Re: [PATCH 02/11] ASoC: ab8500: Revert back to find_next_bit()

Takashi Iwai
2013-12-19T16:06:36Z

At Thu, 19 Dec 2013 15:54:59 +0000,
Lee Jones wrote:
>
> Commit '166a34d ASoC: ab8500: Fix invalid cast to long pointer'
> rather carelessly converts find_next_bit() to fls() (find last
> bit set), which are not the same.

Does it break on the real machines?

fls() behaves differently from find_next_bit(), of course, but in this
case, it should work same in the end, since there are at most two
bits.

Takashi

> Although this implementation may not be portable, the alternative
> breaks audio on anything using the AB8500 CODEC, which is a much
> greater evil. Besides, this driver will never run on anything
> else.
>
> Cc: Takashi Iwai <tiwai@suse.de>
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---
> sound/soc/codecs/ab8500-codec.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/sound/soc/codecs/ab8500-codec.c b/sound/soc/codecs/ab8500-codec.c
> index 1ad92cb..51ae3e9 100644
> --- a/sound/soc/codecs/ab8500-codec.c
> +++ b/sound/soc/codecs/ab8500-codec.c
> @@ -2322,7 +2322,7 @@ static int ab8500_codec_set_dai_tdm_slot(struct snd_soc_dai *dai,
> slot = ffs(tx_mask);
> snd_soc_update_bits(codec, AB8500_DASLOTCONF1, mask, slot);
> snd_soc_update_bits(codec, AB8500_DASLOTCONF3, mask, slot);
> - slot = fls(tx_mask);
> + slot = find_next_bit((unsigned long *)&tx_mask, 32, slot + 1);
> snd_soc_update_bits(codec, AB8500_DASLOTCONF2, mask, slot);
> snd_soc_update_bits(codec, AB8500_DASLOTCONF4, mask, slot);
> break;
> @@ -2364,7 +2364,7 @@ static int ab8500_codec_set_dai_tdm_slot(struct snd_soc_dai *dai,
> AB8500_ADSLOTSEL(slot),
> AB8500_MASK_SLOT(slot),
> AB8500_ADSLOTSELX_AD_OUT_TO_SLOT(AB8500_AD_OUT3, slot));
> - slot = fls(rx_mask);
> + slot = find_next_bit((unsigned long *)&rx_mask, 32, slot + 1);
> snd_soc_update_bits(codec,
> AB8500_ADSLOTSEL(slot),
> AB8500_MASK_SLOT(slot),
> --
> 1.8.3.2
>