gpio: mlxbf3: Add gpio driver support

Add support for the BlueField-3 SoC GPIO driver.
This driver configures and handles GPIO interrupts. It also enables a user
to manipulate certain GPIO pins via libgpiod tools or other kernel drivers.
The usables pins are defined via the "gpio-reserved-ranges" property.

Signed-off-by: Asmaa Mnebhi <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Reviewed-by: Linus Walleij <[e-mail]>
Signed-off-by: Bartosz Golaszewski <[e-mail]>

drivers/gpio/Kconfig

···
 	help
 	  Say Y here if you want GPIO support on Mellanox BlueField 2 SoC.
 
+config GPIO_MLXBF3
+	tristate "Mellanox BlueField 3 SoC GPIO"
+	depends on (MELLANOX_PLATFORM && ARM64) || COMPILE_TEST
+	select GPIO_GENERIC
+	select GPIOLIB_IRQCHIP
+	help
+	  Say Y if you want GPIO support on Mellanox BlueField 3 SoC.
+	  This GPIO controller supports interrupt handling and enables the
+	  manipulation of certain GPIO pins.
+	  This controller should be used in parallel with pinctrl-mlxbf3 to
+	  control the desired GPIOs.
+	  This driver can also be built as a module called mlxbf3-gpio.
+
 config GPIO_ML_IOH
 	tristate "OKI SEMICONDUCTOR ML7213 IOH GPIO support"
 	depends on X86 || COMPILE_TEST

drivers/gpio/Makefile

···
 obj-$(CONFIG_GPIO_ML_IOH)		+= gpio-ml-ioh.o
 obj-$(CONFIG_GPIO_MLXBF)		+= gpio-mlxbf.o
 obj-$(CONFIG_GPIO_MLXBF2)		+= gpio-mlxbf2.o
+obj-$(CONFIG_GPIO_MLXBF3)		+= gpio-mlxbf3.o
 obj-$(CONFIG_GPIO_MM_LANTIQ)		+= gpio-mm-lantiq.o
 obj-$(CONFIG_GPIO_MOCKUP)		+= gpio-mockup.o
 obj-$(CONFIG_GPIO_MOXTET)		+= gpio-moxtet.o

