sc27xx-poweroff.c

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright (C) 2018 Spreadtrum Communications Inc.
 4 * Copyright (C) 2018 Linaro Ltd.
 5 */
 6
 7#include <linux/cpu.h>
 8#include <linux/kernel.h>
 9#include <linux/module.h>
10#include <linux/platform_device.h>
11#include <linux/pm.h>
12#include <linux/regmap.h>
13#include <linux/syscore_ops.h>
14
15#define SC27XX_PWR_PD_HW	0xc2c
16#define SC27XX_PWR_OFF_EN	BIT(0)
17#define SC27XX_SLP_CTRL		0xdf0
18#define SC27XX_LDO_XTL_EN	BIT(3)
19
20static struct regmap *regmap;
21
22/*
23 * On Spreadtrum platform, we need power off system through external SC27xx
24 * series PMICs, and it is one similar SPI bus mapped by regmap to access PMIC,
25 * which is not fast io access.
26 *
27 * So before stopping other cores, we need release other cores' resource by
28 * taking cpus down to avoid racing regmap or spi mutex lock when poweroff
29 * system through PMIC.
30 */
31static void sc27xx_poweroff_shutdown(void *data)
32{
33#ifdef CONFIG_HOTPLUG_CPU
34	int cpu;
35
36	for_each_online_cpu(cpu) {
37		if (cpu != smp_processor_id())
38			remove_cpu(cpu);
39	}
40#endif
41}
42
43static const struct syscore_ops poweroff_syscore_ops = {
44	.shutdown = sc27xx_poweroff_shutdown,
45};
46
47static struct syscore poweroff_syscore = {
48	.ops = &poweroff_syscore_ops,
49};
50
51static void sc27xx_poweroff_do_poweroff(void)
52{
53	/* Disable the external subsys connection's power firstly */
54	regmap_write(regmap, SC27XX_SLP_CTRL, SC27XX_LDO_XTL_EN);
55
56	regmap_write(regmap, SC27XX_PWR_PD_HW, SC27XX_PWR_OFF_EN);
57}
58
59static int sc27xx_poweroff_probe(struct platform_device *pdev)
60{
61	if (regmap)
62		return -EINVAL;
63
64	regmap = dev_get_regmap(pdev->dev.parent, NULL);
65	if (!regmap)
66		return -ENODEV;
67
68	pm_power_off = sc27xx_poweroff_do_poweroff;
69	register_syscore(&poweroff_syscore);
70	return 0;
71}
72
73static struct platform_driver sc27xx_poweroff_driver = {
74	.probe = sc27xx_poweroff_probe,
75	.driver = {
76		.name = "sc27xx-poweroff",
77	},
78};
79module_platform_driver(sc27xx_poweroff_driver);
80
81MODULE_DESCRIPTION("Power off driver for SC27XX PMIC Device");
82MODULE_AUTHOR("Baolin Wang <baolin.wang@unisoc.com>");
83MODULE_LICENSE("GPL v2");