Uses for_each_set_bit() macro to loop over channel bitmaps.

Signed-off-by: Daniel Campello <campe...@chromium.org>
Reviewed-by: Andy Shevchenko <andy.shevche...@gmail.com>
Reviewed-by: Stephen Boyd <swb...@chromium.org>
---

Changes in v4: None
Changes in v3:
 - Added static assert for number of channels.

Changes in v2:
 - Changed prox_stat to chan_prox_stat bitmap.

 drivers/iio/proximity/sx9310.c | 39 ++++++++++++++++++----------------
 1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/drivers/iio/proximity/sx9310.c b/drivers/iio/proximity/sx9310.c
index 20a26b73b5ae90..45569a0657060c 100644
--- a/drivers/iio/proximity/sx9310.c
+++ b/drivers/iio/proximity/sx9310.c
@@ -118,6 +118,7 @@
 
 /* 4 hardware channels, as defined in STAT0: COMB, CS2, CS1 and CS0. */
 #define SX9310_NUM_CHANNELS                            4
+static_assert(SX9310_NUM_CHANNELS < BITS_PER_LONG);
 
 struct sx9310_data {
        /* Serialize access to registers and channel configuration */
@@ -129,7 +130,7 @@ struct sx9310_data {
         * Last reading of the proximity status for each channel.
         * We only send an event to user space when this changes.
         */
-       bool prox_stat[SX9310_NUM_CHANNELS];
+       unsigned long chan_prox_stat;
        bool trigger_enabled;
        /* Ensure correct alignment of timestamp when present. */
        struct {
@@ -139,7 +140,8 @@ struct sx9310_data {
        /* Remember enabled channels and sample rate during suspend. */
        unsigned int suspend_ctrl0;
        struct completion completion;
-       unsigned int chan_read, chan_event;
+       unsigned long chan_read;
+       unsigned long chan_event;
        int channel_users[SX9310_NUM_CHANNELS];
        unsigned int whoami;
 };
@@ -282,15 +284,16 @@ static const struct regmap_config sx9310_regmap_config = {
 };
 
 static int sx9310_update_chan_en(struct sx9310_data *data,
-                                unsigned int chan_read,
-                                unsigned int chan_event)
+                                unsigned long chan_read,
+                                unsigned long chan_event)
 {
        int ret;
+       unsigned long channels = chan_read | chan_event;
 
-       if ((data->chan_read | data->chan_event) != (chan_read | chan_event)) {
+       if ((data->chan_read | data->chan_event) != channels) {
                ret = regmap_update_bits(data->regmap, SX9310_REG_PROX_CTRL0,
                                         SX9310_REG_PROX_CTRL0_SENSOREN_MASK,
-                                        chan_read | chan_event);
+                                        channels);
                if (ret)
                        return ret;
        }
@@ -531,6 +534,7 @@ static void sx9310_push_events(struct iio_dev *indio_dev)
        unsigned int val, chan;
        struct sx9310_data *data = iio_priv(indio_dev);
        s64 timestamp = iio_get_time_ns(indio_dev);
+       unsigned long prox_changed;
 
        /* Read proximity state on all channels */
        ret = regmap_read(data->regmap, SX9310_REG_STAT0, &val);
@@ -539,24 +543,23 @@ static void sx9310_push_events(struct iio_dev *indio_dev)
                return;
        }
 
-       for (chan = 0; chan < SX9310_NUM_CHANNELS; chan++) {
+       /*
+        * Only iterate over channels with changes on proximity status that have
+        * events enabled.
+        */
+       prox_changed = (data->chan_prox_stat ^ val) & data->chan_event;
+
+       for_each_set_bit(chan, &prox_changed, SX9310_NUM_CHANNELS) {
                int dir;
                u64 ev;
-               bool new_prox = val & BIT(chan);
-
-               if (!(data->chan_event & BIT(chan)))
-                       continue;
-               if (new_prox == data->prox_stat[chan])
-                       /* No change on this channel. */
-                       continue;
 
-               dir = new_prox ? IIO_EV_DIR_FALLING : IIO_EV_DIR_RISING;
+               dir = val & BIT(chan) ? IIO_EV_DIR_FALLING : IIO_EV_DIR_RISING;
                ev = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, chan,
                                          IIO_EV_TYPE_THRESH, dir);
 
                iio_push_event(indio_dev, ev, timestamp);
-               data->prox_stat[chan] = new_prox;
        }
+       data->chan_prox_stat = val;
 }
 
 static irqreturn_t sx9310_irq_thread_handler(int irq, void *private)
@@ -713,13 +716,13 @@ static irqreturn_t sx9310_trigger_handler(int irq, void 
*private)
 static int sx9310_buffer_preenable(struct iio_dev *indio_dev)
 {
        struct sx9310_data *data = iio_priv(indio_dev);
-       unsigned int channels = 0;
+       unsigned long channels = 0;
        int bit, ret;
 
        mutex_lock(&data->mutex);
        for_each_set_bit(bit, indio_dev->active_scan_mask,
                         indio_dev->masklength)
-               channels |= BIT(indio_dev->channels[bit].channel);
+               __set_bit(indio_dev->channels[bit].channel, &channels);
 
        ret = sx9310_update_chan_en(data, channels, data->chan_event);
        mutex_unlock(&data->mutex);
-- 
2.28.0.163.g6104cc2f0b6-goog

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