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gpio/mockup: add virtual gpio device 

This patch add basic structure of a virtual gpio device(gpio-mockup)
for testing gpio subsystem. The tester could manipulate such device
through userspace(sysfs or char device) and check the result from
debugfs.

Currently, it support one or more gpiochip(determined by module
parameters with base,ngpio pair). One could test the overlap of
different gpiochip and test the direction and/or output values of
these chips.

Signed-off-by: Kamlakant Patel <kamlakant.patel@broadcom.com>
Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Bamvor Jian Zhang 2016-08-31 11:45:46 +02:00 committed by Linus Walleij
parent e3296f19c8
commit 0f98dd1b27
4 changed files with 231 additions and 0 deletions
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4
Documentation/kernel-parameters.txt
View File

@ -1364,6 +1364,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0.
Default: 1024
gpio-mockup.gpio_mockup_ranges
[HW] Sets the ranges of gpiochip of for this device.
Format: <start1>,<end1>,<start2>,<end2>...
hardlockup_all_cpu_backtrace=
[KNL] Should the hard-lockup detector generate
backtraces on all cpus.

12
drivers/gpio/Kconfig
View File

@ -279,6 +279,18 @@ config GPIO_MM_LANTIQ
(EBU) found on Lantiq SoCs. The gpios are output only as they are
created by attaching a 16bit latch to the bus.
config GPIO_MOCKUP
tristate "GPIO Testing Driver"
depends on GPIOLIB
select GPIO_SYSFS
help
This enables GPIO Testing driver, which provides a way to test GPIO
subsystem through sysfs(or char device) and debugfs. GPIO_SYSFS
must be selected for this test.
User could use it through the script in
tools/testing/selftests/gpio/gpio-mockup.sh. Reference the usage in
it.
config GPIO_MOXART
bool "MOXART GPIO support"
depends on ARCH_MOXART || COMPILE_TEST

1
drivers/gpio/Makefile
View File

@ -74,6 +74,7 @@ obj-$(CONFIG_GPIO_MC9S08DZ60) += gpio-mc9s08dz60.o
obj-$(CONFIG_GPIO_MCP23S08) += gpio-mcp23s08.o
obj-$(CONFIG_GPIO_ML_IOH) += gpio-ml-ioh.o
obj-$(CONFIG_GPIO_MM_LANTIQ) += gpio-mm-lantiq.o
obj-$(CONFIG_GPIO_MOCKUP) += gpio-mockup.o
obj-$(CONFIG_GPIO_MOXART) += gpio-moxart.o
obj-$(CONFIG_GPIO_MPC5200) += gpio-mpc5200.o
obj-$(CONFIG_GPIO_MPC8XXX) += gpio-mpc8xxx.o

214
drivers/gpio/gpio-mockup.c Normal file
View File

@ -0,0 +1,214 @@
/*
* 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[sizeof(GPIO_NAME) + 3];
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) {
sprintf(chip_name, "%s-%c", GPIO_NAME,
pins_name_start + i);
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");