[PATCH] gpio: pcf857x: cleanup irq_demux_work and use threaded irq

[George Cherian]

This patch
        - removes the irq_demux_work
        - Uses devm_request_threaded_irq
        - Call the user handler iff gpio_to_irq is done.

Signed-off-by: George Cherian <george.cher...@ti.com>
---
 drivers/gpio/gpio-pcf857x.c | 52 +++++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 25 deletions(-)

diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c
index 947cff4..aebbba6 100644
--- a/drivers/gpio/gpio-pcf857x.c
+++ b/drivers/gpio/gpio-pcf857x.c
@@ -30,7 +30,7 @@
 #include <linux/of_device.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
-#include <linux/workqueue.h>
+#include <linux/of_irq.h>
 
 
 static const struct i2c_device_id pcf857x_id[] = {
@@ -89,12 +89,12 @@ 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                     irq_mapped;     /* mapped gpio irqs  */
 
        int (*write)(struct i2c_client *client, unsigned data);
        int (*read)(struct i2c_client *client);
@@ -187,38 +187,35 @@ 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);
+       int ret;
 
-       return irq_create_mapping(gpio->irq_domain, offset);
+       ret = irq_create_mapping(gpio->irq_domain, offset);
+       if (ret > 0)
+               gpio->irq_mapped |= (1 << offset);
+
+       return ret;
 }
 
-static void pcf857x_irq_demux_work(struct work_struct *work)
+static irqreturn_t pcf857x_irq(int irq, void *data)
 {
-       struct pcf857x *gpio = container_of(work,
-                                              struct pcf857x,
-                                              work);
+       struct pcf857x  *gpio = data;
        unsigned long change, i, status, flags;
 
        status = gpio->read(gpio->client);
 
        spin_lock_irqsave(&gpio->slock, flags);
+
+       /*
+        * call the interrupt handler iff gpio is used as
+        * interrupt source, just to avoid bad irqs
+        */
 
-       change = gpio->status ^ status;
+       change = ((gpio->status ^ status) & gpio->irq_mapped);
        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;
 }
@@ -226,9 +223,13 @@ static irqreturn_t pcf857x_irq_demux(int irq, void *data)
 static int pcf857x_irq_domain_map(struct irq_domain *domain, unsigned int virq,
                                 irq_hw_number_t hw)
 {
+       struct pcf857x  *gpio = domain->host_data;
        irq_set_chip_and_handler(virq,
                                 &dummy_irq_chip,
                                 handle_level_irq);
+       set_irq_flags(virq, IRQF_VALID);
+       gpio->irq_mapped |= (1 << hw);
+
        return 0;
 }
 
@@ -241,30 +242,31 @@ 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 i2c_client *client)
 {
        int status;
+       struct device_node *node;
 
+       node = client->dev.of_node;
        gpio->irq_domain = irq_domain_add_linear(client->dev.of_node,
                                                 gpio->chip.ngpio,
                                                 &pcf857x_irq_domain_ops,
-                                                NULL);
+                                                gpio);
        if (!gpio->irq_domain)
                goto fail;
 
        /* enable real irq */
-       status = request_irq(client->irq, pcf857x_irq_demux, 0,
-                            dev_name(&client->dev), gpio);
+       status = devm_request_threaded_irq(&client->dev, client->irq,
+                               NULL, pcf857x_irq, IRQF_ONESHOT |
+                               IRQF_TRIGGER_FALLING,
+                               dev_name(&client->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               = client->irq;
 
-- 
1.8.1.4

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