drivers/power/reset/at91-poweroff.c

   1 /*
   2  * Atmel AT91 SAM9 SoCs reset code
   3  *
   4  * Copyright (C) 2007 Atmel Corporation.
   5  * Copyright (C) 2011 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
   6  * Copyright (C) 2014 Free Electrons
   7  *
   8  * This file is licensed under the terms of the GNU General Public
   9  * License version 2.  This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12
  13 #include <linux/io.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/printk.h>
  18
  19 #define AT91_SHDW_CR    0x00            /* Shut Down Control Register */
  20 #define AT91_SHDW_SHDW          BIT(0)                  /* Shut Down command */
  21 #define AT91_SHDW_KEY           (0xa5 << 24)            /* KEY Password */
  22
  23 #define AT91_SHDW_MR    0x04            /* Shut Down Mode Register */
  24 #define AT91_SHDW_WKMODE0       GENMASK(2, 0)           /* Wake-up 0 Mode Selection */
  25 #define AT91_SHDW_CPTWK0_MAX    0xf                     /* Maximum Counter On Wake Up 0 */
  26 #define AT91_SHDW_CPTWK0        (AT91_SHDW_CPTWK0_MAX << 4) /* Counter On Wake Up 0 */
  27 #define AT91_SHDW_CPTWK0_(x)    ((x) << 4)
  28 #define AT91_SHDW_RTTWKEN       BIT(16)                 /* Real Time Timer Wake-up Enable */
  29 #define AT91_SHDW_RTCWKEN       BIT(17)                 /* Real Time Clock Wake-up Enable */
  30
  31 #define AT91_SHDW_SR    0x08            /* Shut Down Status Register */
  32 #define AT91_SHDW_WAKEUP0       BIT(0)                  /* Wake-up 0 Status */
  33 #define AT91_SHDW_RTTWK         BIT(16)                 /* Real-time Timer Wake-up */
  34 #define AT91_SHDW_RTCWK         BIT(17)                 /* Real-time Clock Wake-up [SAM9RL] */
  35
  36 enum wakeup_type {
  37         AT91_SHDW_WKMODE0_NONE          = 0,
  38         AT91_SHDW_WKMODE0_HIGH          = 1,
  39         AT91_SHDW_WKMODE0_LOW           = 2,
  40         AT91_SHDW_WKMODE0_ANYLEVEL      = 3,
  41 };
  42
  43 static const char *shdwc_wakeup_modes[] = {
  44         [AT91_SHDW_WKMODE0_NONE]        = "none",
  45         [AT91_SHDW_WKMODE0_HIGH]        = "high",
  46         [AT91_SHDW_WKMODE0_LOW]         = "low",
  47         [AT91_SHDW_WKMODE0_ANYLEVEL]    = "any",
  48 };
  49
  50 static void __iomem *at91_shdwc_base;
  51
  52 static void __init at91_wakeup_status(void)
  53 {
  54         u32 reg = readl(at91_shdwc_base + AT91_SHDW_SR);
  55         char *reason = "unknown";
  56
  57         /* Simple power-on, just bail out */
  58         if (!reg)
  59                 return;
  60
  61         if (reg & AT91_SHDW_RTTWK)
  62                 reason = "RTT";
  63         else if (reg & AT91_SHDW_RTCWK)
  64                 reason = "RTC";
  65
  66         pr_info("AT91: Wake-Up source: %s\n", reason);
  67 }
  68
  69 static void at91_poweroff(void)
  70 {
  71         writel(AT91_SHDW_KEY | AT91_SHDW_SHDW, at91_shdwc_base + AT91_SHDW_CR);
  72 }
  73
  74 static int at91_poweroff_get_wakeup_mode(struct device_node *np)
  75 {
  76         const char *pm;
  77         unsigned int i;
  78         int err;
  79
  80         err = of_property_read_string(np, "atmel,wakeup-mode", &pm);
  81         if (err < 0)
  82                 return AT91_SHDW_WKMODE0_ANYLEVEL;
  83
  84         for (i = 0; i < ARRAY_SIZE(shdwc_wakeup_modes); i++)
  85                 if (!strcasecmp(pm, shdwc_wakeup_modes[i]))
  86                         return i;
  87
  88         return -ENODEV;
  89 }
  90
  91 static void at91_poweroff_dt_set_wakeup_mode(struct platform_device *pdev)
  92 {
  93         struct device_node *np = pdev->dev.of_node;
  94         int wakeup_mode;
  95         u32 mode = 0, tmp;
  96
  97         wakeup_mode = at91_poweroff_get_wakeup_mode(np);
  98         if (wakeup_mode < 0) {
  99                 dev_warn(&pdev->dev, "shdwc unknown wakeup mode\n");
 100                 return;
 101         }
 102
 103         if (!of_property_read_u32(np, "atmel,wakeup-counter", &tmp)) {
 104                 if (tmp > AT91_SHDW_CPTWK0_MAX) {
 105                         dev_warn(&pdev->dev,
 106                                  "shdwc wakeup counter 0x%x > 0x%x reduce it to 0x%x\n",
 107                                  tmp, AT91_SHDW_CPTWK0_MAX, AT91_SHDW_CPTWK0_MAX);
 108                         tmp = AT91_SHDW_CPTWK0_MAX;
 109                 }
 110                 mode |= AT91_SHDW_CPTWK0_(tmp);
 111         }
 112
 113         if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
 114                         mode |= AT91_SHDW_RTCWKEN;
 115
 116         if (of_property_read_bool(np, "atmel,wakeup-rtt-timer"))
 117                         mode |= AT91_SHDW_RTTWKEN;
 118
 119         writel(wakeup_mode | mode, at91_shdwc_base + AT91_SHDW_MR);
 120 }
 121
 122 static int at91_poweroff_probe(struct platform_device *pdev)
 123 {
 124         struct resource *res;
 125
 126         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 127         at91_shdwc_base = devm_ioremap_resource(&pdev->dev, res);
 128         if (IS_ERR(at91_shdwc_base)) {
 129                 dev_err(&pdev->dev, "Could not map reset controller address\n");
 130                 return PTR_ERR(at91_shdwc_base);
 131         }
 132
 133         at91_wakeup_status();
 134
 135         if (pdev->dev.of_node)
 136                 at91_poweroff_dt_set_wakeup_mode(pdev);
 137
 138         pm_power_off = at91_poweroff;
 139
 140         return 0;
 141 }
 142
 143 static const struct of_device_id at91_poweroff_of_match[] = {
 144         { .compatible = "atmel,at91sam9260-shdwc", },
 145         { .compatible = "atmel,at91sam9rl-shdwc", },
 146         { .compatible = "atmel,at91sam9x5-shdwc", },
 147         { /*sentinel*/ }
 148 };
 149
 150 static struct platform_driver at91_poweroff_driver = {
 151         .probe = at91_poweroff_probe,
 152         .driver = {
 153                 .name = "at91-poweroff",
 154                 .of_match_table = at91_poweroff_of_match,
 155         },
 156 };
 157 module_platform_driver(at91_poweroff_driver);