[PATCH 1/1] iio: use dmaengine_get_dma_device() instead of chan->device->dev
From: Frank . Li
Date: Thu Sep 17 2026 - 18:43:15 EST
From: Frank Li <Frank.Li@xxxxxxx>
Replace direct dma_chan::device::dev access with the proper
dmaengine_get_dma_device() accessor in IIO DMA consumers.
chan->device->dev is not always the device used for DMA mapping.
Some DMA engines support per-channel IOMMU mappings, so different
channels may use different DMA devices. dmaengine_get_dma_device()
returns the correct device for each channel.
This also prepares for making the DMA engine provider data structures
private. DMA consumers should not access DMA engine internals directly.
Assisted-by: LLM
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
Cc: imx@xxxxxxxxxxxxxxx
Cc: vkoul@xxxxxxxxxx
---
drivers/iio/adc/at91-sama5d2_adc.c | 9 ++++++---
drivers/iio/adc/nxp-sar-adc.c | 2 +-
drivers/iio/adc/stm32-adc.c | 10 ++++++----
drivers/iio/adc/stm32-dfsdm-adc.c | 4 ++--
drivers/iio/adc/ti_am335x_adc.c | 4 ++--
drivers/iio/buffer/industrialio-buffer-dmaengine.c | 5 +++--
6 files changed, 20 insertions(+), 14 deletions(-)
diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index e8a5285bb6d4f..0e7d07fb27ca7 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -2016,6 +2016,8 @@ static void at91_adc_dma_init(struct at91_adc_state *st)
unsigned int pages = DIV_ROUND_UP(AT91_HWFIFO_MAX_SIZE *
sample_size * 2, PAGE_SIZE);
+ struct device *dma_dev;
+
if (st->dma_st.dma_chan)
return;
@@ -2026,7 +2028,8 @@ static void at91_adc_dma_init(struct at91_adc_state *st)
goto dma_exit;
}
- st->dma_st.rx_buf = dma_alloc_coherent(st->dma_st.dma_chan->device->dev,
+ dma_dev = dmaengine_get_dma_device(st->dma_st.dma_chan);
+ st->dma_st.rx_buf = dma_alloc_coherent(dma_dev,
pages * PAGE_SIZE,
&st->dma_st.rx_dma_buf,
GFP_KERNEL);
@@ -2054,7 +2057,7 @@ static void at91_adc_dma_init(struct at91_adc_state *st)
return;
dma_free_area:
- dma_free_coherent(st->dma_st.dma_chan->device->dev, pages * PAGE_SIZE,
+ dma_free_coherent(dma_dev, pages * PAGE_SIZE,
st->dma_st.rx_buf, st->dma_st.rx_dma_buf);
dma_chan_disable:
dma_release_channel(st->dma_st.dma_chan);
@@ -2078,7 +2081,7 @@ static void at91_adc_dma_disable(struct at91_adc_state *st)
/* wait for all transactions to be terminated first*/
dmaengine_terminate_sync(st->dma_st.dma_chan);
- dma_free_coherent(st->dma_st.dma_chan->device->dev, pages * PAGE_SIZE,
+ dma_free_coherent(dmaengine_get_dma_device(st->dma_st.dma_chan), pages * PAGE_SIZE,
st->dma_st.rx_buf, st->dma_st.rx_dma_buf);
dma_release_channel(st->dma_st.dma_chan);
st->dma_st.dma_chan = NULL;
diff --git a/drivers/iio/adc/nxp-sar-adc.c b/drivers/iio/adc/nxp-sar-adc.c
index 894d3211b2838..2f716a2f97b80 100644
--- a/drivers/iio/adc/nxp-sar-adc.c
+++ b/drivers/iio/adc/nxp-sar-adc.c
@@ -604,7 +604,7 @@ static void nxp_sar_adc_dma_cb(void *data)
dma_buf = &info->dma_buf;
dma_samples = (u32 *)dma_buf->buf;
- dev_dma = info->dma_chan->device->dev;
+ dev_dma = dmaengine_get_dma_device(info->dma_chan);
/*
* DMA in some corner cases might have already be charged for
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 5c6c06b269be6..6aa672177970a 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -2456,6 +2456,7 @@ static int stm32_adc_dma_request(struct device *dev, struct iio_dev *indio_dev)
{
struct stm32_adc *adc = iio_priv(indio_dev);
struct dma_slave_config config = { };
+ struct device *dma_dev;
int ret;
adc->dma_chan = dma_request_chan(dev, "rx");
@@ -2470,7 +2471,8 @@ static int stm32_adc_dma_request(struct device *dev, struct iio_dev *indio_dev)
return 0;
}
- adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev,
+ dma_dev = dmaengine_get_dma_device(adc->dma_chan);
+ adc->rx_buf = dma_alloc_coherent(dma_dev,
STM32_DMA_BUFFER_SIZE,
