target/linux/generic/backport-5.10/814-v6.4-0005-nvmem-core-add-per-cell-post-processing.patch

   1 From 345ec382cd4b736c36e01f155d08c913b225b736 Mon Sep 17 00:00:00 2001
   2 From: Michael Walle <michael@walle.cc>
   3 Date: Tue, 4 Apr 2023 18:21:24 +0100
   4 Subject: [PATCH] nvmem: core: add per-cell post processing
   5
   6 Instead of relying on the name the consumer is using for the cell, like
   7 it is done for the nvmem .cell_post_process configuration parameter,
   8 provide a per-cell post processing hook. This can then be populated by
   9 the NVMEM provider (or the NVMEM layout) when adding the cell.
  10
  11 Signed-off-by: Michael Walle <michael@walle.cc>
  12 Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
  13 Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
  14 Link: https://lore.kernel.org/r/20230404172148.82422-17-srinivas.kandagatla@linaro.org
  15 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  16 ---
  17  drivers/nvmem/core.c           | 17 +++++++++++++++++
  18  include/linux/nvmem-provider.h |  3 +++
  19  2 files changed, 20 insertions(+)
  20
  21 --- a/drivers/nvmem/core.c
  22 +++ b/drivers/nvmem/core.c
  23 @@ -54,6 +54,7 @@ struct nvmem_cell_entry {
  24         int                     bytes;
  25         int                     bit_offset;
  26         int                     nbits;
  27 +       nvmem_cell_post_process_t read_post_process;
  28         struct device_node      *np;
  29         struct nvmem_device     *nvmem;
  30         struct list_head        node;
  31 @@ -470,6 +471,7 @@ static int nvmem_cell_info_to_nvmem_cell
  32         cell->offset = info->offset;
  33         cell->bytes = info->bytes;
  34         cell->name = info->name;
  35 +       cell->read_post_process = info->read_post_process;
  36
  37         cell->bit_offset = info->bit_offset;
  38         cell->nbits = info->nbits;
  39 @@ -1563,6 +1565,13 @@ static int __nvmem_cell_read(struct nvme
  40         if (cell->bit_offset || cell->nbits)
  41                 nvmem_shift_read_buffer_in_place(cell, buf);
  42
  43 +       if (cell->read_post_process) {
  44 +               rc = cell->read_post_process(nvmem->priv, id, index,
  45 +                                            cell->offset, buf, cell->bytes);
  46 +               if (rc)
  47 +                       return rc;
  48 +       }
  49 +
  50         if (nvmem->cell_post_process) {
  51                 rc = nvmem->cell_post_process(nvmem->priv, id, index,
  52                                               cell->offset, buf, cell->bytes);
  53 @@ -1671,6 +1680,14 @@ static int __nvmem_cell_entry_write(stru
  54             (cell->bit_offset == 0 && len != cell->bytes))
  55                 return -EINVAL;
  56
  57 +       /*
  58 +        * Any cells which have a read_post_process hook are read-only because
  59 +        * we cannot reverse the operation and it might affect other cells,
  60 +        * too.
  61 +        */
  62 +       if (cell->read_post_process)
  63 +               return -EINVAL;
  64 +
  65         if (cell->bit_offset || cell->nbits) {
  66                 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
  67                 if (IS_ERR(buf))
  68 --- a/include/linux/nvmem-provider.h
  69 +++ b/include/linux/nvmem-provider.h
  70 @@ -54,6 +54,8 @@ struct nvmem_keepout {
  71   * @bit_offset:        Bit offset if cell is smaller than a byte.
  72   * @nbits:     Number of bits.
  73   * @np:                Optional device_node pointer.
  74 + * @read_post_process: Callback for optional post processing of cell data
  75 + *                     on reads.
  76   */
  77  struct nvmem_cell_info {
  78         const char              *name;
  79 @@ -62,6 +64,7 @@ struct nvmem_cell_info {
  80         unsigned int            bit_offset;
  81         unsigned int            nbits;
  82         struct device_node      *np;
  83 +       nvmem_cell_post_process_t read_post_process;
  84  };
  85
  86  /**