linux/drivers/gpio/gpio-ge.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for GE FPGA based GPIO
 *
 * Author: Martyn Welch <[email protected]>
 *
 * 2008 (c) GE Intelligent Platforms Embedded Systems, Inc.
 */

/*
 * TODO:
 *
 * Configuration of output modes (totem-pole/open-drain).
 * Interrupt configuration - interrupts are always generated, the FPGA relies
 * on the I/O interrupt controllers mask to stop them from being propagated.
 */

#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/slab.h>

#define GEF_GPIO_DIRECT …
#define GEF_GPIO_IN …
#define GEF_GPIO_OUT …
#define GEF_GPIO_TRIG …
#define GEF_GPIO_POLAR_A …
#define GEF_GPIO_POLAR_B …
#define GEF_GPIO_INT_STAT …
#define GEF_GPIO_OVERRUN …
#define GEF_GPIO_MODE …

static const struct of_device_id gef_gpio_ids[] = …;
MODULE_DEVICE_TABLE(of, gef_gpio_ids);

static int __init gef_gpio_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct gpio_chip *gc;
	void __iomem *regs;
	int ret;

	gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
	if (!gc)
		return -ENOMEM;

	regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(regs))
		return PTR_ERR(regs);

	ret = bgpio_init(gc, dev, 4, regs + GEF_GPIO_IN, regs + GEF_GPIO_OUT,
			 NULL, NULL, regs + GEF_GPIO_DIRECT,
			 BGPIOF_BIG_ENDIAN_BYTE_ORDER);
	if (ret)
		return dev_err_probe(dev, ret, "bgpio_init failed\n");

	/* Setup pointers to chip functions */
	gc->label = devm_kasprintf(dev, GFP_KERNEL, "%pfw", dev_fwnode(dev));
	if (!gc->label)
		return -ENOMEM;

	gc->base = -1;
	gc->ngpio = (uintptr_t)device_get_match_data(dev);

	/* This function adds a memory mapped GPIO chip */
	ret = devm_gpiochip_add_data(dev, gc, NULL);
	if (ret)
		return dev_err_probe(dev, ret, "GPIO chip registration failed\n");

	return 0;
};

static struct platform_driver gef_gpio_driver = …;
module_platform_driver_probe(…);

MODULE_DESCRIPTION(…) …;
MODULE_AUTHOR(…) …;
MODULE_LICENSE(…) …;