drivers/gpio/gpio-ge.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/io.h>
  22 #include <linux/of_device.h>
  23 #include <linux/of_gpio.h>
  24 #include <linux/module.h>
  25
  26 #define GEF_GPIO_DIRECT         0x00
  27 #define GEF_GPIO_IN             0x04
  28 #define GEF_GPIO_OUT            0x08
  29 #define GEF_GPIO_TRIG           0x0C
  30 #define GEF_GPIO_POLAR_A        0x10
  31 #define GEF_GPIO_POLAR_B        0x14
  32 #define GEF_GPIO_INT_STAT       0x18
  33 #define GEF_GPIO_OVERRUN        0x1C
  34 #define GEF_GPIO_MODE           0x20
  35
  36 static void gef_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  37 {
  38         struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
  39         unsigned int data;
  40
  41         data = ioread32be(mmchip->regs + GEF_GPIO_OUT);
  42         if (value)
  43                 data = data | BIT(offset);
  44         else
  45                 data = data & ~BIT(offset);
  46         iowrite32be(data, mmchip->regs + GEF_GPIO_OUT);
  47 }
  48
  49 static int gef_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
  50 {
  51         unsigned int data;
  52         struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
  53
  54         data = ioread32be(mmchip->regs + GEF_GPIO_DIRECT);
  55         data = data | BIT(offset);
  56         iowrite32be(data, mmchip->regs + GEF_GPIO_DIRECT);
  57
  58         return 0;
  59 }
  60
  61 static int gef_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int value)
  62 {
  63         unsigned int data;
  64         struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
  65
  66         /* Set value before switching to output */
  67         gef_gpio_set(mmchip->regs + GEF_GPIO_OUT, offset, value);
  68
  69         data = ioread32be(mmchip->regs + GEF_GPIO_DIRECT);
  70         data = data & ~BIT(offset);
  71         iowrite32be(data, mmchip->regs + GEF_GPIO_DIRECT);
  72
  73         return 0;
  74 }
  75
  76 static int gef_gpio_get(struct gpio_chip *chip, unsigned offset)
  77 {
  78         struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
  79
  80         return !!(ioread32be(mmchip->regs + GEF_GPIO_IN) & BIT(offset));
  81 }
  82
  83 static const struct of_device_id gef_gpio_ids[] = {
  84         {
  85                 .compatible     = "gef,sbc610-gpio",
  86                 .data           = (void *)19,
  87         }, {
  88                 .compatible     = "gef,sbc310-gpio",
  89                 .data           = (void *)6,
  90         }, {
  91                 .compatible     = "ge,imp3a-gpio",
  92                 .data           = (void *)16,
  93         },
  94         { }
  95 };
  96 MODULE_DEVICE_TABLE(of, gef_gpio_ids);
  97
  98 static int __init gef_gpio_probe(struct platform_device *pdev)
  99 {
 100         const struct of_device_id *of_id =
 101                 of_match_device(gef_gpio_ids, &pdev->dev);
 102         struct of_mm_gpio_chip *mmchip;
 103
 104         mmchip = devm_kzalloc(&pdev->dev, sizeof(*mmchip), GFP_KERNEL);
 105         if (!mmchip)
 106                 return -ENOMEM;
 107
 108         /* Setup pointers to chip functions */
 109         mmchip->gc.ngpio = (u16)(uintptr_t)of_id->data;
 110         mmchip->gc.of_gpio_n_cells = 2;
 111         mmchip->gc.direction_input = gef_gpio_dir_in;
 112         mmchip->gc.direction_output = gef_gpio_dir_out;
 113         mmchip->gc.get = gef_gpio_get;
 114         mmchip->gc.set = gef_gpio_set;
 115
 116         /* This function adds a memory mapped GPIO chip */
 117         return of_mm_gpiochip_add(pdev->dev.of_node, mmchip);
 118 };
 119
 120 static struct platform_driver gef_gpio_driver = {
 121         .driver = {
 122                 .name           = "gef-gpio",
 123                 .owner          = THIS_MODULE,
 124                 .of_match_table = gef_gpio_ids,
 125         },
 126 };
 127 module_platform_driver_probe(gef_gpio_driver, gef_gpio_probe);
 128
 129 MODULE_DESCRIPTION("GE I/O FPGA GPIO driver");
 130 MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com");
 131 MODULE_LICENSE("GPL");