[PATCH v2] nvmem: mtk-efuse: Only register socinfo device if needed cells are there

[Nícolas F. R. A. Prado]

Not every efuse region has cells storing SoC information. Only register
an socinfo device if the required cells are present.

This prevents the pointless process of creating an socinfo device,
probing it with the socinfo driver only to ultimately error out like so

  mtk-socinfo mtk-socinfo.0.auto: error -ENOENT: Failed to get socinfo data
  mtk-socinfo mtk-socinfo.0.auto: probe with driver mtk-socinfo failed with error -2

This issue is observed on the mt8183-kukui-jacuzzi-juniper-sku16
platform, which has two efuse regions, but only one of them contains the
SoC data.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado at collabora.com>
---
Changes in v2:
- Added missing include for of.h
- Link to v1: https://lore.kernel.org/r/20240708-mtk-socinfo-no-data-probe-err-v1-1-fb2acd3a47bf@collabora.com
---
 drivers/nvmem/mtk-efuse.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
index 9caf04667341..74def409bc20 100644
--- a/drivers/nvmem/mtk-efuse.c
+++ b/drivers/nvmem/mtk-efuse.c
@@ -11,6 +11,7 @@
 #include <linux/nvmem-provider.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
+#include <linux/of.h>
 
 struct mtk_efuse_pdata {
 	bool uses_post_processing;
@@ -60,6 +61,8 @@ static void mtk_efuse_fixup_dt_cell_info(struct nvmem_device *nvmem,
 		cell->read_post_process = mtk_efuse_gpu_speedbin_pp;
 }
 
+static const char socinfo_data_first_name[] = "socinfo-data1";
+
 static int mtk_efuse_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -69,6 +72,7 @@ static int mtk_efuse_probe(struct platform_device *pdev)
 	struct mtk_efuse_priv *priv;
 	const struct mtk_efuse_pdata *pdata;
 	struct platform_device *socinfo;
+	struct device_node *np;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -92,10 +96,16 @@ static int mtk_efuse_probe(struct platform_device *pdev)
 	if (IS_ERR(nvmem))
 		return PTR_ERR(nvmem);
 
-	socinfo = platform_device_register_data(&pdev->dev, "mtk-socinfo",
-						PLATFORM_DEVID_AUTO, NULL, 0);
-	if (IS_ERR(socinfo))
-		dev_info(dev, "MediaTek SoC Information will be unavailable\n");
+	np = of_get_child_by_name(pdev->dev.of_node, socinfo_data_first_name);
+	if (np) {
+		of_node_put(np);
+		socinfo = platform_device_register_data(&pdev->dev, "mtk-socinfo",
+							PLATFORM_DEVID_AUTO, NULL, 0);
+		if (IS_ERR(socinfo))
+			dev_info(dev, "MediaTek SoC Information will be unavailable\n");
+	} else {
+		dev_info(dev, "Efuse region does not contain SoC information - skipping socinfo driver setup\n");
+	}
 
 	platform_set_drvdata(pdev, socinfo);
 	return 0;

---
base-commit: 0b58e108042b0ed28a71cd7edf5175999955b233
change-id: 20240708-mtk-socinfo-no-data-probe-err-d7558343dc82

Best regards,
-- 
Nícolas F. R. A. Prado <nfraprado at collabora.com>