blob: d27e9361e236c0e4246debe5ad22c3008c416a00 [file] [log] [blame] [edit]
/*
* GPIO Testing Device Driver
*
* Copyright (C) 2014 Kamlakant Patel <kamlakant.patel@broadcom.com>
* Copyright (C) 2015-2016 Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/gpio/driver.h>
#include <linux/platform_device.h>
#define GPIO_NAME "gpio-mockup"
#define MAX_GC 10
enum direction {
OUT,
IN
};
/*
* struct gpio_pin_status - structure describing a GPIO status
* @dir: Configures direction of gpio as "in" or "out", 0=in, 1=out
* @value: Configures status of the gpio as 0(low) or 1(high)
*/
struct gpio_pin_status {
enum direction dir;
bool value;
};
struct mockup_gpio_controller {
struct gpio_chip gc;
struct gpio_pin_status *stats;
};
static int gpio_mockup_ranges[MAX_GC << 1];
static int gpio_mockup_params_nr;
module_param_array(gpio_mockup_ranges, int, &gpio_mockup_params_nr, 0400);
const char pins_name_start = 'A';
static int mockup_gpio_get(struct gpio_chip *gc, unsigned int offset)
{
struct mockup_gpio_controller *cntr = gpiochip_get_data(gc);
return cntr->stats[offset].value;
}
static void mockup_gpio_set(struct gpio_chip *gc, unsigned int offset,
int value)
{
struct mockup_gpio_controller *cntr = gpiochip_get_data(gc);
cntr->stats[offset].value = !!value;
}
static int mockup_gpio_dirout(struct gpio_chip *gc, unsigned int offset,
int value)
{
struct mockup_gpio_controller *cntr = gpiochip_get_data(gc);
mockup_gpio_set(gc, offset, value);
cntr->stats[offset].dir = OUT;
return 0;
}
static int mockup_gpio_dirin(struct gpio_chip *gc, unsigned int offset)
{
struct mockup_gpio_controller *cntr = gpiochip_get_data(gc);
cntr->stats[offset].dir = IN;
return 0;
}
static int mockup_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
{
struct mockup_gpio_controller *cntr = gpiochip_get_data(gc);
return cntr->stats[offset].dir;
}
static int mockup_gpio_add(struct device *dev,
struct mockup_gpio_controller *cntr,
const char *name, int base, int ngpio)
{
int ret;
cntr->gc.base = base;
cntr->gc.ngpio = ngpio;
cntr->gc.label = name;
cntr->gc.owner = THIS_MODULE;
cntr->gc.parent = dev;
cntr->gc.get = mockup_gpio_get;
cntr->gc.set = mockup_gpio_set;
cntr->gc.direction_output = mockup_gpio_dirout;
cntr->gc.direction_input = mockup_gpio_dirin;
cntr->gc.get_direction = mockup_gpio_get_direction;
cntr->stats = devm_kzalloc(dev, sizeof(*cntr->stats) * cntr->gc.ngpio,
GFP_KERNEL);
if (!cntr->stats) {
ret = -ENOMEM;
goto err;
}
ret = devm_gpiochip_add_data(dev, &cntr->gc, cntr);
if (ret)
goto err;
dev_info(dev, "gpio<%d..%d> add successful!", base, base + ngpio);
return 0;
err:
dev_err(dev, "gpio<%d..%d> add failed!", base, base + ngpio);
return ret;
}
static int mockup_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct mockup_gpio_controller *cntr;
int ret;
int i;
int base;
int ngpio;
char *chip_name;
if (gpio_mockup_params_nr < 2)
return -EINVAL;
cntr = devm_kzalloc(dev, sizeof(*cntr) * (gpio_mockup_params_nr >> 1),
GFP_KERNEL);
if (!cntr)
return -ENOMEM;
platform_set_drvdata(pdev, cntr);
for (i = 0; i < gpio_mockup_params_nr >> 1; i++) {
base = gpio_mockup_ranges[i * 2];
if (base == -1)
ngpio = gpio_mockup_ranges[i * 2 + 1];
else
ngpio = gpio_mockup_ranges[i * 2 + 1] - base;
if (ngpio >= 0) {
chip_name = devm_kasprintf(dev, GFP_KERNEL,
"%s-%c", GPIO_NAME,
pins_name_start + i);
if (!chip_name)
return -ENOMEM;
ret = mockup_gpio_add(dev, &cntr[i],
chip_name, base, ngpio);
} else {
ret = -1;
}
if (ret) {
if (base < 0)
dev_err(dev, "gpio<%d..%d> add failed\n",
base, ngpio);
else
dev_err(dev, "gpio<%d..%d> add failed\n",
base, base + ngpio);
return ret;
}
}
return 0;
}
static struct platform_driver mockup_gpio_driver = {
.driver = {
.name = GPIO_NAME,
},
.probe = mockup_gpio_probe,
};
static struct platform_device *pdev;
static int __init mock_device_init(void)
{
int err;
pdev = platform_device_alloc(GPIO_NAME, -1);
if (!pdev)
return -ENOMEM;
err = platform_device_add(pdev);
if (err) {
platform_device_put(pdev);
return err;
}
err = platform_driver_register(&mockup_gpio_driver);
if (err) {
platform_device_unregister(pdev);
return err;
}
return 0;
}
static void __exit mock_device_exit(void)
{
platform_driver_unregister(&mockup_gpio_driver);
platform_device_unregister(pdev);
}
module_init(mock_device_init);
module_exit(mock_device_exit);
MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
MODULE_AUTHOR("Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>");
MODULE_DESCRIPTION("GPIO Testing driver");
MODULE_LICENSE("GPL v2");