Implement SoC driver for Vybrid

From: Stefan Agner <[email protected]>

The existing NVMEM consumer API's do not allow to get a NVMEM cell directly given a device tree node. This patch adds a function to provide this functionality.

Assuming the nvmem cell id name is known, this can be used as follows

struct device_node *cell_np;
struct nvmem_cell *foo_cell;

cell_np = of_find_node_by_name(parent, "foo");
foo_cell = of_nvmem_cell_get_direct(cell_np);

Parent node can also be the of_node of the main SoC device node.

Signed-off-by Sanchayan Maity <[email protected]>

---
  drivers/nvmem/core.c           | 44 +++++++++++++++++++++++++++++-------------
  include/linux/nvmem-consumer.h |  1 +
  2 files changed, 32 insertions(+), 13 deletions(-)

drivers/nvmem/core.c +31 -13

index 965911d..470abee 100644
@@ -743,29 +743,21 @@ static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
 
  #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
  /**
- * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ * of_nvmem_cell_get_direct() - Get a nvmem cell from given device node
   *
- * @dev node: Device tree node that uses the nvmem cell
- * @id: nvmem cell name from nvmem-cell-names property.
+ * @dev node: Device tree node that uses nvmem cell
   *
   * Return: Will be an ERR_PTR() on error or a valid pointer
   * to a struct nvmem_cell.  The nvmem_cell will be freed by the
   * nvmem_cell_put().
   */
-struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
-					    const char *name)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np)
  {
-	struct device_node *cell_np, *nvmem_np;
+	struct device_node *nvmem_np;
  	struct nvmem_cell *cell;
  	struct nvmem_device *nvmem;
  	const __be32 *addr;
-	int rval, len, index;
-
-	index = of_property_match_string(np, "nvmem-cell-names", name);
-
-	cell_np = of_parse_phandle(np, "nvmem-cells", index);
-	if (!cell_np)
-		return ERR_PTR(-EINVAL);
+	int rval, len;
 
  	nvmem_np = of_get_next_parent(cell_np);
  	if (!nvmem_np)

@@ -824,6 +816,32 @@ err_mem:
 
  	return ERR_PTR(rval);
  }
+EXPORT_SYMBOL_GPL(of_nvmem_cell_get_direct);
+
+/**
+ * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ *
+ * @dev node: Device tree node that uses the nvmem cell
+ * @id: nvmem cell name from nvmem-cell-names property.
+ *
+ * Return: Will be an ERR_PTR() on error or a valid pointer
+ * to a struct nvmem_cell.  The nvmem_cell will be freed by the
+ * nvmem_cell_put().
+ */
+struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
+					    const char *name)
+{
+	struct device_node *cell_np;
+	int index;
+
+	index = of_property_match_string(np, "nvmem-cell-names", name);
+
+	cell_np = of_parse_phandle(np, "nvmem-cells", index);
+	if (!cell_np)
+		return ERR_PTR(-EINVAL);
+
+	return of_nvmem_cell_get_direct(cell_np);
+}
  EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
  #endif
 

include/linux/nvmem-consumer.h +1 -0

index 9bb77d3..bf879fc 100644
@@ -136,6 +136,7 @@ static inline int nvmem_device_write(struct nvmem_device *nvmem,
  #endif /* CONFIG_NVMEM */
 
  #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np);
  struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
  				     const char *name);
  struct nvmem_device *of_nvmem_device_get(struct device_node *np,

Quoted 6 lines · Sanchayan Maity

From: Stefan Agner <[email protected]>

The existing NVMEM consumer API's do not allow to get a NVMEM cell directly given a device tree node. This patch adds a function to provide this functionality.

Quoted 8 lines

Assuming the nvmem cell id name is known, this can be used as follows

struct device_node *cell_np;
struct nvmem_cell *foo_cell;

cell_np = of_find_node_by_name(parent, "foo");
foo_cell = of_nvmem_cell_get_direct(cell_np);

I don't see a real gain in adding this new api,
This will encourage people to use non-standard nvmem bindings.

why not just use standard nvmem bindings.. and use

of_nvmem_cell_get(np, "foo");

which should work in your case.

thanks,
srini

Quoted 95 lines

Parent node can also be the of_node of the main SoC device node.

Signed-off-by Sanchayan Maity <[email protected]>

---
  drivers/nvmem/core.c           | 44 +++++++++++++++++++++++++++++-------------
  include/linux/nvmem-consumer.h |  1 +
  2 files changed, 32 insertions(+), 13 deletions(-)

drivers/nvmem/core.c +31 -13

index 965911d..470abee 100644
@@ -743,29 +743,21 @@ static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
 
  #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
  /**
- * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ * of_nvmem_cell_get_direct() - Get a nvmem cell from given device node
   *
- * @dev node: Device tree node that uses the nvmem cell
- * @id: nvmem cell name from nvmem-cell-names property.
+ * @dev node: Device tree node that uses nvmem cell
   *
   * Return: Will be an ERR_PTR() on error or a valid pointer
   * to a struct nvmem_cell.  The nvmem_cell will be freed by the
   * nvmem_cell_put().
   */
-struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
-					    const char *name)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np)
  {
-	struct device_node *cell_np, *nvmem_np;
+	struct device_node *nvmem_np;
  	struct nvmem_cell *cell;
  	struct nvmem_device *nvmem;
  	const __be32 *addr;
-	int rval, len, index;
-
-	index = of_property_match_string(np, "nvmem-cell-names", name);
-
-	cell_np = of_parse_phandle(np, "nvmem-cells", index);
-	if (!cell_np)
-		return ERR_PTR(-EINVAL);
+	int rval, len;
 
  	nvmem_np = of_get_next_parent(cell_np);
  	if (!nvmem_np)

