staging:iio:trigger:bfintmr: Only enable timer when necessary

This patch hooks up the set_trigger_state callback for the blackfin timer
trigger driver and only enables the timer when a trigger consumer requests it to
be enabled. There really is no reason to keep the timer running and generate
interrupts if nobody is listening to them.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/staging/iio/trigger/iio-trig-bfin-timer.c b/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
index 2772ea2fb0dc54a5d33f4bce6972fbc5f331860c..d9d3dc98885c9c6847330c2cd0047469d5d92a01 100644 (file)
--- a/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
+++ b/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
@@ -57,12 +57,28 @@ struct bfin_tmr_state {
        int irq;
 };
 
+static int iio_bfin_tmr_set_state(struct iio_trigger *trig, bool state)
+{
+       struct bfin_tmr_state *st = trig->private_data;
+
+       if (get_gptimer_period(st->t->id) == 0)
+               return -EINVAL;
+
+       if (state)
+               enable_gptimers(st->t->bit);
+       else
+               disable_gptimers(st->t->bit);
+
+       return 0;
+}
+
 static ssize_t iio_bfin_tmr_frequency_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
 {
        struct iio_trigger *trig = to_iio_trigger(dev);
        struct bfin_tmr_state *st = trig->private_data;
        long val;
+       bool enabled;
        int ret;
 
        ret = strict_strtoul(buf, 10, &val);
@@ -74,7 +90,10 @@ static ssize_t iio_bfin_tmr_frequency_store(struct device *dev,
                goto error_ret;
        }
 
-       disable_gptimers(st->t->bit);
+       enabled = get_enabled_gptimers() & st->t->bit;
+
+       if (enabled)
+               disable_gptimers(st->t->bit);
 
        if (!val)
                goto error_ret;
@@ -87,7 +106,9 @@ static ssize_t iio_bfin_tmr_frequency_store(struct device *dev,
 
        set_gptimer_period(st->t->id, val);
        set_gptimer_pwidth(st->t->id, 1);
-       enable_gptimers(st->t->bit);
+
+       if (enabled)
+               enable_gptimers(st->t->bit);
 
 error_ret:
        return ret ? ret : count;
@@ -127,7 +148,6 @@ static const struct attribute_group *iio_bfin_tmr_trigger_attr_groups[] = {
        NULL
 };
 
-
 static irqreturn_t iio_bfin_tmr_trigger_isr(int irq, void *devid)
 {
        struct bfin_tmr_state *st = devid;
@@ -151,6 +171,7 @@ static int iio_bfin_tmr_get_number(int irq)
 
 static const struct iio_trigger_ops iio_bfin_tmr_trigger_ops = {
        .owner = THIS_MODULE,
+       .set_trigger_state = iio_bfin_tmr_set_state,
 };
 
 static int __devinit iio_bfin_tmr_trigger_probe(struct platform_device *pdev)