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linux/drivers/gpio/gpio-altera.c
Uwe Kleine-König 2ae6a45f81 gpio: altera: Convert to platform remove callback returning void 
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2023-10-02 08:53:57 +02:00

357 lines
9.6 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2013 Altera Corporation
* Based on gpio-mpc8xxx.c
*/
#include <linux/io.h>
#include <linux/module.h>
#include <linux/gpio/driver.h>
#include <linux/gpio/legacy-of-mm-gpiochip.h>
#include <linux/platform_device.h>
#define ALTERA_GPIO_MAX_NGPIO 32
#define ALTERA_GPIO_DATA 0x0
#define ALTERA_GPIO_DIR 0x4
#define ALTERA_GPIO_IRQ_MASK 0x8
#define ALTERA_GPIO_EDGE_CAP 0xc
/**
* struct altera_gpio_chip
* @mmchip : memory mapped chip structure.
* @gpio_lock : synchronization lock so that new irq/set/get requests
* will be blocked until the current one completes.
* @interrupt_trigger : specifies the hardware configured IRQ trigger type
* (rising, falling, both, high)
* @mapped_irq : kernel mapped irq number.
*/
struct altera_gpio_chip {
struct of_mm_gpio_chip mmchip;
raw_spinlock_t gpio_lock;
int interrupt_trigger;
int mapped_irq;
};
static void altera_gpio_irq_unmask(struct irq_data *d)
{
struct altera_gpio_chip *altera_gc;
struct of_mm_gpio_chip *mm_gc;
unsigned long flags;
u32 intmask;
altera_gc = gpiochip_get_data(irq_data_get_irq_chip_data(d));
mm_gc = &altera_gc->mmchip;
gpiochip_enable_irq(&mm_gc->gc, irqd_to_hwirq(d));
raw_spin_lock_irqsave(&altera_gc->gpio_lock, flags);
intmask = readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
/* Set ALTERA_GPIO_IRQ_MASK bit to unmask */
intmask |= BIT(irqd_to_hwirq(d));
writel(intmask, mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
raw_spin_unlock_irqrestore(&altera_gc->gpio_lock, flags);
}
static void altera_gpio_irq_mask(struct irq_data *d)
{
struct altera_gpio_chip *altera_gc;
struct of_mm_gpio_chip *mm_gc;
unsigned long flags;
u32 intmask;
altera_gc = gpiochip_get_data(irq_data_get_irq_chip_data(d));
mm_gc = &altera_gc->mmchip;
raw_spin_lock_irqsave(&altera_gc->gpio_lock, flags);
intmask = readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
/* Clear ALTERA_GPIO_IRQ_MASK bit to mask */
intmask &= ~BIT(irqd_to_hwirq(d));
writel(intmask, mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
raw_spin_unlock_irqrestore(&altera_gc->gpio_lock, flags);
gpiochip_disable_irq(&mm_gc->gc, irqd_to_hwirq(d));
}
/*
* This controller's IRQ type is synthesized in hardware, so this function
* just checks if the requested set_type matches the synthesized IRQ type
*/
static int altera_gpio_irq_set_type(struct irq_data *d,
unsigned int type)
{
struct altera_gpio_chip *altera_gc;
altera_gc = gpiochip_get_data(irq_data_get_irq_chip_data(d));
if (type == IRQ_TYPE_NONE) {
irq_set_handler_locked(d, handle_bad_irq);
return 0;
}
if (type == altera_gc->interrupt_trigger) {
if (type == IRQ_TYPE_LEVEL_HIGH)
irq_set_handler_locked(d, handle_level_irq);
else
irq_set_handler_locked(d, handle_simple_irq);
return 0;
}
irq_set_handler_locked(d, handle_bad_irq);
return -EINVAL;
}
static unsigned int altera_gpio_irq_startup(struct irq_data *d)
{
altera_gpio_irq_unmask(d);
return 0;
}
static int altera_gpio_get(struct gpio_chip *gc, unsigned offset)
{
struct of_mm_gpio_chip *mm_gc;
mm_gc = to_of_mm_gpio_chip(gc);