@@ -824,6 +816,32 @@ err_mem:
 
  	return ERR_PTR(rval);
  }
+EXPORT_SYMBOL_GPL(of_nvmem_cell_get_direct);
+
+/**
+ * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ *
+ * @dev node: Device tree node that uses the nvmem cell
+ * @id: nvmem cell name from nvmem-cell-names property.
+ *
+ * Return: Will be an ERR_PTR() on error or a valid pointer
+ * to a struct nvmem_cell.  The nvmem_cell will be freed by the
+ * nvmem_cell_put().
+ */
+struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
+					    const char *name)
+{
+	struct device_node *cell_np;
+	int index;
+
+	index = of_property_match_string(np, "nvmem-cell-names", name);
+
+	cell_np = of_parse_phandle(np, "nvmem-cells", index);
+	if (!cell_np)
+		return ERR_PTR(-EINVAL);
+
+	return of_nvmem_cell_get_direct(cell_np);
+}
  EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
  #endif
 

include/linux/nvmem-consumer.h +1 -0

index 9bb77d3..bf879fc 100644
@@ -136,6 +136,7 @@ static inline int nvmem_device_write(struct nvmem_device *nvmem,
  #endif /* CONFIG_NVMEM */
 
  #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np);
  struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
  				     const char *name);
  struct nvmem_device *of_nvmem_device_get(struct device_node *np,

Hello Srinivas,

Quoted 25 lines · Srinivas Kandagatla

Quoted 6 lines · Sanchayan Maity

From: Stefan Agner <[email protected]>

The existing NVMEM consumer API's do not allow to get a NVMEM cell directly given a device tree node. This patch adds a function to provide this functionality.

Quoted 8 lines

Assuming the nvmem cell id name is known, this can be used as follows

struct device_node *cell_np;
struct nvmem_cell *foo_cell;

cell_np = of_find_node_by_name(parent, "foo");
foo_cell = of_nvmem_cell_get_direct(cell_np);

I don't see a real gain in adding this new api,
This will encourage people to use non-standard nvmem bindings.

why not just use standard nvmem bindings.. and use

of_nvmem_cell_get(np, "foo");

Quoted 1 line

which should work in your case.

It will not work in our case. I believe what you are referring to will work if I were to pass the device node pointer which was a NVMEM consumer containing the nvmem-cells property. In our case, we pass the device node pointer pointing to /soc which is not a nvmem consumer. In this case it will not have nvmem-cells property causing of_nvmem_cell_get to return EINVAL when it calls of_parse_phandle with "nvmem-cells".

Our requirement is to be able to pass the soc node pointer and then be able to get a nvmem cell by specifying it's name. So for our case

ocotp node has cfg0 and cfg1 which we want but we cannot use existing nvmem consumer API since that requires having the nvmem consumer properties in the node we are binding to viz. is a direct nvmem consumer.

Regards,
Sanchayan.

Quoted 98 lines

thanks,
srini

Quoted 95 lines

Parent node can also be the of_node of the main SoC device node.

Signed-off-by Sanchayan Maity <[email protected]>

---
   drivers/nvmem/core.c           | 44 +++++++++++++++++++++++++++++-------------
   include/linux/nvmem-consumer.h |  1 +
   2 files changed, 32 insertions(+), 13 deletions(-)

drivers/nvmem/core.c +31 -13

index 965911d..470abee 100644
@@ -743,29 +743,21 @@ static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
 
   #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
   /**
- * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ * of_nvmem_cell_get_direct() - Get a nvmem cell from given device node
    *
- * @dev node: Device tree node that uses the nvmem cell
- * @id: nvmem cell name from nvmem-cell-names property.
+ * @dev node: Device tree node that uses nvmem cell
    *
    * Return: Will be an ERR_PTR() on error or a valid pointer
    * to a struct nvmem_cell.  The nvmem_cell will be freed by the
    * nvmem_cell_put().
    */
-struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
-					    const char *name)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np)
   {
-	struct device_node *cell_np, *nvmem_np;
+	struct device_node *nvmem_np;
   	struct nvmem_cell *cell;
   	struct nvmem_device *nvmem;
   	const __be32 *addr;
-	int rval, len, index;
-
-	index = of_property_match_string(np, "nvmem-cell-names", name);
-
-	cell_np = of_parse_phandle(np, "nvmem-cells", index);
-	if (!cell_np)
-		return ERR_PTR(-EINVAL);
+	int rval, len;
 
   	nvmem_np = of_get_next_parent(cell_np);
   	if (!nvmem_np)

@@ -824,6 +816,32 @@ err_mem:
 
   	return ERR_PTR(rval);
   }
+EXPORT_SYMBOL_GPL(of_nvmem_cell_get_direct);
+
+/**
+ * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ *
+ * @dev node: Device tree node that uses the nvmem cell
+ * @id: nvmem cell name from nvmem-cell-names property.
+ *
+ * Return: Will be an ERR_PTR() on error or a valid pointer
+ * to a struct nvmem_cell.  The nvmem_cell will be freed by the
+ * nvmem_cell_put().
+ */
+struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
+					    const char *name)
+{
+	struct device_node *cell_np;
+	int index;
+
+	index = of_property_match_string(np, "nvmem-cell-names", name);
+
+	cell_np = of_parse_phandle(np, "nvmem-cells", index);
+	if (!cell_np)
+		return ERR_PTR(-EINVAL);
+
+	return of_nvmem_cell_get_direct(cell_np);
+}
   EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
   #endif
 

include/linux/nvmem-consumer.h +1 -0

index 9bb77d3..bf879fc 100644
@@ -136,6 +136,7 @@ static inline int nvmem_device_write(struct nvmem_device *nvmem,
   #endif /* CONFIG_NVMEM */
 
   #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np);
   struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
   				     const char *name);
   struct nvmem_device *of_nvmem_device_get(struct device_node *np,

Quoted 28 lines · maitysanchayan at gmail.com

Hello Srinivas,

Quoted 25 lines · Srinivas Kandagatla

Quoted 6 lines · Sanchayan Maity

From: Stefan Agner <[email protected]>

The existing NVMEM consumer API's do not allow to get a NVMEM cell directly given a device tree node. This patch adds a function to provide this functionality.

