MXC arch: Add gpio support for the whole platform

This patch bases on the one from Daniel Mack. The most important change to
Daniel's patch is to be more generic. This gpio routine supports at least
the i.MX27 and i.MX31 processors.
Signed-off-by: Juergen Beisert <j.beisert@pengutronix.de>
Acked-by: Daniel Mack <daniel@caiaq.de>

arch/arm/Kconfig

@@ -368,6 +368,8 @@ config ARCH_NS9XXX
 config ARCH_MXC
 	bool "Freescale MXC/iMX-based"
 	select ARCH_MTD_XIP
+	select GENERIC_GPIO
+	select HAVE_GPIO_LIB
 	help
 	  Support for Freescale MXC/iMX-based family of processors
 

arch/arm/mach-mx3/devices.c

@@ -20,6 +20,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/serial.h>
+#include <linux/gpio.h>
 #include <asm/hardware.h>
 #include <asm/arch/imx-uart.h>
 
@@ -151,3 +152,29 @@ int __init imx_init_uart(int uart_no, struct imxuart_platform_data *pdata)
 	return 0;
 }
 
+/* GPIO port description */
+static struct mxc_gpio_port imx_gpio_ports[] = {
+	[0] = {
+		.chip.label = "gpio-0",
+		.base = IO_ADDRESS(GPIO1_BASE_ADDR),
+		.irq = MXC_INT_GPIO1,
+		.virtual_irq_start = MXC_GPIO_INT_BASE
+	},
+	[1] = {
+		.chip.label = "gpio-1",
+		.base = IO_ADDRESS(GPIO2_BASE_ADDR),
+		.irq = MXC_INT_GPIO2,
+		.virtual_irq_start = MXC_GPIO_INT_BASE + GPIO_NUM_PIN
+	},
+	[2] = {
+		.chip.label = "gpio-2",
+		.base = IO_ADDRESS(GPIO3_BASE_ADDR),
+		.irq = MXC_INT_GPIO3,
+		.virtual_irq_start = MXC_GPIO_INT_BASE + GPIO_NUM_PIN * 2
+	}
+};
+
+int __init mxc_register_gpios(void)
+{
+	return mxc_gpio_init(imx_gpio_ports, ARRAY_SIZE(imx_gpio_ports));
+}