return !!(readl(mm_gc->regs + ALTERA_GPIO_DATA) & BIT(offset));
}
static void altera_gpio_set(struct gpio_chip *gc, unsigned offset, int value)
{
struct of_mm_gpio_chip *mm_gc;
struct altera_gpio_chip *chip;
unsigned long flags;
unsigned int data_reg;
mm_gc = to_of_mm_gpio_chip(gc);
chip = gpiochip_get_data(gc);
raw_spin_lock_irqsave(&chip->gpio_lock, flags);
data_reg = readl(mm_gc->regs + ALTERA_GPIO_DATA);
if (value)
data_reg |= BIT(offset);
else
data_reg &= ~BIT(offset);
writel(data_reg, mm_gc->regs + ALTERA_GPIO_DATA);
raw_spin_unlock_irqrestore(&chip->gpio_lock, flags);
}
static int altera_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
{
struct of_mm_gpio_chip *mm_gc;
struct altera_gpio_chip *chip;
unsigned long flags;
unsigned int gpio_ddr;
mm_gc = to_of_mm_gpio_chip(gc);
chip = gpiochip_get_data(gc);
raw_spin_lock_irqsave(&chip->gpio_lock, flags);
/* Set pin as input, assumes software controlled IP */
gpio_ddr = readl(mm_gc->regs + ALTERA_GPIO_DIR);
gpio_ddr &= ~BIT(offset);
writel(gpio_ddr, mm_gc->regs + ALTERA_GPIO_DIR);
raw_spin_unlock_irqrestore(&chip->gpio_lock, flags);
return 0;
}
static int altera_gpio_direction_output(struct gpio_chip *gc,
unsigned offset, int value)
{
struct of_mm_gpio_chip *mm_gc;
struct altera_gpio_chip *chip;
unsigned long flags;
unsigned int data_reg, gpio_ddr;
mm_gc = to_of_mm_gpio_chip(gc);
chip = gpiochip_get_data(gc);
raw_spin_lock_irqsave(&chip->gpio_lock, flags);
/* Sets the GPIO value */
data_reg = readl(mm_gc->regs + ALTERA_GPIO_DATA);
if (value)
data_reg |= BIT(offset);
else
data_reg &= ~BIT(offset);
writel(data_reg, mm_gc->regs + ALTERA_GPIO_DATA);
/* Set pin as output, assumes software controlled IP */
gpio_ddr = readl(mm_gc->regs + ALTERA_GPIO_DIR);
gpio_ddr |= BIT(offset);
writel(gpio_ddr, mm_gc->regs + ALTERA_GPIO_DIR);
raw_spin_unlock_irqrestore(&chip->gpio_lock, flags);
return 0;
}
static void altera_gpio_irq_edge_handler(struct irq_desc *desc)
{
struct altera_gpio_chip *altera_gc;
struct irq_chip *chip;
struct of_mm_gpio_chip *mm_gc;
struct irq_domain *irqdomain;
unsigned long status;
int i;
altera_gc = gpiochip_get_data(irq_desc_get_handler_data(desc));
chip = irq_desc_get_chip(desc);
mm_gc = &altera_gc->mmchip;
irqdomain = altera_gc->mmchip.gc.irq.domain;
chained_irq_enter(chip, desc);
while ((status =
(readl(mm_gc->regs + ALTERA_GPIO_EDGE_CAP) &
readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK)))) {
writel(status, mm_gc->regs + ALTERA_GPIO_EDGE_CAP);
for_each_set_bit(i, &status, mm_gc->gc.ngpio)
generic_handle_domain_irq(irqdomain, i);
}
chained_irq_exit(chip, desc);
}
static void altera_gpio_irq_leveL_high_handler(struct irq_desc *desc)
{
struct altera_gpio_chip *altera_gc;
struct irq_chip *chip;
struct of_mm_gpio_chip *mm_gc;
struct irq_domain *irqdomain;
unsigned long status;
int i;
altera_gc = gpiochip_get_data(irq_desc_get_handler_data(desc));
chip = irq_desc_get_chip(desc);
mm_gc = &altera_gc->mmchip;
irqdomain = altera_gc->mmchip.gc.irq.domain;
chained_irq_enter(chip, desc);
status = readl(mm_gc->regs + ALTERA_GPIO_DATA);
status &= readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
for_each_set_bit(i, &status, mm_gc->gc.ngpio)
generic_handle_domain_irq(irqdomain, i);
chained_irq_exit(chip, desc);
}
static const struct irq_chip altera_gpio_irq_chip = {
