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
  31 struct gemini_powercon {
  32         struct device           *dev;
  33         void __iomem            *base;
  34 };
  35
  36 static 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 */
  74 static struct gemini_powercon *gpw_poweroff;
  75
  76 static 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
  91 static 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
 161 static const struct of_device_id gemini_poweroff_of_match[] = {
 162         {
 163                 .compatible = "cortina,gemini-power-controller",
 164         },
 165         {}
 166 };
 167
 168 static 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 };
 175 builtin_platform_driver(gemini_poweroff_driver);