[PATCH v2 2/7] iommu: mtk_iommu: Lookup phandle to retrieve syscon to infracfg

AngeloGioacchino Del Regno
2022-05-18T10:05:53Z

This driver will get support for more SoCs and the list of infracfg
compatibles is expected to grow: in order to prevent getting this
situation out of control and see a long list of compatible strings,
add support to retrieve a handle to infracfg's regmap through a
new "mediatek,infracfg" phandle.

In order to keep retrocompatibility with older devicetrees, the old
way is kept in place, but also a dev_warn() was added to advertise
this change in hope that the user will see it and eventually update
the devicetree if this is possible.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
drivers/iommu/mtk_iommu.c | 40 +++++++++++++++++++++++++--------------
1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 71b2ace74cd6..d16b95e71ded 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1134,22 +1134,34 @@ static int mtk_iommu_probe(struct platform_device *pdev)
data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN);

if (MTK_IOMMU_HAS_FLAG(data->plat_data, HAS_4GB_MODE)) {
- switch (data->plat_data->m4u_plat) {
- case M4U_MT2712:
- p = "mediatek,mt2712-infracfg";
- break;
- case M4U_MT8173:
- p = "mediatek,mt8173-infracfg";
- break;
- default:
- p = NULL;
+ infracfg = syscon_regmap_lookup_by_phandle(dev->of_node, "mediatek,infracfg");
+ if (IS_ERR(infracfg)) {
+ dev_info(dev, "Cannot find phandle to mediatek,infracfg:"
+ " Please update your devicetree.\n");
+ /*
+ * Legacy devicetrees will not specify a phandle to
+ * mediatek,infracfg: in that case, we use the older
+ * way to retrieve a syscon to infra.
+ *
+ * This is for retrocompatibility purposes only, hence
+ * no more compatibles shall be added to this.
+ */
+ switch (data->plat_data->m4u_plat) {
+ case M4U_MT2712:
+ p = "mediatek,mt2712-infracfg";
+ break;
+ case M4U_MT8173:
+ p = "mediatek,mt8173-infracfg";
+ break;
+ default:
+ p = NULL;
+ }
+
+ infracfg = syscon_regmap_lookup_by_compatible(p);
+ if (IS_ERR(infracfg))
+ return PTR_ERR(infracfg);
}

- infracfg = syscon_regmap_lookup_by_compatible(p);
-
- if (IS_ERR(infracfg))
- return PTR_ERR(infracfg);
-
ret = regmap_read(infracfg, REG_INFRA_MISC, &val);
if (ret)
return ret;
--
2.35.1