[RFC v7 4/6] gpio: mpfs: add polarfire soc gpio support

[Conor Dooley <conor.dooley@xxxxxxxxxxxxx>]

From: Lewis Hanly <lewis.hanly@xxxxxxxxxxxxx>

Add a driver to support the Polarfire SoC gpio controller

Signed-off-by: Lewis Hanly <lewis.hanly@xxxxxxxxxxxxx>
Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
---
Unchanged from last list submission, I'm looking for comments on the
other patches in the series at the moment.
---
 drivers/gpio/Kconfig     |   7 +
 drivers/gpio/Makefile    |   1 +
 drivers/gpio/gpio-mpfs.c | 320 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 328 insertions(+)
 create mode 100644 drivers/gpio/gpio-mpfs.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 3dbddec070281..78fe494e3722c 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -549,6 +549,13 @@ config GPIO_PL061
 	help
 	  Say yes here to support the PrimeCell PL061 GPIO device.
 
+config GPIO_POLARFIRE_SOC
+	bool "Microchip FPGA GPIO support"
+	depends on OF_GPIO
+	select GPIOLIB_IRQCHIP
+	help
+	  Say yes here to support the GPIO device on Microchip FPGAs.
+
 config GPIO_PXA
 	bool "PXA GPIO support"
 	depends on ARCH_PXA || ARCH_MMP || COMPILE_TEST
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index e2a53013780e5..dd6ba21bce76e 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -132,6 +132,7 @@ obj-$(CONFIG_GPIO_PCI_IDIO_16)		+= gpio-pci-idio-16.o
 obj-$(CONFIG_GPIO_PISOSR)		+= gpio-pisosr.o
 obj-$(CONFIG_GPIO_PL061)		+= gpio-pl061.o
 obj-$(CONFIG_GPIO_PMIC_EIC_SPRD)	+= gpio-pmic-eic-sprd.o
+obj-$(CONFIG_GPIO_POLARFIRE_SOC)	+= gpio-mpfs.o
 obj-$(CONFIG_GPIO_PXA)			+= gpio-pxa.o
 obj-$(CONFIG_GPIO_RASPBERRYPI_EXP)	+= gpio-raspberrypi-exp.o
 obj-$(CONFIG_GPIO_RC5T583)		+= gpio-rc5t583.o
diff --git a/drivers/gpio/gpio-mpfs.c b/drivers/gpio/gpio-mpfs.c
new file mode 100644
index 0000000000000..1ac0526ba1029
--- /dev/null
+++ b/drivers/gpio/gpio-mpfs.c
@@ -0,0 +1,320 @@
+// SPDX-License-Identifier: (GPL-2.0)
+/*
+ * Microchip PolarFire SoC (MPFS) GPIO controller driver
+ *
+ * Copyright (c) 2018-2022 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Lewis Hanly <lewis.hanly@xxxxxxxxxxxxx>
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/gpio/driver.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#define MPFS_GPIO_CTRL(i)		(0x4 * (i))
+#define MAX_NUM_GPIO			32
+#define MPFS_GPIO_EN_INT		3
+#define MPFS_GPIO_EN_OUT_BUF		BIT(2)
+#define MPFS_GPIO_EN_IN			BIT(1)
+#define MPFS_GPIO_EN_OUT		BIT(0)
+
+#define MPFS_GPIO_TYPE_INT_EDGE_BOTH	0x80
+#define MPFS_GPIO_TYPE_INT_EDGE_NEG	0x60
+#define MPFS_GPIO_TYPE_INT_EDGE_POS	0x40
+#define MPFS_GPIO_TYPE_INT_LEVEL_LOW	0x20
+#define MPFS_GPIO_TYPE_INT_LEVEL_HIGH	0x00
+#define MPFS_GPIO_TYPE_INT_MASK		GENMASK(7, 5)
+#define MPFS_IRQ_REG			0x80
+#define MPFS_INP_REG			0x84
+#define MPFS_OUTP_REG			0x88
+
+struct mpfs_gpio_chip {
+	void __iomem *base;
+	struct clk *clk;
+	raw_spinlock_t	lock;
+	struct gpio_chip gc;
+};
+
+static void mpfs_gpio_assign_bit(void __iomem *addr, unsigned int bit_offset, bool value)
+{
+	unsigned long reg = readl(addr);
+
+	__assign_bit(bit_offset, &reg, value);
+	writel(reg, addr);
+}
+
+static int mpfs_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio_index)
+{
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+	u32 gpio_cfg;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&mpfs_gpio->lock, flags);
+
+	gpio_cfg = readl(mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index));
+	gpio_cfg |= MPFS_GPIO_EN_IN;
+	gpio_cfg &= ~(MPFS_GPIO_EN_OUT | MPFS_GPIO_EN_OUT_BUF);
+	writel(gpio_cfg, mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index));
+
