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From 345ec382cd4b736c36e01f155d08c913b225b736 Mon Sep 17 00:00:00 2001
From: Michael Walle <michael@walle.cc>
Date: Tue, 4 Apr 2023 18:21:24 +0100
Subject: [PATCH] nvmem: core: add per-cell post processing
Instead of relying on the name the consumer is using for the cell, like
it is done for the nvmem .cell_post_process configuration parameter,
provide a per-cell post processing hook. This can then be populated by
the NVMEM provider (or the NVMEM layout) when adding the cell.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-17-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/nvmem/core.c | 17 +++++++++++++++++
include/linux/nvmem-provider.h | 3 +++
2 files changed, 20 insertions(+)
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -54,6 +54,7 @@ struct nvmem_cell_entry {
int bytes;
int bit_offset;
int nbits;
+ nvmem_cell_post_process_t read_post_process;
struct device_node *np;
struct nvmem_device *nvmem;
struct list_head node;
@@ -470,6 +471,7 @@ static int nvmem_cell_info_to_nvmem_cell
cell->offset = info->offset;
cell->bytes = info->bytes;
cell->name = info->name;
+ cell->read_post_process = info->read_post_process;
cell->bit_offset = info->bit_offset;
cell->nbits = info->nbits;
@@ -1563,6 +1565,13 @@ static int __nvmem_cell_read(struct nvme
if (cell->bit_offset || cell->nbits)
nvmem_shift_read_buffer_in_place(cell, buf);
+ if (cell->read_post_process) {
+ rc = cell->read_post_process(nvmem->priv, id, index,
+ cell->offset, buf, cell->bytes);
+ if (rc)
+ return rc;
+ }
+
if (nvmem->cell_post_process) {
rc = nvmem->cell_post_process(nvmem->priv, id, index,
cell->offset, buf, cell->bytes);
@@ -1671,6 +1680,14 @@ static int __nvmem_cell_entry_write(stru
(cell->bit_offset == 0 && len != cell->bytes))
return -EINVAL;
+ /*
+ * Any cells which have a read_post_process hook are read-only because
+ * we cannot reverse the operation and it might affect other cells,
+ * too.
+ */
+ if (cell->read_post_process)
+ return -EINVAL;
+
if (cell->bit_offset || cell->nbits) {
buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
if (IS_ERR(buf))
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -54,6 +54,8 @@ struct nvmem_keepout {
* @bit_offset: Bit offset if cell is smaller than a byte.
* @nbits: Number of bits.
* @np: Optional device_node pointer.
+ * @read_post_process: Callback for optional post processing of cell data
+ * on reads.
*/
struct nvmem_cell_info {
const char *name;
@@ -62,6 +64,7 @@ struct nvmem_cell_info {
unsigned int bit_offset;
unsigned int nbits;
struct device_node *np;
+ nvmem_cell_post_process_t read_post_process;
};
/**
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