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gpio/sifive: Add GPIO driver for SiFive SoCs
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Adds the GPIO driver for SiFive RISC-V SoCs.

Signed-off-by: Wesley W. Terpstra <wesley@sifive.com>
[Atish: Various fixes and code cleanup]
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Yash Shah <yash.shah@sifive.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/1575976274-13487-6-git-send-email-yash.shah@sifive.com
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yashshah7 authored and Marc Zyngier committed Jan 20, 2020
1 parent 7875f82 commit 96868dc
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9 changes: 9 additions & 0 deletions drivers/gpio/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -479,6 +479,15 @@ config GPIO_SAMA5D2_PIOBU
The difference from regular GPIOs is that they
maintain their value during backup/self-refresh.

config GPIO_SIFIVE
bool "SiFive GPIO support"
depends on OF_GPIO && IRQ_DOMAIN_HIERARCHY
select GPIO_GENERIC
select GPIOLIB_IRQCHIP
select REGMAP_MMIO
help
Say yes here to support the GPIO device on SiFive SoCs.

config GPIO_SIOX
tristate "SIOX GPIO support"
depends on SIOX
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1 change: 1 addition & 0 deletions drivers/gpio/Makefile
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Expand Up @@ -124,6 +124,7 @@ obj-$(CONFIG_ARCH_SA1100) += gpio-sa1100.o
obj-$(CONFIG_GPIO_SAMA5D2_PIOBU) += gpio-sama5d2-piobu.o
obj-$(CONFIG_GPIO_SCH311X) += gpio-sch311x.o
obj-$(CONFIG_GPIO_SCH) += gpio-sch.o
obj-$(CONFIG_GPIO_SIFIVE) += gpio-sifive.o
obj-$(CONFIG_GPIO_SIOX) += gpio-siox.o
obj-$(CONFIG_GPIO_SODAVILLE) += gpio-sodaville.o
obj-$(CONFIG_GPIO_SPEAR_SPICS) += gpio-spear-spics.o
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252 changes: 252 additions & 0 deletions drivers/gpio/gpio-sifive.c
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@@ -0,0 +1,252 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2019 SiFive
*/

#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/of_irq.h>
#include <linux/gpio/driver.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/regmap.h>

#define SIFIVE_GPIO_INPUT_VAL 0x00
#define SIFIVE_GPIO_INPUT_EN 0x04
#define SIFIVE_GPIO_OUTPUT_EN 0x08
#define SIFIVE_GPIO_OUTPUT_VAL 0x0C
#define SIFIVE_GPIO_RISE_IE 0x18
#define SIFIVE_GPIO_RISE_IP 0x1C
#define SIFIVE_GPIO_FALL_IE 0x20
#define SIFIVE_GPIO_FALL_IP 0x24
#define SIFIVE_GPIO_HIGH_IE 0x28
#define SIFIVE_GPIO_HIGH_IP 0x2C
#define SIFIVE_GPIO_LOW_IE 0x30
#define SIFIVE_GPIO_LOW_IP 0x34
#define SIFIVE_GPIO_OUTPUT_XOR 0x40

#define SIFIVE_GPIO_MAX 32
#define SIFIVE_GPIO_IRQ_OFFSET 7

struct sifive_gpio {
void __iomem *base;
struct gpio_chip gc;
struct regmap *regs;
u32 irq_state;
unsigned int trigger[SIFIVE_GPIO_MAX];
unsigned int irq_parent[SIFIVE_GPIO_MAX];
};

static void sifive_gpio_set_ie(struct sifive_gpio *chip, unsigned int offset)
{
unsigned long flags;
unsigned int trigger;

spin_lock_irqsave(&chip->gc.bgpio_lock, flags);
trigger = (chip->irq_state & BIT(offset)) ? chip->trigger[offset] : 0;
regmap_update_bits(chip->regs, SIFIVE_GPIO_RISE_IE, BIT(offset),
(trigger & IRQ_TYPE_EDGE_RISING) ? BIT(offset) : 0);
regmap_update_bits(chip->regs, SIFIVE_GPIO_FALL_IE, BIT(offset),
(trigger & IRQ_TYPE_EDGE_FALLING) ? BIT(offset) : 0);
regmap_update_bits(chip->regs, SIFIVE_GPIO_HIGH_IE, BIT(offset),
(trigger & IRQ_TYPE_LEVEL_HIGH) ? BIT(offset) : 0);
regmap_update_bits(chip->regs, SIFIVE_GPIO_LOW_IE, BIT(offset),
(trigger & IRQ_TYPE_LEVEL_LOW) ? BIT(offset) : 0);
spin_unlock_irqrestore(&chip->gc.bgpio_lock, flags);
}

static int sifive_gpio_irq_set_type(struct irq_data *d, unsigned int trigger)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct sifive_gpio *chip = gpiochip_get_data(gc);
int offset = irqd_to_hwirq(d);

if (offset < 0 || offset >= gc->ngpio)
return -EINVAL;

chip->trigger[offset] = trigger;
sifive_gpio_set_ie(chip, offset);
return 0;
}

static void sifive_gpio_irq_enable(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct sifive_gpio *chip = gpiochip_get_data(gc);
int offset = irqd_to_hwirq(d) % SIFIVE_GPIO_MAX;
u32 bit = BIT(offset);
unsigned long flags;

irq_chip_enable_parent(d);

/* Switch to input */
gc->direction_input(gc, offset);

spin_lock_irqsave(&gc->bgpio_lock, flags);
/* Clear any sticky pending interrupts */
regmap_write(chip->regs, SIFIVE_GPIO_RISE_IP, bit);
regmap_write(chip->regs, SIFIVE_GPIO_FALL_IP, bit);
regmap_write(chip->regs, SIFIVE_GPIO_HIGH_IP, bit);
regmap_write(chip->regs, SIFIVE_GPIO_LOW_IP, bit);
spin_unlock_irqrestore(&gc->bgpio_lock, flags);

