drivers/staging/vme/devices/vme_pio2_cntr.c

   1 /*
   2  * GE PIO2 Counter Driver
   3  *
   4  * Author: Martyn Welch <martyn.welch@ge.com>
   5  * Copyright 2009 GE Intelligent Platforms Embedded Systems, Inc.
   6  *
   7  * This program is free software; you can redistribute  it and/or modify it
   8  * under  the terms of  the GNU General  Public License as published by the
   9  * Free Software Foundation;  either version 2 of the  License, or (at your
  10  * option) any later version.
  11  *
  12  * The PIO-2 has 6 counters, currently this code just disables the interrupts
  13  * and leaves them alone.
  14  *
  15  */
  16
  17 #include <linux/device.h>
  18 #include <linux/types.h>
  19 #include <linux/gpio.h>
  20 #include <linux/vme.h>
  21
  22 #include "vme_pio2.h"
  23
  24 static int pio2_cntr_irq_set(struct pio2_card *card, int id)
  25 {
  26         int retval;
  27         u8 data;
  28
  29         data = PIO2_CNTR_SC_DEV[id] | PIO2_CNTR_RW_BOTH | card->cntr[id].mode;
  30         retval = vme_master_write(card->window, &data, 1, PIO2_CNTR_CTRL[id]);
  31         if (retval < 0)
  32                 return retval;
  33
  34         data = card->cntr[id].count & 0xFF;
  35         retval = vme_master_write(card->window, &data, 1, PIO2_CNTR_DATA[id]);
  36         if (retval < 0)
  37                 return retval;
  38
  39         data = (card->cntr[id].count >> 8) & 0xFF;
  40         retval = vme_master_write(card->window, &data, 1, PIO2_CNTR_DATA[id]);
  41         if (retval < 0)
  42                 return retval;
  43
  44         return 0;
  45 }
  46
  47 int pio2_cntr_reset(struct pio2_card *card)
  48 {
  49         int i, retval = 0;
  50         u8 reg;
  51
  52         /* Clear down all timers */
  53         for (i = 0; i < 6; i++) {
  54                 card->cntr[i].mode = PIO2_CNTR_MODE5;
  55                 card->cntr[i].count = 0;
  56                 retval = pio2_cntr_irq_set(card, i);
  57                 if (retval < 0)
  58                         return retval;
  59         }
  60
  61         /* Ensure all counter interrupts are cleared */
  62         do {
  63                 retval = vme_master_read(card->window, &reg, 1,
  64                         PIO2_REGS_INT_STAT_CNTR);
  65                 if (retval < 0)
  66                         return retval;
  67         } while (reg != 0);
  68
  69         return retval;
  70 }
  71