Re: [PATCH] i2c: imx-lpi2c: use dmaengine_get_dma_device() for DMA mapping

[Frank Li]

On Wed, Sep 16, 2026 at 11:25:26PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@xxxxxxx>
>
> Replace all chan->device->dev references with
> dmaengine_get_dma_device(chan) so that DMA mapping goes through the
> correct device when the DMA controller has per-channel IOMMU domains
> (chan_dma_dev=true). Without this, DMA map/unmap bypasses the IOMMU
> context configured by the eDMA driver.
>
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> ---

Reviewed-by: Frank Li <Frank.Li@xxxxxxx>


>  drivers/i2c/busses/i2c-imx-lpi2c.c | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
> index 49aabef7f115c..60547006f8b44 100644
> --- a/drivers/i2c/busses/i2c-imx-lpi2c.c
> +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
> @@ -780,7 +780,7 @@ static void lpi2c_dma_unmap(struct lpi2c_imx_dma *dma)
>  	struct dma_chan *chan = dma->dma_data_dir == DMA_FROM_DEVICE
>  				? dma->chan_rx : dma->chan_tx;
>
> -	dma_unmap_single(chan->device->dev, dma->dma_addr,
> +	dma_unmap_single(dmaengine_get_dma_device(chan), dma->dma_addr,
>  			 dma->dma_len, dma->dma_data_dir);
>
>  	dma->dma_data_dir = DMA_NONE;
> @@ -789,7 +789,7 @@ static void lpi2c_dma_unmap(struct lpi2c_imx_dma *dma)
>  static void lpi2c_cleanup_rx_cmd_dma(struct lpi2c_imx_dma *dma)
>  {
>  	dmaengine_terminate_sync(dma->chan_tx);
> -	dma_unmap_single(dma->chan_tx->device->dev, dma->dma_tx_addr,
> +	dma_unmap_single(dmaengine_get_dma_device(dma->chan_tx), dma->dma_tx_addr,
>  			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
>  }
>
> @@ -817,10 +817,10 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
>  	struct dma_chan *txchan = dma->chan_tx;
>  	dma_cookie_t cookie;
>
> -	dma->dma_tx_addr = dma_map_single(txchan->device->dev,
> +	dma->dma_tx_addr = dma_map_single(dmaengine_get_dma_device(txchan),
>  					  dma->rx_cmd_buf, dma->rx_cmd_buf_len,
>  					  DMA_TO_DEVICE);
> -	if (dma_mapping_error(txchan->device->dev, dma->dma_tx_addr)) {
> +	if (dma_mapping_error(dmaengine_get_dma_device(txchan), dma->dma_tx_addr)) {
>  		dev_err(&lpi2c_imx->adapter.dev, "DMA map failed, use pio\n");
>  		return -EINVAL;
>  	}
> @@ -844,12 +844,12 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
>  	return 0;
>
>  desc_prepare_err_exit:
> -	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
> +	dma_unmap_single(dmaengine_get_dma_device(txchan), dma->dma_tx_addr,
>  			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
>  	return -EINVAL;
>
>  submit_err_exit:
> -	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
> +	dma_unmap_single(dmaengine_get_dma_device(txchan), dma->dma_tx_addr,
>  			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
>  	dmaengine_desc_free(rx_cmd_desc);
>  	return -EINVAL;
> @@ -872,9 +872,9 @@ static int lpi2c_dma_submit(struct lpi2c_imx_struct *lpi2c_imx)
>  		dma->dma_transfer_dir = DMA_MEM_TO_DEV;
>  	}
>
> -	dma->dma_addr = dma_map_single(chan->device->dev,
> +	dma->dma_addr = dma_map_single(dmaengine_get_dma_device(chan),
>  				       dma->dma_buf, dma->dma_len, dma->dma_data_dir);
> -	if (dma_mapping_error(chan->device->dev, dma->dma_addr)) {
> +	if (dma_mapping_error(dmaengine_get_dma_device(chan), dma->dma_addr)) {
>  		dev_err(&lpi2c_imx->adapter.dev, "DMA map failed, use pio\n");
>  		return -EINVAL;
>  	}
> @@ -1085,7 +1085,7 @@ static int lpi2c_imx_dma_xfer(struct lpi2c_imx_struct *lpi2c_imx,
>  	}
>
>  	if (dma->dma_msg_flag & I2C_M_RD)
> -		dma_unmap_single(dma->chan_tx->device->dev, dma->dma_tx_addr,
> +		dma_unmap_single(dmaengine_get_dma_device(dma->chan_tx), dma->dma_tx_addr,
>  				 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
>  	lpi2c_dma_unmap(dma);
>
>
> ---
> base-commit: e6e35979777d646fe3c7c94dca7dd32fb25d45f4
> change-id: 20260916-i2c-dma-e9cd42e4e7ff
>
> Best regards,
> --
> Peng Fan <peng.fan@xxxxxxx>
>
>