On 2016/3/14 17:48, Dan Carpenter wrote:
> Hello Shawn Lin,
>
> The patch 61cadcf46cfd: "spi: rockchip: check requesting dma channel
> with EPROBE_DEFER" from Mar 9, 2016, leads to the following static
> checker warning:
>
> drivers/spi/spi-rockchip.c:742 rockchip_spi_probe()
> warn: passing zero to 'PTR_ERR'
>
> drivers/spi/spi-rockchip.c
> 732
> 733 rs->dma_tx.ch = dma_request_slave_channel(rs->dev, "tx");
> 734 if (IS_ERR_OR_NULL(rs->dma_tx.ch)) {
> 735 /* Check tx to see if we need defer probing driver */
> 736 if (PTR_ERR(rs->dma_tx.ch) == -EPROBE_DEFER) {
> 737 ret = -EPROBE_DEFER;
> 738 goto err_get_fifo_len;
>
> What's going on here? Are we planning to change dma_request_slave_channel()
> to return error pointers? Also what about other error pointers besides
> EPROBE_DEFER it seems dangerous to leave rs->dma_tx.ch as an error
> pointer. We probably eventually try to free it if it's non-NULL.
yes, we are plannig to return EPROBE_DEFER/NULL for
dma_request_slave_channel to make sure we don't decide
the dma cap based on driver probe sequence.
No any other error pointer will be returned to the caller
>
> 739 }
> 740 dev_warn(rs->dev, "Failed to request TX DMA channel\n");
> 741 }
> 742
>
> regards,
> dan carpenter
>
>
>
--
Best Regards
Shawn Lin
