[PATCH v4 0/1] Add Polarfire SoC GPIO support

[PATCH v4 0/1] Add Polarfire SoC GPIO support

[lewis.hanly]

From: Lewis Hanly <lewis.hanly@microchip.com>

Add a driver to support the Polarfire SoC gpio controller.
Tested with latest 5.19 kernel.

MPFS gpio interrupts are connected to IOMUX configured by system 
register GPIO_INTERRUPT_FAB_CR(31:0). Interrupt connection for
some GPIO's to the PLIC (Platform Level Interrupt Controller) can be 
shared (not directly connected) or direct if connection is available. 

Changes in v4
Changed the interrupt handling from Hierarchical flow to chained interrupt
flow. The reason for the change was with hierarchical flow we requried
a interrupt number mapping array to work with our HW and this was not acceptable.
On reviewing the architecture the chained interrupt flow works better
for our hardware and configurations which are not fixed in Silicon.
Added support to read the optional DT property ngpios.

Changes in v3:
Changed order in kconfig.
Removed blank lines in driver header/source file.
Removed BYTE_BOUNDARY variable and use macro to do *4.
mpfs_gpio_assign_bit parameter uses macro instead of (i * BYTE_BOUNDARY).
Add correct definitions for direction.
Change order of variables in mpfs_gpio_irq_set_type function.
Return dev_err_probe instead of dev_err.
Remove noise of dev_inf.
Avoid using of_match_ptr.
use devm_gpiochip_add_data(..)
Update mpfs_gpio_remove. 

Changes in v2:
Use raw_spinlock.
Use __assign_bit() to assign bit, added a bool variable for value.
Remove unnecessary checking gpio_index.
Remove default from switch statement.
Use const for irq_chip, name updated and use mask/unmask.
Use latest kernel api irq set_chip.
Implemented hierarchical interrupt chip support, although
suggested to use chained interrupt flow I believe this fits better.

Lewis Hanly (1):
  gpio: mpfs: add polarfire soc gpio support

 drivers/gpio/Kconfig     |   7 +
 drivers/gpio/Makefile    |   1 +
 drivers/gpio/gpio-mpfs.c | 318 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 326 insertions(+)
 create mode 100644 drivers/gpio/gpio-mpfs.c

-- 
2.25.1

[PATCH v4 1/1] gpio: mpfs: add polarfire soc gpio support

[lewis.hanly]

From: Lewis Hanly <lewis.hanly@microchip.com>

Add a driver to support the Polarfire SoC gpio controller

Signed-off-by: Lewis Hanly <lewis.hanly@microchip.com>
---
 drivers/gpio/Kconfig     |   7 +
 drivers/gpio/Makefile    |   1 +
 drivers/gpio/gpio-mpfs.c | 318 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 326 insertions(+)
 create mode 100644 drivers/gpio/gpio-mpfs.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b01961999ced..72dc23c65ac1 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -490,6 +490,13 @@ config GPIO_PMIC_EIC_SPRD
 	help
 	  Say yes here to support Spreadtrum PMIC EIC 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 14352f6dfe8e..3b8b6703e593 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -119,6 +119,7 @@ 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 000000000000..5f35a5de9e79
--- /dev/null
+++ b/drivers/gpio/gpio-mpfs.c
@@ -0,0 +1,318 @@
+// 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@microchip.com>
+ */
+
+#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) % MAX_NUM_GPIO;
+
+	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) % MAX_NUM_GPIO;
+
+	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);
+}
+
+static struct irq_chip mpfs_gpio_irqchip = {
+	.name = "mpfs_gpio_irqchip",
+	.irq_set_type = mpfs_gpio_irq_set_type,
+	.irq_mask	= mpfs_gpio_irq_mask,
+	.irq_unmask	= mpfs_gpio_irq_unmask,
+	.flags = IRQCHIP_MASK_ON_SUSPEND,
+};
+
+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));
+	unisgned 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->clk), "input clock not found.\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->chip->parent_device = dev;
+	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_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_of_ids,
+	},
+	.remove = mpfs_gpio_remove,
+};
+builtin_platform_driver(mpfs_gpio_driver);
-- 
2.25.1