Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754349Ab3CKSxA (ORCPT ); Mon, 11 Mar 2013 14:53:00 -0400 Received: from mailhost.informatik.uni-hamburg.de ([134.100.9.70]:62682 "EHLO mailhost.informatik.uni-hamburg.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754140Ab3CKSw6 (ORCPT ); Mon, 11 Mar 2013 14:52:58 -0400 Message-ID: <513E2895.6040904@metafoo.de> Date: Mon, 11 Mar 2013 19:55:17 +0100 From: Lars-Peter Clausen User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20121215 Icedove/3.0.11 MIME-Version: 1.0 To: Tim Gardner CC: linux-kernel@vger.kernel.org, Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , device-drivers-devel@blackfin.uclinux.org, alsa-devel@alsa-project.org Subject: Re: [PATCH] ASoC: adau1373: adau1373_hw_params: Silence overflow warning References: <1362936878-84443-1-git-send-email-tim.gardner@canonical.com> <513DAB80.1020900@metafoo.de> <513DFA55.2050104@canonical.com> In-Reply-To: <513DFA55.2050104@canonical.com> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3579 Lines: 88 On 03/11/2013 04:37 PM, Tim Gardner wrote: > On 03/11/2013 04:01 AM, Lars-Peter Clausen wrote: >> On 03/10/2013 06:34 PM, Tim Gardner wrote: >>> ADAU1373_BCLKDIV_SOURCE is defined as BIT(5) which uses UL constants. On >>> amd64 the result of the ones complement operator is then truncated to >>> unsigned int according to the prototype of snd_soc_update_bits(). I think >>> gcc is correctly warning that the upper 32 bits are lost. >>> >>> sound/soc/codecs/adau1373.c: In function 'adau1373_hw_params': >>> sound/soc/codecs/adau1373.c:940:3: warning: large integer implicitly truncated to unsigned type [-Woverflow] >>> >>> gcc version 4.6.3 >>> >>> Cc: Lars-Peter Clausen >>> Cc: Liam Girdwood >>> Cc: Mark Brown >>> Cc: Jaroslav Kysela >>> Cc: Takashi Iwai >>> Cc: device-drivers-devel@blackfin.uclinux.org >>> Cc: alsa-devel@alsa-project.org >>> Signed-off-by: Tim Gardner >>> --- >>> sound/soc/codecs/adau1373.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/sound/soc/codecs/adau1373.c b/sound/soc/codecs/adau1373.c >>> index 068b3ae..56ed788 100644 >>> --- a/sound/soc/codecs/adau1373.c >>> +++ b/sound/soc/codecs/adau1373.c >>> @@ -132,7 +132,7 @@ struct adau1373 { >>> #define ADAU1373_DAI_FORMAT_I2S 0x2 >>> #define ADAU1373_DAI_FORMAT_DSP 0x3 >>> >>> -#define ADAU1373_BCLKDIV_SOURCE BIT(5) >>> +#define ADAU1373_BCLKDIV_SOURCE (unsigned int)BIT(5) >> >> Hm, that's a bit ugly. How about the following instead: >> >> diff --git a/sound/soc/codecs/adau1373.c b/sound/soc/codecs/adau1373.c >> index 068b3ae..1aa10dd 100644 >> --- a/sound/soc/codecs/adau1373.c >> +++ b/sound/soc/codecs/adau1373.c >> @@ -133,6 +133,8 @@ struct adau1373 { >> #define ADAU1373_DAI_FORMAT_DSP 0x3 >> >> #define ADAU1373_BCLKDIV_SOURCE BIT(5) >> +#define ADAU1373_BCLKDIV_SR_MASK (0x07 << 2) >> +#define ADAU1373_BCLKDIV_BCLK_MASK 0x03 >> #define ADAU1373_BCLKDIV_32 0x03 >> #define ADAU1373_BCLKDIV_64 0x02 >> #define ADAU1373_BCLKDIV_128 0x01 >> @@ -937,7 +939,8 @@ static int adau1373_hw_params(struct snd_pcm_substream >> *substream, >> adau1373_dai->enable_src = (div != 0); >> >> snd_soc_update_bits(codec, ADAU1373_BCLKDIV(dai->id), >> - ~ADAU1373_BCLKDIV_SOURCE, (div << 2) | ADAU1373_BCLKDIV_64); >> + ADAU1373_BCLKDIV_SR_MASK | ADAU1373_BCLKDIV_BCLK_MASK, >> + (div << 2) | ADAU1373_BCLKDIV_64); >> >> switch (params_format(params)) { >> case SNDRV_PCM_FORMAT_S16_LE: >> >> > > That seems way more complicated then need be. It also uses 2 bits in the > mask whereas the original code only used 1, e.g., bit 5. Is that correct ? The BCLKDIV has three fields. The bitclock divider (bit 0-1), the samplerate (bit 2-4) and the source select (bit 5). Here we want to update the bitclock divider field and the samplerate field. When I wrote the code I was lazy and used ~ADAU1373_BCLKDIV_SOURCE as the mask, which for this register is functional equivalent to ADAU1373_BCLKDIV_SR_MASK | ADAU1373_BCLKDIV_BCLK_MASK. > > How about just open coding the macro thusly: > > #define ADAU1373_BCLKDIV_SOURCE (1<<5) /*BIT(5)*/ But now there is a inconsistency where we sometimes use (1<