ARM: pxa: pxa_cplds: add lubbock and mainstone IO

Historically, this support was in arch/arm/mach-pxa/lubbock.c and
arch/arm/mach-pxa/mainstone.c. When gpio-pxa was moved to drivers/pxa,
it became a driver, and its initialization and probing happened at
postcore initcall. The lubbock code used to install the chained lubbock
interrupt handler at init_irq() time.

The consequence of the gpio-pxa change is that the installed chained irq
handler lubbock_irq_handler() was overwritten in pxa_gpio_probe(_dt)(),
removing :
 - the handler
 - the falling edge detection setting of GPIO0, which revealed the
   interrupt request from the lubbock IO board.

As a fix, move the gpio0 chained handler setup to a place where we have
the guarantee that pxa_gpio_probe() was called before, so that lubbock
handler becomes the true IRQ chained handler of GPIO0, demuxing the
lubbock IO board interrupts.

This patch moves all that handling to a mfd driver. It's only purpose
for the time being is the interrupt handling, but in the future it
should encompass all the motherboard CPLDs handling :
 - leds
 - switches
 - hexleds

The same logic applies to mainstone board.

Fixes: 157d2644cb0c ("ARM: pxa: change gpio to platform device")
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-pxa/Kconfig

@@ -691,4 +691,13 @@ config SHARPSL_PM_MAX1111
 config PXA310_ULPI
 	bool
 
+config PXA_SYSTEMS_CPLDS
+	tristate "Motherboard cplds"
+	default ARCH_LUBBOCK || MACH_MAINSTONE
+	help
+	  This driver supports the Lubbock and Mainstone multifunction chip
+	  found on the pxa25x development platform system (Lubbock) and pxa27x
+	  development platform system (Mainstone). This IO board supports the
+	  interrupts handling, ethernet controller, flash chips, etc ...
+
 endif

arch/arm/mach-pxa/Makefile

@@ -90,4 +90,5 @@ obj-$(CONFIG_MACH_RAUMFELD_CONNECTOR)	+= raumfeld.o
 obj-$(CONFIG_MACH_RAUMFELD_SPEAKER)	+= raumfeld.o
 obj-$(CONFIG_MACH_ZIPIT2)	+= z2.o
 
+obj-$(CONFIG_PXA_SYSTEMS_CPLDS)	+= pxa_cplds_irqs.o
 obj-$(CONFIG_TOSA_BT)		+= tosa-bt.o