Quoted 8 lines

Assuming the nvmem cell id name is known, this can be used as follows

struct device_node *cell_np;
struct nvmem_cell *foo_cell;

cell_np = of_find_node_by_name(parent, "foo");
foo_cell = of_nvmem_cell_get_direct(cell_np);

I don't see a real gain in adding this new api,
This will encourage people to use non-standard nvmem bindings.

why not just use standard nvmem bindings.. and use

of_nvmem_cell_get(np, "foo");

Quoted 8 lines

Quoted 1 line

which should work in your case.

It will not work in our case. I believe what you are referring to will work if I were to pass the device node pointer which was a NVMEM consumer containing the nvmem-cells property. In our case, we pass the device node pointer pointing to /soc which is not a nvmem consumer. In this case it will not have nvmem-cells property causing of_nvmem_cell_get to return EINVAL when it calls of_parse_phandle with "nvmem-cells".

I could not see any bindings/ dt patches or dt examples for this this series.. so Am guessing your node would look like:

soc {
	cfg0: cfg0 {
		...
	};
	cfg1: cfg1 {
		...
	};
};

If this is not how it looks, can you share the details.

What Am saying is that why not have:

soc {
	nvmem-cells = <&cfg0>, <&cfg1>;
	nvmem-cell-names = "cfg0", "cfg1";

	cfg0: cfg0 {
		...
	};

	cfg1: cfg1 {
		...
	};
};

Quoted 1 line

Quoted 2 lines

Our requirement is to be able to pass the soc node pointer and then be able to get a nvmem cell by specifying it's name. So for our case

Why?

Quoted 106 lines

ocotp node has cfg0 and cfg1 which we want but we cannot use existing nvmem consumer API since that requires having the nvmem consumer properties in the node we are binding to viz. is a direct nvmem consumer.

Regards,
Sanchayan.

Quoted 98 lines

thanks,
srini

Quoted 95 lines

Parent node can also be the of_node of the main SoC device node.

Signed-off-by Sanchayan Maity <[email protected]>

---
   drivers/nvmem/core.c           | 44 +++++++++++++++++++++++++++++-------------
   include/linux/nvmem-consumer.h |  1 +
   2 files changed, 32 insertions(+), 13 deletions(-)

drivers/nvmem/core.c +31 -13

index 965911d..470abee 100644
@@ -743,29 +743,21 @@ static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
 
   #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
   /**
- * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ * of_nvmem_cell_get_direct() - Get a nvmem cell from given device node
    *
- * @dev node: Device tree node that uses the nvmem cell
- * @id: nvmem cell name from nvmem-cell-names property.
+ * @dev node: Device tree node that uses nvmem cell
    *
    * Return: Will be an ERR_PTR() on error or a valid pointer
    * to a struct nvmem_cell.  The nvmem_cell will be freed by the
    * nvmem_cell_put().
    */
-struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
-					    const char *name)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np)
   {
-	struct device_node *cell_np, *nvmem_np;
+	struct device_node *nvmem_np;
   	struct nvmem_cell *cell;
   	struct nvmem_device *nvmem;
   	const __be32 *addr;
-	int rval, len, index;
-
-	index = of_property_match_string(np, "nvmem-cell-names", name);
-
-	cell_np = of_parse_phandle(np, "nvmem-cells", index);
-	if (!cell_np)
-		return ERR_PTR(-EINVAL);
+	int rval, len;
 
   	nvmem_np = of_get_next_parent(cell_np);
   	if (!nvmem_np)

@@ -824,6 +816,32 @@ err_mem:
 
   	return ERR_PTR(rval);
   }
+EXPORT_SYMBOL_GPL(of_nvmem_cell_get_direct);
+
+/**
+ * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ *
+ * @dev node: Device tree node that uses the nvmem cell
+ * @id: nvmem cell name from nvmem-cell-names property.
+ *
+ * Return: Will be an ERR_PTR() on error or a valid pointer
+ * to a struct nvmem_cell.  The nvmem_cell will be freed by the
+ * nvmem_cell_put().
+ */
+struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
+					    const char *name)
+{
+	struct device_node *cell_np;
+	int index;
+
+	index = of_property_match_string(np, "nvmem-cell-names", name);
+
+	cell_np = of_parse_phandle(np, "nvmem-cells", index);
+	if (!cell_np)
+		return ERR_PTR(-EINVAL);
+
+	return of_nvmem_cell_get_direct(cell_np);
+}
   EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
   #endif
 

include/linux/nvmem-consumer.h +1 -0

index 9bb77d3..bf879fc 100644
@@ -136,6 +136,7 @@ static inline int nvmem_device_write(struct nvmem_device *nvmem,
   #endif /* CONFIG_NVMEM */
 
   #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np);
   struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
   				     const char *name);
   struct nvmem_device *of_nvmem_device_get(struct device_node *np,

Hello Srinivas,

Quoted 73 lines · Srinivas Kandagatla

Quoted 28 lines · maitysanchayan at gmail.com

Hello Srinivas,

Quoted 25 lines · Srinivas Kandagatla

Quoted 6 lines · Sanchayan Maity

From: Stefan Agner <[email protected]>

The existing NVMEM consumer API's do not allow to get a NVMEM cell directly given a device tree node. This patch adds a function to provide this functionality.

Quoted 8 lines

Assuming the nvmem cell id name is known, this can be used as follows

struct device_node *cell_np;
struct nvmem_cell *foo_cell;

cell_np = of_find_node_by_name(parent, "foo");
foo_cell = of_nvmem_cell_get_direct(cell_np);

I don't see a real gain in adding this new api,
This will encourage people to use non-standard nvmem bindings.

why not just use standard nvmem bindings.. and use

of_nvmem_cell_get(np, "foo");

Quoted 8 lines

Quoted 1 line

which should work in your case.