drivers/gpio/gpio-mlxbf3.c

···
+// SPDX-License-Identifier: GPL-2.0-only or BSD-3-Clause
+/* Copyright (C) 2022 NVIDIA CORPORATION & AFFILIATES */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+/*
+ * There are 2 YU GPIO blocks:
+ * gpio[0]: HOST_GPIO0->HOST_GPIO31
+ * gpio[1]: HOST_GPIO32->HOST_GPIO55
+ */
+#define MLXBF3_GPIO_MAX_PINS_PER_BLOCK 32
+
+/*
+ * fw_gpio[x] block registers and their offset
+ */
+#define MLXBF_GPIO_FW_OUTPUT_ENABLE_SET	  0x00
+#define MLXBF_GPIO_FW_DATA_OUT_SET        0x04
+
+#define MLXBF_GPIO_FW_OUTPUT_ENABLE_CLEAR 0x00
+#define MLXBF_GPIO_FW_DATA_OUT_CLEAR      0x04
+
+#define MLXBF_GPIO_CAUSE_RISE_EN          0x00
+#define MLXBF_GPIO_CAUSE_FALL_EN          0x04
+#define MLXBF_GPIO_READ_DATA_IN           0x08
+
+#define MLXBF_GPIO_CAUSE_OR_CAUSE_EVTEN0  0x00
+#define MLXBF_GPIO_CAUSE_OR_EVTEN0        0x14
+#define MLXBF_GPIO_CAUSE_OR_CLRCAUSE      0x18
+
+struct mlxbf3_gpio_context {
+	struct gpio_chip gc;
+
+	/* YU GPIO block address */
+	void __iomem *gpio_set_io;
+	void __iomem *gpio_clr_io;
+	void __iomem *gpio_io;
+
+	/* YU GPIO cause block address */
+	void __iomem *gpio_cause_io;
+};
+
+static void mlxbf3_gpio_irq_enable(struct irq_data *irqd)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct mlxbf3_gpio_context *gs = gpiochip_get_data(gc);
+	irq_hw_number_t offset = irqd_to_hwirq(irqd);
+	unsigned long flags;
+	u32 val;
+
+	gpiochip_enable_irq(gc, offset);
+
+	raw_spin_lock_irqsave(&gs->gc.bgpio_lock, flags);
+	writel(BIT(offset), gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CLRCAUSE);
+
+	val = readl(gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
+	val |= BIT(offset);
+	writel(val, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
+	raw_spin_unlock_irqrestore(&gs->gc.bgpio_lock, flags);
+}
+
+static void mlxbf3_gpio_irq_disable(struct irq_data *irqd)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct mlxbf3_gpio_context *gs = gpiochip_get_data(gc);
+	irq_hw_number_t offset = irqd_to_hwirq(irqd);
+	unsigned long flags;
+	u32 val;
+
+	raw_spin_lock_irqsave(&gs->gc.bgpio_lock, flags);
+	val = readl(gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
+	val &= ~BIT(offset);
+	writel(val, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
+	raw_spin_unlock_irqrestore(&gs->gc.bgpio_lock, flags);
+
+	gpiochip_disable_irq(gc, offset);
+}
+
+static irqreturn_t mlxbf3_gpio_irq_handler(int irq, void *ptr)
+{
+	struct mlxbf3_gpio_context *gs = ptr;
+	struct gpio_chip *gc = &gs->gc;
+	unsigned long pending;
+	u32 level;
+
+	pending = readl(gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CAUSE_EVTEN0);
+	writel(pending, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CLRCAUSE);
+
+	for_each_set_bit(level, &pending, gc->ngpio)
+		generic_handle_domain_irq(gc->irq.domain, level);
+
+	return IRQ_RETVAL(pending);
+}
+
+static int
+mlxbf3_gpio_irq_set_type(struct irq_data *irqd, unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+	struct mlxbf3_gpio_context *gs = gpiochip_get_data(gc);
+	irq_hw_number_t offset = irqd_to_hwirq(irqd);
+	unsigned long flags;
+	u32 val;
+
+	raw_spin_lock_irqsave(&gs->gc.bgpio_lock, flags);
+
+	switch (type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_BOTH:
+		val = readl(gs->gpio_io + MLXBF_GPIO_CAUSE_FALL_EN);
+		val |= BIT(offset);
+		writel(val, gs->gpio_io + MLXBF_GPIO_CAUSE_FALL_EN);
+		val = readl(gs->gpio_io + MLXBF_GPIO_CAUSE_RISE_EN);
+		val |= BIT(offset);
+		writel(val, gs->gpio_io + MLXBF_GPIO_CAUSE_RISE_EN);
