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From:   Claudiu Beznea <claudiu.beznea@microchip.com>
To:     <tglx@linutronix.de>, <maz@kernel.org>, <robh+dt@kernel.org>
CC:     <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <nicolas.ferre@microchip.com>,
        Claudiu Beznea <claudiu.beznea@microchip.com>
Subject: [PATCH 2/2] irqchip/mchp-eic: add support
Date:   Tue, 2 Mar 2021 12:28:46 +0200
Message-ID: <20210302102846.619980-3-claudiu.beznea@microchip.com>
In-Reply-To: <20210302102846.619980-1-claudiu.beznea@microchip.com>
References: <20210302102846.619980-1-claudiu.beznea@microchip.com>
MIME-Version: 1.0
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Add support for Microchip External Interrupt Controller.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 MAINTAINERS                    |   6 +
 drivers/irqchip/Kconfig        |   7 +
 drivers/irqchip/Makefile       |   1 +
 drivers/irqchip/irq-mchp-eic.c | 350 +++++++++++++++++++++++++++++++++
 4 files changed, 364 insertions(+)
 create mode 100644 drivers/irqchip/irq-mchp-eic.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a008b70f3c16..ea99e5a7f519 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11585,6 +11585,12 @@ L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Supported
 F:	drivers/usb/gadget/udc/atmel_usba_udc.*
 
+MICROCHIP EIC DRIVER
+M:	Claudiu Beznea <claudiu.beznea@microchip.com>
+L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
+S:	Supported
+F:	drivers/irqchip/irq-mchp-eic.c
+
 MICROCHIP WILC1000 WIFI DRIVER
 M:	Ajay Singh <ajay.kathat@microchip.com>
 M:	Claudiu Beznea <claudiu.beznea@microchip.com>
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 2aa79c32ee22..7c7ca33c3f7d 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -596,4 +596,11 @@ config MST_IRQ
 	help
 	  Support MStar Interrupt Controller.
 
+config MCHP_EIC
+	bool "Microchip External Interrupt Controller"
+	depends on ARCH_AT91 || COMPILE_TEST
+	select IRQ_DOMAIN
+	help
+	  Support for Microchip External Interrupt Controller.
+
 endmenu
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 94c2885882ee..f3df6eb7c4c3 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -114,3 +114,4 @@ obj-$(CONFIG_LOONGSON_PCH_PIC)		+= irq-loongson-pch-pic.o
 obj-$(CONFIG_LOONGSON_PCH_MSI)		+= irq-loongson-pch-msi.o
 obj-$(CONFIG_MST_IRQ)			+= irq-mst-intc.o
 obj-$(CONFIG_SL28CPLD_INTC)		+= irq-sl28cpld.o
+obj-$(CONFIG_MCHP_EIC)			+= irq-mchp-eic.o
diff --git a/drivers/irqchip/irq-mchp-eic.c b/drivers/irqchip/irq-mchp-eic.c
new file mode 100644
index 000000000000..ec01877fc75f
--- /dev/null
+++ b/drivers/irqchip/irq-mchp-eic.c
@@ -0,0 +1,350 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Microchip External Interrupt Controller driver
+ *
+ * Copyright (C) 2021 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Claudiu Beznea <claudiu.beznea@microchip.com>
+ */
