From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtprelay0017.hostedemail.com ([216.40.44.17]:60422 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751884AbdDGCgz (ORCPT ); Thu, 6 Apr 2017 22:36:55 -0400 Message-ID: <1491532601.3250.1.camel@perches.com> (sfid-20170407_043716_617792_93308DAC) Subject: Re: [PATCH] ath9k: Add cast to u8 to FREQ2FBIN macro From: Joe Perches To: Matthias Kaehlcke Cc: Kalle Valo , ath9k Development , linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, Grant Grundler Date: Thu, 06 Apr 2017 19:36:41 -0700 In-Reply-To: <20170406235427.GC78690@google.com> References: <20170406212135.72157-1-mka@chromium.org> <1491514160.27353.102.camel@perches.com> <20170406235427.GC78690@google.com> Content-Type: text/plain; charset="ISO-8859-1" Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, 2017-04-06 at 16:54 -0700, Matthias Kaehlcke wrote: > Hi Joe, > > El Thu, Apr 06, 2017 at 02:29:20PM -0700 Joe Perches ha dit: > > > On Thu, 2017-04-06 at 14:21 -0700, Matthias Kaehlcke wrote: > > > The macro results are assigned to u8 variables/fields. Adding the cast > > > fixes plenty of clang warnings about "implicit conversion from 'int' to > > > 'u8'". > > > > > > Signed-off-by: Matthias Kaehlcke > > > --- > > > drivers/net/wireless/ath/ath9k/eeprom.h | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/net/wireless/ath/ath9k/eeprom.h b/drivers/net/wireless/ath/ath9k/eeprom.h > > > index 30bf722e33ed..31390af6c33e 100644 > > > --- a/drivers/net/wireless/ath/ath9k/eeprom.h > > > +++ b/drivers/net/wireless/ath/ath9k/eeprom.h > > > @@ -106,7 +106,7 @@ > > > #define AR9285_RDEXT_DEFAULT 0x1F > > > > > > #define ATH9K_POW_SM(_r, _s) (((_r) & 0x3f) << (_s)) > > > -#define FREQ2FBIN(x, y) ((y) ? ((x) - 2300) : (((x) - 4800) / 5)) > > > +#define FREQ2FBIN(x, y) (u8)((y) ? ((x) - 2300) : (((x) - 4800) / 5)) > > > > Maybe better to use: > > > > static inline u8 FREQ2FBIN(int x, int y) > > { > > if (y) > > return x - 2300; > > return (x - 4800) / 5; > > } > > Thanks for your suggestion! Unfortunately in this case an inline > function is not suitable since FREQ2FBIN() is mostly used for > structure initialization: > > static const struct ar9300_eeprom ar9300_default = { > ... > .calFreqPier2G = { > FREQ2FBIN(2412, 1), > FREQ2FBIN(2437, 1), > FREQ2FBIN(2472, 1) > }, > ... Maybe it's better to remove the second argument and write something like: #define FREQ2FBIN(x) \ (u8)(((x) >= 2300 && (x) <= 2555) ? (x) - 2300 : \ ((x) >= 4800 && (x) <= 4800 + (256 * 5) ? ((x) - 4800) / 5) : \ __builtin_const_p(x) ? BUILD_BUG_ON(1) : 0) From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Perches Subject: Re: [PATCH] ath9k: Add cast to u8 to FREQ2FBIN macro Date: Thu, 06 Apr 2017 19:36:41 -0700 Message-ID: <1491532601.3250.1.camel@perches.com> References: <20170406212135.72157-1-mka@chromium.org> <1491514160.27353.102.camel@perches.com> <20170406235427.GC78690@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: Kalle Valo , ath9k Development , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-wireless-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Grant Grundler To: Matthias Kaehlcke Return-path: In-Reply-To: <20170406235427.GC78690-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> Sender: linux-wireless-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On Thu, 2017-04-06 at 16:54 -0700, Matthias Kaehlcke wrote: > Hi Joe, > > El Thu, Apr 06, 2017 at 02:29:20PM -0700 Joe Perches ha dit: > > > On Thu, 2017-04-06 at 14:21 -0700, Matthias Kaehlcke wrote: > > > The macro results are assigned to u8 variables/fields. Adding the cast > > > fixes plenty of clang warnings about "implicit conversion from 'int' to > > > 'u8'". > > > > > > Signed-off-by: Matthias Kaehlcke > > > --- > > > drivers/net/wireless/ath/ath9k/eeprom.h | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/net/wireless/ath/ath9k/eeprom.h b/drivers/net/wireless/ath/ath9k/eeprom.h > > > index 30bf722e33ed..31390af6c33e 100644 > > > --- a/drivers/net/wireless/ath/ath9k/eeprom.h > > > +++ b/drivers/net/wireless/ath/ath9k/eeprom.h > > > @@ -106,7 +106,7 @@ > > > #define AR9285_RDEXT_DEFAULT 0x1F > > > > > > #define ATH9K_POW_SM(_r, _s) (((_r) & 0x3f) << (_s)) > > > -#define FREQ2FBIN(x, y) ((y) ? ((x) - 2300) : (((x) - 4800) / 5)) > > > +#define FREQ2FBIN(x, y) (u8)((y) ? ((x) - 2300) : (((x) - 4800) / 5)) > > > > Maybe better to use: > > > > static inline u8 FREQ2FBIN(int x, int y) > > { > > if (y) > > return x - 2300; > > return (x - 4800) / 5; > > } > > Thanks for your suggestion! Unfortunately in this case an inline > function is not suitable since FREQ2FBIN() is mostly used for > structure initialization: > > static const struct ar9300_eeprom ar9300_default = { > ... > .calFreqPier2G = { > FREQ2FBIN(2412, 1), > FREQ2FBIN(2437, 1), > FREQ2FBIN(2472, 1) > }, > ... Maybe it's better to remove the second argument and write something like: #define FREQ2FBIN(x) \ (u8)(((x) >= 2300 && (x) <= 2555) ? (x) - 2300 : \ ((x) >= 4800 && (x) <= 4800 + (256 * 5) ? ((x) - 4800) / 5) : \ __builtin_const_p(x) ? BUILD_BUG_ON(1) : 0)