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Subject[patch 2/2] xtensa: support s6000 gpio irqs and alternate function selection
Date
The patch implements an irq chip to handle interrupts via gpio.

As interrupts may be needed very early it is up to platform setup code
to initialize gpio by calling s6_setup_gpio. Its parameter is a bitmask
of those pins that should be configured for their alternative function.

Signed-off-by: Daniel Glöckner <dg@emlix.com>
---
arch/xtensa/include/asm/gpio.h | 8 +-
arch/xtensa/platforms/s6105/setup.c | 3 +
arch/xtensa/variants/s6000/gpio.c | 164 ++++++++++++++++++++-
arch/xtensa/variants/s6000/include/variant/gpio.h | 6 +
arch/xtensa/variants/s6000/include/variant/irq.h | 1 +
5 files changed, 176 insertions(+), 6 deletions(-)
create mode 100644 arch/xtensa/variants/s6000/include/variant/gpio.h

diff --git a/arch/xtensa/include/asm/gpio.h b/arch/xtensa/include/asm/gpio.h
index 0763b07..a8c9fc4 100644
--- a/arch/xtensa/include/asm/gpio.h
+++ b/arch/xtensa/include/asm/gpio.h
@@ -38,14 +38,14 @@ static inline int gpio_cansleep(unsigned int gpio)
return __gpio_cansleep(gpio);
}

-/*
- * Not implemented, yet.
- */
static inline int gpio_to_irq(unsigned int gpio)
{
- return -ENOSYS;
+ return __gpio_to_irq(gpio);
}

+/*
+ * Not implemented, yet.
+ */
static inline int irq_to_gpio(unsigned int irq)
{
return -EINVAL;
diff --git a/arch/xtensa/platforms/s6105/setup.c b/arch/xtensa/platforms/s6105/setup.c
index ae041d5..1dbf133 100644
--- a/arch/xtensa/platforms/s6105/setup.c
+++ b/arch/xtensa/platforms/s6105/setup.c
@@ -10,6 +10,8 @@
#include <asm/bootparam.h>

#include <variant/hardware.h>
+#include <variant/gpio.h>
+
#include <platform/gpio.h>

void platform_halt(void)
@@ -47,6 +49,7 @@ void __init platform_setup(char **cmdline)

void __init platform_init(bp_tag_t *first)
{
+ s6_setup_gpio(0);
gpio_request(GPIO_LED1_NGREEN, "led1_green");
gpio_request(GPIO_LED1_RED, "led1_red");
gpio_direction_output(GPIO_LED1_NGREEN, 1);
diff --git a/arch/xtensa/variants/s6000/gpio.c b/arch/xtensa/variants/s6000/gpio.c
index 33a8d95..d71c8c2 100644
--- a/arch/xtensa/variants/s6000/gpio.c
+++ b/arch/xtensa/variants/s6000/gpio.c
@@ -4,15 +4,20 @@
* Copyright (c) 2009 emlix GmbH
* Authors: Oskar Schirmer <os@emlix.com>
* Johannes Weiner <jw@emlix.com>
+ * Daniel Gloeckner <dg@emlix.com>
*/
+#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/io.h>
+#include <linux/irq.h>
#include <linux/gpio.h>

#include <variant/hardware.h>

+#define IRQ_BASE XTENSA_NR_IRQS
+
#define S6_GPIO_DATA 0x000
#define S6_GPIO_IS 0x404
#define S6_GPIO_IBE 0x408
@@ -52,20 +57,175 @@ static void set(struct gpio_chip *chip, unsigned int off, int val)
writeb(val ? ~0 : 0, S6_REG_GPIO + S6_GPIO_DATA + S6_GPIO_OFFSET(off));
}

+static int to_irq(struct gpio_chip *chip, unsigned offset)
+{
+ if (offset < 8)
+ return offset + IRQ_BASE;
+ return -EINVAL;
+}
+
static struct gpio_chip gpiochip = {
.owner = THIS_MODULE,
.direction_input = direction_input,
.get = get,
.direction_output = direction_output,
.set = set,
+ .to_irq = to_irq,
.base = 0,
.ngpio = 24,
.can_sleep = 0, /* no blocking io needed */
.exported = 0, /* no exporting to userspace */
};