It will not work in our case. I believe what you are referring to will work if I were to pass the device node pointer which was a NVMEM consumer containing the nvmem-cells property. In our case, we pass the device node pointer pointing to /soc which is not a nvmem consumer. In this case it will not have nvmem-cells property causing of_nvmem_cell_get to return EINVAL when it calls of_parse_phandle with "nvmem-cells".

I could not see any bindings/ dt patches or dt examples for this this series.. so Am guessing your node would look like:

soc {
	cfg0: cfg0 {
		...
	};
	cfg1: cfg1 {
		...
	};
};

If this is not how it looks, can you share the details.

What Am saying is that why not have:

soc {
	nvmem-cells = <&cfg0>, <&cfg1>;
	nvmem-cell-names = "cfg0", "cfg1";

	cfg0: cfg0 {
		...
	};

	cfg1: cfg1 {
		...
	};
};

Quoted 3 lines

Our requirement is to be able to pass the soc node pointer and then be able to get a nvmem cell by specifying it's name. So for our case

Quoted 1 line

Why?

Sorry for not providing the background directly. The patches before this series used that approach. In the previous discussions it has been pointed out that it is not acceptable to have additional device tree bindings for providing data that the driver wants at the SoC node level or to have bindings just for the SoC bus driver alone since we aren't really describing the hardware.

For the discussion,
https://lkml.org/lkml/2016/5/23/573
https://lkml.org/lkml/2016/5/2/71

Regards,
Sanchayan.

Quoted 106 lines

Quoted 106 lines

ocotp node has cfg0 and cfg1 which we want but we cannot use existing nvmem consumer API since that requires having the nvmem consumer properties in the node we are binding to viz. is a direct nvmem consumer.

Regards,
Sanchayan.

Quoted 98 lines

thanks,
srini

Quoted 95 lines

Parent node can also be the of_node of the main SoC device node.

Signed-off-by Sanchayan Maity <[email protected]>

---
    drivers/nvmem/core.c           | 44 +++++++++++++++++++++++++++++-------------
    include/linux/nvmem-consumer.h |  1 +
    2 files changed, 32 insertions(+), 13 deletions(-)

drivers/nvmem/core.c +31 -13

index 965911d..470abee 100644
@@ -743,29 +743,21 @@ static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
 
    #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
    /**
- * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ * of_nvmem_cell_get_direct() - Get a nvmem cell from given device node
     *
- * @dev node: Device tree node that uses the nvmem cell
- * @id: nvmem cell name from nvmem-cell-names property.
+ * @dev node: Device tree node that uses nvmem cell
     *
     * Return: Will be an ERR_PTR() on error or a valid pointer
     * to a struct nvmem_cell.  The nvmem_cell will be freed by the
     * nvmem_cell_put().
     */
-struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
-					    const char *name)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np)
    {
-	struct device_node *cell_np, *nvmem_np;
+	struct device_node *nvmem_np;
    	struct nvmem_cell *cell;
    	struct nvmem_device *nvmem;
    	const __be32 *addr;
-	int rval, len, index;
-
-	index = of_property_match_string(np, "nvmem-cell-names", name);
-
-	cell_np = of_parse_phandle(np, "nvmem-cells", index);
-	if (!cell_np)
-		return ERR_PTR(-EINVAL);
+	int rval, len;
 
    	nvmem_np = of_get_next_parent(cell_np);
    	if (!nvmem_np)

@@ -824,6 +816,32 @@ err_mem:
 
    	return ERR_PTR(rval);
    }
+EXPORT_SYMBOL_GPL(of_nvmem_cell_get_direct);
+
+/**
+ * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ *
+ * @dev node: Device tree node that uses the nvmem cell
+ * @id: nvmem cell name from nvmem-cell-names property.
+ *
+ * Return: Will be an ERR_PTR() on error or a valid pointer
+ * to a struct nvmem_cell.  The nvmem_cell will be freed by the
+ * nvmem_cell_put().
+ */
+struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
+					    const char *name)
+{
+	struct device_node *cell_np;
+	int index;
+
+	index = of_property_match_string(np, "nvmem-cell-names", name);
+
+	cell_np = of_parse_phandle(np, "nvmem-cells", index);
+	if (!cell_np)
+		return ERR_PTR(-EINVAL);
+
+	return of_nvmem_cell_get_direct(cell_np);
+}
    EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
    #endif
 

include/linux/nvmem-consumer.h +1 -0

index 9bb77d3..bf879fc 100644
@@ -136,6 +136,7 @@ static inline int nvmem_device_write(struct nvmem_device *nvmem,
    #endif /* CONFIG_NVMEM */
 
    #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np);
    struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
    				     const char *name);
    struct nvmem_device *of_nvmem_device_get(struct device_node *np,

Quoted 76 lines · maitysanchayan at gmail.com

Hello Srinivas,

Quoted 73 lines · Srinivas Kandagatla

Quoted 28 lines · maitysanchayan at gmail.com

Hello Srinivas,

Quoted 25 lines · Srinivas Kandagatla

Quoted 6 lines · Sanchayan Maity

From: Stefan Agner <[email protected]>

The existing NVMEM consumer API's do not allow to get a NVMEM cell directly given a device tree node. This patch adds a function to provide this functionality.

Quoted 8 lines

Assuming the nvmem cell id name is known, this can be used as follows

struct device_node *cell_np;
struct nvmem_cell *foo_cell;

cell_np = of_find_node_by_name(parent, "foo");
foo_cell = of_nvmem_cell_get_direct(cell_np);

I don't see a real gain in adding this new api,
This will encourage people to use non-standard nvmem bindings.

why not just use standard nvmem bindings.. and use

of_nvmem_cell_get(np, "foo");

Quoted 8 lines

Quoted 1 line

which should work in your case.

It will not work in our case. I believe what you are referring to will work if I were to pass the device node pointer which was a NVMEM consumer containing the nvmem-cells property. In our case, we pass the device node pointer pointing to /soc which is not a nvmem consumer. In this case it will not have nvmem-cells property causing of_nvmem_cell_get to return EINVAL when it calls of_parse_phandle with "nvmem-cells".

