arch/powerpc/platforms/85xx/sgy_cts1000.c

   1 /*
   2  * Servergy CTS-1000 Setup
   3  *
   4  * Maintained by Ben Collins <ben.c@servergy.com>
   5  *
   6  * Copyright 2012 by Servergy, Inc.
   7  *
   8  * This program is free software; you can redistribute  it and/or modify it
   9  * under  the terms of  the GNU General  Public License as published by the
  10  * Free Software Foundation;  either version 2 of the  License, or (at your
  11  * option) any later version.
  12  */
  13
  14 #include <linux/platform_device.h>
  15 #include <linux/device.h>
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/of_gpio.h>
  19 #include <linux/of_irq.h>
  20 #include <linux/workqueue.h>
  21 #include <linux/reboot.h>
  22 #include <linux/interrupt.h>
  23
  24 #include <asm/machdep.h>
  25
  26 static struct device_node *halt_node;
  27
  28 static struct of_device_id child_match[] = {
  29         {
  30                 .compatible = "sgy,gpio-halt",
  31         },
  32         {},
  33 };
  34
  35 static void gpio_halt_wfn(struct work_struct *work)
  36 {
  37         /* Likely wont return */
  38         orderly_poweroff(true);
  39 }
  40 static DECLARE_WORK(gpio_halt_wq, gpio_halt_wfn);
  41
  42 static void gpio_halt_cb(void)
  43 {
  44         enum of_gpio_flags flags;
  45         int trigger, gpio;
  46
  47         if (!halt_node)
  48                 return;
  49
  50         gpio = of_get_gpio_flags(halt_node, 0, &flags);
  51
  52         if (!gpio_is_valid(gpio))
  53                 return;
  54
  55         trigger = (flags == OF_GPIO_ACTIVE_LOW);
  56
  57         printk(KERN_INFO "gpio-halt: triggering GPIO.\n");
  58
  59         /* Probably wont return */
  60         gpio_set_value(gpio, trigger);
  61 }
  62
  63 /* This IRQ means someone pressed the power button and it is waiting for us
  64  * to handle the shutdown/poweroff. */
  65 static irqreturn_t gpio_halt_irq(int irq, void *__data)
  66 {
  67         printk(KERN_INFO "gpio-halt: shutdown due to power button IRQ.\n");
  68         schedule_work(&gpio_halt_wq);
  69
  70         return IRQ_HANDLED;
  71 };
  72
  73 static int gpio_halt_probe(struct platform_device *pdev)
  74 {
  75         enum of_gpio_flags flags;
  76         struct device_node *node = pdev->dev.of_node;
  77         int gpio, err, irq;
  78         int trigger;
  79
  80         if (!node)
  81                 return -ENODEV;
  82
  83         /* If there's no matching child, this isn't really an error */
  84         halt_node = of_find_matching_node(node, child_match);
  85         if (!halt_node)
  86                 return 0;
  87
  88         /* Technically we could just read the first one, but punish
  89          * DT writers for invalid form. */
  90         if (of_gpio_count(halt_node) != 1)
  91                 return -EINVAL;
  92
  93         /* Get the gpio number relative to the dynamic base. */
  94         gpio = of_get_gpio_flags(halt_node, 0, &flags);
  95         if (!gpio_is_valid(gpio))
  96                 return -EINVAL;
  97
  98         err = gpio_request(gpio, "gpio-halt");
  99         if (err) {
 100                 printk(KERN_ERR "gpio-halt: error requesting GPIO %d.\n",
 101                        gpio);
 102                 halt_node = NULL;
 103                 return err;
 104         }
 105
 106         trigger = (flags == OF_GPIO_ACTIVE_LOW);
 107
 108         gpio_direction_output(gpio, !trigger);
 109
 110         /* Now get the IRQ which tells us when the power button is hit */
 111         irq = irq_of_parse_and_map(halt_node, 0);
 112         err = request_irq(irq, gpio_halt_irq, IRQF_TRIGGER_RISING |
 113                           IRQF_TRIGGER_FALLING, "gpio-halt", halt_node);
 114         if (err) {
 115                 printk(KERN_ERR "gpio-halt: error requesting IRQ %d for "
 116                        "GPIO %d.\n", irq, gpio);
 117                 gpio_free(gpio);
 118                 halt_node = NULL;
 119                 return err;
 120         }
 121
 122         /* Register our halt function */
 123         ppc_md.halt = gpio_halt_cb;
 124         ppc_md.power_off = gpio_halt_cb;
 125
 126         printk(KERN_INFO "gpio-halt: registered GPIO %d (%d trigger, %d"
 127                " irq).\n", gpio, trigger, irq);
 128
 129         return 0;
 130 }
 131
 132 static int gpio_halt_remove(struct platform_device *pdev)
 133 {
 134         if (halt_node) {
 135                 int gpio = of_get_gpio(halt_node, 0);
 136                 int irq = irq_of_parse_and_map(halt_node, 0);
 137
 138                 free_irq(irq, halt_node);
 139
 140                 ppc_md.halt = NULL;
 141                 ppc_md.power_off = NULL;
 142
 143                 gpio_free(gpio);
 144
 145                 halt_node = NULL;
 146         }
 147
 148         return 0;
 149 }
 150
 151 static struct of_device_id gpio_halt_match[] = {
 152         /* We match on the gpio bus itself and scan the children since they
 153          * wont be matched against us. We know the bus wont match until it
 154          * has been registered too. */
 155         {
 156                 .compatible = "fsl,qoriq-gpio",
 157         },
 158         {},
 159 };
 160 MODULE_DEVICE_TABLE(of, gpio_halt_match);
 161
 162 static struct platform_driver gpio_halt_driver = {
 163         .driver = {
 164                 .name           = "gpio-halt",
 165                 .owner          = THIS_MODULE,
 166                 .of_match_table = gpio_halt_match,
 167         },
 168         .probe          = gpio_halt_probe,
 169         .remove         = gpio_halt_remove,
 170 };
 171
 172 module_platform_driver(gpio_halt_driver);
 173
 174 MODULE_DESCRIPTION("Driver to support GPIO triggered system halt for Servergy CTS-1000 Systems.");
 175 MODULE_VERSION("1.0");
 176 MODULE_AUTHOR("Ben Collins <ben.c@servergy.com>");
 177 MODULE_LICENSE("GPL");