drivers/gpio/gpio-ts4800.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * GPIO driver for the TS-4800 board
   4  *
   5  * Copyright (c) 2016 - Savoir-faire Linux
   6  */
   7
   8 #include <linux/gpio/driver.h>
   9 #include <linux/module.h>
  10 #include <linux/of.h>
  11 #include <linux/platform_device.h>
  12
  13 #define DEFAULT_PIN_NUMBER      16
  14 #define INPUT_REG_OFFSET        0x00
  15 #define OUTPUT_REG_OFFSET       0x02
  16 #define DIRECTION_REG_OFFSET    0x04
  17
  18 static int ts4800_gpio_probe(struct platform_device *pdev)
  19 {
  20         struct device_node *node;
  21         struct gpio_chip *chip;
  22         void __iomem *base_addr;
  23         int retval;
  24         u32 ngpios;
  25
  26         chip = devm_kzalloc(&pdev->dev, sizeof(struct gpio_chip), GFP_KERNEL);
  27         if (!chip)
  28                 return -ENOMEM;
  29
  30         base_addr = devm_platform_ioremap_resource(pdev, 0);
  31         if (IS_ERR(base_addr))
  32                 return PTR_ERR(base_addr);
  33
  34         node = pdev->dev.of_node;
  35         if (!node)
  36                 return -EINVAL;
  37
  38         retval = of_property_read_u32(node, "ngpios", &ngpios);
  39         if (retval == -EINVAL)
  40                 ngpios = DEFAULT_PIN_NUMBER;
  41         else if (retval)
  42                 return retval;
  43
  44         retval = bgpio_init(chip, &pdev->dev, 2, base_addr + INPUT_REG_OFFSET,
  45                             base_addr + OUTPUT_REG_OFFSET, NULL,
  46                             base_addr + DIRECTION_REG_OFFSET, NULL, 0);
  47         if (retval) {
  48                 dev_err(&pdev->dev, "bgpio_init failed\n");
  49                 return retval;
  50         }
  51
  52         chip->ngpio = ngpios;
  53
  54         platform_set_drvdata(pdev, chip);
  55
  56         return devm_gpiochip_add_data(&pdev->dev, chip, NULL);
  57 }
  58
  59 static const struct of_device_id ts4800_gpio_of_match[] = {
  60         { .compatible = "technologic,ts4800-gpio", },
  61         {},
  62 };
  63 MODULE_DEVICE_TABLE(of, ts4800_gpio_of_match);
  64
  65 static struct platform_driver ts4800_gpio_driver = {
  66         .driver = {
  67                    .name = "ts4800-gpio",
  68                    .of_match_table = ts4800_gpio_of_match,
  69                    },
  70         .probe = ts4800_gpio_probe,
  71 };
  72
  73 module_platform_driver_probe(ts4800_gpio_driver, ts4800_gpio_probe);
  74
  75 MODULE_AUTHOR("Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>");
  76 MODULE_DESCRIPTION("TS4800 FPGA GPIO driver");
  77 MODULE_LICENSE("GPL v2");