arch/arm/plat-mxc/Makefile

@@ -3,4 +3,4 @@
 #
 
 # Common support
-obj-y := irq.o clock.o
+obj-y := irq.o clock.o gpio.o

arch/arm/plat-mxc/gpio.c

+/*
+ * MXC GPIO support. (c) 2008 Daniel Mack <daniel@caiaq.de>
+ * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
+ *
+ * Based on code from Freescale,
+ * Copyright 2004-2006 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * 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.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/gpio.h>
+#include <asm/hardware.h>
+#include <asm-generic/bug.h>
+
+static struct mxc_gpio_port *mxc_gpio_ports;
+static int gpio_table_size;
+
+/* Note: This driver assumes 32 GPIOs are handled in one register */
+
+static void _clear_gpio_irqstatus(struct mxc_gpio_port *port, u32 index)
+{
+	__raw_writel(1 << index, port->base + GPIO_ISR);
+}
+
+static void _set_gpio_irqenable(struct mxc_gpio_port *port, u32 index,
+				int enable)
+{
+	u32 l;
+
+	l = __raw_readl(port->base + GPIO_IMR);
+	l = (l & (~(1 << index))) | (!!enable << index);
+	__raw_writel(l, port->base + GPIO_IMR);
+}
+
+static void gpio_ack_irq(u32 irq)
+{
+	u32 gpio = irq_to_gpio(irq);
+	_clear_gpio_irqstatus(&mxc_gpio_ports[gpio / 32], gpio & 0x1f);
+}
+
+static void gpio_mask_irq(u32 irq)
+{
+	u32 gpio = irq_to_gpio(irq);
+	_set_gpio_irqenable(&mxc_gpio_ports[gpio / 32], gpio & 0x1f, 0);
+}
+
+static void gpio_unmask_irq(u32 irq)
+{
+	u32 gpio = irq_to_gpio(irq);
+	_set_gpio_irqenable(&mxc_gpio_ports[gpio / 32], gpio & 0x1f, 1);
+}
+
+static int gpio_set_irq_type(u32 irq, u32 type)
+{
+	u32 gpio = irq_to_gpio(irq);
+	struct mxc_gpio_port *port = &mxc_gpio_ports[gpio / 32];
+	u32 bit, val;
+	int edge;
+	void __iomem *reg = port->base;
+
+	switch (type) {
+	case IRQT_RISING:
+		edge = GPIO_INT_RISE_EDGE;
+		break;
+	case IRQT_FALLING:
+		edge = GPIO_INT_FALL_EDGE;
+		break;
+	case IRQT_LOW:
+		edge = GPIO_INT_LOW_LEV;
+		break;
+	case IRQT_HIGH:
+		edge = GPIO_INT_HIGH_LEV;
+		break;
+	default:	/* this includes IRQT_BOTHEDGE */
+		return -EINVAL;
+	}
+
+	reg += GPIO_ICR1 + ((gpio & 0x10) >> 2); /* lower or upper register */
+	bit = gpio & 0xf;
+	val = __raw_readl(reg) & ~(0x3 << (bit << 1));
+	__raw_writel(val | (edge << (bit << 1)), reg);
+	_clear_gpio_irqstatus(port, gpio & 0x1f);
+
+	return 0;
+}
+
+/* handle n interrupts in one status register */
+static void mxc_gpio_irq_handler(struct mxc_gpio_port *port, u32 irq_stat)
+{
+	u32 gpio_irq_no;
+
+	gpio_irq_no = port->virtual_irq_start;
+	for (; irq_stat != 0; irq_stat >>= 1, gpio_irq_no++) {
+
+		if ((irq_stat & 1) == 0)
+			continue;
+
+		BUG_ON(!(irq_desc[gpio_irq_no].handle_irq));
+		irq_desc[gpio_irq_no].handle_irq(gpio_irq_no,
+				&irq_desc[gpio_irq_no]);
+	}
+}
+
+#ifdef CONFIG_ARCH_MX3
+/* MX3 has one interrupt *per* gpio port */
+static void mx3_gpio_irq_handler(u32 irq, struct irq_desc *desc)
+{
+	u32 irq_stat;
+	struct mxc_gpio_port *port = (struct mxc_gpio_port *)get_irq_data(irq);
+
+	irq_stat = __raw_readl(port->base + GPIO_ISR) &
+			__raw_readl(port->base + GPIO_IMR);
+	BUG_ON(!irq_stat);
+	mxc_gpio_irq_handler(port, irq_stat);
+}
+#endif
+
+#ifdef CONFIG_ARCH_MX2
+/* MX2 has one interrupt *for all* gpio ports */
+static void mx2_gpio_irq_handler(u32 irq, struct irq_desc *desc)
+{
+	int i;
+	u32 irq_msk, irq_stat;
+	struct mxc_gpio_port *port = (struct mxc_gpio_port *)get_irq_data(irq);
+
+	/* walk through all interrupt status registers */
+	for (i = 0; i < gpio_table_size; i++) {
+		irq_msk = __raw_readl(port[i].base + GPIO_IMR);
+		if (!irq_msk)
+			continue;
+
+		irq_stat = __raw_readl(port[i].base + GPIO_ISR) & irq_msk;
+		if (irq_stat)
+			mxc_gpio_irq_handler(&port[i], irq_stat);
+	}
+}
+#endif
+
+static struct irq_chip gpio_irq_chip = {
+	.ack = gpio_ack_irq,
+	.mask = gpio_mask_irq,
+	.unmask = gpio_unmask_irq,
+	.set_type = gpio_set_irq_type,
+};
+
+static void _set_gpio_direction(struct gpio_chip *chip, unsigned offset,
+				int dir)
+{
+	struct mxc_gpio_port *port =
+		container_of(chip, struct mxc_gpio_port, chip);
+	u32 l;
+
+	l = __raw_readl(port->base + GPIO_GDIR);
+	if (dir)
+		l |= 1 << offset;
+	else
+		l &= ~(1 << offset);
+	__raw_writel(l, port->base + GPIO_GDIR);
+}
+
+static void mxc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct mxc_gpio_port *port =
+		container_of(chip, struct mxc_gpio_port, chip);
+	void __iomem *reg = port->base + GPIO_DR;
+	u32 l;
+
+	l = (__raw_readl(reg) & (~(1 << offset))) | (value << offset);
+	__raw_writel(l, reg);
+}
+
+static int mxc_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct mxc_gpio_port *port =
+		container_of(chip, struct mxc_gpio_port, chip);
+
+	return (__raw_readl(port->base + GPIO_DR) >> offset) & 1;
+}
+
+static int mxc_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	_set_gpio_direction(chip, offset, 0);
+	return 0;
+}
+
+static int mxc_gpio_direction_output(struct gpio_chip *chip,
+				     unsigned offset, int value)
+{
+	_set_gpio_direction(chip, offset, 1);
+	mxc_gpio_set(chip, offset, value);
+	return 0;
+}
+
+int __init mxc_gpio_init(struct mxc_gpio_port *port, int cnt)
+{
+	int i, j;
+
+	/* save for local usage */
+	mxc_gpio_ports = port;
+	gpio_table_size = cnt;
+
+	printk(KERN_INFO "MXC GPIO hardware\n");
+
+	for (i = 0; i < cnt; i++) {
+		/* disable the interrupt and clear the status */
+		__raw_writel(0, port[i].base + GPIO_IMR);
+		__raw_writel(~0, port[i].base + GPIO_ISR);
+		for (j = port[i].virtual_irq_start;
+			j < port[i].virtual_irq_start + 32; j++) {
+			set_irq_chip(j, &gpio_irq_chip);
+			set_irq_handler(j, handle_edge_irq);
+			set_irq_flags(j, IRQF_VALID);
+		}
+
+		/* register gpio chip */
+		port[i].chip.direction_input = mxc_gpio_direction_input;
+		port[i].chip.direction_output = mxc_gpio_direction_output;
+		port[i].chip.get = mxc_gpio_get;
+		port[i].chip.set = mxc_gpio_set;
+		port[i].chip.base = i * 32;
+		port[i].chip.ngpio = 32;
+
+		/* its a serious configuration bug when it fails */
+		BUG_ON( gpiochip_add(&port[i].chip) < 0 );
+
+#ifdef CONFIG_ARCH_MX3
+		/* setup one handler for each entry */
+		set_irq_chained_handler(port[i].irq, mx3_gpio_irq_handler);
+		set_irq_data(port[i].irq, &port[i]);
+#endif
+	}
+
+#ifdef CONFIG_ARCH_MX2
+	/* setup one handler for all GPIO interrupts */
+	set_irq_chained_handler(port[0].irq, mx2_gpio_irq_handler);
+	set_irq_data(port[0].irq, port);
+#endif
+	return 0;
+}