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/irqchip/chained_irq.h>
+
+#define MCHP_EIC_GFCS			(0x0)
+#define MCHP_EIC_SCFG(x)		(0x4 + (x) * 0x4)
+#define MCHP_EIC_SCFG_FRZ		BIT(31)
+#define MCHP_EIC_SCFG_EN		BIT(16)
+#define MCHP_EIC_SCFG_LVL		BIT(9)
+#define MCHP_EIC_SCFG_POL		BIT(8)
+#define MCHP_EIC_SCFG_GFEN		BIT(4)
+#define MCHP_EIC_SCFG_GFSEL		GENMASK(1, 0)
+
+#define MCHP_EIC_NIRQ			(2)
+#define MCHP_EIC_DEFAULT_WAIT_US	(100)
+
+/**
+ * struct mchp_eic - EIC private data structure
+ * @base: base address
+ * @dev: eic device
+ * @clk: peripheral clock
+ * @chip: irq chip
+ * @domain: irq domain
+ * @irqs: irqs b/w eic and gic
+ * @scfg: backup for scfg registers (necessary for backup and self-refresh mode)
+ * @wakeup_source: wakeup source mask
+ */
+struct mchp_eic {
+	void __iomem *base;
+	struct device *dev;
+	struct clk *clk;
+	struct irq_chip *chip;
+	struct irq_domain *domain;
+	u32 irqs[MCHP_EIC_NIRQ];
+	u32 scfg[MCHP_EIC_NIRQ];
+	u32 wakeup_source;
+};
+
+static void mchp_eic_wait_rdy(struct mchp_eic *eic, unsigned int hwirq,
+			      int delay_us)
+{
+	unsigned int tmp = readl(eic->base + MCHP_EIC_SCFG(hwirq));
+
+	while (delay_us >= 0 && tmp & BIT(hwirq)) {
+		udelay(1);
+		delay_us -= 1;
+		tmp = readl(eic->base + MCHP_EIC_SCFG(hwirq));
+	}
+
+	if (delay_us < 0)
+		dev_err(eic->dev, "Failed to configure IRQ=%u!\n", hwirq);
+}
+
+static void mchp_eic_irq_mask(struct irq_data *d)
+{
+	struct mchp_eic *eic = irq_data_get_irq_chip_data(d);
+	unsigned int tmp;
+
+	tmp = readl(eic->base + MCHP_EIC_SCFG(d->hwirq));
+	tmp &= ~MCHP_EIC_SCFG_EN;
+	writel(tmp, eic->base + MCHP_EIC_SCFG(d->hwirq));
+}
+
+static void mchp_eic_irq_unmask(struct irq_data *d)
+{
+	struct mchp_eic *eic = irq_data_get_irq_chip_data(d);
+	unsigned int tmp;
+
+	tmp = readl(eic->base + MCHP_EIC_SCFG(d->hwirq));
+	tmp |= MCHP_EIC_SCFG_EN;
+	writel(tmp, eic->base + MCHP_EIC_SCFG(d->hwirq));
+	mchp_eic_wait_rdy(eic, d->hwirq, MCHP_EIC_DEFAULT_WAIT_US);
+}
+
+static int mchp_eic_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct mchp_eic *eic = irq_data_get_irq_chip_data(d);
+	unsigned int tmp;
+
+	tmp = readl(eic->base + MCHP_EIC_SCFG(d->hwirq));
+	tmp &= ~(MCHP_EIC_SCFG_POL | MCHP_EIC_SCFG_LVL);
+	switch (type) {
+	case IRQ_TYPE_LEVEL_HIGH:
+		irq_set_handler_locked(d, handle_level_irq);
+		tmp |= MCHP_EIC_SCFG_POL | MCHP_EIC_SCFG_LVL;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		irq_set_handler_locked(d, handle_level_irq);
+		tmp |= MCHP_EIC_SCFG_LVL;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		irq_set_handler_locked(d, handle_edge_irq);
+		tmp |= MCHP_EIC_SCFG_POL;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		irq_set_handler_locked(d, handle_edge_irq);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	writel(tmp, eic->base + MCHP_EIC_SCFG(d->hwirq));
+
+	return 0;
+}
+
+static void mchp_eic_irq_ack(struct irq_data *d)
