[PATCH] gpio: add interrupt support on pca953x

[Haojian Zhuang]

Support interrupt on pca953x gpio expander.

Signed-off-by: Haojian Zhuang <haojian.zhuang at marvell.com>
---
 drivers/gpio/pca953x.c |  121 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 119 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/pca953x.c b/drivers/gpio/pca953x.c
index 6a2fb3f..2d6b9e8 100644
--- a/drivers/gpio/pca953x.c
+++ b/drivers/gpio/pca953x.c
@@ -16,6 +16,7 @@
 #include <linux/gpio.h>
 #include <linux/i2c.h>
 #include <linux/i2c/pca953x.h>
+#include <linux/irq.h>
 #ifdef CONFIG_OF_GPIO
 #include <linux/of_platform.h>
 #include <linux/of_gpio.h>
@@ -50,12 +51,19 @@ MODULE_DEVICE_TABLE(i2c, pca953x_id);

 struct pca953x_chip {
 	unsigned gpio_start;
+	unsigned irq_start;
 	uint16_t reg_output;
 	uint16_t reg_direction;
+	uint16_t irq_mask;
+	uint16_t irq_falling_edge;
+	uint16_t irq_rising_edge;
+	uint16_t last_input;

-	struct i2c_client *client;
 	struct pca953x_platform_data *dyn_pdata;
-	struct gpio_chip gpio_chip;
+	struct i2c_client	*client;
+	struct gpio_chip	gpio_chip;
+	struct mutex		irq_lock;
+	struct work_struct	irq_work;
 	char **names;
 };

@@ -250,11 +258,113 @@ pca953x_get_alt_pdata(struct i2c_client *client)
 }
 #endif

+#define PCA953X_NUM_IRQ			16
+
+static void pca953x_irq_work(struct work_struct *work)
+{
+	DECLARE_BITMAP(rising, PCA953X_NUM_IRQ);
+	DECLARE_BITMAP(falling, PCA953X_NUM_IRQ);
+	struct pca953x_chip *chip;
+	unsigned short input, mask;
+	int ret, irq;
+
+	chip = container_of(work, struct pca953x_chip, irq_work);
+	ret = pca953x_read_reg(chip, PCA953X_INPUT, &input);
+	if (ret < 0)
+		return;
+
+	mutex_lock(&chip->irq_lock);
+	mask = (input ^ chip->last_input) & chip->irq_mask;
+	rising[0] = (input & mask) & chip->irq_rising_edge;
+	falling[0] = (~input & mask) & chip->irq_falling_edge;
+
+	while (!bitmap_empty(rising, PCA953X_NUM_IRQ)) {
+		irq = find_first_bit(rising, PCA953X_NUM_IRQ);
+		clear_bit(irq, rising);
+		generic_handle_irq(chip->irq_start + irq);
+	}
+	while (!bitmap_empty(falling, PCA953X_NUM_IRQ)) {
+		irq = find_first_bit(falling, PCA953X_NUM_IRQ);
+		clear_bit(irq, falling);
+		generic_handle_irq(chip->irq_start + irq);
+	}
+	chip->last_input = input;
+	mutex_unlock(&chip->irq_lock);
+}
+
+static void pca953x_irq_handler(unsigned int irq, struct irq_desc *desc)
+{
+	struct pca953x_chip *chip = desc->handler_data;
+
+	desc->chip->ack(irq);
+	schedule_work(&chip->irq_work);
+}
+
+static void pca953x_irq_enable(unsigned int irq)
+{
+	struct pca953x_chip *chip = get_irq_chip_data(irq);
+
+	chip->irq_mask |= 1u << (irq - chip->irq_start);
+}
+
+static void pca953x_irq_disable(unsigned int irq)
+{
+	struct pca953x_chip *chip = get_irq_chip_data(irq);
+
+	chip->irq_mask &= ~(1u << (irq - chip->irq_start));
+}
+
+static int pca953x_irq_type(unsigned int irq, unsigned int trigger)
+{
+	struct pca953x_chip *chip = get_irq_chip_data(irq);
+	unsigned short mask = 1u << (irq - chip->irq_start);
+
+	if (trigger & IRQ_TYPE_EDGE_RISING)
+		chip->irq_rising_edge |= mask;
+	else
+		chip->irq_rising_edge &= ~mask;
+	if (trigger & IRQ_TYPE_EDGE_FALLING)
+		chip->irq_falling_edge |= mask;
+	else
+		chip->irq_falling_edge &= ~mask;
+	return 0;
+}
+
+static struct irq_chip pca953x_irqchip = {
+	.name		= "GPIO",
+	.enable		= pca953x_irq_enable,
+	.disable	= pca953x_irq_disable,
+	.set_type	= pca953x_irq_type,
+};
+
+static void pca953x_setup_irq(struct i2c_client *client)
+{
+	struct pca953x_chip *chip = i2c_get_clientdata(client);
+	int i;
+
+	if (!client->irq)
+		return;
+
+	mutex_init(&chip->irq_lock);
+	chip->irq_start = gpio_to_irq(chip->gpio_start);
+	for (i = 0; i < chip->gpio_chip.ngpio; i++) {
+		set_irq_chip(chip->irq_start + i, &pca953x_irqchip);
+		set_irq_chip_data(chip->irq_start + i, chip);
+		set_irq_handler(chip->irq_start + i, handle_edge_irq);
+		set_irq_flags(chip->irq_start + i, IRQF_VALID);
+	}
+	set_irq_type(client->irq, IRQ_TYPE_EDGE_FALLING);
+	set_irq_data(client->irq, chip);
+	set_irq_chained_handler(client->irq, pca953x_irq_handler);
+	INIT_WORK(&chip->irq_work, pca953x_irq_work);
+}
+
 static int __devinit pca953x_probe(struct i2c_client *client,
 				   const struct i2c_device_id *id)
 {
 	struct pca953x_platform_data *pdata;
 	struct pca953x_chip *chip;
+	unsigned short input;
 	int ret;

 	chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
@@ -282,12 +392,18 @@ static int __devinit pca953x_probe(struct
i2c_client *client,
 	chip->gpio_start = pdata->gpio_base;

 	chip->names = pdata->names;
+	chip->irq_mask = -1UL;

 	/* initialize cached registers from their original values.
 	 * we can't share this chip with another i2c master.
 	 */
 	pca953x_setup_gpio(chip, id->driver_data);

+	/* clear interrupt status */
+	ret = pca953x_read_reg(chip, PCA953X_INPUT, &input);
+	if (ret)
+		goto out_failed;
+
 	ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output);
 	if (ret)
 		goto out_failed;
@@ -314,6 +430,7 @@ static int __devinit pca953x_probe(struct
i2c_client *client,
 	}

 	i2c_set_clientdata(client, chip);
+	pca953x_setup_irq(client);
 	return 0;

 out_failed:
-- 
1.5.6.5