+	raw_spin_unlock_irqrestore(&mpfs_gpio->lock, flags);
+
+	return 0;
+}
+
+static int mpfs_gpio_direction_output(struct gpio_chip *gc, unsigned int gpio_index, int value)
+{
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+	u32 gpio_cfg;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&mpfs_gpio->lock, flags);
+
+	gpio_cfg = readl(mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index));
+	gpio_cfg |= MPFS_GPIO_EN_OUT | MPFS_GPIO_EN_OUT_BUF;
+	gpio_cfg &= ~MPFS_GPIO_EN_IN;
+	writel(gpio_cfg, mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index));
+
+	mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_OUTP_REG, gpio_index, value);
+
+	raw_spin_unlock_irqrestore(&mpfs_gpio->lock, flags);
+
+	return 0;
+}
+
+static int mpfs_gpio_get_direction(struct gpio_chip *gc,
+				   unsigned int gpio_index)
+{
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+	u32 gpio_cfg;
+
+	gpio_cfg = readl(mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index));
+	if (gpio_cfg & MPFS_GPIO_EN_IN)
+		return GPIO_LINE_DIRECTION_IN;
+
+	return GPIO_LINE_DIRECTION_OUT;
+}
+
+static int mpfs_gpio_get(struct gpio_chip *gc,
+			 unsigned int gpio_index)
+{
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+
+	return !!(readl(mpfs_gpio->base + MPFS_INP_REG) & BIT(gpio_index));
+}
+
+static void mpfs_gpio_set(struct gpio_chip *gc, unsigned int gpio_index, int value)
+{
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&mpfs_gpio->lock, flags);
+
+	mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_OUTP_REG,
+			     gpio_index, value);
+
+	raw_spin_unlock_irqrestore(&mpfs_gpio->lock, flags);
+}
+
+static int mpfs_gpio_irq_set_type(struct irq_data *data, unsigned int type)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+	int gpio_index = irqd_to_hwirq(data);
+	u32 interrupt_type;
+	u32 gpio_cfg;
+	unsigned long flags;
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_BOTH:
+		interrupt_type = MPFS_GPIO_TYPE_INT_EDGE_BOTH;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		interrupt_type = MPFS_GPIO_TYPE_INT_EDGE_NEG;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		interrupt_type = MPFS_GPIO_TYPE_INT_EDGE_POS;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		interrupt_type = MPFS_GPIO_TYPE_INT_LEVEL_HIGH;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		interrupt_type = MPFS_GPIO_TYPE_INT_LEVEL_LOW;
+		break;
+	}
+
+	raw_spin_lock_irqsave(&mpfs_gpio->lock, flags);
+
+	gpio_cfg = readl(mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index));
+	gpio_cfg &= ~MPFS_GPIO_TYPE_INT_MASK;
+	gpio_cfg |= interrupt_type;
+	writel(gpio_cfg, mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index));
+
+	raw_spin_unlock_irqrestore(&mpfs_gpio->lock, flags);
+
+	return 0;
+}
+
+static void mpfs_gpio_irq_unmask(struct irq_data *data)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+	int gpio_index = irqd_to_hwirq(data);
+
+	gpiochip_enable_irq(gc, gpio_index);
+	mpfs_gpio_direction_input(gc, gpio_index);
+	mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_IRQ_REG, gpio_index, 1);
+	mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index),
+			     MPFS_GPIO_EN_INT, 1);
+}
+
+static void mpfs_gpio_irq_mask(struct irq_data *data)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
+	struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
+	int gpio_index = irqd_to_hwirq(data);
+
+	mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_IRQ_REG, gpio_index, 1);
+	mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index),
+			     MPFS_GPIO_EN_INT, 0);
+	gpiochip_disable_irq(gc, gpio_index);
+}
+
+static const struct irq_chip mpfs_gpio_irqchip = {
