mfd: Convert AB3100 driver to threaded IRQ

This converts the AB3100 core MFD driver to use a threaded
interrupt handler instead of the explicit top/bottom-half
construction with a workqueue. This saves some code and make it
more similar to other modern MFD drivers.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

2 files changed, 13 insertions, 33 deletions

diff --git a/drivers/mfd/ab3100-core.c b/drivers/mfd/ab3100-core.c
index fd42a80e7bf9..aa3824a1b4f2 100644
--- a/drivers/mfd/ab3100-core.c
+++ b/drivers/mfd/ab3100-core.c
@@ -365,10 +365,13 @@ int ab3100_event_registers_startup_state_get(struct ab3100 *ab3100,
 }
 EXPORT_SYMBOL(ab3100_event_registers_startup_state_get);
 
-/* Interrupt handling worker */
-static void ab3100_work(struct work_struct *work)
+/*
+ * This is a threaded interrupt handler so we can make some
+ * I2C calls etc.
+ */
+static irqreturn_t ab3100_irq_handler(int irq, void *data)
 {
-        struct ab3100 *ab3100 = container_of(work, struct ab3100, work);
+        struct ab3100 *ab3100 = data;
         u8 event_regs[3];
         u32 fatevent;
         int err;
@@ -376,7 +379,7 @@ static void ab3100_work(struct work_struct *work)
         err = ab3100_get_register_page_interruptible(ab3100, AB3100_EVENTA1,
                                        event_regs, 3);
         if (err)
-                goto err_event_wq;
+                goto err_event;
 
         fatevent = (event_regs[0] << 16) |
                 (event_regs[1] << 8) |
@@ -398,29 +401,11 @@ static void ab3100_work(struct work_struct *work)
         dev_dbg(ab3100->dev,
                 "IRQ Event: 0x%08x\n", fatevent);
 
-        /* By now the IRQ should be acked and deasserted so enable it again */
-        enable_irq(ab3100->i2c_client->irq);
-        return;
+        return IRQ_HANDLED;
 
- err_event_wq:
+ err_event:
         dev_dbg(ab3100->dev,
-                "error in event workqueue\n");
-        /* Enable the IRQ anyway, what choice do we have? */
-        enable_irq(ab3100->i2c_client->irq);
-        return;
-}
-
-static irqreturn_t ab3100_irq_handler(int irq, void *data)
-{
-        struct ab3100 *ab3100 = data;
-        /*
-         * Disable the IRQ and dispatch a worker to handle the
-         * event. Since the chip resides on I2C this is slow
-         * stuff and we will re-enable the interrupts once th
-         * worker has finished.
-         */
-        disable_irq_nosync(irq);
-        schedule_work(&ab3100->work);
+                "error reading event status\n");
         return IRQ_HANDLED;
 }
 
@@ -904,12 +889,10 @@ static int __init ab3100_probe(struct i2c_client *client,
         if (err)
                 goto exit_no_setup;
 
-        INIT_WORK(&ab3100->work, ab3100_work);
-
         /* This real unpredictable IRQ is of course sampled for entropy */
-        err = request_irq(client->irq, ab3100_irq_handler,
-                          IRQF_DISABLED | IRQF_SAMPLE_RANDOM,
-                          "AB3100 IRQ", ab3100);
+        err = request_threaded_irq(client->irq, NULL, ab3100_irq_handler,
+                          IRQF_ONESHOT,
+                          "ab3100-core", ab3100);
         if (err)
                 goto exit_no_irq;
 
diff --git a/include/linux/mfd/ab3100.h b/include/linux/mfd/ab3100.h
index e9aa4c9d749d..9a881c305a50 100644
--- a/include/linux/mfd/ab3100.h
+++ b/include/linux/mfd/ab3100.h
@@ -6,7 +6,6 @@
  */
 
 #include <linux/device.h>
-#include <linux/workqueue.h>
 #include <linux/regulator/machine.h>
 
 #ifndef MFD_AB3100_H
@@ -74,7 +73,6 @@
  * @testreg_client: secondary client for test registers
  * @chip_name: name of this chip variant
  * @chip_id: 8 bit chip ID for this chip variant
- * @work: an event handling worker
  * @event_subscribers: event subscribers are listed here
  * @startup_events: a copy of the first reading of the event registers
  * @startup_events_read: whether the first events have been read
@@ -90,7 +88,6 @@ struct ab3100 {
         struct i2c_client *testreg_client;
         char chip_name[32];
         u8 chip_id;
-        struct work_struct work;
         struct blocking_notifier_head event_subscribers;
         u32 startup_events;
         bool startup_events_read;