This change has a few parts:
1. Remove the buffer from the trigger handler's stack
2. Having it dynamically allocated means it should be cache-aligned
3. The buffer would now adapt to the actual number of bytes needed,
whether it's more than 16 bytes, or less
4. Having it in the heap somewhere, allows it to work with DMA
This is a fix + enhancement in one.
Fixes: af3008485ea03 ("iio: ad_sigma_delta: allocate data dynamically for samples")
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
---
drivers/iio/adc/ad_sigma_delta.c | 12 ++++++++++--
include/linux/iio/adc/ad_sigma_delta.h | 2 ++
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
index ec0e38566ece..91d5dda53d29 100644
--- a/drivers/iio/adc/ad_sigma_delta.c
+++ b/drivers/iio/adc/ad_sigma_delta.c
@@ -360,6 +360,11 @@ static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
if (ret)
return ret;
+ kfree(sigma_delta->buf_data);
+ sigma_delta->buf_data = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
+ if (!sigma_delta->buf_data)
+ return -ENOMEM;
+
spi_bus_lock(sigma_delta->spi->master);
sigma_delta->bus_locked = true;
sigma_delta->keep_cs_asserted = true;
@@ -403,12 +408,12 @@ static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
+ uint8_t *data = sigma_delta->buf_data;
unsigned int reg_size;
unsigned int data_reg;
- uint8_t data[16];
int ret;
- memset(data, 0x00, 16);
+ memset(data, 0x00, indio_dev->scan_bytes);
reg_size = indio_dev->channels[0].scan_type.realbits +
indio_dev->channels[0].scan_type.shift;
@@ -568,6 +573,9 @@ EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger);
*/
void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev)
{
+ struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
+
+ kfree(sigma_delta->buf_data);
ad_sd_remove_trigger(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
}
diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h
index 6e9fb1932dde..36dc49b8dfd5 100644
--- a/include/linux/iio/adc/ad_sigma_delta.h
+++ b/include/linux/iio/adc/ad_sigma_delta.h
@@ -75,6 +75,8 @@ struct ad_sigma_delta {
const struct ad_sigma_delta_info *info;
+ uint8_t *buf_data;
+
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
--
2.20.1
