power: reset: add Odroid Go Ultra poweroff driver

The Hardkernel Odroid Go Ultra poweroff scheme requires requesting a poweroff
to its two PMICs in order, this represents the poweroff scheme needed to complete
a clean poweroff of the system.

This implement this scheme by implementing a self registering driver to permit
using probe defer until both pmics are finally probed.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/reset/Kconfig

@@ -141,6 +141,13 @@ config POWER_RESET_OCELOT_RESET
 	help
 	  This driver supports restart for Microsemi Ocelot SoC and similar.
 
+config POWER_RESET_ODROID_GO_ULTRA_POWEROFF
+	bool "Odroid Go Ultra power-off driver"
+	depends on ARCH_MESON || COMPILE_TEST
+	depends on I2C && OF
+	help
+	  This driver supports Power off for Odroid Go Ultra device.
+
 config POWER_RESET_OXNAS
 	bool "OXNAS SoC restart driver"
 	depends on ARCH_OXNAS

drivers/power/reset/Makefile

@@ -17,6 +17,7 @@ obj-$(CONFIG_POWER_RESET_MT6323) += mt6323-poweroff.o
 obj-$(CONFIG_POWER_RESET_OXNAS) += oxnas-restart.o
 obj-$(CONFIG_POWER_RESET_QCOM_PON) += qcom-pon.o
 obj-$(CONFIG_POWER_RESET_OCELOT_RESET) += ocelot-reset.o
+obj-$(CONFIG_POWER_RESET_ODROID_GO_ULTRA_POWEROFF) += odroid-go-ultra-poweroff.o
 obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o
 obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
 obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o

