drm/imx: Add i.MX8qxp Display Controller interrupt controller

i.MX8qxp Display Controller has a built-in interrupt controller to support
Enable/Status/Preset/Clear interrupt bit.  Add driver for it.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Link: https://lore.kernel.org/r/20250414035028.1561475-12-victor.liu@nxp.com

drivers/gpu/drm/imx/dc/Kconfig

@@ -1,6 +1,7 @@
 config DRM_IMX8_DC
 	tristate "Freescale i.MX8 Display Controller Graphics"
 	depends on DRM && COMMON_CLK && OF && (ARCH_MXC || COMPILE_TEST)
+	select GENERIC_IRQ_CHIP
 	select REGMAP
 	select REGMAP_MMIO
 	help

drivers/gpu/drm/imx/dc/Makefile

@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
 imx8-dc-drm-objs := dc-cf.o dc-de.o dc-drv.o dc-ed.o dc-fg.o dc-fl.o dc-fu.o \
-		    dc-fw.o dc-lb.o dc-pe.o dc-tc.o
+		    dc-fw.o dc-ic.o dc-lb.o dc-pe.o dc-tc.o
 
 obj-$(CONFIG_DRM_IMX8_DC) += imx8-dc-drm.o

drivers/gpu/drm/imx/dc/dc-drv.c

@@ -15,6 +15,7 @@ static struct platform_driver * const dc_drivers[] = {
 	&dc_fg_driver,
 	&dc_fl_driver,
 	&dc_fw_driver,
+	&dc_ic_driver,
 	&dc_lb_driver,
 	&dc_pe_driver,
 	&dc_tc_driver,

drivers/gpu/drm/imx/dc/dc-drv.h

@@ -54,6 +54,7 @@ extern struct platform_driver dc_ed_driver;
 extern struct platform_driver dc_fg_driver;
 extern struct platform_driver dc_fl_driver;
 extern struct platform_driver dc_fw_driver;
+extern struct platform_driver dc_ic_driver;
 extern struct platform_driver dc_lb_driver;
 extern struct platform_driver dc_pe_driver;
 extern struct platform_driver dc_tc_driver;