+{
+	/* Nothing to do here. */
+}
+
+static int mchp_eic_irq_set_wake(struct irq_data *d, unsigned int on)
+{
+	struct mchp_eic *eic = irq_data_get_irq_chip_data(d);
+
+	irq_set_irq_wake(eic->irqs[d->hwirq], on);
+	if (on)
+		eic->wakeup_source |= BIT(d->hwirq);
+	else
+		eic->wakeup_source &= BIT(d->hwirq);
+
+	return 0;
+}
+
+static struct irq_chip mchp_eic_chip = {
+	.name		= "eic-irq",
+	.flags		= IRQCHIP_MASK_ON_SUSPEND,
+	.irq_mask	= mchp_eic_irq_mask,
+	.irq_unmask	= mchp_eic_irq_unmask,
+	.irq_set_type	= mchp_eic_irq_set_type,
+	.irq_ack	= mchp_eic_irq_ack,
+	.irq_set_wake	= mchp_eic_irq_set_wake,
+};
+
+static int mchp_eic_domain_map(struct irq_domain *d, unsigned int virq,
+			       irq_hw_number_t hw)
+{
+	struct mchp_eic *eic = d->host_data;
+
+	irq_set_chip_data(virq, eic);
+	irq_set_chip_and_handler(virq, eic->chip, handle_bad_irq);
+	irq_set_probe(virq);
+
+	return 0;
+}
+
+static int mchp_eic_domain_xlate(struct irq_domain *d, struct device_node *node,
+				 const u32 *intspec, unsigned int intsize,
+				 irq_hw_number_t *out_hwirq,
+				 unsigned int *out_type)
+{
+	struct mchp_eic *eic = d->host_data;
+	unsigned int tmp, i;
+
+	if (WARN_ON(intsize < 2))
+		return -EINVAL;
+
+	if (WARN_ON(intspec[0] > MCHP_EIC_NIRQ))
+		return -EINVAL;
+
+	*out_hwirq = intspec[0];
+	*out_type = intspec[1] & IRQ_TYPE_SENSE_MASK;
+
+	if (intsize == 3) {
+		/* Validate against available filters. */
+		for (i = 0; i <= MCHP_EIC_SCFG_GFSEL; i++) {
+			if (intspec[2] == (2 << i))
+				break;
+		}
+		if (i == MCHP_EIC_SCFG_GFSEL + 1)
+			return -EINVAL;
+
+		/* Enable glitch filter. */
+		tmp = readl(eic->base + MCHP_EIC_SCFG(*out_hwirq));
+		tmp |= MCHP_EIC_SCFG_GFEN;
+		tmp &= ~MCHP_EIC_SCFG_GFSEL;
+		tmp |= i;
+		writel(tmp, eic->base + MCHP_EIC_SCFG(*out_hwirq));
+
+		/* Wait for glitch filter to be enabled. */
+		mchp_eic_wait_rdy(eic, *out_hwirq, MCHP_EIC_DEFAULT_WAIT_US);
+	}
+
+	return 0;
+}
+
+static const struct irq_domain_ops mchp_eic_domain_ops = {
+	.map		= mchp_eic_domain_map,
+	.xlate		= mchp_eic_domain_xlate,
+};
+
+static void mchp_eic_irq_handler(struct irq_desc *desc)
+{
+	struct mchp_eic *eic = irq_desc_get_handler_data(desc);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	unsigned int hwirq, irq = irq_desc_get_irq(desc);
+
+	for (hwirq = 0; hwirq < MCHP_EIC_NIRQ; hwirq++) {
+		if (eic->irqs[hwirq] == irq)
+			break;
+	}
+	if (hwirq == MCHP_EIC_NIRQ)
+		return;
+
+	chained_irq_enter(chip, desc);
+	generic_handle_irq(irq_find_mapping(eic->domain, hwirq));
+	chained_irq_exit(chip, desc);
+}
+
+static int mchp_eic_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct mchp_eic *eic;
+	int ret, i;
+
+	eic = devm_kzalloc(&pdev->dev, sizeof(*eic), GFP_KERNEL);
+	if (!eic)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	eic->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(eic->base))
+		return PTR_ERR(eic->base);
