drivers/iio/trigger/iio-trig-interrupt.c

   1 /*
   2  * Industrial I/O - generic interrupt based trigger support
   3  *
   4  * Copyright (c) 2008-2013 Jonathan Cameron
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/slab.h>
  16
  17 #include <linux/iio/iio.h>
  18 #include <linux/iio/trigger.h>
  19
  20
  21 struct iio_interrupt_trigger_info {
  22         unsigned int irq;
  23 };
  24
  25 static irqreturn_t iio_interrupt_trigger_poll(int irq, void *private)
  26 {
  27         /* Timestamp not currently provided */
  28         iio_trigger_poll(private, 0);
  29         return IRQ_HANDLED;
  30 }
  31
  32 static const struct iio_trigger_ops iio_interrupt_trigger_ops = {
  33         .owner = THIS_MODULE,
  34 };
  35
  36 static int iio_interrupt_trigger_probe(struct platform_device *pdev)
  37 {
  38         struct iio_interrupt_trigger_info *trig_info;
  39         struct iio_trigger *trig;
  40         unsigned long irqflags;
  41         struct resource *irq_res;
  42         int irq, ret = 0;
  43
  44         irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
  45
  46         if (irq_res == NULL)
  47                 return -ENODEV;
  48
  49         irqflags = (irq_res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
  50
  51         irq = irq_res->start;
  52
  53         trig = iio_trigger_alloc("irqtrig%d", irq_res->start);
  54         if (!trig) {
  55                 ret = -ENOMEM;
  56                 goto error_ret;
  57         }
  58
  59         trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
  60         if (!trig_info) {
  61                 ret = -ENOMEM;
  62                 goto error_put_trigger;
  63         }
  64         iio_trigger_set_drvdata(trig, trig_info);
  65         trig_info->irq = irq;
  66         trig->ops = &iio_interrupt_trigger_ops;
  67         ret = request_irq(irq, iio_interrupt_trigger_poll,
  68                           irqflags, trig->name, trig);
  69         if (ret) {
  70                 dev_err(&pdev->dev,
  71                         "request IRQ-%d failed", irq);
  72                 goto error_free_trig_info;
  73         }
  74
  75         ret = iio_trigger_register(trig);
  76         if (ret)
  77                 goto error_release_irq;
  78         platform_set_drvdata(pdev, trig);
  79
  80         return 0;
  81
  82 /* First clean up the partly allocated trigger */
  83 error_release_irq:
  84         free_irq(irq, trig);
  85 error_free_trig_info:
  86         kfree(trig_info);
  87 error_put_trigger:
  88         iio_trigger_put(trig);
  89 error_ret:
  90         return ret;
  91 }
  92
  93 static int iio_interrupt_trigger_remove(struct platform_device *pdev)
  94 {
  95         struct iio_trigger *trig;
  96         struct iio_interrupt_trigger_info *trig_info;
  97
  98         trig = platform_get_drvdata(pdev);
  99         trig_info = iio_trigger_get_drvdata(trig);
 100         iio_trigger_unregister(trig);
 101         free_irq(trig_info->irq, trig);
 102         kfree(trig_info);
 103         iio_trigger_put(trig);
 104
 105         return 0;
 106 }
 107
 108 static struct platform_driver iio_interrupt_trigger_driver = {
 109         .probe = iio_interrupt_trigger_probe,
 110         .remove = iio_interrupt_trigger_remove,
 111         .driver = {
 112                 .name = "iio_interrupt_trigger",
 113                 .owner = THIS_MODULE,
 114         },
 115 };
 116
 117 module_platform_driver(iio_interrupt_trigger_driver);
 118
 119 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
 120 MODULE_DESCRIPTION("Interrupt trigger for the iio subsystem");
 121 MODULE_LICENSE("GPL v2");