arch/arm/mach-pxa/pxa_cplds_irqs.c

@@ -0,0 +1,200 @@
+/*
+ * Intel Reference Systems cplds
+ *
+ * Copyright (C) 2014 Robert Jarzmik
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Cplds motherboard driver, supporting lubbock and mainstone SoC board.
+ */
+
+#include <linux/bitops.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+
+#define FPGA_IRQ_MASK_EN 0x0
+#define FPGA_IRQ_SET_CLR 0x10
+
+#define CPLDS_NB_IRQ	32
+
+struct cplds {
+	void __iomem *base;
+	int irq;
+	unsigned int irq_mask;
+	struct gpio_desc *gpio0;
+	struct irq_domain *irqdomain;
+};
+
+static irqreturn_t cplds_irq_handler(int in_irq, void *d)
+{
+	struct cplds *fpga = d;
+	unsigned long pending;
+	unsigned int bit;
+
+	pending = readl(fpga->base + FPGA_IRQ_SET_CLR) & fpga->irq_mask;
+	for_each_set_bit(bit, &pending, CPLDS_NB_IRQ)
+		generic_handle_irq(irq_find_mapping(fpga->irqdomain, bit));
+
+	return IRQ_HANDLED;
+}
+
+static void cplds_irq_mask_ack(struct irq_data *d)
+{
+	struct cplds *fpga = irq_data_get_irq_chip_data(d);
+	unsigned int cplds_irq = irqd_to_hwirq(d);
+	unsigned int set, bit = BIT(cplds_irq);
+
+	fpga->irq_mask &= ~bit;
+	writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);
+	set = readl(fpga->base + FPGA_IRQ_SET_CLR);
+	writel(set & ~bit, fpga->base + FPGA_IRQ_SET_CLR);
+}
+
+static void cplds_irq_unmask(struct irq_data *d)
+{
+	struct cplds *fpga = irq_data_get_irq_chip_data(d);
+	unsigned int cplds_irq = irqd_to_hwirq(d);
+	unsigned int bit = BIT(cplds_irq);
+
+	fpga->irq_mask |= bit;
+	writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);
+}
+
+static struct irq_chip cplds_irq_chip = {
+	.name		= "pxa_cplds",
+	.irq_mask_ack	= cplds_irq_mask_ack,
+	.irq_unmask	= cplds_irq_unmask,
+	.flags		= IRQCHIP_MASK_ON_SUSPEND | IRQCHIP_SKIP_SET_WAKE,
+};
+
+static int cplds_irq_domain_map(struct irq_domain *d, unsigned int irq,
+				   irq_hw_number_t hwirq)
+{
+	struct cplds *fpga = d->host_data;
+
+	irq_set_chip_and_handler(irq, &cplds_irq_chip, handle_level_irq);
+	irq_set_chip_data(irq, fpga);
+
+	return 0;
+}
+
+static const struct irq_domain_ops cplds_irq_domain_ops = {
+	.xlate = irq_domain_xlate_twocell,
+	.map = cplds_irq_domain_map,
+};
+
+static int cplds_resume(struct platform_device *pdev)
+{
+	struct cplds *fpga = platform_get_drvdata(pdev);
+
+	writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);
+
+	return 0;
+}
+
+static int cplds_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct cplds *fpga;
+	int ret;
+	unsigned int base_irq = 0;
+	unsigned long irqflags = 0;
+
+	fpga = devm_kzalloc(&pdev->dev, sizeof(*fpga), GFP_KERNEL);
+	if (!fpga)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (res) {
+		fpga->irq = (unsigned int)res->start;
+		irqflags = res->flags;
+	}
+	if (!fpga->irq)
+		return -ENODEV;
+
+	base_irq = platform_get_irq(pdev, 1);
+	if (base_irq < 0)
+		base_irq = 0;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	fpga->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(fpga->base))
+		return PTR_ERR(fpga->base);
+
+	platform_set_drvdata(pdev, fpga);
+
+	writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);
+	writel(0, fpga->base + FPGA_IRQ_SET_CLR);
+
+	ret = devm_request_irq(&pdev->dev, fpga->irq, cplds_irq_handler,
+			       irqflags, dev_name(&pdev->dev), fpga);
+	if (ret == -ENOSYS)
+		return -EPROBE_DEFER;
+
+	if (ret) {
+		dev_err(&pdev->dev, "couldn't request main irq%d: %d\n",
+			fpga->irq, ret);
+		return ret;
+	}
+
+	irq_set_irq_wake(fpga->irq, 1);
+	fpga->irqdomain = irq_domain_add_linear(pdev->dev.of_node,
+					       CPLDS_NB_IRQ,
+					       &cplds_irq_domain_ops, fpga);
+	if (!fpga->irqdomain)
+		return -ENODEV;
+
+	if (base_irq) {
+		ret = irq_create_strict_mappings(fpga->irqdomain, base_irq, 0,
+						 CPLDS_NB_IRQ);
+		if (ret) {
+			dev_err(&pdev->dev, "couldn't create the irq mapping %d..%d\n",
+				base_irq, base_irq + CPLDS_NB_IRQ);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int cplds_remove(struct platform_device *pdev)
+{
+	struct cplds *fpga = platform_get_drvdata(pdev);
+
+	irq_set_chip_and_handler(fpga->irq, NULL, NULL);
+
+	return 0;
+}
+
+static const struct of_device_id cplds_id_table[] = {
+	{ .compatible = "intel,lubbock-cplds-irqs", },
+	{ .compatible = "intel,mainstone-cplds-irqs", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, cplds_id_table);
+
+static struct platform_driver cplds_driver = {
+	.driver		= {
+		.name	= "pxa_cplds_irqs",
+		.of_match_table = of_match_ptr(cplds_id_table),
+	},
+	.probe		= cplds_probe,
+	.remove		= cplds_remove,
+	.resume		= cplds_resume,
+};
+
+module_platform_driver(cplds_driver);
+
+MODULE_DESCRIPTION("PXA Cplds interrupts driver");
+MODULE_AUTHOR("Robert Jarzmik <robert.jarzmik@free.fr>");
+MODULE_LICENSE("GPL");