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
20 static 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 */
sc27xx_poweroff_shutdown(void)31 static void sc27xx_poweroff_shutdown(void)
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
43 static struct syscore_ops poweroff_syscore_ops = {
44 .shutdown = sc27xx_poweroff_shutdown,
45 };
46
sc27xx_poweroff_do_poweroff(void)47 static void sc27xx_poweroff_do_poweroff(void)
48 {
49 /* Disable the external subsys connection's power firstly */
50 regmap_write(regmap, SC27XX_SLP_CTRL, SC27XX_LDO_XTL_EN);
51
52 regmap_write(regmap, SC27XX_PWR_PD_HW, SC27XX_PWR_OFF_EN);
53 }
54
sc27xx_poweroff_probe(struct platform_device * pdev)55 static int sc27xx_poweroff_probe(struct platform_device *pdev)
56 {
57 if (regmap)
58 return -EINVAL;
59
60 regmap = dev_get_regmap(pdev->dev.parent, NULL);
61 if (!regmap)
62 return -ENODEV;
63
64 pm_power_off = sc27xx_poweroff_do_poweroff;
65 register_syscore_ops(&poweroff_syscore_ops);
66 return 0;
67 }
68
69 static struct platform_driver sc27xx_poweroff_driver = {
70 .probe = sc27xx_poweroff_probe,
71 .driver = {
72 .name = "sc27xx-poweroff",
73 },
74 };
75 module_platform_driver(sc27xx_poweroff_driver);
76
77 MODULE_DESCRIPTION("Power off driver for SC27XX PMIC Device");
78 MODULE_AUTHOR("Baolin Wang <baolin.wang@unisoc.com>");
79 MODULE_LICENSE("GPL v2");
80