arch/x86/mach-rdc321x/gpio.c

   1 /*
   2  *  GPIO support for RDC SoC R3210/R8610
   3  *
   4  *  Copyright (C) 2007, Florian Fainelli <florian@openwrt.org>
   5  *  Copyright (C) 2008, Volker Weiss <dev@tintuc.de>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  */
  22
  23
  24 #include <linux/spinlock.h>
  25 #include <linux/io.h>
  26 #include <linux/types.h>
  27 #include <linux/module.h>
  28
  29 #include <asm/gpio.h>
  30 #include <asm/mach-rdc321x/rdc321x_defs.h>
  31
  32
  33 /* spin lock to protect our private copy of GPIO data register plus
  34    the access to PCI conf registers. */
  35 static DEFINE_SPINLOCK(gpio_lock);
  36
  37 /* copy of GPIO data registers */
  38 static u32 gpio_data_reg1;
  39 static u32 gpio_data_reg2;
  40
  41 static u32 gpio_request_data[2];
  42
  43
  44 static inline void rdc321x_conf_write(unsigned addr, u32 value)
  45 {
  46         outl((1 << 31) | (7 << 11) | addr, RDC3210_CFGREG_ADDR);
  47         outl(value, RDC3210_CFGREG_DATA);
  48 }
  49
  50 static inline void rdc321x_conf_or(unsigned addr, u32 value)
  51 {
  52         outl((1 << 31) | (7 << 11) | addr, RDC3210_CFGREG_ADDR);
  53         value |= inl(RDC3210_CFGREG_DATA);
  54         outl(value, RDC3210_CFGREG_DATA);
  55 }
  56
  57 static inline u32 rdc321x_conf_read(unsigned addr)
  58 {
  59         outl((1 << 31) | (7 << 11) | addr, RDC3210_CFGREG_ADDR);
  60
  61         return inl(RDC3210_CFGREG_DATA);
  62 }
  63
  64 /* configure pin as GPIO */
  65 static void rdc321x_configure_gpio(unsigned gpio)
  66 {
  67         unsigned long flags;
  68
  69         spin_lock_irqsave(&gpio_lock, flags);
  70         rdc321x_conf_or(gpio < 32
  71                 ? RDC321X_GPIO_CTRL_REG1 : RDC321X_GPIO_CTRL_REG2,
  72                 1 << (gpio & 0x1f));
  73         spin_unlock_irqrestore(&gpio_lock, flags);
  74 }
  75
  76 /* initially setup the 2 copies of the gpio data registers.
  77    This function must be called by the platform setup code. */
  78 void __init rdc321x_gpio_setup()
  79 {
  80         /* this might not be, what others (BIOS, bootloader, etc.)
  81            wrote to these registers before, but it's a good guess. Still
  82            better than just using 0xffffffff. */
  83
  84         gpio_data_reg1 = rdc321x_conf_read(RDC321X_GPIO_DATA_REG1);
  85         gpio_data_reg2 = rdc321x_conf_read(RDC321X_GPIO_DATA_REG2);
  86 }
  87
  88 /* determine, if gpio number is valid */
  89 static inline int rdc321x_is_gpio(unsigned gpio)
  90 {
  91         return gpio <= RDC321X_MAX_GPIO;
  92 }
  93
  94 /* request GPIO */
  95 int rdc_gpio_request(unsigned gpio, const char *label)
  96 {
  97         unsigned long flags;
  98
  99         if (!rdc321x_is_gpio(gpio))
 100                 return -EINVAL;
 101
 102         spin_lock_irqsave(&gpio_lock, flags);
 103         if (gpio_request_data[(gpio & 0x20) ? 1 : 0] & (1 << (gpio & 0x1f)))
 104                 goto inuse;
 105         gpio_request_data[(gpio & 0x20) ? 1 : 0] |= (1 << (gpio & 0x1f));
 106         spin_unlock_irqrestore(&gpio_lock, flags);
 107
 108         return 0;
 109 inuse:
 110         spin_unlock_irqrestore(&gpio_lock, flags);
 111         return -EINVAL;
 112 }
 113 EXPORT_SYMBOL(rdc_gpio_request);
 114
 115 /* release previously-claimed GPIO */
 116 void rdc_gpio_free(unsigned gpio)
 117 {
 118         unsigned long flags;
 119
 120         if (!rdc321x_is_gpio(gpio))
 121                 return;
 122
 123         spin_lock_irqsave(&gpio_lock, flags);
 124         gpio_request_data[(gpio & 0x20) ? 1 : 0] &= ~(1 << (gpio & 0x1f));
 125         spin_unlock_irqrestore(&gpio_lock, flags);
 126 }
 127 EXPORT_SYMBOL(rdc_gpio_free);
 128
 129 /* read GPIO pin */
 130 int rdc_gpio_get_value(unsigned gpio)
 131 {
 132         u32 reg;
 133         unsigned long flags;
 134
 135         spin_lock_irqsave(&gpio_lock, flags);
 136         reg = rdc321x_conf_read(gpio < 32
 137                 ? RDC321X_GPIO_DATA_REG1 : RDC321X_GPIO_DATA_REG2);
 138         spin_unlock_irqrestore(&gpio_lock, flags);
 139
 140         return (1 << (gpio & 0x1f)) & reg ? 1 : 0;
 141 }
 142 EXPORT_SYMBOL(rdc_gpio_get_value);
 143
 144 /* set GPIO pin to value */
 145 void rdc_gpio_set_value(unsigned gpio, int value)
 146 {
 147         unsigned long flags;
 148         u32 reg;
 149
 150         reg = 1 << (gpio & 0x1f);
 151         if (gpio < 32) {
 152                 spin_lock_irqsave(&gpio_lock, flags);
 153                 if (value)
 154                         gpio_data_reg1 |= reg;
 155                 else
 156                         gpio_data_reg1 &= ~reg;
 157                 rdc321x_conf_write(RDC321X_GPIO_DATA_REG1, gpio_data_reg1);
 158                 spin_unlock_irqrestore(&gpio_lock, flags);
 159         } else {
 160                 spin_lock_irqsave(&gpio_lock, flags);
 161                 if (value)
 162                         gpio_data_reg2 |= reg;
 163                 else
 164                         gpio_data_reg2 &= ~reg;
 165                 rdc321x_conf_write(RDC321X_GPIO_DATA_REG2, gpio_data_reg2);
 166                 spin_unlock_irqrestore(&gpio_lock, flags);
 167         }
 168 }
 169 EXPORT_SYMBOL(rdc_gpio_set_value);
 170
 171 /* configure GPIO pin as input */
 172 int rdc_gpio_direction_input(unsigned gpio)
 173 {
 174         if (!rdc321x_is_gpio(gpio))
 175                 return -EINVAL;
 176
 177         rdc321x_configure_gpio(gpio);
 178
 179         return 0;
 180 }
 181 EXPORT_SYMBOL(rdc_gpio_direction_input);
 182
 183 /* configure GPIO pin as output and set value */
 184 int rdc_gpio_direction_output(unsigned gpio, int value)
 185 {
 186         if (!rdc321x_is_gpio(gpio))
 187                 return -EINVAL;
 188
 189         gpio_set_value(gpio, value);
 190         rdc321x_configure_gpio(gpio);
 191
 192         return 0;
 193 }
 194 EXPORT_SYMBOL(rdc_gpio_direction_output);