1 files changed, 79 insertions, 0 deletions
diff --git a/drivers/power/reset/sc27xx-poweroff.c b/drivers/power/reset/sc27xx-poweroff.c
new file mode 100644
index 0000000000..90287c3199
--- /dev/null
+++ b/drivers/power/reset/sc27xx-poweroff.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Spreadtrum Communications Inc.
+ * Copyright (C) 2018 Linaro Ltd.
+ */
+
+#include <linux/cpu.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/regmap.h>
+#include <linux/syscore_ops.h>
+
+#define SC27XX_PWR_PD_HW	0xc2c
+#define SC27XX_PWR_OFF_EN	BIT(0)
+#define SC27XX_SLP_CTRL		0xdf0
+#define SC27XX_LDO_XTL_EN	BIT(3)
+
+static struct regmap *regmap;
+
+/*
+ * On Spreadtrum platform, we need power off system through external SC27xx
+ * series PMICs, and it is one similar SPI bus mapped by regmap to access PMIC,
+ * which is not fast io access.
+ *
+ * So before stopping other cores, we need release other cores' resource by
+ * taking cpus down to avoid racing regmap or spi mutex lock when poweroff
+ * system through PMIC.
+ */
+static void sc27xx_poweroff_shutdown(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		if (cpu != smp_processor_id())
+			remove_cpu(cpu);
+	}
+#endif
+}
+
+static struct syscore_ops poweroff_syscore_ops = {
+	.shutdown = sc27xx_poweroff_shutdown,
+};
+
+static void sc27xx_poweroff_do_poweroff(void)
+{
+	/* Disable the external subsys connection's power firstly */
+	regmap_write(regmap, SC27XX_SLP_CTRL, SC27XX_LDO_XTL_EN);
+
+	regmap_write(regmap, SC27XX_PWR_PD_HW, SC27XX_PWR_OFF_EN);
+}
+
+static int sc27xx_poweroff_probe(struct platform_device *pdev)
+{
+	if (regmap)
+		return -EINVAL;
+
+	regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!regmap)
+		return -ENODEV;
+
+	pm_power_off = sc27xx_poweroff_do_poweroff;
+	register_syscore_ops(&poweroff_syscore_ops);
+	return 0;
+}
+
+static struct platform_driver sc27xx_poweroff_driver = {
+	.probe = sc27xx_poweroff_probe,
+	.driver = {
+		.name = "sc27xx-poweroff",
+	},
+};
+module_platform_driver(sc27xx_poweroff_driver);
+
+MODULE_DESCRIPTION("Power off driver for SC27XX PMIC Device");
+MODULE_AUTHOR("Baolin Wang <baolin.wang@unisoc.com>");
+MODULE_LICENSE("GPL v2");