Hi Andy,

I love your patch! Perhaps something to improve:

[auto build test WARNING on slave-dma/next]
[also build test WARNING on linus/master v5.8-rc2 next-20200622]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use  as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Andy-Shevchenko/dmaengine-acpi-Drop-double-check-for-ACPI-companion-device/20200622-170946
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/slave-dma.git next
config: i386-randconfig-s002-20200622 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-13) 9.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.2-dirty
        # save the attached .config to linux build tree
        make W=1 C=1 ARCH=i386 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)

>> drivers/dma/acpi-dma.c:380:24: sparse: sparse: incorrect type in return expression (different base types) @@     expected struct dma_chan * @@     got int [assigned] ret @@
>> drivers/dma/acpi-dma.c:380:24: sparse:     expected struct dma_chan *
>> drivers/dma/acpi-dma.c:380:24: sparse:     got int [assigned] ret

vim +380 drivers/dma/acpi-dma.c

   347	
   348	/**
   349	 * acpi_dma_request_slave_chan_by_index - Get the DMA slave channel
   350	 * @dev:	struct device to get DMA request from
   351	 * @index:	index of FixedDMA descriptor for @dev
   352	 *
   353	 * Return:
   354	 * Pointer to appropriate dma channel on success or an error pointer.
   355	 */
   356	struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
   357			size_t index)
   358	{
   359		struct acpi_dma_parser_data pdata;
   360		struct acpi_dma_spec *dma_spec = &pdata.dma_spec;
   361		struct acpi_device *adev = ACPI_COMPANION(dev);
   362		struct list_head resource_list;
   363		struct acpi_dma *adma;
   364		struct dma_chan *chan = NULL;
   365		int found;
   366		int ret;
   367	
   368		memset(&pdata, 0, sizeof(pdata));
   369		pdata.index = index;
   370	
   371		/* Initial values for the request line and channel */
   372		dma_spec->chan_id = -1;
   373		dma_spec->slave_id = -1;
   374	
   375		INIT_LIST_HEAD(&resource_list);
   376		ret = acpi_dev_get_resources(adev, &resource_list,
   377					     acpi_dma_parse_fixed_dma, &pdata);
   378		acpi_dev_free_resource_list(&resource_list);
   379		if (ret < 0)
 > 380			return ret;
   381	
   382		if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0)
   383			return ERR_PTR(-ENODEV);
   384	
   385		mutex_lock(&acpi_dma_lock);
   386	
   387		list_for_each_entry(adma, &acpi_dma_list, dma_controllers) {
   388			/*
   389			 * We are not going to call translation function if slave_id
   390			 * doesn't fall to the request range.
   391			 */
   392			found = acpi_dma_update_dma_spec(adma, dma_spec);
   393			if (found < 0)
   394				continue;
   395			chan = adma->acpi_dma_xlate(dma_spec, adma);
   396			/*
   397			 * Try to get a channel only from the DMA controller that
   398			 * matches the slave_id. See acpi_dma_update_dma_spec()
   399			 * description for the details.
   400			 */
   401			if (found > 0 || chan)
   402				break;
   403		}
   404	
   405		mutex_unlock(&acpi_dma_lock);
   406		return chan ? chan : ERR_PTR(-EPROBE_DEFER);
   407	}
   408	EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index);
   409	

---
0-DAY CI Kernel Test Service, Intel Corporation
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