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		val = readl(gs->gpio_io + MLXBF_GPIO_CAUSE_RISE_EN);
+		val |= BIT(offset);
+		writel(val, gs->gpio_io + MLXBF_GPIO_CAUSE_RISE_EN);
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		val = readl(gs->gpio_io + MLXBF_GPIO_CAUSE_FALL_EN);
+		val |= BIT(offset);
+		writel(val, gs->gpio_io + MLXBF_GPIO_CAUSE_FALL_EN);
+		break;
+	default:
+		raw_spin_unlock_irqrestore(&gs->gc.bgpio_lock, flags);
+		return -EINVAL;
+	}
+
+	raw_spin_unlock_irqrestore(&gs->gc.bgpio_lock, flags);
+
+	irq_set_handler_locked(irqd, handle_edge_irq);
+
+	return 0;
+}
+
+/* This function needs to be defined for handle_edge_irq() */
+static void mlxbf3_gpio_irq_ack(struct irq_data *data)
+{
+}
+
+static const struct irq_chip gpio_mlxbf3_irqchip = {
+	.name = "MLNXBF33",
+	.irq_ack = mlxbf3_gpio_irq_ack,
+	.irq_set_type = mlxbf3_gpio_irq_set_type,
+	.irq_enable = mlxbf3_gpio_irq_enable,
+	.irq_disable = mlxbf3_gpio_irq_disable,
+	.flags = IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static int mlxbf3_gpio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mlxbf3_gpio_context *gs;
+	struct gpio_irq_chip *girq;
+	struct gpio_chip *gc;
+	int ret, irq;
+
+	gs = devm_kzalloc(dev, sizeof(*gs), GFP_KERNEL);
+	if (!gs)
+		return -ENOMEM;
+
+	gs->gpio_io = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(gs->gpio_io))
+		return PTR_ERR(gs->gpio_io);
+
+	gs->gpio_cause_io = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(gs->gpio_cause_io))
+		return PTR_ERR(gs->gpio_cause_io);
+
+	gs->gpio_set_io = devm_platform_ioremap_resource(pdev, 2);
+	if (IS_ERR(gs->gpio_set_io))
+		return PTR_ERR(gs->gpio_set_io);
+
+	gs->gpio_clr_io = devm_platform_ioremap_resource(pdev, 3);
+	if (IS_ERR(gs->gpio_clr_io))
+		return PTR_ERR(gs->gpio_clr_io);
+	gc = &gs->gc;
+
+	ret = bgpio_init(gc, dev, 4,
+			gs->gpio_io + MLXBF_GPIO_READ_DATA_IN,
+			gs->gpio_set_io + MLXBF_GPIO_FW_DATA_OUT_SET,
+			gs->gpio_clr_io + MLXBF_GPIO_FW_DATA_OUT_CLEAR,
+			gs->gpio_set_io + MLXBF_GPIO_FW_OUTPUT_ENABLE_SET,
+			gs->gpio_clr_io + MLXBF_GPIO_FW_OUTPUT_ENABLE_CLEAR, 0);
+
+	gc->request = gpiochip_generic_request;
+	gc->free = gpiochip_generic_free;
+	gc->owner = THIS_MODULE;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq >= 0) {
+		girq = &gs->gc.irq;
+		gpio_irq_chip_set_chip(girq, &gpio_mlxbf3_irqchip);
+		girq->default_type = IRQ_TYPE_NONE;
+		/* This will let us handle the parent IRQ in the driver */
+		girq->num_parents = 0;
+		girq->parents = NULL;
+		girq->parent_handler = NULL;
+		girq->handler = handle_bad_irq;
+
+		/*
+		 * Directly request the irq here instead of passing
+		 * a flow-handler because the irq is shared.
+		 */
+		ret = devm_request_irq(dev, irq, mlxbf3_gpio_irq_handler,
+				       IRQF_SHARED, dev_name(dev), gs);
+		if (ret)
+			return dev_err_probe(dev, ret, "failed to request IRQ");
+	}
+
+	platform_set_drvdata(pdev, gs);
+
+	ret = devm_gpiochip_add_data(dev, &gs->gc, gs);
+	if (ret)
+		dev_err_probe(dev, ret, "Failed adding memory mapped gpiochip\n");
+
+	return 0;
+}
+
+static const struct acpi_device_id mlxbf3_gpio_acpi_match[] = {
+	{ "MLNXBF33", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, mlxbf3_gpio_acpi_match);
+
+static struct platform_driver mlxbf3_gpio_driver = {
+	.driver = {
+		.name = "mlxbf3_gpio",
+		.acpi_match_table = mlxbf3_gpio_acpi_match,
+	},
+	.probe    = mlxbf3_gpio_probe,
+};
+module_platform_driver(mlxbf3_gpio_driver);
+
+MODULE_DESCRIPTION("NVIDIA BlueField-3 GPIO Driver");
+MODULE_AUTHOR("Asmaa Mnebhi <[e-mail]>");
+MODULE_LICENSE("Dual BSD/GPL");