samples/blackfin/gptimers-example.c

   1 /*
   2  * Simple gptimers example
   3  *      http://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:drivers:gptimers
   4  *
   5  * Copyright 2007-2009 Analog Devices Inc.
   6  *
   7  * Licensed under the GPL-2 or later.
   8  */
   9
  10 #include <linux/interrupt.h>
  11 #include <linux/module.h>
  12
  13 #include <asm/gptimers.h>
  14 #include <asm/portmux.h>
  15
  16 /* ... random driver includes ... */
  17
  18 #define DRIVER_NAME "gptimer_example"
  19
  20 #ifdef IRQ_TIMER5
  21 #define SAMPLE_IRQ_TIMER IRQ_TIMER5
  22 #else
  23 #define SAMPLE_IRQ_TIMER IRQ_TIMER2
  24 #endif
  25
  26 struct gptimer_data {
  27         uint32_t period, width;
  28 };
  29 static struct gptimer_data data;
  30
  31 /* ... random driver state ... */
  32
  33 static irqreturn_t gptimer_example_irq(int irq, void *dev_id)
  34 {
  35         struct gptimer_data *data = dev_id;
  36
  37         /* make sure it was our timer which caused the interrupt */
  38         if (!get_gptimer_intr(TIMER5_id))
  39                 return IRQ_NONE;
  40
  41         /* read the width/period values that were captured for the waveform */
  42         data->width = get_gptimer_pwidth(TIMER5_id);
  43         data->period = get_gptimer_period(TIMER5_id);
  44
  45         /* acknowledge the interrupt */
  46         clear_gptimer_intr(TIMER5_id);
  47
  48         /* tell the upper layers we took care of things */
  49         return IRQ_HANDLED;
  50 }
  51
  52 /* ... random driver code ... */
  53
  54 static int __init gptimer_example_init(void)
  55 {
  56         int ret;
  57
  58         /* grab the peripheral pins */
  59         ret = peripheral_request(P_TMR5, DRIVER_NAME);
  60         if (ret) {
  61                 printk(KERN_NOTICE DRIVER_NAME ": peripheral request failed\n");
  62                 return ret;
  63         }
  64
  65         /* grab the IRQ for the timer */
  66         ret = request_irq(SAMPLE_IRQ_TIMER, gptimer_example_irq,
  67                         IRQF_SHARED, DRIVER_NAME, &data);
  68         if (ret) {
  69                 printk(KERN_NOTICE DRIVER_NAME ": IRQ request failed\n");
  70                 peripheral_free(P_TMR5);
  71                 return ret;
  72         }
  73
  74         /* setup the timer and enable it */
  75         set_gptimer_config(TIMER5_id,
  76                         WDTH_CAP | PULSE_HI | PERIOD_CNT | IRQ_ENA);
  77         enable_gptimers(TIMER5bit);
  78
  79         return 0;
  80 }
  81 module_init(gptimer_example_init);
  82
  83 static void __exit gptimer_example_exit(void)
  84 {
  85         disable_gptimers(TIMER5bit);
  86         free_irq(SAMPLE_IRQ_TIMER, &data);
  87         peripheral_free(P_TMR5);
  88 }
  89 module_exit(gptimer_example_exit);
  90
  91 MODULE_LICENSE("BSD");