drivers/gpu/drm/imx/dc/dc-ic.c

@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2024 NXP
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+
+#define USERINTERRUPTMASK(n)	(0x8 + 4 * (n))
+#define INTERRUPTENABLE(n)	(0x10 + 4 * (n))
+#define INTERRUPTPRESET(n)	(0x18 + 4 * (n))
+#define INTERRUPTCLEAR(n)	(0x20 + 4 * (n))
+#define INTERRUPTSTATUS(n)	(0x28 + 4 * (n))
+#define USERINTERRUPTENABLE(n)	(0x40 + 4 * (n))
+#define USERINTERRUPTPRESET(n)	(0x48 + 4 * (n))
+#define USERINTERRUPTCLEAR(n)	(0x50 + 4 * (n))
+#define USERINTERRUPTSTATUS(n)	(0x58 + 4 * (n))
+
+#define IRQ_COUNT	49
+#define IRQ_RESERVED	35
+#define REG_NUM		2
+
+struct dc_ic_data {
+	struct regmap		*regs;
+	struct clk		*clk_axi;
+	int			irq[IRQ_COUNT];
+	struct irq_domain	*domain;
+};
+
+struct dc_ic_entry {
+	struct dc_ic_data *data;
+	int irq;
+};
+
+static const struct regmap_range dc_ic_regmap_write_ranges[] = {
+	regmap_reg_range(USERINTERRUPTMASK(0), INTERRUPTCLEAR(1)),
+	regmap_reg_range(USERINTERRUPTENABLE(0), USERINTERRUPTCLEAR(1)),
+};
+
+static const struct regmap_access_table dc_ic_regmap_write_table = {
+	.yes_ranges = dc_ic_regmap_write_ranges,
+	.n_yes_ranges = ARRAY_SIZE(dc_ic_regmap_write_ranges),
+};
+
+static const struct regmap_range dc_ic_regmap_read_ranges[] = {
+	regmap_reg_range(USERINTERRUPTMASK(0), INTERRUPTENABLE(1)),
+	regmap_reg_range(INTERRUPTSTATUS(0), INTERRUPTSTATUS(1)),
+	regmap_reg_range(USERINTERRUPTENABLE(0), USERINTERRUPTENABLE(1)),
+	regmap_reg_range(USERINTERRUPTSTATUS(0), USERINTERRUPTSTATUS(1)),
+};
+
+static const struct regmap_access_table dc_ic_regmap_read_table = {
+	.yes_ranges = dc_ic_regmap_read_ranges,
+	.n_yes_ranges = ARRAY_SIZE(dc_ic_regmap_read_ranges),
+};
+
+static const struct regmap_range dc_ic_regmap_volatile_ranges[] = {
+	regmap_reg_range(INTERRUPTPRESET(0), INTERRUPTCLEAR(1)),
+	regmap_reg_range(USERINTERRUPTPRESET(0), USERINTERRUPTCLEAR(1)),
+};
+
+static const struct regmap_access_table dc_ic_regmap_volatile_table = {
+	.yes_ranges = dc_ic_regmap_volatile_ranges,
+	.n_yes_ranges = ARRAY_SIZE(dc_ic_regmap_volatile_ranges),
+};
+
+static const struct regmap_config dc_ic_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.fast_io = true,
+	.wr_table = &dc_ic_regmap_write_table,
+	.rd_table = &dc_ic_regmap_read_table,
+	.volatile_table = &dc_ic_regmap_volatile_table,
+	.max_register = USERINTERRUPTSTATUS(1),
+};
+
+static void dc_ic_irq_handler(struct irq_desc *desc)
+{
+	struct dc_ic_entry *entry = irq_desc_get_handler_data(desc);
+	struct dc_ic_data *data = entry->data;
+	unsigned int status, enable;
+	unsigned int virq;
+
+	chained_irq_enter(irq_desc_get_chip(desc), desc);
+
+	regmap_read(data->regs, USERINTERRUPTSTATUS(entry->irq / 32), &status);
+	regmap_read(data->regs, USERINTERRUPTENABLE(entry->irq / 32), &enable);
+
+	status &= enable;
+
+	if (status & BIT(entry->irq % 32)) {
+		virq = irq_find_mapping(data->domain, entry->irq);
+		if (virq)
+			generic_handle_irq(virq);
+	}
+
+	chained_irq_exit(irq_desc_get_chip(desc), desc);
+}
+
+static const unsigned long unused_irq[REG_NUM] = {0x00000000, 0xfffe0008};
+
+static int dc_ic_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct irq_chip_generic *gc;
+	struct dc_ic_entry *entry;
+	struct irq_chip_type *ct;
+	struct dc_ic_data *data;
+	void __iomem *base;
+	int i, ret;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	entry = devm_kcalloc(dev, IRQ_COUNT, sizeof(*entry), GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base)) {
+		dev_err(dev, "failed to initialize reg\n");
+		return PTR_ERR(base);
+	}
+
+	data->regs = devm_regmap_init_mmio(dev, base, &dc_ic_regmap_config);