drivers/power/reset/odroid-go-ultra-poweroff.c

@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2023 Neil Armstrong <neil.armstrong@linaro.org>
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/of_platform.h>
+#include <linux/mfd/rk808.h>
+#include <linux/regmap.h>
+#include <linux/module.h>
+#include <linux/reboot.h>
+#include <linux/i2c.h>
+
+/*
+ * The Odroid Go Ultra has 2 PMICs:
+ * - RK818 (manages the battery and USB-C power supply)
+ * - RK817
+ * Both PMICs feeds power to the S922X SoC, so they must be powered-off in sequence.
+ * Vendor does power-off the RK817 first, then the RK818 so here we follow this sequence.
+ */
+
+struct odroid_go_ultra_poweroff_data {
+	struct device *dev;
+	struct device *rk817;
+	struct device *rk818;
+};
+
+static int odroid_go_ultra_poweroff_prepare(struct sys_off_data *data)
+{
+	struct odroid_go_ultra_poweroff_data *poweroff_data = data->cb_data;
+	struct regmap *rk817, *rk818;
+	int ret;
+
+	/* RK817 Regmap */
+	rk817 = dev_get_regmap(poweroff_data->rk817, NULL);
+	if (!rk817) {
+		dev_err(poweroff_data->dev, "failed to get rk817 regmap\n");
+		return notifier_from_errno(-EINVAL);
+	}
+
+	/* RK818 Regmap */
+	rk818 = dev_get_regmap(poweroff_data->rk818, NULL);
+	if (!rk818) {
+		dev_err(poweroff_data->dev, "failed to get rk818 regmap\n");
+		return notifier_from_errno(-EINVAL);
+	}
+
+	dev_info(poweroff_data->dev, "Setting PMICs for power off");
+
+	/* RK817 */
+	ret = regmap_update_bits(rk817, RK817_SYS_CFG(3), DEV_OFF, DEV_OFF);
+	if (ret) {
+		dev_err(poweroff_data->dev, "failed to poweroff rk817\n");
+		return notifier_from_errno(ret);
+	}
+
+	/* RK818 */
+	ret = regmap_update_bits(rk818, RK818_DEVCTRL_REG, DEV_OFF, DEV_OFF);
+	if (ret) {
+		dev_err(poweroff_data->dev, "failed to poweroff rk818\n");
+		return notifier_from_errno(ret);
+	}
+
+	return NOTIFY_OK;
+}
+
+static void odroid_go_ultra_poweroff_put_pmic_device(void *data)
+{
+	struct device *dev = data;
+
+	put_device(dev);
+}
+
+static int odroid_go_ultra_poweroff_get_pmic_device(struct device *dev, const char *compatible,
+						    struct device **pmic)
+{
+	struct device_node *pmic_node;
+	struct i2c_client *pmic_client;
+
+	pmic_node = of_find_compatible_node(NULL, NULL, compatible);
+	if (!pmic_node)
+		return -ENODEV;
+
+	pmic_client = of_find_i2c_device_by_node(pmic_node);
+	of_node_put(pmic_node);
+	if (!pmic_client)
+		return -EPROBE_DEFER;
+
+	*pmic = &pmic_client->dev;
+
+	return devm_add_action_or_reset(dev, odroid_go_ultra_poweroff_put_pmic_device, *pmic);
+}
+
+static int odroid_go_ultra_poweroff_probe(struct platform_device *pdev)
+{
+	struct odroid_go_ultra_poweroff_data *poweroff_data;
+	int ret;
+
+	poweroff_data = devm_kzalloc(&pdev->dev, sizeof(*poweroff_data), GFP_KERNEL);
+	if (!poweroff_data)
+		return -ENOMEM;
+
+	dev_set_drvdata(&pdev->dev, poweroff_data);
+
+	/* RK818 PMIC Device */
+	ret = odroid_go_ultra_poweroff_get_pmic_device(&pdev->dev, "rockchip,rk818",
+						       &poweroff_data->rk818);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "failed to get rk818 mfd data\n");
+
+	/* RK817 PMIC Device */
+	ret = odroid_go_ultra_poweroff_get_pmic_device(&pdev->dev, "rockchip,rk817",
+						       &poweroff_data->rk817);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "failed to get rk817 mfd data\n");
+
+	/* Register as SYS_OFF_MODE_POWER_OFF_PREPARE because regmap_update_bits may sleep */
+	ret = devm_register_sys_off_handler(&pdev->dev,
+					    SYS_OFF_MODE_POWER_OFF_PREPARE,
+					    SYS_OFF_PRIO_DEFAULT,
+					    odroid_go_ultra_poweroff_prepare,
+					    poweroff_data);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "failed to register sys-off handler\n");
+
+	dev_info(&pdev->dev, "Registered Power-Off handler\n");
+
+	return 0;
+}
+static struct platform_device *pdev;
+
+static struct platform_driver odroid_go_ultra_poweroff_driver = {
+	.driver = {
+		.name	= "odroid-go-ultra-poweroff",
+	},
+	.probe = odroid_go_ultra_poweroff_probe,
+};
+
+static int __init odroid_go_ultra_poweroff_init(void)
+{
+	int ret;
+
+	/* Only create when running on the Odroid Go Ultra device */
+	if (!of_device_is_compatible(of_root, "hardkernel,odroid-go-ultra"))
+		return -ENODEV;
+
+	ret = platform_driver_register(&odroid_go_ultra_poweroff_driver);
+	if (ret)
+		return ret;
+
+	pdev = platform_device_register_resndata(NULL, "odroid-go-ultra-poweroff", -1,
+						 NULL, 0, NULL, 0);
+
+	if (IS_ERR(pdev)) {
+		platform_driver_unregister(&odroid_go_ultra_poweroff_driver);
+		return PTR_ERR(pdev);
+	}
+
+	return 0;
+}
+
+static void __exit odroid_go_ultra_poweroff_exit(void)
+{
+	/* Only delete when running on the Odroid Go Ultra device */
+	if (!of_device_is_compatible(of_root, "hardkernel,odroid-go-ultra"))
+		return;
+
+	platform_device_unregister(pdev);
+	platform_driver_unregister(&odroid_go_ultra_poweroff_driver);
+}
+
+module_init(odroid_go_ultra_poweroff_init);
+module_exit(odroid_go_ultra_poweroff_exit);
+
+MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");
+MODULE_DESCRIPTION("Odroid Go Ultra poweroff driver");
+MODULE_LICENSE("GPL");