LXR linux/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
  22static 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
  65static const struct of_device_id ts4800_gpio_of_match[] = {
  66        { .compatible = "technologic,ts4800-gpio", },
  67        {},
  68};
  69MODULE_DEVICE_TABLE(of, ts4800_gpio_of_match);
  70
  71static 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
  79module_platform_driver_probe(ts4800_gpio_driver, ts4800_gpio_probe);
  80
  81MODULE_AUTHOR("Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>");
  82MODULE_DESCRIPTION("TS4800 FPGA GPIO driver");
  83MODULE_LICENSE("GPL v2");
  84