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From:   Catalin Popescu <catalin.popescu@leica-geosystems.com>
To:     srinivas.kandagatla@linaro.org
Cc:     linux-kernel@vger.kernel.org,
        Catalin Popescu <catalin.popescu@leica-geosystems.com>
Subject: [PATCH] nvmem: fix issue within nvmem_register with fixed-layout.
Date:   Thu, 30 Nov 2023 17:29:22 +0100
Message-Id: <20231130162922.2989774-1-catalin.popescu@leica-geosystems.com>
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fixed-layout is natively supported by NVMEM framework.
Yet, it's not been declared as a supported layout. As a
result, nvmem_register always returns -EPROBE_DEFER if
configuration has no layout and the NVMEM provider DT
uses a fixed layout.

As a fix, declare fixed-layout as a supported layout
and use add_cells callback to parse the cells. This adds
consistency over layouts parsing as fixed-layout parsing
is handled in the same way than others nvmem layouts.

Signed-off-by: Catalin Popescu <catalin.popescu@leica-geosystems.com>
---
 drivers/nvmem/core.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index bf42b7e826db..3467c94207e8 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -746,7 +746,9 @@ static int nvmem_add_cells_from_legacy_of(struct nvmem_device *nvmem)
 	return nvmem_add_cells_from_dt(nvmem, nvmem->dev.of_node);
 }
 
-static int nvmem_add_cells_from_fixed_layout(struct nvmem_device *nvmem)
+static int nvmem_add_cells_from_fixed_layout(struct device *dev,
+					     struct nvmem_device *nvmem,
+					     struct nvmem_layout *layout)
 {
 	struct device_node *layout_np;
 	int err = 0;
@@ -755,8 +757,7 @@ static int nvmem_add_cells_from_fixed_layout(struct nvmem_device *nvmem)
 	if (!layout_np)
 		return 0;
 
-	if (of_device_is_compatible(layout_np, "fixed-layout"))
-		err = nvmem_add_cells_from_dt(nvmem, layout_np);
+	err = nvmem_add_cells_from_dt(nvmem, layout_np);
 
 	of_node_put(layout_np);
 
@@ -1003,10 +1004,6 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 			goto err_remove_cells;
 	}
 
-	rval = nvmem_add_cells_from_fixed_layout(nvmem);
-	if (rval)
-		goto err_remove_cells;
-
 	rval = nvmem_add_cells_from_layout(nvmem);
 	if (rval)
 		goto err_remove_cells;
@@ -2126,6 +2123,19 @@ const char *nvmem_dev_name(struct nvmem_device *nvmem)
 }
 EXPORT_SYMBOL_GPL(nvmem_dev_name);
 
+static const struct of_device_id fixed_layout_of_match_table[] = {
+	{ .compatible = "fixed-layout", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, fixed_layout_of_match_table);
+
+static struct nvmem_layout fixed_layout = {
+	.name = "NVMEM fixed layout",
+	.of_match_table = fixed_layout_of_match_table,
+	.add_cells = nvmem_add_cells_from_fixed_layout,
+};
+module_nvmem_layout_driver(fixed_layout);
+
 static int __init nvmem_init(void)
 {
 	return bus_register(&nvmem_bus_type);
-- 
2.34.1