nvmem: core: add nvmem cell post processing callback

Some NVMEM providers have certain nvmem cells encoded, which requires
post processing before actually using it.

For example mac-address is stored in either in ascii or delimited or reverse-order.

Having a post-process callback hook to provider drivers would enable them to
do this vendor specific post processing before nvmem consumers see it.

Tested-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20211013131957.30271-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index f37d783..d7013c9 100644 (file)
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -38,6 +38,7 @@ struct nvmem_device {
        unsigned int            nkeepout;
        nvmem_reg_read_t        reg_read;
        nvmem_reg_write_t       reg_write;
+       nvmem_cell_post_process_t cell_post_process;
        struct gpio_desc        *wp_gpio;
        void *priv;
 };
@@ -796,6 +797,7 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
        nvmem->type = config->type;
        nvmem->reg_read = config->reg_read;
        nvmem->reg_write = config->reg_write;
+       nvmem->cell_post_process = config->cell_post_process;
        nvmem->keepout = config->keepout;
        nvmem->nkeepout = config->nkeepout;
        if (config->of_node)
@@ -1440,6 +1442,13 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem,
        if (cell->bit_offset || cell->nbits)
                nvmem_shift_read_buffer_in_place(cell, buf);
 
+       if (nvmem->cell_post_process) {
+               rc = nvmem->cell_post_process(nvmem->priv, id,
+                                             cell->offset, buf, cell->bytes);
+               if (rc)
+                       return rc;
+       }
+
        if (len)
                *len = cell->bytes;
 

diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 104505e..98efb7b 100644 (file)
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -19,6 +19,9 @@ typedef int (*nvmem_reg_read_t)(void *priv, unsigned int offset,
                                void *val, size_t bytes);
 typedef int (*nvmem_reg_write_t)(void *priv, unsigned int offset,
                                 void *val, size_t bytes);
+/* used for vendor specific post processing of cell data */
+typedef int (*nvmem_cell_post_process_t)(void *priv, const char *id, unsigned int offset,
+                                         void *buf, size_t bytes);
 
 enum nvmem_type {
        NVMEM_TYPE_UNKNOWN = 0,
@@ -62,6 +65,7 @@ struct nvmem_keepout {
  * @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.
+ * @cell_post_process: Callback for vendor specific post processing of cell data
  * @size:      Device size.
  * @word_size: Minimum read/write access granularity.
  * @stride:    Minimum read/write access stride.
@@ -92,6 +96,7 @@ struct nvmem_config {
        bool                    no_of_node;
        nvmem_reg_read_t        reg_read;
        nvmem_reg_write_t       reg_write;
+       nvmem_cell_post_process_t cell_post_process;
        int     size;
        int     word_size;
        int     stride;