/* Enable interrupts */
assign_bit(offset, (unsigned long *)&chip->irq_state, 1);
sifive_gpio_set_ie(chip, offset);
}

static void sifive_gpio_irq_disable(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct sifive_gpio *chip = gpiochip_get_data(gc);
int offset = irqd_to_hwirq(d) % SIFIVE_GPIO_MAX;

assign_bit(offset, (unsigned long *)&chip->irq_state, 0);
sifive_gpio_set_ie(chip, offset);
irq_chip_disable_parent(d);
}

static void sifive_gpio_irq_eoi(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct sifive_gpio *chip = gpiochip_get_data(gc);
int offset = irqd_to_hwirq(d) % SIFIVE_GPIO_MAX;
u32 bit = BIT(offset);
unsigned long flags;

spin_lock_irqsave(&gc->bgpio_lock, flags);
/* Clear all pending interrupts */
regmap_write(chip->regs, SIFIVE_GPIO_RISE_IP, bit);
regmap_write(chip->regs, SIFIVE_GPIO_FALL_IP, bit);
regmap_write(chip->regs, SIFIVE_GPIO_HIGH_IP, bit);
regmap_write(chip->regs, SIFIVE_GPIO_LOW_IP, bit);
spin_unlock_irqrestore(&gc->bgpio_lock, flags);

irq_chip_eoi_parent(d);
}

static struct irq_chip sifive_gpio_irqchip = {
.name = "sifive-gpio",
.irq_set_type = sifive_gpio_irq_set_type,
.irq_mask = irq_chip_mask_parent,
.irq_unmask = irq_chip_unmask_parent,
.irq_enable = sifive_gpio_irq_enable,
.irq_disable = sifive_gpio_irq_disable,
.irq_eoi = sifive_gpio_irq_eoi,
};

static int sifive_gpio_child_to_parent_hwirq(struct gpio_chip *gc,
unsigned int child,
unsigned int child_type,
unsigned int *parent,
unsigned int *parent_type)
{
*parent_type = IRQ_TYPE_NONE;
*parent = child + SIFIVE_GPIO_IRQ_OFFSET;
return 0;
}

static const struct regmap_config sifive_gpio_regmap_config = {
.reg_bits = 32,
.reg_stride = 4,
.val_bits = 32,
.fast_io = true,
.disable_locking = true,
};

static int sifive_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *node = pdev->dev.of_node;
struct device_node *irq_parent;
struct irq_domain *parent;
struct gpio_irq_chip *girq;
struct sifive_gpio *chip;
int ret, ngpio;

chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;

chip->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(chip->base)) {
dev_err(dev, "failed to allocate device memory\n");
return PTR_ERR(chip->base);
}

chip->regs = devm_regmap_init_mmio(dev, chip->base,
&sifive_gpio_regmap_config);
if (IS_ERR(chip->regs))
return PTR_ERR(chip->regs);

ngpio = of_irq_count(node);
if (ngpio >= SIFIVE_GPIO_MAX) {
dev_err(dev, "Too many GPIO interrupts (max=%d)\n",
SIFIVE_GPIO_MAX);
return -ENXIO;
}

irq_parent = of_irq_find_parent(node);
if (!irq_parent) {
dev_err(dev, "no IRQ parent node\n");
return -ENODEV;
}
parent = irq_find_host(irq_parent);
if (!parent) {
dev_err(dev, "no IRQ parent domain\n");
return -ENODEV;
}

ret = bgpio_init(&chip->gc, dev, 4,
chip->base + SIFIVE_GPIO_INPUT_VAL,
chip->base + SIFIVE_GPIO_OUTPUT_VAL,
NULL,
chip->base + SIFIVE_GPIO_OUTPUT_EN,
chip->base + SIFIVE_GPIO_INPUT_EN,
0);
if (ret) {
dev_err(dev, "unable to init generic GPIO\n");
return ret;
}

/* Disable all GPIO interrupts before enabling parent interrupts */
regmap_write(chip->regs, SIFIVE_GPIO_RISE_IE, 0);
regmap_write(chip->regs, SIFIVE_GPIO_FALL_IE, 0);
regmap_write(chip->regs, SIFIVE_GPIO_HIGH_IE, 0);
regmap_write(chip->regs, SIFIVE_GPIO_LOW_IE, 0);
chip->irq_state = 0;

chip->gc.base = -1;
chip->gc.ngpio = ngpio;
chip->gc.label = dev_name(dev);
chip->gc.parent = dev;
chip->gc.owner = THIS_MODULE;
girq = &chip->gc.irq;
girq->chip = &sifive_gpio_irqchip;
girq->fwnode = of_node_to_fwnode(node);
girq->parent_domain = parent;
girq->child_to_parent_hwirq = sifive_gpio_child_to_parent_hwirq;
girq->handler = handle_bad_irq;
girq->default_type = IRQ_TYPE_NONE;

platform_set_drvdata(pdev, chip);
return gpiochip_add_data(&chip->gc, chip);
}

static const struct of_device_id sifive_gpio_match[] = {
{ .compatible = "sifive,gpio0" },
{ .compatible = "sifive,fu540-c000-gpio" },
{ },
};

static struct platform_driver sifive_gpio_driver = {
.probe = sifive_gpio_probe,
.driver = {
.name = "sifive_gpio",
.of_match_table = of_match_ptr(sifive_gpio_match),
},
};
builtin_platform_driver(sifive_gpio_driver)

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