Re: [RFC PATCH 1/4] nvmem: core: allow specifying of_node

[Srinivas Kandagatla]

On 22/03/2021 18:19, Michael Walle wrote:
Until now, the of_node of the parent device is used. Some devices
provide more than just the nvmem provider. To avoid name space clashes,
add a way to allow specifying the nvmem cells in subnodes. Consider the
following example:

     flash@0 {
         compatible = "jedec,spi-nor";

         partitions {
             compatible = "fixed-partitions";
             #address-cells = <1>;
             #size-cells = <1>;

             partition@0 {
                 reg = <0x000000 0x010000>;
             };
         };

         otp {
             compatible = "mtd-user-otp";

I would have expected this to come up as a proper device, but am not 
100% sure how MTD handles flashes and its partitions.

             #address-cells = <1>;
             #size-cells = <1>;

             serial-number@0 {
                 reg = <0x0 0x8>;
             };
         };
     };

There the nvmem provider might be the MTD partition or the OTP region of
the flash.

Add a new config->of_node parameter, which if set, will be used instead
of the parent's of_node.

Signed-off-by: Michael Walle <mich...@walle.cc>
---

Patch is fine as it its.
If you plan to take this via mtd tree here is my Ack

Acked-by: Srinivas Kandagatla <srinivas.kandaga...@linaro.org>


--srini

  drivers/nvmem/core.c           | 4 +++-
  include/linux/nvmem-provider.h | 2 ++
  2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index bca671ff4e54..62d363a399d3 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -789,7 +789,9 @@ struct nvmem_device *nvmem_register(const struct 
nvmem_config *config)
        nvmem->reg_write = config->reg_write;
        nvmem->keepout = config->keepout;
        nvmem->nkeepout = config->nkeepout;
-       if (!config->no_of_node)
+       if (config->of_node)
+               nvmem->dev.of_node = config->of_node;
+       else if (!config->no_of_node)
                nvmem->dev.of_node = config->dev->of_node;
  
  	switch (config->id) {
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index e162b757b6d5..471cb7b9e896 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -57,6 +57,7 @@ struct nvmem_keepout {
   * @type:     Type of the nvmem storage
   * @read_only:        Device is read-only.
   * @root_only:        Device is accessibly to root only.
+ * @of_node:   If given, this will be used instead of the parent's of_node.
   * @no_of_node:       Device should not use the parent's of_node even if it's 
!NULL.
   * @reg_read: Callback to read data.
   * @reg_write:        Callback to write data.
@@ -86,6 +87,7 @@ struct nvmem_config {
        enum nvmem_type         type;
        bool                    read_only;
        bool                    root_only;
+       struct device_node      *of_node;
        bool                    no_of_node;
        nvmem_reg_read_t        reg_read;
        nvmem_reg_write_t       reg_write;