[PATCH 1/2] gpio add interrupt support on pca953x
Marc Zyngier
maz at misterjones.org
Tue Dec 22 14:59:47 EST 2009
On Tue, 22 Dec 2009 21:41:51 +0800
Eric Miao <eric.y.miao at gmail.com> wrote:
Eric, Haojian,
> Marc Zyngier was doing the similar thing, and submitted a patch to
> Andrew Morton already, but I prefer a full-functional IRQ chip based
> solution, so you may want to work with him together on this.
>
> Marc,
>
> Do you have the link to your patch?
Here's the current state of my tree, quickly rebased to 2.6.33-rc1.
To summarize, the main differences with Haojian's patch:
- uses threaded irqs/nested irqs
- setup is slightly more complicated (interrupt source mask and base
interrupt number), but more correct (no dependency on gpio_to_irq()
being a linear mapping, which is not always the case)
From d8dc00d1ebedcc889c41add70cceb8f15f106261 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz at misterjones.org>
Date: Tue, 22 Dec 2009 17:38:29 +0100
Subject: [PATCH] Add interrupt handling capability to pca953x.
Most of the GPIO expanders controlled by the pca953x driver are
able to report changes on the input pins through an *INT pin.
This patch implements the irq_chip functionality (edge detection
only).
The driver has been tested on an Arcom Zeus.
Signed-off-by: Marc Zyngier <maz at misterjones.org>
---
drivers/gpio/pca953x.c | 207 ++++++++++++++++++++++++++++++++++++++++---
include/linux/i2c/pca953x.h | 5 +
2 files changed, 199 insertions(+), 13 deletions(-)
diff --git a/drivers/gpio/pca953x.c b/drivers/gpio/pca953x.c
index 6a2fb3f..06c34a0 100644
--- a/drivers/gpio/pca953x.c
+++ b/drivers/gpio/pca953x.c
@@ -14,6 +14,8 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
#include <linux/i2c.h>
#include <linux/i2c/pca953x.h>
#ifdef CONFIG_OF_GPIO
@@ -26,23 +28,28 @@
#define PCA953X_INVERT 2
#define PCA953X_DIRECTION 3
+#define PCA953X_GPIOS 0x00FF
+#define PCA953X_INT 0x0100
+
static const struct i2c_device_id pca953x_id[] = {
- { "pca9534", 8, },
- { "pca9535", 16, },
+ { "pca9534", 8 | PCA953X_INT, },
+ { "pca9535", 16 | PCA953X_INT, },
{ "pca9536", 4, },
- { "pca9537", 4, },
- { "pca9538", 8, },
- { "pca9539", 16, },
- { "pca9554", 8, },
- { "pca9555", 16, },
+ { "pca9537", 4 | PCA953X_INT, },
+ { "pca9538", 8 | PCA953X_INT, },
+ { "pca9539", 16 | PCA953X_INT, },
+ { "pca9554", 8 | PCA953X_INT, },
+ { "pca9555", 16 | PCA953X_INT, },
{ "pca9556", 8, },
{ "pca9557", 8, },
{ "max7310", 8, },
- { "max7315", 8, },
- { "pca6107", 8, },
- { "tca6408", 8, },
- { "tca6416", 16, },
+ { "max7312", 16 | PCA953X_INT, },
+ { "max7313", 16 | PCA953X_INT, },
+ { "max7315", 8 | PCA953X_INT, },
+ { "pca6107", 8 | PCA953X_INT, },
+ { "tca6408", 8 | PCA953X_INT, },
+ { "tca6416", 16 | PCA953X_INT, },
/* NYET: { "tca6424", 24, }, */
{ }
};
@@ -53,6 +60,15 @@ struct pca953x_chip {
uint16_t reg_output;
uint16_t reg_direction;
+ struct mutex irq_lock;
+ uint16_t irq_interrupt;
+ uint16_t irq_mask;
+ uint16_t irq_stat;
+ uint16_t irq_trig_raise;
+ uint16_t irq_trig_fall;
+
+ int irq_base;
+
struct i2c_client *client;
struct pca953x_platform_data *dyn_pdata;
struct gpio_chip gpio_chip;
@@ -202,6 +218,121 @@ static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
gc->names = chip->names;
}
+static int pca953x_gpio_to_irq(struct gpio_chip *gc, unsigned off)
+{
+ struct pca953x_chip *chip;
+
+ chip = container_of(gc, struct pca953x_chip, gpio_chip);
+ if (chip->irq_interrupt & (1 << off))
+ return chip->irq_base + off;
+
+ return -ENXIO;
+}
+
+static void pca953x_irq_mask(unsigned int irq)
+{
+ struct pca953x_chip *chip = get_irq_chip_data(irq);
+
+ chip->irq_mask &= ~(1 << (irq - chip->irq_base));
+}
+
+static void pca953x_irq_unmask(unsigned int irq)
+{
+ struct pca953x_chip *chip = get_irq_chip_data(irq);
+
+ chip->irq_mask |= 1 << (irq - chip->irq_base);
+}
+
+static void pca953x_irq_bus_lock(unsigned int irq)
+{
+ struct pca953x_chip *chip = get_irq_chip_data(irq);
+
+ mutex_lock(&chip->irq_lock);
+}
+
+static void pca953x_irq_bus_sync_unlock(unsigned int irq)
+{
+ struct pca953x_chip *chip = get_irq_chip_data(irq);
+
+ mutex_unlock(&chip->irq_lock);
+}
+
+static int pca953x_irq_set_type(unsigned int irq, unsigned int type)
+{
+ struct pca953x_chip *chip = get_irq_chip_data(irq);