I could not see any bindings/ dt patches or dt examples for this this series.. so Am guessing your node would look like:

soc {
	cfg0: cfg0 {
		...
	};
	cfg1: cfg1 {
		...
	};
};

If this is not how it looks, can you share the details.

What Am saying is that why not have:

soc {
	nvmem-cells = <&cfg0>, <&cfg1>;
	nvmem-cell-names = "cfg0", "cfg1";

	cfg0: cfg0 {
		...
	};

	cfg1: cfg1 {
		...
	};
};

Quoted 3 lines

Our requirement is to be able to pass the soc node pointer and then be able to get a nvmem cell by specifying it's name. So for our case

Quoted 9 lines

Quoted 1 line

Why?

Sorry for not providing the background directly. The patches before this series used that approach. In the previous discussions it has been pointed out that it is not acceptable to have additional device tree bindings for providing data that the driver wants at the SoC node level or to have bindings just for the SoC bus driver alone since we aren't really describing the hardware.

SOC driver seems to search for an arbitrary node by its name, which is not a binding and can break anytime in cases If the scope of nvmem provider is out of soc node or if the nvmem cells are not named as expected. That looks very fragile.

If the soc node is actual consumer of nvmem cells, I see no reason why we should not use proper nvmem bindings?

Given the fact that the patch is potentially bypassing the nvmem bindings, am not happy to take it!

thanks,
srini

Quoted 114 lines

For the discussion,
https://lkml.org/lkml/2016/5/23/573
https://lkml.org/lkml/2016/5/2/71

Regards,
Sanchayan.

Quoted 106 lines

Quoted 106 lines

ocotp node has cfg0 and cfg1 which we want but we cannot use existing nvmem consumer API since that requires having the nvmem consumer properties in the node we are binding to viz. is a direct nvmem consumer.

Regards,
Sanchayan.

Quoted 98 lines

thanks,
srini

Quoted 95 lines

Parent node can also be the of_node of the main SoC device node.

Signed-off-by Sanchayan Maity <[email protected]>

---
    drivers/nvmem/core.c           | 44 +++++++++++++++++++++++++++++-------------
    include/linux/nvmem-consumer.h |  1 +
    2 files changed, 32 insertions(+), 13 deletions(-)

drivers/nvmem/core.c +31 -13

index 965911d..470abee 100644
@@ -743,29 +743,21 @@ static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
 
    #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
    /**
- * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ * of_nvmem_cell_get_direct() - Get a nvmem cell from given device node
     *
- * @dev node: Device tree node that uses the nvmem cell
- * @id: nvmem cell name from nvmem-cell-names property.
+ * @dev node: Device tree node that uses nvmem cell
     *
     * Return: Will be an ERR_PTR() on error or a valid pointer
     * to a struct nvmem_cell.  The nvmem_cell will be freed by the
     * nvmem_cell_put().
     */
-struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
-					    const char *name)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np)
    {
-	struct device_node *cell_np, *nvmem_np;
+	struct device_node *nvmem_np;
    	struct nvmem_cell *cell;
    	struct nvmem_device *nvmem;
    	const __be32 *addr;
-	int rval, len, index;
-
-	index = of_property_match_string(np, "nvmem-cell-names", name);
-
-	cell_np = of_parse_phandle(np, "nvmem-cells", index);
-	if (!cell_np)
-		return ERR_PTR(-EINVAL);
+	int rval, len;
 
    	nvmem_np = of_get_next_parent(cell_np);
    	if (!nvmem_np)

@@ -824,6 +816,32 @@ err_mem:
 
    	return ERR_PTR(rval);
    }
+EXPORT_SYMBOL_GPL(of_nvmem_cell_get_direct);
+
+/**
+ * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ *
+ * @dev node: Device tree node that uses the nvmem cell
+ * @id: nvmem cell name from nvmem-cell-names property.
+ *
+ * Return: Will be an ERR_PTR() on error or a valid pointer
+ * to a struct nvmem_cell.  The nvmem_cell will be freed by the
+ * nvmem_cell_put().
+ */
+struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
+					    const char *name)
+{
+	struct device_node *cell_np;
+	int index;
+
+	index = of_property_match_string(np, "nvmem-cell-names", name);
+
+	cell_np = of_parse_phandle(np, "nvmem-cells", index);
+	if (!cell_np)
+		return ERR_PTR(-EINVAL);
+
+	return of_nvmem_cell_get_direct(cell_np);
+}
    EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
    #endif
 

include/linux/nvmem-consumer.h +1 -0

index 9bb77d3..bf879fc 100644
@@ -136,6 +136,7 @@ static inline int nvmem_device_write(struct nvmem_device *nvmem,
    #endif /* CONFIG_NVMEM */
 
    #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np);
    struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
    				     const char *name);
    struct nvmem_device *of_nvmem_device_get(struct device_node *np,

Quoted 4 lines · Srinivas Kandagatla

Quoted 3 lines · maitysanchayan at gmail.com

Hello Srinivas,

On 16-07-07 1

Quoted 13 lines

Quoted 4 lines

Quoted 4 lines

Quoted 3 lines

Our requirement is to be able to pass the soc node pointer and then be able to get a nvmem cell by specifying it's name. So for our case

Quoted 9 lines

Quoted 1 line

Why?

Sorry for not providing the background directly. The patches before this series used that approach. In the previous discussions it has been pointed out that it is not acceptable to have additional device tree bindings for providing data that the driver wants at the SoC node level or to have bindings just for the SoC bus driver alone since we aren't really describing the hardware.

Quoted 4 lines

SOC driver seems to search for an arbitrary node by its name, which is not a binding and can break anytime in cases If the scope of nvmem provider is out of soc node or if the nvmem cells are not named as expected. That looks very fragile.

In that case, that just "won't happen" because the soc driver is a very soc specific driver only used for this device tree. We it will always bind to that high level soc node.

Quoted 1 line

Quoted 2 lines

If the soc node is actual consumer of nvmem cells, I see no reason why we should not use proper nvmem bindings?

