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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2017-2018 Cadence
*
* Authors:
* Jan Kotas <jank@cadence.com>
* Boris Brezillon <boris.brezillon@free-electrons.com>
*/
#include <linux/gpio/driver.h>
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#define CDNS_GPIO_BYPASS_MODE 0x00
#define CDNS_GPIO_DIRECTION_MODE 0x04
#define CDNS_GPIO_OUTPUT_EN 0x08
#define CDNS_GPIO_OUTPUT_VALUE 0x0c
#define CDNS_GPIO_INPUT_VALUE 0x10
#define CDNS_GPIO_IRQ_MASK 0x14
#define CDNS_GPIO_IRQ_EN 0x18
#define CDNS_GPIO_IRQ_DIS 0x1c
#define CDNS_GPIO_IRQ_STATUS 0x20
#define CDNS_GPIO_IRQ_TYPE 0x24
#define CDNS_GPIO_IRQ_VALUE 0x28
#define CDNS_GPIO_IRQ_ANY_EDGE 0x2c
struct cdns_gpio_chip {
struct gpio_chip gc;
struct clk *pclk;
void __iomem *regs;
u32 bypass_orig;
};
static int cdns_gpio_request(struct gpio_chip *chip, unsigned int offset)
{
struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
unsigned long flags;
spin_lock_irqsave(&chip->bgpio_lock, flags);
iowrite32(ioread32(cgpio->regs + CDNS_GPIO_BYPASS_MODE) & ~BIT(offset),
cgpio->regs + CDNS_GPIO_BYPASS_MODE);
spin_unlock_irqrestore(&chip->bgpio_lock, flags);
return 0;
}
static void cdns_gpio_free(struct gpio_chip *chip, unsigned int offset)
{
struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
unsigned long flags;
spin_lock_irqsave(&chip->bgpio_lock, flags);
iowrite32(ioread32(cgpio->regs + CDNS_GPIO_BYPASS_MODE) |
(BIT(offset) & cgpio->bypass_orig),
cgpio->regs + CDNS_GPIO_BYPASS_MODE);
spin_unlock_irqrestore(&chip->bgpio_lock, flags);
}
static void cdns_gpio_irq_mask(struct irq_data *d)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
iowrite32(BIT(d->hwirq), cgpio->regs + CDNS_GPIO_IRQ_DIS);
}
static void cdns_gpio_irq_unmask(struct irq_data *d)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
iowrite32(BIT(d->hwirq), cgpio->regs + CDNS_GPIO_IRQ_EN);
}
static int cdns_gpio_irq_set_type(struct irq_data *d, unsigned int type)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
unsigned long flags;
u32 int_value;
u32 int_type;
u32 mask = BIT(d->hwirq);
int ret = 0;
spin_lock_irqsave(&chip->bgpio_lock, flags);
int_value = ioread32(cgpio->regs + CDNS_GPIO_IRQ_VALUE) & ~mask;
int_type = ioread32(cgpio->regs + CDNS_GPIO_IRQ_TYPE) & ~mask;
/*
* The GPIO controller doesn't have an ACK register.
* All interrupt statuses are cleared on a status register read.
* Don't support edge interrupts for now.
*/
if (type == IRQ_TYPE_LEVEL_HIGH) {
int_type |= mask;
int_value |= mask;
} else if (type == IRQ_TYPE_LEVEL_LOW) {
int_type |= mask;
} else {
ret = -EINVAL;
goto err_irq_type;
}
iowrite32(int_value, cgpio->regs + CDNS_GPIO_IRQ_VALUE);
iowrite32(int_type, cgpio->regs + CDNS_GPIO_IRQ_TYPE);
err_irq_type:
spin_unlock_irqrestore(&chip->bgpio_lock, flags);
return ret;
}
static void cdns_gpio_irq_handler(struct irq_desc *desc)
{
struct gpio_chip *chip = irq_desc_get_handler_data(desc);
struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
struct irq_chip *irqchip = irq_desc_get_chip(desc);
unsigned long status;
int hwirq;
chained_irq_enter(irqchip, desc);
status = ioread32(cgpio->regs + CDNS_GPIO_IRQ_STATUS) &
~ioread32(cgpio->regs + CDNS_GPIO_IRQ_MASK);
for_each_set_bit(hwirq, &status, chip->ngpio)
generic_handle_irq(irq_find_mapping(chip->irq.domain, hwirq));
chained_irq_exit(irqchip, desc);
}
static struct irq_chip cdns_gpio_irqchip = {
.name = "cdns-gpio",
.irq_mask = cdns_gpio_irq_mask,
.irq_unmask = cdns_gpio_irq_unmask,
.irq_set_type = cdns_gpio_irq_set_type
};
static int cdns_gpio_probe(struct platform_device *pdev)
{
struct cdns_gpio_chip *cgpio;
int ret, irq;
u32 dir_prev;
u32 num_gpios = 32;
cgpio = devm_kzalloc(&pdev->dev, sizeof(*cgpio), GFP_KERNEL);
if (!cgpio)
return -ENOMEM;
cgpio->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(cgpio->regs))
return PTR_ERR(cgpio->regs);
of_property_read_u32(pdev->dev.of_node, "ngpios", &num_gpios);
if (num_gpios > 32) {
dev_err(&pdev->dev, "ngpios must be less or equal 32\n");
return -EINVAL;
}
/*
* Set all pins as inputs by default, otherwise:
* gpiochip_lock_as_irq:
* tried to flag a GPIO set as output for IRQ
* Generic GPIO driver stores the direction value internally,
* so it needs to be changed before bgpio_init() is called.
