PHASE_)SYSRESET_GPIO) += sysreset_gpio.o
 obj-$(CONFIG_$(PHASE_)SYSRESET_MAX77663) += sysreset_max77663.o
+obj-$(CONFIG_$(PHASE_)SYSRESET_MAX8907) += sysreset_max8907.o
 obj-$(CONFIG_SYSRESET_MPC83XX) += sysreset_mpc83xx.o
 obj-$(CONFIG_SYSRESET_MICROBLAZE) += sysreset_microblaze.o
 obj-$(CONFIG_SYSRESET_OCTEON) += sysreset_octeon.o

drivers/sysreset/sysreset_max8907.c

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Copyright(C) 2024 Svyatoslav Ryhel <clamor95@gmail.com>
+ */
+
+#include <dm.h>
+#include <i2c.h>
+#include <errno.h>
+#include <sysreset.h>
+#include <power/pmic.h>
+#include <power/max8907.h>
+
+static int max8907_sysreset_request(struct udevice *dev, enum sysreset_t type)
+{
+	switch (type) {
+	case SYSRESET_POWER:
+	case SYSRESET_POWER_OFF:
+		/* MAX8907: PWR_OFF > RESET_CNFG */
+		pmic_clrsetbits(dev->parent, MAX8907_REG_RESET_CNFG,
+				MASK_POWER_OFF, MASK_POWER_OFF);
+		break;
+	default:
+		return -EPROTONOSUPPORT;
+	}
+
+	return -EINPROGRESS;
+}
+
+static struct sysreset_ops max8907_sysreset = {
+	.request = max8907_sysreset_request,
+};
+
+U_BOOT_DRIVER(sysreset_max8907) = {
+	.id	= UCLASS_SYSRESET,
+	.name	= MAX8907_RST_DRIVER,
+	.ops	= &max8907_sysreset,
+};

include/power/max8907.h

@@ -12,6 +12,7 @@
 /* Drivers name */
 #define MAX8907_LDO_DRIVER		"max8907_ldo"
 #define MAX8907_SD_DRIVER		"max8907_sd"
+#define MAX8907_RST_DRIVER		"max8907_rst"
 
 /* MAX8907 register map */
 #define MAX8907_REG_SDCTL1		0x04
@@ -39,6 +40,9 @@
 #define MAX8907_REG_LDOCTL18		0x72
 #define MAX8907_REG_LDOCTL20		0x9C
 
+#define MAX8907_REG_RESET_CNFG		0x0F
+#define   MASK_POWER_OFF		BIT(6)
+
 /* MAX8907 configuration values */
 #define MAX8907_CTL			0
 #define MAX8907_SEQCNT			1