linux-kernel - [PATCH 3/5] nvmem: core: Allow ignoring length when reading a cell

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Date:   Sun, 22 Jan 2017 23:02:38 +0000
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     gregkh@...uxfoundation.org
Cc:     maxime.ripard@...e-electrons.com, linux-kernel@...r.kernel.org,
        Vivek Gautam <vivek.gautam@...eaurora.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: [PATCH 3/5] nvmem: core: Allow ignoring length when reading a cell

From: Vivek Gautam <vivek.gautam@...eaurora.org>

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>
Reviewed-by: Stephen Boyd <sboyd@...eaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
---
 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 398ea7f..78aa06a 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 buffer on success. The
  * buffer should be freed by the consumer with a kfree().
-- 
2.7.4