drivers/gpio/gpio-ts4800.c

   1 /*
   2  * GPIO driver for the TS-4800 board
   3  *
   4  * Copyright (c) 2016 - Savoir-faire Linux
   5  *
   6  * This file is licensed under the terms of the GNU General Public
   7  * License version 2. This program is licensed "as is" without any
   8  * warranty of any kind, whether express or implied.
   9  */
  10
  11 #include <linux/gpio/driver.h>
  12 #include <linux/module.h>
  13 #include <linux/of_address.h>
  14 #include <linux/of_device.h>
  15 #include <linux/platform_device.h>
  16
  17 #define DEFAULT_PIN_NUMBER      16
  18 #define INPUT_REG_OFFSET        0x00
  19 #define OUTPUT_REG_OFFSET       0x02
  20 #define DIRECTION_REG_OFFSET    0x04
  21
  22 static int ts4800_gpio_probe(struct platform_device *pdev)
  23 {
  24         struct device_node *node;
  25         struct gpio_chip *chip;
  26         void __iomem *base_addr;
  27         int retval;
  28         u32 ngpios;
  29
  30         chip = devm_kzalloc(&pdev->dev, sizeof(struct gpio_chip), GFP_KERNEL);
  31         if (!chip)
  32                 return -ENOMEM;
  33
  34         base_addr = devm_platform_ioremap_resource(pdev, 0);
  35         if (IS_ERR(base_addr))
  36                 return PTR_ERR(base_addr);
  37
  38         node = pdev->dev.of_node;
  39         if (!node)
  40                 return -EINVAL;
  41
  42         retval = of_property_read_u32(node, "ngpios", &ngpios);
  43         if (retval == -EINVAL)
  44                 ngpios = DEFAULT_PIN_NUMBER;
  45         else if (retval)
  46                 return retval;
  47
  48         retval = bgpio_init(chip, &pdev->dev, 2, base_addr + INPUT_REG_OFFSET,
  49                             base_addr + OUTPUT_REG_OFFSET, NULL,
  50                             base_addr + DIRECTION_REG_OFFSET, NULL, 0);
  51         if (retval) {
  52                 dev_err(&pdev->dev, "bgpio_init failed\n");
  53                 return retval;
  54         }
  55
  56         chip->ngpio = ngpios;
  57
  58         platform_set_drvdata(pdev, chip);
  59
  60         return devm_gpiochip_add_data(&pdev->dev, chip, NULL);
  61 }
  62
  63 static const struct of_device_id ts4800_gpio_of_match[] = {
  64         { .compatible = "technologic,ts4800-gpio", },
  65         {},
  66 };
  67 MODULE_DEVICE_TABLE(of, ts4800_gpio_of_match);
  68
  69 static struct platform_driver ts4800_gpio_driver = {
  70         .driver = {
  71                    .name = "ts4800-gpio",
  72                    .of_match_table = ts4800_gpio_of_match,
  73                    },
  74         .probe = ts4800_gpio_probe,
  75 };
  76
  77 module_platform_driver_probe(ts4800_gpio_driver, ts4800_gpio_probe);
  78
  79 MODULE_AUTHOR("Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>");
  80 MODULE_DESCRIPTION("TS4800 FPGA GPIO driver");
  81 MODULE_LICENSE("GPL v2");