arch/powerpc/platforms/86xx/gef_gpio.c

   1 /*
   2  * Driver for GE FPGA based GPIO
   3  *
   4  * Author: Martyn Welch <martyn.welch@ge.com>
   5  *
   6  * 2008 (c) GE Intelligent Platforms Embedded Systems, Inc.
   7  *
   8  * This file is licensed under the terms of the GNU General Public License
   9  * version 2.  This program is licensed "as is" without any warranty of any
  10  * kind, whether express or implied.
  11  */
  12
  13 /* TODO
  14  *
  15  * Configuration of output modes (totem-pole/open-drain)
  16  * Interrupt configuration - interrupts are always generated the FPGA relies on
  17  *      the I/O interrupt controllers mask to stop them propergating
  18  */
  19
  20 #include <linux/kernel.h>
  21 #include <linux/compiler.h>
  22 #include <linux/init.h>
  23 #include <linux/io.h>
  24 #include <linux/of.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_platform.h>
  27 #include <linux/of_gpio.h>
  28 #include <linux/gpio.h>
  29 #include <linux/slab.h>
  30
  31 #define GEF_GPIO_DIRECT         0x00
  32 #define GEF_GPIO_IN             0x04
  33 #define GEF_GPIO_OUT            0x08
  34 #define GEF_GPIO_TRIG           0x0C
  35 #define GEF_GPIO_POLAR_A        0x10
  36 #define GEF_GPIO_POLAR_B        0x14
  37 #define GEF_GPIO_INT_STAT       0x18
  38 #define GEF_GPIO_OVERRUN        0x1C
  39 #define GEF_GPIO_MODE           0x20
  40
  41 static void _gef_gpio_set(void __iomem *reg, unsigned int offset, int value)
  42 {
  43         unsigned int data;
  44
  45         data = ioread32be(reg);
  46         /* value: 0=low; 1=high */
  47         if (value & 0x1)
  48                 data = data | (0x1 << offset);
  49         else
  50                 data = data & ~(0x1 << offset);
  51
  52         iowrite32be(data, reg);
  53 }
  54
  55
  56 static int gef_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
  57 {
  58         unsigned int data;
  59         struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
  60
  61         data = ioread32be(mmchip->regs + GEF_GPIO_DIRECT);
  62         data = data | (0x1 << offset);
  63         iowrite32be(data, mmchip->regs + GEF_GPIO_DIRECT);
  64
  65         return 0;
  66 }
  67
  68 static int gef_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int value)
  69 {
  70         unsigned int data;
  71         struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
  72
  73         /* Set direction before switching to input */
  74         _gef_gpio_set(mmchip->regs + GEF_GPIO_OUT, offset, value);
  75
  76         data = ioread32be(mmchip->regs + GEF_GPIO_DIRECT);
  77         data = data & ~(0x1 << offset);
  78         iowrite32be(data, mmchip->regs + GEF_GPIO_DIRECT);
  79
  80         return 0;
  81 }
  82
  83 static int gef_gpio_get(struct gpio_chip *chip, unsigned offset)
  84 {
  85         unsigned int data;
  86         int state = 0;
  87         struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
  88
  89         data = ioread32be(mmchip->regs + GEF_GPIO_IN);
  90         state = (int)((data >> offset) & 0x1);
  91
  92         return state;
  93 }
  94
  95 static void gef_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  96 {
  97         struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
  98
  99         _gef_gpio_set(mmchip->regs + GEF_GPIO_OUT, offset, value);
 100 }
 101
 102 static int __init gef_gpio_init(void)
 103 {
 104         struct device_node *np;
 105         int retval;
 106         struct of_mm_gpio_chip *gef_gpio_chip;
 107
 108         for_each_compatible_node(np, NULL, "gef,sbc610-gpio") {
 109
 110                 pr_debug("%s: Initialising GEF GPIO\n", np->full_name);
 111
 112                 /* Allocate chip structure */
 113                 gef_gpio_chip = kzalloc(sizeof(*gef_gpio_chip), GFP_KERNEL);
 114                 if (!gef_gpio_chip) {
 115                         pr_err("%s: Unable to allocate structure\n",
 116                                 np->full_name);
 117                         continue;
 118                 }
 119
 120                 /* Setup pointers to chip functions */
 121                 gef_gpio_chip->gc.of_gpio_n_cells = 2;
 122                 gef_gpio_chip->gc.ngpio = 19;
 123                 gef_gpio_chip->gc.direction_input = gef_gpio_dir_in;
 124                 gef_gpio_chip->gc.direction_output = gef_gpio_dir_out;
 125                 gef_gpio_chip->gc.get = gef_gpio_get;
 126                 gef_gpio_chip->gc.set = gef_gpio_set;
 127
 128                 /* This function adds a memory mapped GPIO chip */
 129                 retval = of_mm_gpiochip_add(np, gef_gpio_chip);
 130                 if (retval) {
 131                         kfree(gef_gpio_chip);
 132                         pr_err("%s: Unable to add GPIO\n", np->full_name);
 133                 }
 134         }
 135
 136         for_each_compatible_node(np, NULL, "gef,sbc310-gpio") {
 137
 138                 pr_debug("%s: Initialising GEF GPIO\n", np->full_name);
 139
 140                 /* Allocate chip structure */
 141                 gef_gpio_chip = kzalloc(sizeof(*gef_gpio_chip), GFP_KERNEL);
 142                 if (!gef_gpio_chip) {
 143                         pr_err("%s: Unable to allocate structure\n",
 144                                 np->full_name);
 145                         continue;
 146                 }
 147
 148                 /* Setup pointers to chip functions */
 149                 gef_gpio_chip->gc.of_gpio_n_cells = 2;
 150                 gef_gpio_chip->gc.ngpio = 6;
 151                 gef_gpio_chip->gc.direction_input = gef_gpio_dir_in;
 152                 gef_gpio_chip->gc.direction_output = gef_gpio_dir_out;
 153                 gef_gpio_chip->gc.get = gef_gpio_get;
 154                 gef_gpio_chip->gc.set = gef_gpio_set;
 155
 156                 /* This function adds a memory mapped GPIO chip */
 157                 retval = of_mm_gpiochip_add(np, gef_gpio_chip);
 158                 if (retval) {
 159                         kfree(gef_gpio_chip);
 160                         pr_err("%s: Unable to add GPIO\n", np->full_name);
 161                 }
 162         }
 163
 164         return 0;
 165 };
 166 arch_initcall(gef_gpio_init);
 167
 168 MODULE_DESCRIPTION("GE I/O FPGA GPIO driver");
 169 MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com");
 170 MODULE_LICENSE("GPL");