linux/drivers/gpio/gpio-exar.c
Jan Kiszka a589e211bd gpio: exar: Use correct property prefix and document bindings
The device-specific property should be prefixed with the vendor name,
not "linux,", as Linus Walleij pointed out. Change this and document the
bindings of this platform device.

We didn't ship the old binding in a release yet. So we can still change
it without breaking an official API.

Fixes: 380b1e2f3a ("gpio-exar/8250-exar: Make set of exported GPIOs configurable")
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-08-01 13:43:55 +02:00

205 lines
5.4 KiB
C

/*
* 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);
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);
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");