*/
dir_prev = ioread32(cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
iowrite32(GENMASK(num_gpios - 1, 0),
cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
ret = bgpio_init(&cgpio->gc, &pdev->dev, 4,
cgpio->regs + CDNS_GPIO_INPUT_VALUE,
cgpio->regs + CDNS_GPIO_OUTPUT_VALUE,
NULL,
NULL,
cgpio->regs + CDNS_GPIO_DIRECTION_MODE,
BGPIOF_READ_OUTPUT_REG_SET);
if (ret) {
dev_err(&pdev->dev, "Failed to register generic gpio, %d\n",
ret);
goto err_revert_dir;
}
cgpio->gc.label = dev_name(&pdev->dev);
cgpio->gc.ngpio = num_gpios;
cgpio->gc.parent = &pdev->dev;
cgpio->gc.base = -1;
cgpio->gc.owner = THIS_MODULE;
cgpio->gc.request = cdns_gpio_request;
cgpio->gc.free = cdns_gpio_free;
cgpio->pclk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(cgpio->pclk)) {
ret = PTR_ERR(cgpio->pclk);
dev_err(&pdev->dev,
"Failed to retrieve peripheral clock, %d\n", ret);
goto err_revert_dir;
}
ret = clk_prepare_enable(cgpio->pclk);
if (ret) {
dev_err(&pdev->dev,
"Failed to enable the peripheral clock, %d\n", ret);
goto err_revert_dir;
}
/*
* Optional irq_chip support
*/
irq = platform_get_irq(pdev, 0);
if (irq >= 0) {
struct gpio_irq_chip *girq;
girq = &cgpio->gc.irq;
girq->chip = &cdns_gpio_irqchip;
girq->parent_handler = cdns_gpio_irq_handler;
girq->num_parents = 1;
girq->parents = devm_kcalloc(&pdev->dev, 1,
sizeof(*girq->parents),
GFP_KERNEL);
if (!girq->parents) {
ret = -ENOMEM;
goto err_disable_clk;
}
girq->parents[0] = irq;
girq->default_type = IRQ_TYPE_NONE;
girq->handler = handle_level_irq;
}
ret = devm_gpiochip_add_data(&pdev->dev, &cgpio->gc, cgpio);
if (ret < 0) {
dev_err(&pdev->dev, "Could not register gpiochip, %d\n", ret);
goto err_disable_clk;
}
cgpio->bypass_orig = ioread32(cgpio->regs + CDNS_GPIO_BYPASS_MODE);
/*
* Enable gpio outputs, ignored for input direction
*/
iowrite32(GENMASK(num_gpios - 1, 0),
cgpio->regs + CDNS_GPIO_OUTPUT_EN);
iowrite32(0, cgpio->regs + CDNS_GPIO_BYPASS_MODE);
platform_set_drvdata(pdev, cgpio);
return 0;
err_disable_clk:
clk_disable_unprepare(cgpio->pclk);
err_revert_dir:
iowrite32(dir_prev, cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
return ret;
}
static int cdns_gpio_remove(struct platform_device *pdev)
{
struct cdns_gpio_chip *cgpio = platform_get_drvdata(pdev);
iowrite32(cgpio->bypass_orig, cgpio->regs + CDNS_GPIO_BYPASS_MODE);
clk_disable_unprepare(cgpio->pclk);
return 0;
}
static const struct of_device_id cdns_of_ids[] = {
{ .compatible = "cdns,gpio-r1p02" },
{ /* sentinel */ },
};
static struct platform_driver cdns_gpio_driver = {
.driver = {
.name = "cdns-gpio",
.of_match_table = cdns_of_ids,
},
.probe = cdns_gpio_probe,
.remove = cdns_gpio_remove,
};
module_platform_driver(cdns_gpio_driver);
MODULE_AUTHOR("Jan Kotas <jank@cadence.com>");
MODULE_DESCRIPTION("Cadence GPIO driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:cdns-gpio");
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