arch/arm/mach-msm/gpiomux.c

   1 /* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License version 2 and
   5  * only version 2 as published by the Free Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  15  * 02110-1301, USA.
  16  */
  17 #include <linux/module.h>
  18 #include <linux/spinlock.h>
  19 #include "gpiomux.h"
  20
  21 static DEFINE_SPINLOCK(gpiomux_lock);
  22
  23 int msm_gpiomux_write(unsigned gpio,
  24                       gpiomux_config_t active,
  25                       gpiomux_config_t suspended)
  26 {
  27         struct msm_gpiomux_config *cfg = msm_gpiomux_configs + gpio;
  28         unsigned long irq_flags;
  29         gpiomux_config_t setting;
  30
  31         if (gpio >= GPIOMUX_NGPIOS)
  32                 return -EINVAL;
  33
  34         spin_lock_irqsave(&gpiomux_lock, irq_flags);
  35
  36         if (active & GPIOMUX_VALID)
  37                 cfg->active = active;
  38
  39         if (suspended & GPIOMUX_VALID)
  40                 cfg->suspended = suspended;
  41
  42         setting = cfg->ref ? active : suspended;
  43         if (setting & GPIOMUX_VALID)
  44                 __msm_gpiomux_write(gpio, setting);
  45
  46         spin_unlock_irqrestore(&gpiomux_lock, irq_flags);
  47         return 0;
  48 }
  49 EXPORT_SYMBOL(msm_gpiomux_write);
  50
  51 int msm_gpiomux_get(unsigned gpio)
  52 {
  53         struct msm_gpiomux_config *cfg = msm_gpiomux_configs + gpio;
  54         unsigned long irq_flags;
  55
  56         if (gpio >= GPIOMUX_NGPIOS)
  57                 return -EINVAL;
  58
  59         spin_lock_irqsave(&gpiomux_lock, irq_flags);
  60         if (cfg->ref++ == 0 && cfg->active & GPIOMUX_VALID)
  61                 __msm_gpiomux_write(gpio, cfg->active);
  62         spin_unlock_irqrestore(&gpiomux_lock, irq_flags);
  63         return 0;
  64 }
  65 EXPORT_SYMBOL(msm_gpiomux_get);
  66
  67 int msm_gpiomux_put(unsigned gpio)
  68 {
  69         struct msm_gpiomux_config *cfg = msm_gpiomux_configs + gpio;
  70         unsigned long irq_flags;
  71
  72         if (gpio >= GPIOMUX_NGPIOS)
  73                 return -EINVAL;
  74
  75         spin_lock_irqsave(&gpiomux_lock, irq_flags);
  76         BUG_ON(cfg->ref == 0);
  77         if (--cfg->ref == 0 && cfg->suspended & GPIOMUX_VALID)
  78                 __msm_gpiomux_write(gpio, cfg->suspended);
  79         spin_unlock_irqrestore(&gpiomux_lock, irq_flags);
  80         return 0;
  81 }
  82 EXPORT_SYMBOL(msm_gpiomux_put);
  83
  84 static int __init gpiomux_init(void)
  85 {
  86         unsigned n;
  87
  88         for (n = 0; n < GPIOMUX_NGPIOS; ++n) {
  89                 msm_gpiomux_configs[n].ref = 0;
  90                 if (!(msm_gpiomux_configs[n].suspended & GPIOMUX_VALID))
  91                         continue;
  92                 __msm_gpiomux_write(n, msm_gpiomux_configs[n].suspended);
  93         }
  94         return 0;
  95 }
  96 postcore_initcall(gpiomux_init);