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         struct resource *res;
  27         void __iomem *base_addr;
  28         int retval;
  29         u32 ngpios;
  30
  31         chip = devm_kzalloc(&pdev->dev, sizeof(struct gpio_chip), GFP_KERNEL);
  32         if (!chip)
  33                 return -ENOMEM;
  34
  35         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  36         base_addr = devm_ioremap_resource(&pdev->dev, res);
  37         if (IS_ERR(base_addr))
  38                 return PTR_ERR(base_addr);
  39
  40         node = pdev->dev.of_node;
  41         if (!node)
  42                 return -EINVAL;
  43
  44         retval = of_property_read_u32(node, "ngpios", &ngpios);
  45         if (retval == -EINVAL)
  46                 ngpios = DEFAULT_PIN_NUMBER;
  47         else if (retval)
  48                 return retval;
  49
  50         retval = bgpio_init(chip, &pdev->dev, 2, base_addr + INPUT_REG_OFFSET,
  51                             base_addr + OUTPUT_REG_OFFSET, NULL,
  52                             base_addr + DIRECTION_REG_OFFSET, NULL, 0);
  53         if (retval) {
  54                 dev_err(&pdev->dev, "bgpio_init failed\n");
  55                 return retval;
  56         }
  57
  58         chip->ngpio = ngpios;
  59
  60         platform_set_drvdata(pdev, chip);
  61
  62         return devm_gpiochip_add_data(&pdev->dev, chip, NULL);
  63 }
  64
  65 static const struct of_device_id ts4800_gpio_of_match[] = {
  66         { .compatible = "technologic,ts4800-gpio", },
  67         {},
  68 };
  69 MODULE_DEVICE_TABLE(of, ts4800_gpio_of_match);
  70
  71 static struct platform_driver ts4800_gpio_driver = {
  72         .driver = {
  73                    .name = "ts4800-gpio",
  74                    .of_match_table = ts4800_gpio_of_match,
  75                    },
  76         .probe = ts4800_gpio_probe,
  77 };
  78
  79 module_platform_driver_probe(ts4800_gpio_driver, ts4800_gpio_probe);
  80
  81 MODULE_AUTHOR("Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>");
  82 MODULE_DESCRIPTION("TS4800 FPGA GPIO driver");
  83 MODULE_LICENSE("GPL v2");