LXR linux/drivers/power/reset/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)
  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 struct syscore_ops poweroff_syscore_ops = {
  44        .shutdown = sc27xx_poweroff_shutdown,
  45};
  46
  47static 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
  55static 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
  69static struct platform_driver sc27xx_poweroff_driver = {
  70        .probe = sc27xx_poweroff_probe,
  71        .driver = {
  72                .name = "sc27xx-poweroff",
  73        },
  74};
  75module_platform_driver(sc27xx_poweroff_driver);
  76
  77MODULE_DESCRIPTION("Power off driver for SC27XX PMIC Device");
  78MODULE_AUTHOR("Baolin Wang <baolin.wang@unisoc.com>");
  79MODULE_LICENSE("GPL v2");
  80