gpio: pca953x.c: add interrupt handling capability
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.
[akpm@linux-foundation.org: the compiler does inlining for us nowadays]
Signed-off-by: Marc Zyngier <maz@misterjones.org>
Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Nate Case <ncase@xes-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/gpio/pca953x.c b/drivers/gpio/pca953x.c
index 6a2fb3f..ab5daab 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 @@
uint16_t reg_output;
uint16_t reg_direction;
+#ifdef CONFIG_GPIO_PCA953X_IRQ
+ struct mutex irq_lock;
+ uint16_t irq_mask;
+ uint16_t irq_stat;
+ uint16_t irq_trig_raise;
+ uint16_t irq_trig_fall;
+ int irq_base;
+#endif
+
struct i2c_client *client;
struct pca953x_platform_data *dyn_pdata;
struct gpio_chip gpio_chip;
@@ -202,6 +218,210 @@
gc->names = chip->names;
}
+#ifdef CONFIG_GPIO_PCA953X_IRQ
+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);
+ return chip->irq_base + off;
+}
+
+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 level = irq - chip->irq_base;
+ uint16_t mask = 1 << level;
+
+ if (!(type & IRQ_TYPE_EDGE_BOTH)) {
+ dev_err(&chip->client->dev, "irq %d: unsupported type %d\n",
+ irq, 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 pca953x_gpio_direction_input(&chip->gpio_chip, level);
+}
+
+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 uint16_t pca953x_irq_pending(struct pca953x_chip *chip)
+{
+ uint16_t cur_stat;
+ uint16_t old_stat;
+ uint16_t pending;
+ uint16_t trigger;
+ int ret;
+
+ ret = pca953x_read_reg(chip, PCA953X_INPUT, &cur_stat);
+ if (ret)
+ return 0;
+
+ /* Remove output pins from the equation */
+ cur_stat &= chip->reg_direction;
+
+ old_stat = chip->irq_stat;
+ trigger = (cur_stat ^ old_stat) & chip->irq_mask;
+
+ if (!trigger)
+ return 0;
+
+ chip->irq_stat = cur_stat;
+
+ pending = (old_stat & chip->irq_trig_fall) |
+ (cur_stat & chip->irq_trig_raise);
+ pending &= trigger;
+
+ return pending;
+}
+
+static irqreturn_t pca953x_irq_handler(int irq, void *devid)
+{
+ struct pca953x_chip *chip = devid;
+ uint16_t pending;
+ uint16_t level;
+
+ pending = pca953x_irq_pending(chip);
+
+ if (!pending)
+ return IRQ_HANDLED;
+
+ do {
+ level = __ffs(pending);
+ handle_nested_irq(level + chip->irq_base);
+
+ pending &= ~(1 << level);
+ } while (pending);
+
+ return IRQ_HANDLED;
+}
+
+static int pca953x_irq_setup(struct pca953x_chip *chip,
+ const struct i2c_device_id *id)
+{
+ struct i2c_client *client = chip->client;
+ struct pca953x_platform_data *pdata = client->dev.platform_data;
+ int ret;
+
+ if (pdata->irq_base && (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->reg_direction;
+ chip->irq_base = pdata->irq_base;
+ mutex_init(&chip->irq_lock);
+
+ for (lvl = 0; lvl < chip->gpio_chip.ngpio; 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);
+#ifdef CONFIG_ARM
+ set_irq_flags(irq, IRQF_VALID);
+#else
+ set_irq_noprobe(irq);
+#endif
+ }
+
+ 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;
+ }
+
+ return 0;
+
+out_failed:
+ chip->irq_base = 0;
+ return ret;
+}
+
+static void pca953x_irq_teardown(struct pca953x_chip *chip)
+{
+ if (chip->irq_base)
+ free_irq(chip->client->irq, chip);
+}
+#else /* CONFIG_GPIO_PCA953X_IRQ */
+static int pca953x_irq_setup(struct pca953x_chip *chip,
+ const struct i2c_device_id *id)
+{
+ struct i2c_client *client = chip->client;
+ struct pca953x_platform_data *pdata = client->dev.platform_data;
+
+ if (pdata->irq_base && (id->driver_data & PCA953X_INT))
+ dev_warn(&client->dev, "interrupt support not compiled in\n");
+
+ return 0;
+}
+
+static void pca953x_irq_teardown(struct pca953x_chip *chip)
+{
+}
+#endif
+
/*
* Handlers for alternative sources of platform_data
*/
@@ -286,7 +506,7 @@
/* 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)
@@ -301,6 +521,9 @@
if (ret)
goto out_failed;
+ ret = pca953x_irq_setup(chip, id);
+ if (ret)
+ goto out_failed;
ret = gpiochip_add(&chip->gpio_chip);
if (ret)
@@ -317,6 +540,7 @@
return 0;
out_failed:
+ pca953x_irq_teardown(chip);
kfree(chip->dyn_pdata);
kfree(chip);
return ret;
@@ -345,6 +569,7 @@
return ret;
}
+ pca953x_irq_teardown(chip);
kfree(chip->dyn_pdata);
kfree(chip);
return 0;