+	if (IS_ERR(data->regs))
+		return PTR_ERR(data->regs);
+
+	data->clk_axi = devm_clk_get(dev, NULL);
+	if (IS_ERR(data->clk_axi))
+		return dev_err_probe(dev, PTR_ERR(data->clk_axi),
+				     "failed to get AXI clock\n");
+
+	for (i = 0; i < IRQ_COUNT; i++) {
+		/* skip the reserved IRQ */
+		if (i == IRQ_RESERVED)
+			continue;
+
+		ret = platform_get_irq(pdev, i);
+		if (ret < 0)
+			return ret;
+	}
+
+	dev_set_drvdata(dev, data);
+
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return ret;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0) {
+		dev_err(dev, "failed to get runtime PM sync: %d\n", ret);
+		return ret;
+	}
+
+	for (i = 0; i < REG_NUM; i++) {
+		/* mask and clear all interrupts */
+		regmap_write(data->regs, USERINTERRUPTENABLE(i), 0x0);
+		regmap_write(data->regs, INTERRUPTENABLE(i), 0x0);
+		regmap_write(data->regs, USERINTERRUPTCLEAR(i), 0xffffffff);
+		regmap_write(data->regs, INTERRUPTCLEAR(i), 0xffffffff);
+
+		/* set all interrupts to user mode */
+		regmap_write(data->regs, USERINTERRUPTMASK(i), 0xffffffff);
+	}
+
+	data->domain = irq_domain_add_linear(dev->of_node, IRQ_COUNT,
+					     &irq_generic_chip_ops, data);
+	if (!data->domain) {
+		dev_err(dev, "failed to create IRQ domain\n");
+		pm_runtime_put(dev);
+		return -ENOMEM;
+	}
+	irq_domain_set_pm_device(data->domain, dev);
+
+	ret = irq_alloc_domain_generic_chips(data->domain, 32, 1, "DC",
+					     handle_level_irq, 0, 0, 0);
+	if (ret) {
+		dev_err(dev, "failed to alloc generic IRQ chips: %d\n", ret);
+		irq_domain_remove(data->domain);
+		pm_runtime_put(dev);
+		return ret;
+	}
+
+	for (i = 0; i < IRQ_COUNT; i += 32) {
+		gc = irq_get_domain_generic_chip(data->domain, i);
+		gc->reg_base = base;
+		gc->unused = unused_irq[i / 32];
+		ct = gc->chip_types;
+		ct->chip.irq_ack = irq_gc_ack_set_bit;
+		ct->chip.irq_mask = irq_gc_mask_clr_bit;
+		ct->chip.irq_unmask = irq_gc_mask_set_bit;
+		ct->regs.ack = USERINTERRUPTCLEAR(i / 32);
+		ct->regs.mask = USERINTERRUPTENABLE(i / 32);
+	}
+
+	for (i = 0; i < IRQ_COUNT; i++) {
+		/* skip the reserved IRQ */
+		if (i == IRQ_RESERVED)
+			continue;
+
+		data->irq[i] = irq_of_parse_and_map(dev->of_node, i);
+
+		entry[i].data = data;
+		entry[i].irq = i;
+
+		irq_set_chained_handler_and_data(data->irq[i],
+						 dc_ic_irq_handler, &entry[i]);
+	}
+
+	return 0;
+}
+
+static void dc_ic_remove(struct platform_device *pdev)
+{
+	struct dc_ic_data *data = dev_get_drvdata(&pdev->dev);
+	int i;
+
+	for (i = 0; i < IRQ_COUNT; i++) {
+		if (i == IRQ_RESERVED)
+			continue;
+
+		irq_set_chained_handler_and_data(data->irq[i], NULL, NULL);
+	}
+
+	irq_domain_remove(data->domain);
+
+	pm_runtime_put_sync(&pdev->dev);
+}
+
+static int dc_ic_runtime_suspend(struct device *dev)
+{
+	struct dc_ic_data *data = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(data->clk_axi);
+
+	return 0;
+}
+
+static int dc_ic_runtime_resume(struct device *dev)
+{
+	struct dc_ic_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(data->clk_axi);
+	if (ret)
+		dev_err(dev, "failed to enable AXI clock: %d\n", ret);
+
+	return ret;
+}
+
+static const struct dev_pm_ops dc_ic_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				      pm_runtime_force_resume)
+	RUNTIME_PM_OPS(dc_ic_runtime_suspend, dc_ic_runtime_resume, NULL)
+};
+
+static const struct of_device_id dc_ic_dt_ids[] = {
+	{ .compatible = "fsl,imx8qxp-dc-intc", },
+	{ /* sentinel */ }
+};
+
+struct platform_driver dc_ic_driver = {
+	.probe = dc_ic_probe,
+	.remove = dc_ic_remove,
+	.driver = {
+		.name = "imx8-dc-intc",
+		.suppress_bind_attrs = true,
+		.of_match_table	= dc_ic_dt_ids,
+		.pm = pm_sleep_ptr(&dc_ic_pm_ops),
+	},
+};