[bug report] dmaengine: loongson: New driver for the Loongson Multi-Channel DMA controller

[bug report] dmaengine: loongson: New driver for the Loongson Multi-Channel DMA controller

[Dan Carpenter]

Hello Binbin Zhou,

Commit 1c0028e725f1 ("dmaengine: loongson: New driver for the
Loongson Multi-Channel DMA controller") from Mar 7, 2026
(linux-next), leads to the following Smatch static checker warning:

	drivers/dma/loongson/loongson2-apb-cmc-dma.c:677 loongson2_cmc_dma_probe()
	warn: unsigned 'lchan->irq' is never less than zero.

drivers/dma/loongson/loongson2-apb-cmc-dma.c
    669         ret = dmaenginem_async_device_register(ddev);
    670         if (ret)
    671                 return dev_err_probe(dev, ret, "Failed to register DMA engine device.\n");
    672 
    673         for (i = 0; i < nr_chans; i++) {
    674                 lchan = &lddev->chan[i];
    675 
    676                 lchan->irq = platform_get_irq(pdev, i);
--> 677                 if (lchan->irq < 0)

lchan->irq is unsigned so the error checking doesn't work

    678                         return lchan->irq;
    679 
    680                 ret = devm_request_irq(dev, lchan->irq, loongson2_cmc_dma_chan_irq, IRQF_SHARED,
    681                                        dev_name(chan2dev(lchan)), lchan);
    682                 if (ret)
    683                         return ret;
    684         }
    685 
    686         ret = loongson2_cmc_dma_acpi_controller_register(lddev);
    687         if (ret)
    688                 return dev_err_probe(dev, ret, "Failed to register dma controller with ACPI.\n");
    689 
    690         ret = loongson2_cmc_dma_of_controller_register(lddev);
    691         if (ret)

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regards,
dan carpenter