.name = "altera-gpio",
.irq_mask = altera_gpio_irq_mask,
.irq_unmask = altera_gpio_irq_unmask,
.irq_set_type = altera_gpio_irq_set_type,
.irq_startup = altera_gpio_irq_startup,
.irq_shutdown = altera_gpio_irq_mask,
.flags = IRQCHIP_IMMUTABLE,
GPIOCHIP_IRQ_RESOURCE_HELPERS,
};
static int altera_gpio_probe(struct platform_device *pdev)
{
struct device_node *node = pdev->dev.of_node;
int reg, ret;
struct altera_gpio_chip *altera_gc;
struct gpio_irq_chip *girq;
altera_gc = devm_kzalloc(&pdev->dev, sizeof(*altera_gc), GFP_KERNEL);
if (!altera_gc)
return -ENOMEM;
raw_spin_lock_init(&altera_gc->gpio_lock);
if (of_property_read_u32(node, "altr,ngpio", &reg))
/* By default assume maximum ngpio */
altera_gc->mmchip.gc.ngpio = ALTERA_GPIO_MAX_NGPIO;
else
altera_gc->mmchip.gc.ngpio = reg;
if (altera_gc->mmchip.gc.ngpio > ALTERA_GPIO_MAX_NGPIO) {
dev_warn(&pdev->dev,
"ngpio is greater than %d, defaulting to %d\n",
ALTERA_GPIO_MAX_NGPIO, ALTERA_GPIO_MAX_NGPIO);
altera_gc->mmchip.gc.ngpio = ALTERA_GPIO_MAX_NGPIO;
}
altera_gc->mmchip.gc.direction_input = altera_gpio_direction_input;
altera_gc->mmchip.gc.direction_output = altera_gpio_direction_output;
altera_gc->mmchip.gc.get = altera_gpio_get;
altera_gc->mmchip.gc.set = altera_gpio_set;
altera_gc->mmchip.gc.owner = THIS_MODULE;
altera_gc->mmchip.gc.parent = &pdev->dev;
altera_gc->mapped_irq = platform_get_irq_optional(pdev, 0);
if (altera_gc->mapped_irq < 0)
goto skip_irq;
if (of_property_read_u32(node, "altr,interrupt-type", &reg)) {
dev_err(&pdev->dev,
"altr,interrupt-type value not set in device tree\n");
return -EINVAL;
}
altera_gc->interrupt_trigger = reg;
girq = &altera_gc->mmchip.gc.irq;
gpio_irq_chip_set_chip(girq, &altera_gpio_irq_chip);
if (altera_gc->interrupt_trigger == IRQ_TYPE_LEVEL_HIGH)
girq->parent_handler = altera_gpio_irq_leveL_high_handler;
else
girq->parent_handler = altera_gpio_irq_edge_handler;
girq->num_parents = 1;
girq->parents = devm_kcalloc(&pdev->dev, 1, sizeof(*girq->parents),
GFP_KERNEL);
if (!girq->parents)
return -ENOMEM;
girq->default_type = IRQ_TYPE_NONE;
girq->handler = handle_bad_irq;
girq->parents[0] = altera_gc->mapped_irq;
skip_irq:
ret = of_mm_gpiochip_add_data(node, &altera_gc->mmchip, altera_gc);
if (ret) {
dev_err(&pdev->dev, "Failed adding memory mapped gpiochip\n");
return ret;
}
platform_set_drvdata(pdev, altera_gc);
return 0;
}
static void altera_gpio_remove(struct platform_device *pdev)
{
struct altera_gpio_chip *altera_gc = platform_get_drvdata(pdev);
of_mm_gpiochip_remove(&altera_gc->mmchip);
}
static const struct of_device_id altera_gpio_of_match[] = {
{ .compatible = "altr,pio-1.0", },
{},
};
MODULE_DEVICE_TABLE(of, altera_gpio_of_match);
static struct platform_driver altera_gpio_driver = {
.driver = {
.name = "altera_gpio",
.of_match_table = altera_gpio_of_match,
},
.probe = altera_gpio_probe,
.remove_new = altera_gpio_remove,
};
static int __init altera_gpio_init(void)
{
return platform_driver_register(&altera_gpio_driver);
}
subsys_initcall(altera_gpio_init);
static void __exit altera_gpio_exit(void)
{
platform_driver_unregister(&altera_gpio_driver);
}
module_exit(altera_gpio_exit);
MODULE_AUTHOR("Tien Hock Loh <thloh@altera.com>");
MODULE_DESCRIPTION("Altera GPIO driver");
MODULE_LICENSE("GPL");
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