Re: [PATCH] MFD: AB8500 mask off irrelevant bits from the SPImessage

From: Samuel Ortiz
Date: Fri Jun 18 2010 - 17:19:32 EST


Hi Linus,

On Fri, May 28, 2010 at 02:59:44AM +0200, Linus Walleij wrote:
> The registers on the AB8500 are only 8 bits wide, so the content
> of the remaining bits is undefined. Let's mask off the undefined
> stuff when returning a register in an SPI read.
Patch applied, sorry for the delay.

Cheers,
Samuel.


> Acked-by: Rabin Vincent <rabin.vincent@xxxxxxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>
> ---
> drivers/mfd/ab8500-spi.c | 7 ++++++-
> 1 files changed, 6 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/mfd/ab8500-spi.c b/drivers/mfd/ab8500-spi.c
> index b81d4f7..e1c8b62 100644
> --- a/drivers/mfd/ab8500-spi.c
> +++ b/drivers/mfd/ab8500-spi.c
> @@ -68,7 +68,12 @@ static int ab8500_spi_read(struct ab8500 *ab8500, u16 addr)
>
> ret = spi_sync(spi, &msg);
> if (!ret)
> - ret = ab8500->rx_buf[0];
> + /*
> + * Only the 8 lowermost bytes are
> + * defined with value, the rest may
> + * vary depending on chip/board noise.
> + */
> + ret = ab8500->rx_buf[0] & 0xFFU;
>
> return ret;
> }
> --
> 1.6.3.3
>

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