Return probe defer if requesting a dma channel without a dma controller probed.
Signed-off-by: Ludovic Desroches <[email protected]> --- drivers/i2c/busses/i2c-at91.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c index 77fb647..df3f4c4 100644 --- a/drivers/i2c/busses/i2c-at91.c +++ b/drivers/i2c/busses/i2c-at91.c @@ -679,14 +679,21 @@ static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr) dma_cap_zero(mask); dma_cap_set(DMA_SLAVE, mask); - dma->chan_tx = dma_request_slave_channel_compat(mask, filter, pdata, - dev->dev, "tx"); - if (!dma->chan_tx) { + dma->chan_tx = dma_request_slave_channel_reason(dev->dev, "tx"); + if (IS_ERR(dma->chan_tx)) { + ret = PTR_ERR(dma->chan_tx); + if (ret == -EPROBE_DEFER) { + dev_warn(dev->dev, "no DMA channel available at the moment\n"); + return ret; + } dev_err(dev->dev, "can't get a DMA channel for tx\n"); - ret = -EBUSY; goto error; } + /* + * No reason to check EPROBE_DEFER here since we have already request + * tx channel. If it fails here, it's for another reason. + */ dma->chan_rx = dma_request_slave_channel_compat(mask, filter, pdata, dev->dev, "rx"); if (!dma->chan_rx) { @@ -722,7 +729,7 @@ error: dev_info(dev->dev, "can't use DMA\n"); if (dma->chan_rx) dma_release_channel(dma->chan_rx); - if (dma->chan_tx) + if (!IS_ERR(dma->chan_tx)) dma_release_channel(dma->chan_tx); return ret; } @@ -788,8 +795,11 @@ static int at91_twi_probe(struct platform_device *pdev) clk_prepare_enable(dev->clk); if (dev->pdata->has_dma_support) { - if (at91_twi_configure_dma(dev, phy_addr) == 0) + rc = at91_twi_configure_dma(dev, phy_addr); + if (rc == 0) dev->use_dma = true; + else if (rc == -EPROBE_DEFER) + return rc; } rc = of_property_read_u32(dev->dev->of_node, "clock-frequency", -- 2.0.3 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
