gpio: pcf857x: enable gpio_to_irq() support

pcf857x chip has some pins, but interrupt pin is only 1 pin.
And gpiolib requests 1 interrupt per 1 gpio pin.

Thus, this patch added demuxed irq to pcf857x driver,
and enabled gpio_to_irq().

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c
index 076e236..12e3e48 100644 (file)
--- a/drivers/gpio/gpio-pcf857x.c
+++ b/drivers/gpio/gpio-pcf857x.c
@@ -23,7 +23,12 @@
 #include <linux/gpio.h>
 #include <linux/i2c.h>
 #include <linux/i2c/pcf857x.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
 #include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
 
 
 static const struct i2c_device_id pcf857x_id[] = {
@@ -60,7 +65,12 @@ struct pcf857x {
        struct gpio_chip        chip;
        struct i2c_client       *client;
        struct mutex            lock;           /* protect 'out' */
+       struct work_struct      work;           /* irq demux work */
+       struct irq_domain       *irq_domain;    /* for irq demux  */
+       spinlock_t              slock;          /* protect irq demux */
        unsigned                out;            /* software latch */
+       unsigned                status;         /* current status */
+       int                     irq;            /* real irq number */
 
        int (*write)(struct i2c_client *client, unsigned data);
        int (*read)(struct i2c_client *client);
@@ -150,6 +160,100 @@ static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value)
 
 /*-------------------------------------------------------------------------*/
 
+static int pcf857x_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+       struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
+
+       return irq_create_mapping(gpio->irq_domain, offset);
+}
+
+static void pcf857x_irq_demux_work(struct work_struct *work)
+{
+       struct pcf857x *gpio = container_of(work,
+                                              struct pcf857x,
+                                              work);
+       unsigned long change, i, status, flags;
+
+       status = gpio->read(gpio->client);
+
+       spin_lock_irqsave(&gpio->slock, flags);
+
+       change = gpio->status ^ status;
+       for_each_set_bit(i, &change, gpio->chip.ngpio)
+               generic_handle_irq(irq_find_mapping(gpio->irq_domain, i));
+       gpio->status = status;
+
+       spin_unlock_irqrestore(&gpio->slock, flags);
+}
+
+static irqreturn_t pcf857x_irq_demux(int irq, void *data)
+{
+       struct pcf857x  *gpio = data;
+
+       /*
+        * pcf857x can't read/write data here,
+        * since i2c data access might go to sleep.
+        */
+       schedule_work(&gpio->work);
+
+       return IRQ_HANDLED;
+}
+
+static int pcf857x_irq_domain_map(struct irq_domain *domain, unsigned int virq,
+                                irq_hw_number_t hw)
+{
+       irq_set_chip_and_handler(virq,
+                                &dummy_irq_chip,
+                                handle_level_irq);
+       return 0;
+}
+
+static struct irq_domain_ops pcf857x_irq_domain_ops = {
+       .map    = pcf857x_irq_domain_map,
+};
+
+static void pcf857x_irq_domain_cleanup(struct pcf857x *gpio)
+{
+       if (gpio->irq_domain)
+               irq_domain_remove(gpio->irq_domain);
+
+       if (gpio->irq)
+               free_irq(gpio->irq, gpio);
+}
+
+static int pcf857x_irq_domain_init(struct pcf857x *gpio,
+                                  struct pcf857x_platform_data *pdata,
+                                  struct device *dev)
+{
+       int status;
+
+       gpio->irq_domain = irq_domain_add_linear(dev->of_node,
+                                                gpio->chip.ngpio,
+                                                &pcf857x_irq_domain_ops,
+                                                NULL);
+       if (!gpio->irq_domain)
+               goto fail;
+
+       /* enable real irq */
+       status = request_irq(pdata->irq, pcf857x_irq_demux, 0,
+                            dev_name(dev), gpio);
+       if (status)
+               goto fail;
+
+       /* enable gpio_to_irq() */
+       INIT_WORK(&gpio->work, pcf857x_irq_demux_work);
+       gpio->chip.to_irq       = pcf857x_to_irq;
+       gpio->irq               = pdata->irq;
+
+       return 0;
+
+fail:
+       pcf857x_irq_domain_cleanup(gpio);
+       return -EINVAL;
+}
+
+/*-------------------------------------------------------------------------*/
+
 static int pcf857x_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
 {
@@ -168,6 +272,7 @@ static int pcf857x_probe(struct i2c_client *client,
                return -ENOMEM;
 
        mutex_init(&gpio->lock);
+       spin_lock_init(&gpio->slock);
 
        gpio->chip.base                 = pdata ? pdata->gpio_base : -1;
        gpio->chip.can_sleep            = 1;
@@ -179,6 +284,15 @@ static int pcf857x_probe(struct i2c_client *client,
        gpio->chip.direction_output     = pcf857x_output;
        gpio->chip.ngpio                = id->driver_data;
 
+       /* enable gpio_to_irq() if platform has settings */
+       if (pdata->irq) {
+               status = pcf857x_irq_domain_init(gpio, pdata, &client->dev);
+               if (status < 0) {
+                       dev_err(&client->dev, "irq_domain init failed\n");
+                       goto fail;
+               }
+       }
+
        /* NOTE:  the OnSemi jlc1562b is also largely compatible with
         * these parts, notably for output.  It has a low-resolution
         * DAC instead of pin change IRQs; and its inputs can be the
@@ -248,6 +362,7 @@ static int pcf857x_probe(struct i2c_client *client,
         * all-ones reset state.  Otherwise it flags pins to be driven low.
         */
        gpio->out = pdata ? ~pdata->n_latch : ~0;
+       gpio->status = gpio->out;
 
        status = gpiochip_add(&gpio->chip);
        if (status < 0)
@@ -278,6 +393,10 @@ static int pcf857x_probe(struct i2c_client *client,
 fail:
        dev_dbg(&client->dev, "probe error %d for '%s'\n",
                        status, client->name);
+
+       if (pdata->irq)
+               pcf857x_irq_domain_cleanup(gpio);
+
        kfree(gpio);
        return status;
 }
@@ -299,6 +418,9 @@ static int pcf857x_remove(struct i2c_client *client)
                }
        }
 
+       if (pdata->irq)
+               pcf857x_irq_domain_cleanup(gpio);
+
        status = gpiochip_remove(&gpio->chip);
        if (status == 0)
                kfree(gpio);

diff --git a/include/linux/i2c/pcf857x.h b/include/linux/i2c/pcf857x.h
index 0767a2a..781e6bd 100644 (file)
--- a/include/linux/i2c/pcf857x.h
+++ b/include/linux/i2c/pcf857x.h
@@ -10,6 +10,7 @@
  * @setup: optional callback issued once the GPIOs are valid
  * @teardown: optional callback issued before the GPIOs are invalidated
  * @context: optional parameter passed to setup() and teardown()
+ * @irq: optional interrupt number
  *
  * In addition to the I2C_BOARD_INFO() state appropriate to each chip,
  * the i2c_board_info used with the pcf875x driver must provide its
@@ -39,6 +40,8 @@ struct pcf857x_platform_data {
                                        int gpio, unsigned ngpio,
                                        void *context);
        void            *context;
+
+       int             irq;
 };
 
 #endif /* __LINUX_PCF857X_H */