linux-stable/drivers/gpio/gpio-mb86s7x.c
Ard Biesheuvel eb32889928 gpio: mb86s70: Revert "Return error if requesting an already assigned gpio"
Commit fd9c963c56 ("gpio: mb86s70: Return error if requesting an
already assigned gpio") adds code that infers from the state of the
GPIO Pin Function Register (PFR) whether a GPIO has been assigned
already. This assumes that the pin functions are set to 'peripheral'
when the driver is loaded, which is not guaranteed. Also, the GPIO
layer is perfectly capable of keeping track of which GPIOs have been
assigned already, so we shouldn't need this check in the first place.

This reverts commit fd9c963c56.

Cc: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-10-31 13:13:34 +01:00

222 lines
5.4 KiB
C

/*
* linux/drivers/gpio/gpio-mb86s7x.c
*
* Copyright (C) 2015 Fujitsu Semiconductor Limited
* Copyright (C) 2015 Linaro Ltd.
*
* 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, version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/io.h>
#include <linux/init.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/of_device.h>
#include <linux/gpio/driver.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
/*
* Only first 8bits of a register correspond to each pin,
* so there are 4 registers for 32 pins.
*/
#define PDR(x) (0x0 + x / 8 * 4)
#define DDR(x) (0x10 + x / 8 * 4)
#define PFR(x) (0x20 + x / 8 * 4)
#define OFFSET(x) BIT((x) % 8)
struct mb86s70_gpio_chip {
struct gpio_chip gc;
void __iomem *base;
struct clk *clk;
spinlock_t lock;
};
static int mb86s70_gpio_request(struct gpio_chip *gc, unsigned gpio)
{
struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
unsigned long flags;
u32 val;
spin_lock_irqsave(&gchip->lock, flags);
val = readl(gchip->base + PFR(gpio));
val &= ~OFFSET(gpio);
writel(val, gchip->base + PFR(gpio));
spin_unlock_irqrestore(&gchip->lock, flags);
return 0;
}
static void mb86s70_gpio_free(struct gpio_chip *gc, unsigned gpio)
{
struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
unsigned long flags;
u32 val;
spin_lock_irqsave(&gchip->lock, flags);
val = readl(gchip->base + PFR(gpio));
val |= OFFSET(gpio);
writel(val, gchip->base + PFR(gpio));
spin_unlock_irqrestore(&gchip->lock, flags);
}
static int mb86s70_gpio_direction_input(struct gpio_chip *gc, unsigned gpio)
{
struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
unsigned long flags;
unsigned char val;
spin_lock_irqsave(&gchip->lock, flags);
val = readl(gchip->base + DDR(gpio));
val &= ~OFFSET(gpio);
writel(val, gchip->base + DDR(gpio));
spin_unlock_irqrestore(&gchip->lock, flags);
return 0;
}
static int mb86s70_gpio_direction_output(struct gpio_chip *gc,
unsigned gpio, int value)
{
struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
unsigned long flags;
unsigned char val;
spin_lock_irqsave(&gchip->lock, flags);
val = readl(gchip->base + PDR(gpio));
if (value)
val |= OFFSET(gpio);
else
val &= ~OFFSET(gpio);
writel(val, gchip->base + PDR(gpio));
val = readl(gchip->base + DDR(gpio));
val |= OFFSET(gpio);
writel(val, gchip->base + DDR(gpio));
spin_unlock_irqrestore(&gchip->lock, flags);
return 0;
}
static int mb86s70_gpio_get(struct gpio_chip *gc, unsigned gpio)
{
struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
return !!(readl(gchip->base + PDR(gpio)) & OFFSET(gpio));
}
static void mb86s70_gpio_set(struct gpio_chip *gc, unsigned gpio, int value)
{
struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
unsigned long flags;
unsigned char val;
spin_lock_irqsave(&gchip->lock, flags);
val = readl(gchip->base + PDR(gpio));
if (value)
val |= OFFSET(gpio);
else
val &= ~OFFSET(gpio);
writel(val, gchip->base + PDR(gpio));
spin_unlock_irqrestore(&gchip->lock, flags);
}
static int mb86s70_gpio_probe(struct platform_device *pdev)
{
struct mb86s70_gpio_chip *gchip;
struct resource *res;
int ret;
gchip = devm_kzalloc(&pdev->dev, sizeof(*gchip), GFP_KERNEL);
if (gchip == NULL)
return -ENOMEM;
platform_set_drvdata(pdev, gchip);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
gchip->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(gchip->base))
return PTR_ERR(gchip->base);
gchip->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(gchip->clk))
return PTR_ERR(gchip->clk);
ret = clk_prepare_enable(gchip->clk);
if (ret)
return ret;
spin_lock_init(&gchip->lock);
gchip->gc.direction_output = mb86s70_gpio_direction_output;
gchip->gc.direction_input = mb86s70_gpio_direction_input;
gchip->gc.request = mb86s70_gpio_request;
gchip->gc.free = mb86s70_gpio_free;
gchip->gc.get = mb86s70_gpio_get;
gchip->gc.set = mb86s70_gpio_set;
gchip->gc.label = dev_name(&pdev->dev);
gchip->gc.ngpio = 32;
gchip->gc.owner = THIS_MODULE;
gchip->gc.parent = &pdev->dev;
gchip->gc.base = -1;
ret = gpiochip_add_data(&gchip->gc, gchip);
if (ret) {
dev_err(&pdev->dev, "couldn't register gpio driver\n");
clk_disable_unprepare(gchip->clk);
}
return ret;
}
static int mb86s70_gpio_remove(struct platform_device *pdev)
{
struct mb86s70_gpio_chip *gchip = platform_get_drvdata(pdev);
gpiochip_remove(&gchip->gc);
clk_disable_unprepare(gchip->clk);
return 0;
}
static const struct of_device_id mb86s70_gpio_dt_ids[] = {
{ .compatible = "fujitsu,mb86s70-gpio" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mb86s70_gpio_dt_ids);
static struct platform_driver mb86s70_gpio_driver = {
.driver = {
.name = "mb86s70-gpio",
.of_match_table = mb86s70_gpio_dt_ids,
},
.probe = mb86s70_gpio_probe,
.remove = mb86s70_gpio_remove,
};
module_platform_driver(mb86s70_gpio_driver);
MODULE_DESCRIPTION("MB86S7x GPIO Driver");
MODULE_ALIAS("platform:mb86s70-gpio");
MODULE_LICENSE("GPL");