LXR linux/drivers/power/reset/gemini-poweroff.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Gemini power management controller
   4 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
   5 *
   6 * Inspired by code from the SL3516 board support by Jason Lee
   7 * Inspired by code from Janos Laube <janos.dev@gmail.com>
   8 */
   9#include <linux/of.h>
  10#include <linux/of_platform.h>
  11#include <linux/platform_device.h>
  12#include <linux/pm.h>
  13#include <linux/bitops.h>
  14#include <linux/interrupt.h>
  15#include <linux/io.h>
  16#include <linux/reboot.h>
  17
  18#define GEMINI_PWC_ID           0x00010500
  19#define GEMINI_PWC_IDREG        0x00
  20#define GEMINI_PWC_CTRLREG      0x04
  21#define GEMINI_PWC_STATREG      0x08
  22
  23#define GEMINI_CTRL_SHUTDOWN    BIT(0)
  24#define GEMINI_CTRL_ENABLE      BIT(1)
  25#define GEMINI_CTRL_IRQ_CLR     BIT(2)
  26
  27#define GEMINI_STAT_CIR         BIT(4)
  28#define GEMINI_STAT_RTC         BIT(5)
  29#define GEMINI_STAT_POWERBUTTON BIT(6)
  30
  31struct gemini_powercon {
  32        struct device           *dev;
  33        void __iomem            *base;
  34};
  35
  36static irqreturn_t gemini_powerbutton_interrupt(int irq, void *data)
  37{
  38        struct gemini_powercon *gpw = data;
  39        u32 val;
  40
  41        /* ACK the IRQ */
  42        val = readl(gpw->base + GEMINI_PWC_CTRLREG);
  43        val |= GEMINI_CTRL_IRQ_CLR;
  44        writel(val, gpw->base + GEMINI_PWC_CTRLREG);
  45
  46        val = readl(gpw->base + GEMINI_PWC_STATREG);
  47        val &= 0x70U;
  48        switch (val) {
  49        case GEMINI_STAT_CIR:
  50                /*
  51                 * We do not yet have a driver for the infrared
  52                 * controller so it can cause spurious poweroff
  53                 * events. Ignore those for now.
  54                 */
  55                dev_info(gpw->dev, "infrared poweroff - ignored\n");
  56                break;
  57        case GEMINI_STAT_RTC:
  58                dev_info(gpw->dev, "RTC poweroff\n");
  59                orderly_poweroff(true);
  60                break;
  61        case GEMINI_STAT_POWERBUTTON:
  62                dev_info(gpw->dev, "poweroff button pressed\n");
  63                orderly_poweroff(true);
  64                break;
  65        default:
  66                dev_info(gpw->dev, "other power management IRQ\n");
  67                break;
  68        }
  69
  70        return IRQ_HANDLED;
  71}
  72
  73/* This callback needs this static local as it has void as argument */
  74static struct gemini_powercon *gpw_poweroff;
  75
  76static void gemini_poweroff(void)
  77{
  78        struct gemini_powercon *gpw = gpw_poweroff;
  79        u32 val;
  80
  81        dev_crit(gpw->dev, "Gemini power off\n");
  82        val = readl(gpw->base + GEMINI_PWC_CTRLREG);
  83        val |= GEMINI_CTRL_ENABLE | GEMINI_CTRL_IRQ_CLR;
  84        writel(val, gpw->base + GEMINI_PWC_CTRLREG);
  85
  86        val &= ~GEMINI_CTRL_ENABLE;
  87        val |= GEMINI_CTRL_SHUTDOWN;
  88        writel(val, gpw->base + GEMINI_PWC_CTRLREG);
  89}
  90
  91static int gemini_poweroff_probe(struct platform_device *pdev)
  92{
  93        struct device *dev = &pdev->dev;
  94        struct resource *res;
  95        struct gemini_powercon *gpw;
  96        u32 val;
  97        int irq;
  98        int ret;
  99
 100        gpw = devm_kzalloc(dev, sizeof(*gpw), GFP_KERNEL);
 101        if (!gpw)
 102                return -ENOMEM;
 103
 104        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 105        gpw->base = devm_ioremap_resource(dev, res);
 106        if (IS_ERR(gpw->base))
 107                return PTR_ERR(gpw->base);
 108
 109        irq = platform_get_irq(pdev, 0);
 110        if (!irq)
 111                return -EINVAL;
 112
 113        gpw->dev = dev;
 114
 115        val = readl(gpw->base + GEMINI_PWC_IDREG);
 116        val &= 0xFFFFFF00U;
 117        if (val != GEMINI_PWC_ID) {
 118                dev_err(dev, "wrong power controller ID: %08x\n",
 119                        val);
 120                return -ENODEV;
 121        }
 122
 123        /*
 124         * Enable the power controller. This is crucial on Gemini
 125         * systems: if this is not done, pressing the power button
 126         * will result in unconditional poweroff without any warning.
 127         * This makes the kernel handle the poweroff.
 128         */
 129        val = readl(gpw->base + GEMINI_PWC_CTRLREG);
 130        val |= GEMINI_CTRL_ENABLE;
 131        writel(val, gpw->base + GEMINI_PWC_CTRLREG);
 132
 133        /* Clear the IRQ */
 134        val = readl(gpw->base + GEMINI_PWC_CTRLREG);
 135        val |= GEMINI_CTRL_IRQ_CLR;
 136        writel(val, gpw->base + GEMINI_PWC_CTRLREG);
 137
 138        /* Wait for this to clear */
 139        val = readl(gpw->base + GEMINI_PWC_STATREG);
 140        while (val & 0x70U)
 141                val = readl(gpw->base + GEMINI_PWC_STATREG);
 142
 143        /* Clear the IRQ again */
 144        val = readl(gpw->base + GEMINI_PWC_CTRLREG);
 145        val |= GEMINI_CTRL_IRQ_CLR;
 146        writel(val, gpw->base + GEMINI_PWC_CTRLREG);
 147
 148        ret = devm_request_irq(dev, irq, gemini_powerbutton_interrupt, 0,
 149                               "poweroff", gpw);
 150        if (ret)
 151                return ret;
 152
 153        pm_power_off = gemini_poweroff;
 154        gpw_poweroff = gpw;
 155
 156        dev_info(dev, "Gemini poweroff driver registered\n");
 157
 158        return 0;
 159}
 160
 161static const struct of_device_id gemini_poweroff_of_match[] = {
 162        {
 163                .compatible = "cortina,gemini-power-controller",
 164        },
 165        {}
 166};
 167
 168static struct platform_driver gemini_poweroff_driver = {
 169        .probe = gemini_poweroff_probe,
 170        .driver = {
 171                .name = "gemini-poweroff",
 172                .of_match_table = gemini_poweroff_of_match,
 173        },
 174};
 175builtin_platform_driver(gemini_poweroff_driver);
 176