gpio-ge.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Driver for GE FPGA based GPIO
  4 *
  5 * Author: Martyn Welch <martyn.welch@ge.com>
  6 *
  7 * 2008 (c) GE Intelligent Platforms Embedded Systems, Inc.
  8 */
  9
 10/*
 11 * TODO:
 12 *
 13 * Configuration of output modes (totem-pole/open-drain).
 14 * Interrupt configuration - interrupts are always generated, the FPGA relies
 15 * on the I/O interrupt controllers mask to stop them from being propagated.
 16 */
 17
 18#include <linux/gpio/driver.h>
 19#include <linux/gpio/generic.h>
 20#include <linux/io.h>
 21#include <linux/kernel.h>
 22#include <linux/mod_devicetable.h>
 23#include <linux/module.h>
 24#include <linux/platform_device.h>
 25#include <linux/property.h>
 26#include <linux/slab.h>
 27
 28#define GEF_GPIO_DIRECT		0x00
 29#define GEF_GPIO_IN		0x04
 30#define GEF_GPIO_OUT		0x08
 31#define GEF_GPIO_TRIG		0x0C
 32#define GEF_GPIO_POLAR_A	0x10
 33#define GEF_GPIO_POLAR_B	0x14
 34#define GEF_GPIO_INT_STAT	0x18
 35#define GEF_GPIO_OVERRUN	0x1C
 36#define GEF_GPIO_MODE		0x20
 37
 38static const struct of_device_id gef_gpio_ids[] = {
 39	{
 40		.compatible	= "gef,sbc610-gpio",
 41		.data		= (void *)19,
 42	}, {
 43		.compatible	= "gef,sbc310-gpio",
 44		.data		= (void *)6,
 45	}, {
 46		.compatible	= "ge,imp3a-gpio",
 47		.data		= (void *)16,
 48	},
 49	{ }
 50};
 51MODULE_DEVICE_TABLE(of, gef_gpio_ids);
 52
 53static int __init gef_gpio_probe(struct platform_device *pdev)
 54{
 55	struct gpio_generic_chip_config config;
 56	struct device *dev = &pdev->dev;
 57	struct gpio_generic_chip *chip;
 58	struct gpio_chip *gc;
 59	void __iomem *regs;
 60	int ret;
 61
 62	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
 63	if (!chip)
 64		return -ENOMEM;
 65
 66	regs = devm_platform_ioremap_resource(pdev, 0);
 67	if (IS_ERR(regs))
 68		return PTR_ERR(regs);
 69
 70	config = (struct gpio_generic_chip_config) {
 71		.dev = dev,
 72		.sz = 4,
 73		.dat = regs + GEF_GPIO_IN,
 74		.set = regs + GEF_GPIO_OUT,
 75		.dirin = regs + GEF_GPIO_DIRECT,
 76		.flags = GPIO_GENERIC_BIG_ENDIAN_BYTE_ORDER,
 77	};
 78
 79	ret = gpio_generic_chip_init(chip, &config);
 80	if (ret)
 81		return dev_err_probe(dev, ret,
 82				     "failed to initialize the generic GPIO chip\n");
 83
 84	gc = &chip->gc;
 85
 86	/* Setup pointers to chip functions */
 87	gc->label = devm_kasprintf(dev, GFP_KERNEL, "%pfw", dev_fwnode(dev));
 88	if (!gc->label)
 89		return -ENOMEM;
 90
 91	gc->base = -1;
 92	gc->ngpio = (uintptr_t)device_get_match_data(dev);
 93
 94	/* This function adds a memory mapped GPIO chip */
 95	ret = devm_gpiochip_add_data(dev, gc, NULL);
 96	if (ret)
 97		return dev_err_probe(dev, ret, "GPIO chip registration failed\n");
 98
 99	return 0;
100};
101
102static struct platform_driver gef_gpio_driver = {
103	.driver = {
104		.name		= "gef-gpio",
105		.of_match_table	= gef_gpio_ids,
106	},
107};
108module_platform_driver_probe(gef_gpio_driver, gef_gpio_probe);
109
110MODULE_DESCRIPTION("GE I/O FPGA GPIO driver");
111MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
112MODULE_LICENSE("GPL");