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SubjectRe: [PATCH] leds: leds-lp5521: Avoid writing uninitialized value to LP5521_REG_OP_MODE register
On Wed, 05 Oct 2011 17:19:38 +0800
Axel Lin <axel.lin@gmail.com> wrote:

> If lp5521_read fails, engine_state variable is not initialized.
> If lp5521_read fails, we should return error.
> This patch fixes below warning.
>
> CC drivers/leds/leds-lp5521.o
> drivers/leds/leds-lp5521.c: In function 'lp5521_set_engine_mode':
> drivers/leds/leds-lp5521.c:168: warning: 'engine_state' may be used uninitialized in this function
>
> Signed-off-by: Axel Lin <axel.lin@gmail.com>
> ---
> drivers/leds/leds-lp5521.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/leds/leds-lp5521.c b/drivers/leds/leds-lp5521.c
> index 9fc122c..89134d9 100644
> --- a/drivers/leds/leds-lp5521.c
> +++ b/drivers/leds/leds-lp5521.c
> @@ -175,6 +175,8 @@ static int lp5521_set_engine_mode(struct lp5521_engine *engine, u8 mode)
> mode = LP5521_CMD_DIRECT;
>
> ret = lp5521_read(client, LP5521_REG_OP_MODE, &engine_state);
> + if (ret < 0)
> + return ret;
>
> /* set mode only for this engine */
> engine_state &= ~(engine->engine_mask);

OK. And the later "ret |=" whcih was previously a bug is now just
unneeded.

--- a/drivers/leds/leds-lp5521.c~leds-leds-lp5521-avoid-writing-uninitialized-value-to-lp5521_reg_op_mode-register-fix
+++ a/drivers/leds/leds-lp5521.c
@@ -182,9 +182,7 @@ static int lp5521_set_engine_mode(struct
engine_state &= ~(engine->engine_mask);
mode &= engine->engine_mask;
engine_state |= mode;
- ret |= lp5521_write(client, LP5521_REG_OP_MODE, engine_state);
-
- return ret;
+ return lp5521_write(client, LP5521_REG_OP_MODE, engine_state);
}

static int lp5521_load_program(struct lp5521_engine *eng, const u8 *pattern)
_


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