[PATCH v2 02/12] media: stm32: dcmi: perform dmaengine_slave_config at probe
From: Alain Volmat <alain.volmat@foss.st.com>
Date: 2026-01-06 11:59:28
Also in:
dri-devel, linux-devicetree, linux-media, lkml
Subsystem:
media drivers for stm32 - dcmi / dcmipp, media input infrastructure (v4l/dvb), the rest · Maintainers:
Hugues Fruchet, Alain Volmat, Mauro Carvalho Chehab, Linus Torvalds
Perform the dma channel configuration at probe time right after the channel allocation since this is fixed for the whole lifetime of the driver. Signed-off-by: Alain Volmat <alain.volmat@foss.st.com> --- drivers/media/platform/st/stm32/stm32-dcmi.c | 32 +++++++++++++--------------- 1 file changed, 15 insertions(+), 17 deletions(-)
diff --git a/drivers/media/platform/st/stm32/stm32-dcmi.c b/drivers/media/platform/st/stm32/stm32-dcmi.c
index 619b0d981211..787c5d778db2 100644
--- a/drivers/media/platform/st/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/st/stm32/stm32-dcmi.c@@ -301,23 +301,6 @@ static int dcmi_start_dma(struct stm32_dcmi *dcmi, struct dcmi_buf *buf) { struct dma_async_tx_descriptor *desc = NULL; - struct dma_slave_config config; - int ret; - - memset(&config, 0, sizeof(config)); - - config.src_addr = (dma_addr_t)dcmi->res->start + DCMI_DR; - config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; - config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; - config.dst_maxburst = 4; - - /* Configure DMA channel */ - ret = dmaengine_slave_config(dcmi->dma_chan, &config); - if (ret < 0) { - dev_err(dcmi->dev, "%s: DMA channel config failed (%d)\n", - __func__, ret); - return ret; - } /* * Avoid call of dmaengine_terminate_sync() between
@@ -1888,6 +1871,7 @@ static int dcmi_probe(struct platform_device *pdev) struct vb2_queue *q; struct dma_chan *chan; struct dma_slave_caps caps; + struct dma_slave_config dma_config; struct clk *mclk; int ret = 0;
@@ -1954,6 +1938,19 @@ static int dcmi_probe(struct platform_device *pdev) if (!ret && caps.max_sg_burst) dcmi->dma_max_burst = caps.max_sg_burst * DMA_SLAVE_BUSWIDTH_4_BYTES; + memset(&dma_config, 0, sizeof(dma_config)); + + dma_config.src_addr = (dma_addr_t)dcmi->res->start + DCMI_DR; + dma_config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + + /* Configure DMA channel */ + ret = dmaengine_slave_config(chan, &dma_config); + if (ret < 0) { + dev_err(dcmi->dev, "%s: DMA channel config failed (%d)\n", + __func__, ret); + goto err_dma_slave_config; + } + spin_lock_init(&dcmi->irqlock); mutex_init(&dcmi->lock); mutex_init(&dcmi->dma_lock);
@@ -2072,6 +2069,7 @@ static int dcmi_probe(struct platform_device *pdev) v4l2_device_unregister(&dcmi->v4l2_dev); err_media_device_cleanup: media_device_cleanup(&dcmi->mdev); +err_dma_slave_config: dma_release_channel(dcmi->dma_chan); return ret;
--
2.34.1