+
+	eic->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(eic->clk))
+		return PTR_ERR(eic->clk);
+
+	ret = clk_prepare_enable(eic->clk);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < MCHP_EIC_NIRQ; i++) {
+		/* Disable it, if any. */
+		writel(0UL, eic->base + MCHP_EIC_SCFG(i));
+
+		res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
+		if (!res) {
+			ret = dev_err_probe(&pdev->dev, -EINVAL,
+					    "Failed to get hwirq=%d\n", i);
+			goto clk_unprepare;
+		}
+
+		eic->irqs[i] = res->start;
+		irq_set_chained_handler(res->start, mchp_eic_irq_handler);
+		irq_set_handler_data(res->start, eic);
+	}
+
+	eic->dev = &pdev->dev;
+	eic->chip = &mchp_eic_chip;
+
+	eic->domain = irq_domain_add_linear(pdev->dev.of_node, MCHP_EIC_NIRQ,
+					    &mchp_eic_domain_ops, eic);
+	if (!eic->domain) {
+		ret = dev_err_probe(&pdev->dev, -ENODEV,
+				    "Failed to regiter irq domain!\n");
+		goto clk_unprepare;
+	}
+	eic->domain->name = "eic";
+
+	platform_set_drvdata(pdev, eic);
+
+	dev_info(&pdev->dev, "EIC registered, nr_irqs %u\n", MCHP_EIC_NIRQ);
+
+	return 0;
+
+clk_unprepare:
+	clk_disable_unprepare(eic->clk);
+	return ret;
+}
+
+static int mchp_eic_remove(struct platform_device *pdev)
+{
+	struct mchp_eic *eic = platform_get_drvdata(pdev);
+
+	irq_domain_remove(eic->domain);
+	clk_disable_unprepare(eic->clk);
+
+	return 0;
+}
+
+static int __maybe_unused mchp_eic_suspend(struct device *dev)
+{
+	struct mchp_eic *eic = dev_get_drvdata(dev);
+	unsigned int hwirq;
+
+	for (hwirq = 0; hwirq < MCHP_EIC_NIRQ; hwirq++)
+		eic->scfg[hwirq] = readl(eic->base + MCHP_EIC_SCFG(hwirq));
+
+	if (!eic->wakeup_source)
+		clk_disable_unprepare(eic->clk);
+
+	return 0;
+}
+
+static int __maybe_unused mchp_eic_resume(struct device *dev)
+{
+	struct mchp_eic *eic = dev_get_drvdata(dev);
+	unsigned int hwirq;
+
+	if (!eic->wakeup_source)
+		clk_prepare_enable(eic->clk);
+
+	for (hwirq = 0; hwirq < MCHP_EIC_NIRQ; hwirq++) {
+		writel(eic->scfg[hwirq], eic->base + MCHP_EIC_SCFG(hwirq));
+		mchp_eic_wait_rdy(eic, hwirq, MCHP_EIC_DEFAULT_WAIT_US);
+	}
+
+	return 0;
+}
+
+static const struct dev_pm_ops mchp_eic_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(mchp_eic_suspend, mchp_eic_resume)
+};
+
+static const struct of_device_id mchp_eic_dt_ids[] = {
+	{ .compatible = "microchip,sama7g5-eic", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, mchp_eic_dt_ids);
+
+static struct platform_driver mchp_eic_device_driver = {
+	.probe		= mchp_eic_probe,
+	.remove		= mchp_eic_remove,
+	.driver		= {
+		.name = "mchp-eic",
+		.of_match_table = of_match_ptr(mchp_eic_dt_ids),
+		.pm = pm_ptr(&mchp_eic_pm_ops),
+	},
+};
+module_platform_driver(mchp_eic_device_driver);
+
+MODULE_DESCRIPTION("Microchip External Interrupt Controller");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Claudiu Beznea <claudiu.beznea@microchip.com>");
-- 
2.25.1