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Subject[PATCH v4 5/6] gpio: sifive: Add GPIO driver for SiFive SoCs
Date
Adds the GPIO driver for SiFive RISC-V SoCs.

Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
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>
---
drivers/gpio/Kconfig | 9 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-sifive.c | 252 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 262 insertions(+)
create mode 100644 drivers/gpio/gpio-sifive.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 38e096e..05e8a41 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -453,6 +453,15 @@ 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
+ 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
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index d2fd19c..bf7984e 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -121,6 +121,7 @@ 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
diff --git a/drivers/gpio/gpio-sifive.c b/drivers/gpio/gpio-sifive.c
new file mode 100644
index 0000000..147a1bd
--- /dev/null
+++ b/drivers/gpio/gpio-sifive.c
@@ -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)
--
2.7.4
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