There is a reason: We don't describe the hardware with it...

The cfg0/cfg1 register which Sanchayan needs to read in the soc bus driver are just two register with a unique ID of the SoC. In whatever

driver throughout the system we use that ID (e.g. in a random generator for initialization) we never describe an actual hardware relation... Its just software and how we use that unique ID. The device tree is ment to describe hardware. Hence the NVMEM consumer binding is not suited for such NVMEM cells...

By describing the NVMEM cells location in device tree (producer API, the NVMEM cells are in hardware at that location, so using the device tree for that part is fine) and hard coding the NVMEM cell we need in the driver code we don't violate the device tree matra "describe the hardware"...

Looking-up the nodes direcly is what Rob suggested here:
https://lkml.org/lkml/2016/5/23/573

Quoted 4 lines

Given the fact that the patch is potentially bypassing the nvmem bindings, am not happy to take it!

If you can provide a solution acceptable by the device tree folks and works without this patch, I am happy to do it...

Btw, I am not entirely happy with the API name, but did not had a better idea... And we we should probably add a note that the device tree consumer binding is the preferred way to do it.

--
Stefan

Quoted 118 lines

thanks,
srini

Quoted 114 lines

For the discussion,
https://lkml.org/lkml/2016/5/23/573
https://lkml.org/lkml/2016/5/2/71

Regards,
Sanchayan.

Quoted 106 lines

Quoted 106 lines

ocotp node has cfg0 and cfg1 which we want but we cannot use existing nvmem consumer API since that requires having the nvmem consumer properties in the node we are binding to viz. is a direct nvmem consumer.

Regards,
Sanchayan.

Quoted 98 lines

thanks,
srini

Quoted 95 lines

Parent node can also be the of_node of the main SoC device node.

Signed-off-by Sanchayan Maity <[email protected]>

---
     drivers/nvmem/core.c           | 44 +++++++++++++++++++++++++++++-------------
     include/linux/nvmem-consumer.h |  1 +
     2 files changed, 32 insertions(+), 13 deletions(-)

drivers/nvmem/core.c +31 -13

index 965911d..470abee 100644
@@ -743,29 +743,21 @@ static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
 
     #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
     /**
- * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ * of_nvmem_cell_get_direct() - Get a nvmem cell from given device node
      *
- * @dev node: Device tree node that uses the nvmem cell
- * @id: nvmem cell name from nvmem-cell-names property.
+ * @dev node: Device tree node that uses nvmem cell
      *
      * Return: Will be an ERR_PTR() on error or a valid pointer
      * to a struct nvmem_cell.  The nvmem_cell will be freed by the
      * nvmem_cell_put().
      */
-struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
-					    const char *name)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np)
     {
-	struct device_node *cell_np, *nvmem_np;
+	struct device_node *nvmem_np;
     	struct nvmem_cell *cell;
     	struct nvmem_device *nvmem;
     	const __be32 *addr;
-	int rval, len, index;
-
-	index = of_property_match_string(np, "nvmem-cell-names", name);
-
-	cell_np = of_parse_phandle(np, "nvmem-cells", index);
-	if (!cell_np)
-		return ERR_PTR(-EINVAL);
+	int rval, len;
 
     	nvmem_np = of_get_next_parent(cell_np);
     	if (!nvmem_np)

@@ -824,6 +816,32 @@ err_mem:
 
     	return ERR_PTR(rval);
     }
+EXPORT_SYMBOL_GPL(of_nvmem_cell_get_direct);
+
+/**
+ * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ *
+ * @dev node: Device tree node that uses the nvmem cell
+ * @id: nvmem cell name from nvmem-cell-names property.
+ *
+ * Return: Will be an ERR_PTR() on error or a valid pointer
+ * to a struct nvmem_cell.  The nvmem_cell will be freed by the
+ * nvmem_cell_put().
+ */
+struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
+					    const char *name)
+{
+	struct device_node *cell_np;
+	int index;
+
+	index = of_property_match_string(np, "nvmem-cell-names", name);
+
+	cell_np = of_parse_phandle(np, "nvmem-cells", index);
+	if (!cell_np)
+		return ERR_PTR(-EINVAL);
+
+	return of_nvmem_cell_get_direct(cell_np);
+}
     EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
     #endif
 

include/linux/nvmem-consumer.h +1 -0

index 9bb77d3..bf879fc 100644
@@ -136,6 +136,7 @@ static inline int nvmem_device_write(struct nvmem_device *nvmem,
     #endif /* CONFIG_NVMEM */
 
     #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np);
     struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
     				     const char *name);
     struct nvmem_device *of_nvmem_device_get(struct device_node *np,

Quoted 5 lines · Stefan Agner

Quoted 4 lines · Srinivas Kandagatla

Quoted 3 lines · maitysanchayan at gmail.com

Hello Srinivas,

On 16-07-07 1

...

Quoted 23 lines

Quoted 13 lines

Quoted 4 lines

Quoted 4 lines

Quoted 3 lines

Our requirement is to be able to pass the soc node pointer and then be able to get a nvmem cell by specifying it's name. So for our case

Quoted 9 lines

Quoted 1 line

Why?

Sorry for not providing the background directly. The patches before this series used that approach. In the previous discussions it has been pointed out that it is not acceptable to have additional device tree bindings for providing data that the driver wants at the SoC node level or to have bindings just for the SoC bus driver alone since we aren't really describing the hardware.

Quoted 4 lines

SOC driver seems to search for an arbitrary node by its name, which is not a binding and can break anytime in cases If the scope of nvmem provider is out of soc node or if the nvmem cells are not named as expected. That looks very fragile.

In that case, that just "won't happen" because the soc driver is a very soc specific driver only used for this device tree. We it will always bind to that high level soc node.

Quoted 1 line

Quoted 7 lines

Quoted 2 lines

If the soc node is actual consumer of nvmem cells, I see no reason why we should not use proper nvmem bindings?

There is a reason: We don't describe the hardware with it...

