[PATCH V6 3/3] nvmem: core: add support for fixed cells *layout*

From: Rafał Miłecki
Date: Mon Mar 27 2023 - 10:18:32 EST


From: Rafał Miłecki <rafal@xxxxxxxxxx>

This adds support for the "fixed-layout" NVMEM layout binding. It allows
defining NVMEM cells in a layout DT node named "nvmem-layout".

While NVMEM subsystem supports layout drivers it has been discussed that
"fixed-layout" may actually be supperted internally. It's because:
1. It's a very basic layout
2. It allows sharing code with legacy syntax parsing
3. It's safer for soc_device_match() due to -EPROBE_DEFER
4. This will make the syntax transition easier

Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
Reviewed-by: Michael Walle <michael@xxxxxxxx>
---
V6: s/nvmem_add_cells_fixed/nvmem_add_cells_from_fixed_layout/
---
drivers/nvmem/core.c | 32 +++++++++++++++++++++++++++++---
1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index a62973d010ff..b3d5a29477f9 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -696,7 +696,7 @@ static int nvmem_validate_keepouts(struct nvmem_device *nvmem)
return 0;
}

-static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
+static int nvmem_add_cells_from_dt(struct nvmem_device *nvmem, struct device_node *np)
{
struct nvmem_layout *layout = nvmem->layout;
struct device *dev = &nvmem->dev;
@@ -704,7 +704,7 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
const __be32 *addr;
int len, ret;

- for_each_child_of_node(dev->of_node, child) {
+ for_each_child_of_node(np, child) {
struct nvmem_cell_info info = {0};

addr = of_get_property(child, "reg", &len);
@@ -742,6 +742,28 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
return 0;
}

+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)
+{
+ struct device_node *layout_np;
+ int err = 0;
+
+ layout_np = of_nvmem_layout_get_container(nvmem);
+ if (!layout_np)
+ return 0;
+
+ if (of_device_is_compatible(layout_np, "fixed-layout"))
+ err = nvmem_add_cells_from_dt(nvmem, layout_np);
+
+ of_node_put(layout_np);
+
+ return err;
+}
+
int __nvmem_layout_register(struct nvmem_layout *layout, struct module *owner)
{
layout->owner = owner;
@@ -972,7 +994,7 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
if (rval)
goto err_remove_cells;

- rval = nvmem_add_cells_from_of(nvmem);
+ rval = nvmem_add_cells_from_legacy_of(nvmem);
if (rval)
goto err_remove_cells;

@@ -982,6 +1004,10 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
if (rval)
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;
--
2.34.1