+ uint16_t mask = 1 << (irq - chip->irq_base);
+
+ if (!(type & IRQ_TYPE_EDGE_BOTH)) {
+ dev_err(&chip->client->dev, "unsupported irq type %d\n", type);
+ return -EINVAL;
+ }
+
+ if (type & IRQ_TYPE_EDGE_FALLING)
+ chip->irq_trig_fall |= mask;
+ else
+ chip->irq_trig_fall &= ~mask;
+
+ if (type & IRQ_TYPE_EDGE_RISING)
+ chip->irq_trig_raise |= mask;
+ else
+ chip->irq_trig_raise &= ~mask;
+
+ return 0;
+}
+
+static struct irq_chip pca953x_irq_chip = {
+ .name = "pca953x",
+ .mask = pca953x_irq_mask,
+ .unmask = pca953x_irq_unmask,
+ .bus_lock = pca953x_irq_bus_lock,
+ .bus_sync_unlock = pca953x_irq_bus_sync_unlock,
+ .set_type = pca953x_irq_set_type,
+};
+
+static irqreturn_t pca953x_irq_handler(int irq, void *devid)
+{
+ struct pca953x_chip *chip = devid;
+ uint16_t cur_stat;
+ uint16_t old_stat;
+ uint16_t pending;
+ int ret;
+
+ ret = pca953x_read_reg(chip, PCA953X_INPUT, &cur_stat);
+ if (ret)
+ return IRQ_HANDLED;
+
+ cur_stat &= (chip->irq_interrupt & chip->reg_direction);
+ old_stat = chip->irq_stat;
+ pending = (cur_stat ^ old_stat) & chip->irq_mask;
+
+ if (!pending)
+ return IRQ_HANDLED;
+
+ chip->irq_stat = cur_stat;
+
+ do {
+ uint16_t level;
+ uint16_t level_mask;
+ int trigger = 0;
+
+ level = __ffs(pending);
+ level_mask = 1 << level;
+
+ if (old_stat & level_mask & chip->irq_trig_fall)
+ trigger = 1;
+
+ if (cur_stat & level_mask & chip->irq_trig_raise)
+ trigger = 1;
+
+ if (trigger)
+ handle_nested_irq(level + chip->irq_base);
+
+ pending &= ~level_mask;
+ } while (pending);
+
+ return IRQ_HANDLED;
+}
+
/*
* Handlers for alternative sources of platform_data
*/
@@ -286,7 +417,7 @@ static int __devinit pca953x_probe(struct i2c_client *client,
/* initialize cached registers from their original values.
* we can't share this chip with another i2c master.
*/
- pca953x_setup_gpio(chip, id->driver_data);
+ pca953x_setup_gpio(chip, id->driver_data & PCA953X_GPIOS);
ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output);
if (ret)
@@ -301,10 +432,57 @@ static int __devinit pca953x_probe(struct i2c_client *client,
if (ret)
goto out_failed;
+ if (pdata->interrupt && (id->driver_data & PCA953X_INT)) {
+ int lvl;
+
+ ret = pca953x_read_reg(chip, PCA953X_INPUT,
+ &chip->irq_stat);
+ if (ret)
+ goto out_failed;
+
+ /*
+ * There is no way to know which GPIO line generated the
+ * interrupt. We have to rely on the previous read for
+ * this purpose.
+ */
+ chip->irq_stat &= chip->irq_interrupt & chip->reg_direction;
+ chip->irq_interrupt = pdata->interrupt;
+ chip->irq_base = pdata->irq_base;
+ mutex_init(&chip->irq_lock);
+
+ /* FIXME: Error handling? */
+ for (lvl = 0; lvl < chip->gpio_chip.ngpio; lvl++) {
+ if (chip->irq_interrupt & (1 << lvl)) {
+ int irq = lvl + chip->irq_base;
+
+ set_irq_chip_data(irq, chip);
+ set_irq_chip_and_handler(irq, &pca953x_irq_chip,
+ handle_edge_irq);
+ set_irq_nested_thread(irq, 1);
+ set_irq_flags(irq, IRQF_VALID);
+ }
+ }
+
+ ret = request_threaded_irq(client->irq,
+ NULL,
+ pca953x_irq_handler,
+ IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+ dev_name(&client->dev), chip);
+ if (ret) {
+ dev_err(&client->dev, "failed to request irq %d\n",
+ client->irq);
+ goto out_failed;
+ }
+
+ chip->gpio_chip.to_irq = pca953x_gpio_to_irq;
+ }
ret = gpiochip_add(&chip->gpio_chip);
- if (ret)
+ if (ret) {
+ if (pdata->interrupt)
+ free_irq(client->irq, chip);
goto out_failed;
+ }
if (pdata->setup) {
ret = pdata->setup(client, chip->gpio_chip.base,
@@ -345,6 +523,9 @@ static int pca953x_remove(struct i2c_client *client)
return ret;
}
+ if (chip->irq_interrupt)
+ free_irq(client->irq, chip);
+
kfree(chip->dyn_pdata);
kfree(chip);
return 0;
diff --git a/include/linux/i2c/pca953x.h b/include/linux/i2c/pca953x.h
index 81736d6..6a2c8a6 100644
--- a/include/linux/i2c/pca953x.h
+++ b/include/linux/i2c/pca953x.h
@@ -7,6 +7,11 @@ struct pca953x_platform_data {
/* initial polarity inversion setting */
uint16_t invert;
+ /* input bitmask to trigger the interrupt */
+ uint16_t interrupt;
+
+ int irq_base;
+
void *context; /* param to setup/teardown */
int (*setup)(struct i2c_client *client,
--
1.6.0.4
--
I'm the slime oozin' out from your TV set...
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