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