The cfg0/cfg1 register which Sanchayan needs to read in the soc bus driver are just two register with a unique ID of the SoC. In whatever

"Unique ID of the SOC" doesn't this mean that its a part of soc hw description/configuration/setup?

Am still not clear why this setup any different to other use cases like mac address/calibration data?

I still feel that this should be described in the DT.

Rob,
What do you think?

Quoted 8 lines

driver throughout the system we use that ID (e.g. in a random generator for initialization) we never describe an actual hardware relation... Its just software and how we use that unique ID. The device tree is ment to describe hardware. Hence the NVMEM consumer binding is not suited for such NVMEM cells...

Quoted 5 lines

By describing the NVMEM cells location in device tree (producer API, the NVMEM cells are in hardware at that location, so using the device tree for that part is fine) and hard coding the NVMEM cell we need in the driver code we don't violate the device tree matra "describe the hardware"...

IMHO, We should indeed describe the SOC hardware and its relationship w.r.t to nvmem provider in device tree. Reasoning being these both are some form of IP blocks/hw which depend on each other.

Quoted 3 lines

Looking-up the nodes direcly is what Rob suggested here:
https://lkml.org/lkml/2016/5/23/573

I did read this, I was not convinced that we should do a direct lookup for nvmem cells.

thanks,
srini

Quoted 136 lines

Quoted 4 lines

Given the fact that the patch is potentially bypassing the nvmem bindings, am not happy to take it!

If you can provide a solution acceptable by the device tree folks and works without this patch, I am happy to do it...

Btw, I am not entirely happy with the API name, but did not had a better idea... And we we should probably add a note that the device tree consumer binding is the preferred way to do it.

--
Stefan

Quoted 118 lines

thanks,
srini

Quoted 114 lines

For the discussion,
https://lkml.org/lkml/2016/5/23/573
https://lkml.org/lkml/2016/5/2/71

Regards,
Sanchayan.

Quoted 106 lines

Quoted 106 lines

ocotp node has cfg0 and cfg1 which we want but we cannot use existing nvmem consumer API since that requires having the nvmem consumer properties in the node we are binding to viz. is a direct nvmem consumer.

Regards,
Sanchayan.

Quoted 98 lines

thanks,
srini

Quoted 95 lines

Parent node can also be the of_node of the main SoC device node.

Signed-off-by Sanchayan Maity <[email protected]>

---
     drivers/nvmem/core.c           | 44 +++++++++++++++++++++++++++++-------------
     include/linux/nvmem-consumer.h |  1 +
     2 files changed, 32 insertions(+), 13 deletions(-)

drivers/nvmem/core.c +31 -13

index 965911d..470abee 100644
@@ -743,29 +743,21 @@ static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
 
     #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
     /**
- * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ * of_nvmem_cell_get_direct() - Get a nvmem cell from given device node
      *
- * @dev node: Device tree node that uses the nvmem cell
- * @id: nvmem cell name from nvmem-cell-names property.
+ * @dev node: Device tree node that uses nvmem cell
      *
      * Return: Will be an ERR_PTR() on error or a valid pointer
      * to a struct nvmem_cell.  The nvmem_cell will be freed by the
      * nvmem_cell_put().
      */
-struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
-					    const char *name)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np)
     {
-	struct device_node *cell_np, *nvmem_np;
+	struct device_node *nvmem_np;
     	struct nvmem_cell *cell;
     	struct nvmem_device *nvmem;
     	const __be32 *addr;
-	int rval, len, index;
-
-	index = of_property_match_string(np, "nvmem-cell-names", name);
-
-	cell_np = of_parse_phandle(np, "nvmem-cells", index);
-	if (!cell_np)
-		return ERR_PTR(-EINVAL);
+	int rval, len;
 
     	nvmem_np = of_get_next_parent(cell_np);
     	if (!nvmem_np)

@@ -824,6 +816,32 @@ err_mem:
 
     	return ERR_PTR(rval);
     }
+EXPORT_SYMBOL_GPL(of_nvmem_cell_get_direct);
+
+/**
+ * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ *
+ * @dev node: Device tree node that uses the nvmem cell
+ * @id: nvmem cell name from nvmem-cell-names property.
+ *
+ * Return: Will be an ERR_PTR() on error or a valid pointer
+ * to a struct nvmem_cell.  The nvmem_cell will be freed by the
+ * nvmem_cell_put().
+ */
+struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
+					    const char *name)
+{
+	struct device_node *cell_np;
+	int index;
+
+	index = of_property_match_string(np, "nvmem-cell-names", name);
+
+	cell_np = of_parse_phandle(np, "nvmem-cells", index);
+	if (!cell_np)
+		return ERR_PTR(-EINVAL);
+
+	return of_nvmem_cell_get_direct(cell_np);
+}
     EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
     #endif
 

include/linux/nvmem-consumer.h +1 -0

index 9bb77d3..bf879fc 100644
@@ -136,6 +136,7 @@ static inline int nvmem_device_write(struct nvmem_device *nvmem,
     #endif /* CONFIG_NVMEM */
 
     #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np);
     struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
     				     const char *name);
     struct nvmem_device *of_nvmem_device_get(struct device_node *np,

Quoted 5 lines · Stefan Agner

Quoted 4 lines · Srinivas Kandagatla

Quoted 3 lines · maitysanchayan at gmail.com

Hello Srinivas,

On 16-07-07 1

...

Quoted 23 lines

Quoted 13 lines

Quoted 4 lines

Quoted 4 lines

Quoted 3 lines

Our requirement is to be able to pass the soc node pointer and then be able to get a nvmem cell by specifying it's name. So for our case

Quoted 9 lines

Quoted 1 line

Why?

Sorry for not providing the background directly. The patches before this series used that approach. In the previous discussions it has been pointed out that it is not acceptable to have additional device tree bindings for providing data that the driver wants at the SoC node level or to have bindings just for the SoC bus driver alone since we aren't really describing the hardware.