-static int gpio_init(void)
+int __init s6_setup_gpio(u32 afsel)
{
+ writeb(afsel, S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_AFSEL);
+ writeb(afsel >> 8, S6_REG_GPIO + S6_GPIO_BANK(1) + S6_GPIO_AFSEL);
+ writeb(afsel >> 16, S6_REG_GPIO + S6_GPIO_BANK(2) + S6_GPIO_AFSEL);
return gpiochip_add(&gpiochip);
}
-device_initcall(gpio_init);
+
+static void ack(unsigned int irq)
+{
+ writeb(1 << (irq - IRQ_BASE), S6_REG_GPIO + S6_GPIO_IC);
+}
+
+static void mask(unsigned int irq)
+{
+ u8 r = readb(S6_REG_GPIO + S6_GPIO_IE);
+ r &= ~(1 << (irq - IRQ_BASE));
+ writeb(r, S6_REG_GPIO + S6_GPIO_IE);
+}
+
+static void unmask(unsigned int irq)
+{
+ u8 m = readb(S6_REG_GPIO + S6_GPIO_IE);
+ m |= 1 << (irq - IRQ_BASE);
+ writeb(m, S6_REG_GPIO + S6_GPIO_IE);
+}
+
+static int set_type(unsigned int irq, unsigned int type)
+{
+ const u8 m = 1 << (irq - IRQ_BASE);
+ irq_flow_handler_t handler;
+ struct irq_desc *desc;
+ u8 reg;
+
+ if (type == IRQ_TYPE_PROBE) {
+ if ((readb(S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_AFSEL) & m)
+ || (readb(S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_IE) & m)
+ || readb(S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_DIR
+ + S6_GPIO_MASK(irq - IRQ_BASE)))
+ return 0;
+ type = IRQ_TYPE_EDGE_BOTH;
+ }
+
+ reg = readb(S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_IS);
+ if (type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH)) {
+ reg |= m;
+ handler = handle_level_irq;
+ } else {
+ reg = ~m;
+ handler = handle_edge_irq;
+ }
+ writeb(reg, S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_IS);
+ desc = irq_to_desc(irq);
+ desc->handle_irq = handler;
+
+ reg = readb(S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_IEV);
+ if (type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_EDGE_RISING))
+ reg |= m;
+ else
+ reg &= ~m;
+ writeb(reg, S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_IEV);
+
+ reg = readb(S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_IBE);
+ if ((type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH)
+ reg |= m;
+ else
+ reg &= ~m;
+ writeb(reg, S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_IBE);
+ return 0;
+}
+
+static struct irq_chip gpioirqs = {
+ .name = "GPIO",
+ .ack = ack,
+ .mask = mask,
+ .unmask = unmask,
+ .set_type = set_type,
+};
+
+static u8 demux_masks[4];
+
+static void demux_irqs(unsigned int irq, struct irq_desc *desc)
+{
+ u8 *mask = get_irq_desc_data(desc);
+ u8 pending;
+ int cirq;
+
+ desc->chip->mask(irq);
+ desc->chip->ack(irq);
+ pending = readb(S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_MIS) & *mask;
+ cirq = IRQ_BASE - 1;
+ while (pending) {
+ int n = ffs(pending);
+ cirq += n;
+ pending >>= n;
+ generic_handle_irq(cirq);
+ }
+ desc->chip->unmask(irq);
+}
+
+extern const signed char *platform_irq_mappings[XTENSA_NR_IRQS];
+
+void __init variant_init_IRQ(void)
+{
+ int irq, n;
+ writeb(0, S6_REG_GPIO + S6_GPIO_BANK(0) + S6_GPIO_IE);
+ for (irq = n = 0; irq < XTENSA_NR_IRQS; irq++) {
+ const signed char *mapping = platform_irq_mappings[irq];
+ int alone = 1;
+ u8 mask;
+ if (!mapping)
+ continue;
+ for(mask = 0; *mapping != -1; mapping++)
+ switch (*mapping) {
+ case S6_INTC_GPIO(0):
+ mask |= 1 << 0;
+ break;
+ case S6_INTC_GPIO(1):
+ mask |= 1 << 1;
+ break;
+ case S6_INTC_GPIO(2):
+ mask |= 1 << 2;
+ break;
+ case S6_INTC_GPIO(3):
+ mask |= 0x1f << 3;
+ break;
+ default:
+ alone = 0;
+ }
+ if (mask) {
+ int cirq, i;
+ if (!alone) {
+ printk(KERN_ERR "chained irq chips can't share"
+ " parent irq %i\n", irq);
+ continue;
+ }
+ demux_masks[n] = mask;
+ cirq = IRQ_BASE - 1;
+ do {
+ i = ffs(mask);
+ cirq += i;
+ mask >>= i;
+ set_irq_chip(cirq, &gpioirqs);
+ set_irq_type(irq, IRQ_TYPE_LEVEL_LOW);
+ } while (mask);
+ set_irq_data(irq, demux_masks + n);
+ set_irq_chained_handler(irq, demux_irqs);
+ if (++n == ARRAY_SIZE(demux_masks))
+ break;
+ }
+ }
+}
diff --git a/arch/xtensa/variants/s6000/include/variant/gpio.h b/arch/xtensa/variants/s6000/include/variant/gpio.h
new file mode 100644
index 0000000..70cb330
--- /dev/null
+++ b/arch/xtensa/variants/s6000/include/variant/gpio.h
@@ -0,0 +1,6 @@
+#ifndef __XTENSA_VARIANT_S6000_GPIO_H
+#define __XTENSA_VARIANT_S6000_GPIO_H
+
+int s6_setup_gpio(u32 afsel) __init;
+
+#endif
diff --git a/arch/xtensa/variants/s6000/include/variant/irq.h b/arch/xtensa/variants/s6000/include/variant/irq.h
index fa031cb..55403d1 100644
--- a/arch/xtensa/variants/s6000/include/variant/irq.h
+++ b/arch/xtensa/variants/s6000/include/variant/irq.h
@@ -2,6 +2,7 @@
#define __XTENSA_S6000_IRQ_H

#define NO_IRQ (-1)
+#define VARIANT_NR_IRQS 8 /* GPIO interrupts */

extern void variant_irq_enable(unsigned int irq);
extern void variant_irq_disable(unsigned int irq);
--
1.6.2.107.ge47ee
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