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/gpio/generic.h>
10#include <linux/module.h>
11#include <linux/platform_device.h>
12#include <linux/property.h>
13
14#define DEFAULT_PIN_NUMBER      16
15#define INPUT_REG_OFFSET        0x00
16#define OUTPUT_REG_OFFSET       0x02
17#define DIRECTION_REG_OFFSET    0x04
18
19static int ts4800_gpio_probe(struct platform_device *pdev)
20{
21	struct gpio_generic_chip_config config;
22	struct device *dev = &pdev->dev;
23	struct gpio_generic_chip *chip;
24	void __iomem *base_addr;
25	int retval;
26	u32 ngpios;
27
28	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
29	if (!chip)
30		return -ENOMEM;
31
32	base_addr = devm_platform_ioremap_resource(pdev, 0);
33	if (IS_ERR(base_addr))
34		return PTR_ERR(base_addr);
35
36	retval = device_property_read_u32(dev, "ngpios", &ngpios);
37	if (retval == -EINVAL)
38		ngpios = DEFAULT_PIN_NUMBER;
39	else if (retval)
40		return retval;
41
42	config = (struct gpio_generic_chip_config) {
43		.dev = dev,
44		.sz = 2,
45		.dat = base_addr + INPUT_REG_OFFSET,
46		.set = base_addr + OUTPUT_REG_OFFSET,
47		.dirout = base_addr + DIRECTION_REG_OFFSET,
48	};
49
50	retval = gpio_generic_chip_init(chip, &config);
51	if (retval)
52		return dev_err_probe(dev, retval,
53				     "failed to initialize the generic GPIO chip\n");
54
55	chip->gc.ngpio = ngpios;
56
57	return devm_gpiochip_add_data(dev, &chip->gc, NULL);
58}
59
60static const struct of_device_id ts4800_gpio_of_match[] = {
61	{ .compatible = "technologic,ts4800-gpio", },
62	{},
63};
64MODULE_DEVICE_TABLE(of, ts4800_gpio_of_match);
65
66static struct platform_driver ts4800_gpio_driver = {
67	.driver = {
68		   .name = "ts4800-gpio",
69		   .of_match_table = ts4800_gpio_of_match,
70		   },
71	.probe = ts4800_gpio_probe,
72};
73
74module_platform_driver_probe(ts4800_gpio_driver, ts4800_gpio_probe);
75
76MODULE_AUTHOR("Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>");
77MODULE_DESCRIPTION("TS4800 FPGA GPIO driver");
78MODULE_LICENSE("GPL v2");