Quoted 4 lines

SOC driver seems to search for an arbitrary node by its name, which is not a binding and can break anytime in cases If the scope of nvmem provider is out of soc node or if the nvmem cells are not named as expected. That looks very fragile.

In that case, that just "won't happen" because the soc driver is a very soc specific driver only used for this device tree. We it will always bind to that high level soc node.

Quoted 1 line

Quoted 7 lines

Quoted 2 lines

If the soc node is actual consumer of nvmem cells, I see no reason why we should not use proper nvmem bindings?

There is a reason: We don't describe the hardware with it...

The cfg0/cfg1 register which Sanchayan needs to read in the soc bus driver are just two register with a unique ID of the SoC. In whatever

"Unique ID of the SOC" doesn't this mean that its a part of soc hw description/configuration/setup?

Am still not clear why this setup any different to other use cases like mac address/calibration data?

I still feel that this should be described in the DT.

Rob,
What do you think?

Quoted 8 lines

driver throughout the system we use that ID (e.g. in a random generator for initialization) we never describe an actual hardware relation... Its just software and how we use that unique ID. The device tree is ment to describe hardware. Hence the NVMEM consumer binding is not suited for such NVMEM cells...

Quoted 5 lines

By describing the NVMEM cells location in device tree (producer API, the NVMEM cells are in hardware at that location, so using the device tree for that part is fine) and hard coding the NVMEM cell we need in the driver code we don't violate the device tree matra "describe the hardware"...

IMHO, We should indeed describe the SOC hardware and its relationship w.r.t to nvmem provider in device tree. Reasoning being these both are some form of IP blocks/hw which depend on each other.

Quoted 3 lines

Looking-up the nodes direcly is what Rob suggested here:
https://lkml.org/lkml/2016/5/23/573

I did read this, I was not convinced that we should do a direct lookup for nvmem cells.

thanks,
srini

Quoted 136 lines

Quoted 4 lines

Given the fact that the patch is potentially bypassing the nvmem bindings, am not happy to take it!

If you can provide a solution acceptable by the device tree folks and works without this patch, I am happy to do it...

Btw, I am not entirely happy with the API name, but did not had a better idea... And we we should probably add a note that the device tree consumer binding is the preferred way to do it.

--
Stefan

Quoted 118 lines

thanks,
srini

Quoted 114 lines

For the discussion,
https://lkml.org/lkml/2016/5/23/573
https://lkml.org/lkml/2016/5/2/71

Regards,
Sanchayan.

Quoted 106 lines

Quoted 106 lines

ocotp node has cfg0 and cfg1 which we want but we cannot use existing nvmem consumer API since that requires having the nvmem consumer properties in the node we are binding to viz. is a direct nvmem consumer.

Regards,
Sanchayan.

Quoted 98 lines

thanks,
srini

Quoted 95 lines

Parent node can also be the of_node of the main SoC device node.

Signed-off-by Sanchayan Maity <[email protected]>

---
     drivers/nvmem/core.c           | 44 +++++++++++++++++++++++++++++-------------
     include/linux/nvmem-consumer.h |  1 +
     2 files changed, 32 insertions(+), 13 deletions(-)

drivers/nvmem/core.c +31 -13

index 965911d..470abee 100644
@@ -743,29 +743,21 @@ static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
 
     #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
     /**
- * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ * of_nvmem_cell_get_direct() - Get a nvmem cell from given device node
      *
- * @dev node: Device tree node that uses the nvmem cell
- * @id: nvmem cell name from nvmem-cell-names property.
+ * @dev node: Device tree node that uses nvmem cell
      *
      * Return: Will be an ERR_PTR() on error or a valid pointer
      * to a struct nvmem_cell.  The nvmem_cell will be freed by the
      * nvmem_cell_put().
      */
-struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
-					    const char *name)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np)
     {
-	struct device_node *cell_np, *nvmem_np;
+	struct device_node *nvmem_np;
     	struct nvmem_cell *cell;
     	struct nvmem_device *nvmem;
     	const __be32 *addr;
-	int rval, len, index;
-
-	index = of_property_match_string(np, "nvmem-cell-names", name);
-
-	cell_np = of_parse_phandle(np, "nvmem-cells", index);
-	if (!cell_np)
-		return ERR_PTR(-EINVAL);
+	int rval, len;
 
     	nvmem_np = of_get_next_parent(cell_np);
     	if (!nvmem_np)

@@ -824,6 +816,32 @@ err_mem:
 
     	return ERR_PTR(rval);
     }
+EXPORT_SYMBOL_GPL(of_nvmem_cell_get_direct);
+
+/**
+ * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
+ *
+ * @dev node: Device tree node that uses the nvmem cell
+ * @id: nvmem cell name from nvmem-cell-names property.
+ *
+ * Return: Will be an ERR_PTR() on error or a valid pointer
+ * to a struct nvmem_cell.  The nvmem_cell will be freed by the
+ * nvmem_cell_put().
+ */
+struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
+					    const char *name)
+{
+	struct device_node *cell_np;
+	int index;
+
+	index = of_property_match_string(np, "nvmem-cell-names", name);
+
+	cell_np = of_parse_phandle(np, "nvmem-cells", index);
+	if (!cell_np)
+		return ERR_PTR(-EINVAL);
+
+	return of_nvmem_cell_get_direct(cell_np);
+}
     EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
     #endif
 

include/linux/nvmem-consumer.h +1 -0

index 9bb77d3..bf879fc 100644
@@ -136,6 +136,7 @@ static inline int nvmem_device_write(struct nvmem_device *nvmem,
     #endif /* CONFIG_NVMEM */
 
     #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
+struct nvmem_cell *of_nvmem_cell_get_direct(struct device_node *cell_np);
     struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
     				     const char *name);
     struct nvmem_device *of_nvmem_device_get(struct device_node *np,

root@colibri-vf:/sys/bus/soc/devices/soc0# cat family
Freescale Vybrid VF610
root@colibri-vf:/sys/bus/soc/devices/soc0# cat machine
Freescale Vybrid