iio: proximity: sx9500: use stack allocated struct for scan data

Use a stack-allocated struct in sx9500_trigger_handler() to hold the
IIO buffer scan data. Since the scan buffer isn't used outside of this
function, it doesn't need to be in struct sx9500_data.

By always allocating enough space for the maximum number of channels,
we can avoid having to reallocate the buffer each time buffered reads
are enabled.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250722-iio-use-more-iio_declare_buffer_with_ts-4-v2-1-9e566f3a4c6a@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/proximity/sx9500.c b/drivers/iio/proximity/sx9500.c
index 05844f17a15f6980ab7d55536e5fecfc5e4fe8c0..6c67bae7488c4533ea513597f182af504a22c86d 100644 (file)
--- a/drivers/iio/proximity/sx9500.c
+++ b/drivers/iio/proximity/sx9500.c
@@ -88,7 +88,6 @@ struct sx9500_data {
        bool prox_stat[SX9500_NUM_CHANNELS];
        bool event_enabled[SX9500_NUM_CHANNELS];
        bool trigger_enabled;
-       u16 *buffer;
        /* Remember enabled channels and sample rate during suspend. */
        unsigned int suspend_ctrl0;
        struct completion completion;
@@ -578,22 +577,6 @@ out_unlock:
        return ret;
 }
 
-static int sx9500_update_scan_mode(struct iio_dev *indio_dev,
-                                  const unsigned long *scan_mask)
-{
-       struct sx9500_data *data = iio_priv(indio_dev);
-
-       mutex_lock(&data->mutex);
-       kfree(data->buffer);
-       data->buffer = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
-       mutex_unlock(&data->mutex);
-
-       if (data->buffer == NULL)
-               return -ENOMEM;
-
-       return 0;
-}
-
 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(
        "2.500000 3.333333 5 6.666666 8.333333 11.111111 16.666666 33.333333");
 
@@ -612,7 +595,6 @@ static const struct iio_info sx9500_info = {
        .write_raw = &sx9500_write_raw,
        .read_event_config = &sx9500_read_event_config,
        .write_event_config = &sx9500_write_event_config,
-       .update_scan_mode = &sx9500_update_scan_mode,
 };
 
 static int sx9500_set_trigger_state(struct iio_trigger *trig,
@@ -649,6 +631,10 @@ static irqreturn_t sx9500_trigger_handler(int irq, void *private)
        struct iio_dev *indio_dev = pf->indio_dev;
        struct sx9500_data *data = iio_priv(indio_dev);
        int val, bit, ret, i = 0;
+       struct {
+               u16 chan[SX9500_NUM_CHANNELS];
+               aligned_s64 timestamp;
+       } scan = { };
 
        mutex_lock(&data->mutex);
 
@@ -658,10 +644,10 @@ static irqreturn_t sx9500_trigger_handler(int irq, void *private)
                if (ret < 0)
                        goto out;
 
-               data->buffer[i++] = val;
+               scan.chan[i++] = val;
        }
 
-       iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
+       iio_push_to_buffers_with_timestamp(indio_dev, &scan,
                                           iio_get_time_ns(indio_dev));
 
 out:
@@ -984,7 +970,6 @@ static void sx9500_remove(struct i2c_client *client)
        iio_triggered_buffer_cleanup(indio_dev);
        if (client->irq > 0)
                iio_trigger_unregister(data->trig);
-       kfree(data->buffer);
 }
 
 static int sx9500_suspend(struct device *dev)