linux-kernel - [PATCH] nvmem: core: Allow ignoring length when reading a cell

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Date:   Mon, 19 Dec 2016 12:23:09 +0530
From:   Vivek Gautam <vivek.gautam@...eaurora.org>
To:     srinivas.kandagatla@...aro.org, maxime.ripard@...e-electrons.com
Cc:     sboyd@...eaurora.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org,
        Vivek Gautam <vivek.gautam@...eaurora.org>
Subject: [PATCH] nvmem: core: Allow ignoring length when reading a cell

nvmem_cell_read() API fills in the argument 'len' with
the number of bytes read from the cell. Many users don't
care about this length value. So allow users to pass a
NULL pointer to this len field.

Signed-off-by: Vivek Gautam <vivek.gautam@...eaurora.org>
---

Based on torvalds's master branch.
 - Tested against 'next-20161219' tag on db410c (apq8016) target
   for thermal sensors.

 drivers/nvmem/core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 965911d..4c38842 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -970,7 +970,8 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem,
 	if (cell->bit_offset || cell->nbits)
 		nvmem_shift_read_buffer_in_place(cell, buf);
 
-	*len = cell->bytes;
+	if (len)
+		*len = cell->bytes;
 
 	return 0;
 }
@@ -979,7 +980,8 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem,
  * nvmem_cell_read() - Read a given nvmem cell
  *
  * @cell: nvmem cell to be read.
- * @len: pointer to length of cell which will be populated on successful read.
+ * @len: pointer to length of cell which will be populated on successful read;
+ *	 can be NULL.
  *
  * Return: ERR_PTR() on error or a valid pointer to a char * buffer on success.
  * The buffer should be freed by the consumer with a kfree().
-- 
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