iommu/omap: Use syscon_regmap_lookup_by_phandle_args

Use syscon_regmap_lookup_by_phandle_args() which is a wrapper over
syscon_regmap_lookup_by_phandle() combined with getting the syscon
argument.  Except simpler code this annotates within one line that given
phandle has arguments, so grepping for code would be easier.

There is also no real benefit in printing errors on missing syscon
argument, because this is done just too late: runtime check on
static/build-time data.  Dtschema and Devicetree bindings offer the
static/build-time check for this already.

Reviewed-by: Robin Murphy <[email protected]>
Signed-off-by: Krzysztof Kozlowski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>

Author: krzk

drivers/iommu/omap-iommu.c

@@ -1127,18 +1127,12 @@ static int omap_iommu_dra7_get_dsp_system_cfg(struct platform_device *pdev,
 	if (!of_device_is_compatible(np, "ti,dra7-dsp-iommu"))
 		return 0;
 
-	obj->syscfg =
-		syscon_regmap_lookup_by_phandle(np, "ti,syscon-mmuconfig");
+	obj->syscfg = syscon_regmap_lookup_by_phandle_args(np, "ti,syscon-mmuconfig",
+							   1, &obj->id);
 	if (IS_ERR(obj->syscfg))
 		return dev_err_probe(&pdev->dev, PTR_ERR(obj->syscfg),
 				     "ti,syscon-mmuconfig property is missing\n");
 
-	if (of_property_read_u32_index(np, "ti,syscon-mmuconfig", 1,
-				       &obj->id)) {
-		dev_err(&pdev->dev, "couldn't get the IOMMU instance id within subsystem\n");
-		return -EINVAL;
-	}
-
 	if (obj->id != 0 && obj->id != 1) {
 		dev_err(&pdev->dev, "invalid IOMMU instance id\n");
 		return -EINVAL;