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>

3 files changed, 257 insertions, 1 deletions

diff --git a/arch/arm/plat-mxc/Makefile b/arch/arm/plat-mxc/Makefile
index 3eb181cb7afb..66272a6fc323 100644
--- a/arch/arm/plat-mxc/Makefile
+++ b/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
diff --git a/arch/arm/plat-mxc/gpio.c b/arch/arm/plat-mxc/gpio.c
new file mode 100644
index 000000000000..4a7736717d86
--- /dev/null
+++ b/arch/arm/plat-mxc/gpio.c
@@ -0,0 +1,253 @@
+/*
+ * 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;
+}
diff --git a/arch/arm/plat-mxc/irq.c b/arch/arm/plat-mxc/irq.c
index 2ad5a6917b3f..88f0cfababda 100644
--- a/arch/arm/plat-mxc/irq.c
+++ b/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");
 }