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/*
* GPIO driver for Exar XR17V35X chip
*
* Copyright (C) 2015 Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/gpio/driver.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#define EXAR_OFFSET_MPIOLVL_LO 0x90
#define EXAR_OFFSET_MPIOSEL_LO 0x93
#define EXAR_OFFSET_MPIOLVL_HI 0x96
#define EXAR_OFFSET_MPIOSEL_HI 0x99
#define DRIVER_NAME "gpio_exar"
static DEFINE_IDA(ida_index);
struct exar_gpio_chip {
struct gpio_chip gpio_chip;
struct mutex lock;
int index;
void __iomem *regs;
char name[20];
unsigned int first_pin;
};
static void exar_update(struct gpio_chip *chip, unsigned int reg, int val,
unsigned int offset)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
int temp;
mutex_lock(&exar_gpio->lock);
temp = readb(exar_gpio->regs + reg);
temp &= ~BIT(offset);
if (val)
temp |= BIT(offset);
writeb(temp, exar_gpio->regs + reg);
mutex_unlock(&exar_gpio->lock);
}
static int exar_set_direction(struct gpio_chip *chip, int direction,
unsigned int offset)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
unsigned int bit = (offset + exar_gpio->first_pin) % 8;
exar_update(chip, addr, direction, bit);
return 0;
}
static int exar_get(struct gpio_chip *chip, unsigned int reg)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
int value;
mutex_lock(&exar_gpio->lock);
value = readb(exar_gpio->regs + reg);
mutex_unlock(&exar_gpio->lock);
return value;
}
static int exar_get_direction(struct gpio_chip *chip, unsigned int offset)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
unsigned int bit = (offset + exar_gpio->first_pin) % 8;
return !!(exar_get(chip, addr) & BIT(bit));
}
static int exar_get_value(struct gpio_chip *chip, unsigned int offset)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO;
unsigned int bit = (offset + exar_gpio->first_pin) % 8;
return !!(exar_get(chip, addr) & BIT(bit));
}
static void exar_set_value(struct gpio_chip *chip, unsigned int offset,
int value)
{
struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO;
unsigned int bit = (offset + exar_gpio->first_pin) % 8;
exar_update(chip, addr, value, bit);
}
static int exar_direction_output(struct gpio_chip *chip, unsigned int offset,
int value)
{
exar_set_value(chip, offset, value);
return exar_set_direction(chip, 0, offset);
}
static int exar_direction_input(struct gpio_chip *chip, unsigned int offset)
{
return exar_set_direction(chip, 1, offset);
}
static int gpio_exar_probe(struct platform_device *pdev)
{
struct pci_dev *pcidev = to_pci_dev(pdev->dev.parent);
struct exar_gpio_chip *exar_gpio;
u32 first_pin, ngpios;
void __iomem *p;
int index, ret;
/*
* The UART driver must have mapped region 0 prior to registering this
* device - use it.
*/
p = pcim_iomap_table(pcidev)[0];
if (!p)
return -ENOMEM;
ret = device_property_read_u32(&pdev->dev, "exar,first-pin",
&first_pin);
if (ret)
return ret;
ret = device_property_read_u32(&pdev->dev, "ngpios", &ngpios);
if (ret)
return ret;
exar_gpio = devm_kzalloc(&pdev->dev, sizeof(*exar_gpio), GFP_KERNEL);
if (!exar_gpio)
return -ENOMEM;
mutex_init(&exar_gpio->lock);
index = ida_simple_get(&ida_index, 0, 0, GFP_KERNEL);
if (index < 0) {
ret = index;
goto err_mutex_destroy;
}
sprintf(exar_gpio->name, "exar_gpio%d", index);
exar_gpio->gpio_chip.label = exar_gpio->name;
exar_gpio->gpio_chip.parent = &pdev->dev;
exar_gpio->gpio_chip.direction_output = exar_direction_output;
exar_gpio->gpio_chip.direction_input = exar_direction_input;
exar_gpio->gpio_chip.get_direction = exar_get_direction;
exar_gpio->gpio_chip.get = exar_get_value;
exar_gpio->gpio_chip.set = exar_set_value;
exar_gpio->gpio_chip.base = -1;
exar_gpio->gpio_chip.ngpio = ngpios;
exar_gpio->regs = p;
exar_gpio->index = index;
exar_gpio->first_pin = first_pin;
ret = devm_gpiochip_add_data(&pdev->dev,
&exar_gpio->gpio_chip, exar_gpio);
if (ret)
goto err_destroy;
platform_set_drvdata(pdev, exar_gpio);
return 0;
err_destroy:
ida_simple_remove(&ida_index, index);
err_mutex_destroy:
mutex_destroy(&exar_gpio->lock);
return ret;
}
static int gpio_exar_remove(struct platform_device *pdev)
{
struct exar_gpio_chip *exar_gpio = platform_get_drvdata(pdev);
ida_simple_remove(&ida_index, exar_gpio->index);
mutex_destroy(&exar_gpio->lock);
return 0;
}
static struct platform_driver gpio_exar_driver = {
.probe = gpio_exar_probe,
.remove = gpio_exar_remove,
.driver = {
.name = DRIVER_NAME,
},
};
module_platform_driver(gpio_exar_driver);
MODULE_ALIAS("platform:" DRIVER_NAME);
MODULE_DESCRIPTION("Exar GPIO driver");
MODULE_AUTHOR("Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>");
MODULE_LICENSE("GPL");
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