sh: mach-x3proto: Support for baseboard GPIOs.

This adds trivial support for the GPIOs implemented through the baseboard
CPLD, used for driving the button matrix.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/boards/mach-x3proto/Makefile

 obj-y += setup.o ilsel.o
+
+obj-$(CONFIG_GENERIC_GPIO)	+= gpio.o

arch/sh/boards/mach-x3proto/gpio.c

+/*
+ * arch/sh/boards/mach-x3proto/gpio.c
+ *
+ * Renesas SH-X3 Prototype Baseboard GPIO Support.
+ *
+ * Copyright (C) 2010  Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <mach/ilsel.h>
+#include <mach/hardware.h>
+
+#define KEYCTLR	0xb81c0000
+#define KEYOUTR	0xb81c0002
+#define KEYDETR 0xb81c0004
+
+static DEFINE_SPINLOCK(x3proto_gpio_lock);
+static unsigned int x3proto_gpio_irq_map[NR_BASEBOARD_GPIOS] = { 0, };
+
+static int x3proto_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
+{
+	unsigned long flags;
+	unsigned int data;
+
+	spin_lock_irqsave(&x3proto_gpio_lock, flags);
+	data = __raw_readw(KEYCTLR);
+	data |= (1 << gpio);
+	__raw_writew(data, KEYCTLR);
+	spin_unlock_irqrestore(&x3proto_gpio_lock, flags);
+
+	return 0;
+}
+
+static int x3proto_gpio_get(struct gpio_chip *chip, unsigned gpio)
+{
+	return !!(__raw_readw(KEYDETR) & (1 << gpio));
+}
+
+static int x3proto_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
+{
+	return x3proto_gpio_irq_map[gpio];
+}
+
+static void x3proto_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
+{
+	struct irq_chip *chip = get_irq_desc_chip(desc);
+	unsigned long mask;
+	int pin;
+
+	chip->mask_ack(irq);
+
+	mask = __raw_readw(KEYDETR);
+
+	for_each_set_bit(pin, &mask, NR_BASEBOARD_GPIOS)
+		generic_handle_irq(x3proto_gpio_to_irq(NULL, pin));
+
+	chip->unmask(irq);
+}
+
+struct gpio_chip x3proto_gpio_chip = {
+	.label			= "x3proto-gpio",
+	.direction_input	= x3proto_gpio_direction_input,
+	.get			= x3proto_gpio_get,
+	.to_irq			= x3proto_gpio_to_irq,
+	.base			= -1,
+	.ngpio			= NR_BASEBOARD_GPIOS,
+};
+
+int __init x3proto_gpio_setup(void)
+{
+	unsigned int ilsel;
+	int ret, i;
+
+	ilsel = ilsel_enable(ILSEL_KEY);
+	if (unlikely(ilsel < 0))
+		return ilsel;
+
+	ret = gpiochip_add(&x3proto_gpio_chip);
+	if (unlikely(ret))
+		goto err_gpio;
+
+	for (i = 0; i < NR_BASEBOARD_GPIOS; i++) {
+		unsigned long flags;
+		unsigned int irq = create_irq();
+
+		if (unlikely(irq < 0)) {
+			ret = -EINVAL;
+			goto err_irq;
+		}
+
+		spin_lock_irqsave(&x3proto_gpio_lock, flags);
+		x3proto_gpio_irq_map[i] = irq;
+		set_irq_chip_and_handler_name(irq, &dummy_irq_chip,
+					handle_simple_irq, "gpio");
+		spin_unlock_irqrestore(&x3proto_gpio_lock, flags);
+	}
+
+	pr_info("registering '%s' support, handling GPIOs %u -> %u, "
+		"bound to IRQ %u\n",
+		x3proto_gpio_chip.label, x3proto_gpio_chip.base,
+		x3proto_gpio_chip.base + x3proto_gpio_chip.ngpio,
+		ilsel);
+
+	set_irq_chained_handler(ilsel, x3proto_gpio_irq_handler);
+	set_irq_wake(ilsel, 1);
+
+	return 0;
+
+err_irq:
+	for (; i >= 0; --i)
+		if (x3proto_gpio_irq_map[i])
+			destroy_irq(x3proto_gpio_irq_map[i]);
+
+	ret = gpiochip_remove(&x3proto_gpio_chip);
+	if (unlikely(ret))
+		pr_err("Failed deregistering GPIO\n");
+
+err_gpio:
+	synchronize_irq(ilsel);
+
+	ilsel_disable(ILSEL_KEY);
+
+	return ret;
+}

arch/sh/include/mach-x3proto/mach/hardware.h

+#ifndef __MACH_X3PROTO_HARDWARE_H
+#define __MACH_X3PROTO_HARDWARE_H
+
+struct gpio_chip;
+
+/* arch/sh/boards/mach-x3proto/gpio.c */
+int x3proto_gpio_setup(void);
+extern struct gpio_chip x3proto_gpio_chip;
+
+#define NR_BASEBOARD_GPIOS	16
+
+#endif /* __MACH_X3PROTO_HARDWARE_H */