arch/arm/plat-mxc/irq.c

@@ -71,5 +71,8 @@ void __init mxc_init_irq(void)
 	reg |= (0xF << 28);
 	__raw_writel(reg, AVIC_NIPRIORITY6);
 
+	/* init architectures chained interrupt handler */
+	mxc_register_gpios();
+
 	printk(KERN_INFO "MXC IRQ initialized\n");
 }

include/asm-arm/arch-mxc/common.h

@@ -17,5 +17,6 @@ extern void mxc_map_io(void);
 extern void mxc_init_irq(void);
 extern struct sys_timer mxc_timer;
 extern int mxc_clocks_init(unsigned long fref);
+extern int mxc_register_gpios(void);
 
 #endif

include/asm-arm/arch-mxc/gpio.h

+/*
+ * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
+ *
+ * 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.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#ifndef __ASM_ARCH_MXC_GPIO_H__
+#define __ASM_ARCH_MXC_GPIO_H__
+
+#include <asm/hardware.h>
+#include <asm-generic/gpio.h>
+
+/* use gpiolib dispatchers */
+#define gpio_get_value		__gpio_get_value
+#define gpio_set_value		__gpio_set_value
+#define gpio_cansleep		__gpio_cansleep
+
+#define gpio_to_irq(gpio)	(MXC_MAX_INT_LINES + (gpio))
+#define irq_to_gpio(irq)	((irq) - MXC_MAX_INT_LINES)
+
+struct mxc_gpio_port {
+	void __iomem *base;
+	int irq;
+	int virtual_irq_start;
+	struct gpio_chip chip;
+};
+
+int mxc_gpio_init(struct mxc_gpio_port*, int);
+
+#endif

include/asm-arm/arch-mxc/mx31.h

@@ -347,6 +347,25 @@
 #define SYSTEM_REV_MIN		CHIP_REV_1_0
 #define SYSTEM_REV_NUM		3
 
+/* gpio and gpio based interrupt handling */
+#define GPIO_DR		 	0x00
+#define GPIO_GDIR	 	0x04
+#define GPIO_PSR	 	0x08
+#define GPIO_ICR1	 	0x0C
+#define GPIO_ICR2	 	0x10
+#define GPIO_IMR	 	0x14
+#define GPIO_ISR	 	0x18
+#define GPIO_INT_LOW_LEV	0x0
+#define GPIO_INT_HIGH_LEV	0x1
+#define GPIO_INT_RISE_EDGE	0x2
+#define GPIO_INT_FALL_EDGE	0x3
+#define GPIO_INT_NONE		0x4
+
+/* Mandatory defines used globally */
+
+/* this CPU supports up to 96 GPIOs */
+#define ARCH_NR_GPIOS		96
+
 #if !defined(__ASSEMBLY__) && !defined(__MXC_BOOT_UNCOMPRESS)
 
 /* this is a i.MX31 CPU */