&adc->rx_dma_buf, GFP_KERNEL);
if (!adc->rx_buf) {
@@ -2490,7 +2492,7 @@ static int stm32_adc_dma_request(struct device *dev, struct iio_dev *indio_dev)
return 0;
err_free:
- dma_free_coherent(adc->dma_chan->device->dev, STM32_DMA_BUFFER_SIZE,
+ dma_free_coherent(dma_dev, STM32_DMA_BUFFER_SIZE,
adc->rx_buf, adc->rx_dma_buf);
err_release:
dma_release_channel(adc->dma_chan);
@@ -2617,7 +2619,7 @@ static int stm32_adc_probe(struct platform_device *pdev)
err_dma_disable:
if (adc->dma_chan) {
- dma_free_coherent(adc->dma_chan->device->dev,
+ dma_free_coherent(dmaengine_get_dma_device(adc->dma_chan),
STM32_DMA_BUFFER_SIZE,
adc->rx_buf, adc->rx_dma_buf);
dma_release_channel(adc->dma_chan);
@@ -2640,7 +2642,7 @@ static void stm32_adc_remove(struct platform_device *pdev)
pm_runtime_put_noidle(&pdev->dev);
iio_triggered_buffer_cleanup(indio_dev);
if (adc->dma_chan) {
- dma_free_coherent(adc->dma_chan->device->dev,
+ dma_free_coherent(dmaengine_get_dma_device(adc->dma_chan),
STM32_DMA_BUFFER_SIZE,
adc->rx_buf, adc->rx_dma_buf);
dma_release_channel(adc->dma_chan);
diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index 00f05e167afc9..674767da3ac37 100644
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -1484,7 +1484,7 @@ static void stm32_dfsdm_dma_release(struct iio_dev *indio_dev)
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
if (adc->dma_chan) {
- dma_free_coherent(adc->dma_chan->device->dev,
+ dma_free_coherent(dmaengine_get_dma_device(adc->dma_chan),
DFSDM_DMA_BUFFER_SIZE,
adc->rx_buf, adc->dma_buf);
dma_release_channel(adc->dma_chan);
@@ -1504,7 +1504,7 @@ static int stm32_dfsdm_dma_request(struct device *dev,
return ret;
}
- adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev,
+ adc->rx_buf = dma_alloc_coherent(dmaengine_get_dma_device(adc->dma_chan),
DFSDM_DMA_BUFFER_SIZE,
&adc->dma_buf, GFP_KERNEL);
if (!adc->rx_buf) {
diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index 1516dd332f905..e53c839e87ef3 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -548,7 +548,7 @@ static int tiadc_request_dma(struct platform_device *pdev,
}
/* RX buffer */
- dma->buf = dma_alloc_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
+ dma->buf = dma_alloc_coherent(dmaengine_get_dma_device(dma->chan), DMA_BUFFER_SIZE,
&dma->addr, GFP_KERNEL);
if (!dma->buf)
goto err;
@@ -688,7 +688,7 @@ static void tiadc_remove(struct platform_device *pdev)
u32 step_en;
if (dma->chan) {
- dma_free_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
+ dma_free_coherent(dmaengine_get_dma_device(dma->chan), DMA_BUFFER_SIZE,
dma->buf, dma->addr);
dma_release_channel(dma->chan);
}
diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
index 559880e0cad72..b9f8b5b3aa6b6 100644
--- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c
+++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c
@@ -254,6 +254,7 @@ static const struct iio_dev_attr *iio_dmaengine_buffer_attrs[] = {
*/
static struct iio_buffer *iio_dmaengine_buffer_alloc(struct dma_chan *chan)
{
+ struct device *dma_dev = dmaengine_get_dma_device(chan);
struct dmaengine_buffer *dmaengine_buffer;
unsigned int width, src_width, dest_width;
struct dma_slave_caps caps;
@@ -281,9 +282,9 @@ static struct iio_buffer *iio_dmaengine_buffer_alloc(struct dma_chan *chan)
INIT_LIST_HEAD(&dmaengine_buffer->active);
dmaengine_buffer->chan = chan;
dmaengine_buffer->align = width;
- dmaengine_buffer->max_size = dma_get_max_seg_size(chan->device->dev);
+ dmaengine_buffer->max_size = dma_get_max_seg_size(dma_dev);
- iio_dma_buffer_init(&dmaengine_buffer->queue, chan->device->dev,
+ iio_dma_buffer_init(&dmaengine_buffer->queue, dma_dev,
&iio_dmaengine_default_ops);
dmaengine_buffer->queue.buffer.attrs = iio_dmaengine_buffer_attrs;
--
2.43.0