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Subject[patch 10/12] xtensa: support s6000 gpio irqs and alternate function selection
Date
From: Daniel Glöckner <dg@emlix.com>

Implement an irq chip to handle interrupts via gpio. The GPIO chip
initialization function now takes a bitmask denoting pins that should
be configured for their alternate function.

Signed-off-by: Daniel Glöckner <dg@emlix.com>
Signed-off-by: Johannes Weiner <jw@emlix.com>
---
arch/xtensa/include/asm/gpio.h | 8 +-
arch/xtensa/platforms/s6105/setup.c | 2 +-
arch/xtensa/variants/s6000/gpio.c | 163 ++++++++++++++++++++-
arch/xtensa/variants/s6000/include/variant/gpio.h | 2 +-
4 files changed, 168 insertions(+), 7 deletions(-)
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 855ddea..95fa23c 100644
--- a/arch/xtensa/platforms/s6105/setup.c
+++ b/arch/xtensa/platforms/s6105/setup.c
@@ -49,7 +49,7 @@ void __init platform_setup(char **cmdline)

void __init platform_init(bp_tag_t *first)
{
- s6_gpio_init();
+ s6_gpio_init(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 79317fd..5171e56 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
@@ -52,19 +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 */
};

-int s6_gpio_init(void)
+int s6_gpio_init(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);
}
+
+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
index 8327f62..8484ab0 100644
--- a/arch/xtensa/variants/s6000/include/variant/gpio.h
+++ b/arch/xtensa/variants/s6000/include/variant/gpio.h
@@ -1,6 +1,6 @@
#ifndef _XTENSA_VARIANT_S6000_GPIO_H
#define _XTENSA_VARIANT_S6000_GPIO_H

-extern int s6_gpio_init(void);
+extern int s6_gpio_init(u32 afsel);

#endif /* _XTENSA_VARIANT_S6000_GPIO_H */
--
1.6.2.107.ge47ee
--
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