+	.name = "mpfs",
+	.irq_set_type = mpfs_gpio_irq_set_type,
+	.irq_mask	= mpfs_gpio_irq_mask,
+	.irq_unmask	= mpfs_gpio_irq_unmask,
+	.flags = IRQCHIP_IMMUTABLE | IRQCHIP_MASK_ON_SUSPEND,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static void mpfs_gpio_irq_handler(struct irq_desc *desc)
+{
+	struct irq_chip *irqchip = irq_desc_get_chip(desc);
+	struct mpfs_gpio_chip *mpfs_gpio =
+		gpiochip_get_data(irq_desc_get_handler_data(desc));
+	unsigned long status;
+	int offset;
+
+	chained_irq_enter(irqchip, desc);
+
+	status = readl(mpfs_gpio->base + MPFS_IRQ_REG);
+	for_each_set_bit(offset, &status, mpfs_gpio->gc.ngpio) {
+		mpfs_gpio_assign_bit(mpfs_gpio->base + MPFS_IRQ_REG, offset, 1);
+		generic_handle_irq(irq_find_mapping(mpfs_gpio->gc.irq.domain, offset));
+	}
+
+	chained_irq_exit(irqchip, desc);
+}
+
+static int mpfs_gpio_probe(struct platform_device *pdev)
+{
+	struct clk *clk;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = pdev->dev.of_node;
+	struct mpfs_gpio_chip *mpfs_gpio;
+	struct gpio_irq_chip *girq;
+	int i, ret, ngpios, nirqs;
+
+	mpfs_gpio = devm_kzalloc(dev, sizeof(*mpfs_gpio), GFP_KERNEL);
+	if (!mpfs_gpio)
+		return -ENOMEM;
+
+	mpfs_gpio->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(mpfs_gpio->base))
+		return dev_err_probe(dev, PTR_ERR(mpfs_gpio->base), "failed to ioremap memory resource\n");
+
+	clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(clk))
+		return dev_err_probe(dev, PTR_ERR(clk), "devm_clk_get failed\n");
+
+	ret = clk_prepare_enable(clk);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to enable clock\n");
+
+	mpfs_gpio->clk = clk;
+
+	ngpios = MAX_NUM_GPIO;
+	device_property_read_u32(dev, "ngpios", &ngpios);
+	if (ngpios > MAX_NUM_GPIO)
+		ngpios = MAX_NUM_GPIO;
+
+	raw_spin_lock_init(&mpfs_gpio->lock);
+	mpfs_gpio->gc.direction_input = mpfs_gpio_direction_input;
+	mpfs_gpio->gc.direction_output = mpfs_gpio_direction_output;
+	mpfs_gpio->gc.get_direction = mpfs_gpio_get_direction;
+	mpfs_gpio->gc.get = mpfs_gpio_get;
+	mpfs_gpio->gc.set = mpfs_gpio_set;
+	mpfs_gpio->gc.base = -1;
+	mpfs_gpio->gc.ngpio = ngpios;
+	mpfs_gpio->gc.label = dev_name(dev);
+	mpfs_gpio->gc.parent = dev;
+	mpfs_gpio->gc.owner = THIS_MODULE;
+
+	nirqs = of_irq_count(node);
+	if (nirqs > MAX_NUM_GPIO) {
+		ret = -ENXIO;
+		goto cleanup_clock;
+	}
+	girq = &mpfs_gpio->gc.irq;
+	gpio_irq_chip_set_chip(girq, &mpfs_gpio_irqchip);
+	girq->handler = handle_simple_irq;
+	girq->parent_handler = mpfs_gpio_irq_handler;
+	girq->default_type = IRQ_TYPE_NONE;
+	girq->num_parents = nirqs;
+	girq->parents = devm_kcalloc(&pdev->dev, nirqs,
+				     sizeof(*girq->parents), GFP_KERNEL);
+	if (!girq->parents) {
+		ret = -ENOMEM;
+		goto cleanup_clock;
+	}
+	for (i = 0; i < nirqs; i++)
+		girq->parents[i] = platform_get_irq(pdev, i);
+
+	ret = gpiochip_add_data(&mpfs_gpio->gc, mpfs_gpio);
+	if (ret)
+		goto cleanup_clock;
+
+	platform_set_drvdata(pdev, mpfs_gpio);
+
+	return 0;
+
+cleanup_clock:
+	clk_disable_unprepare(mpfs_gpio->clk);
+	return ret;
+}
+
+static int mpfs_gpio_remove(struct platform_device *pdev)
+{
+	struct mpfs_gpio_chip *mpfs_gpio = platform_get_drvdata(pdev);
+
+	gpiochip_remove(&mpfs_gpio->gc);
+	clk_disable_unprepare(mpfs_gpio->clk);
+
+	return 0;
+}
+
+static const struct of_device_id mpfs_gpio_of_ids[] = {
+	{ .compatible = "microchip,mpfs-gpio", },
+	{ /* end of list */ }
+};
+
+static struct platform_driver mpfs_gpio_driver = {
+	.probe = mpfs_gpio_probe,
+	.driver = {
+		.name = "microchip,mpfs-gpio",
+		.of_match_table = mpfs_gpio_of_ids,
+	},
+	.remove = mpfs_gpio_remove,
+};
+builtin_platform_driver(mpfs_gpio_driver);
-- 
2.43.2