From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [RFC 02/11] i2c: add quirk checks to core Date: Sat, 10 Jan 2015 00:05:07 +0300 Message-ID: <54B04283.5070705@cogentembedded.com> References: <1420824103-24169-1-git-send-email-wsa@the-dreams.de> <1420824103-24169-3-git-send-email-wsa@the-dreams.de> <54B02D7F.7040501@cogentembedded.com> <20150109204522.GB1904@katana> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150109204522.GB1904@katana> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Wolfram Sang Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-mips-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org, Benjamin Herrenschmidt , Ludovic Desroches , Yingjoe Chen , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org Hello. On 01/09/2015 11:45 PM, Wolfram Sang wrote: >>> Let the core do the checks if HW quirks prevent a transfer. Saves code >> >from drivers and adds consistency. >>> Signed-off-by: Wolfram Sang >>> --- >>> drivers/i2c/i2c-core.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 53 insertions(+) >>> >>> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c >>> index 39d25a8cb1ad..7b10a19abf5b 100644 >>> --- a/drivers/i2c/i2c-core.c >>> +++ b/drivers/i2c/i2c-core.c >>> @@ -2063,6 +2063,56 @@ module_exit(i2c_exit); >>> * ---------------------------------------------------- >>> */ >>> >>> +/* Check if val is exceeding the quirk IFF quirk is non 0 */ >>> +#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) >>> + >>> +static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) >>> +{ >>> + dev_err(&adap->dev, "quirk: %s (addr 0x%04x, size %u)\n", err_msg, msg->addr, msg->len); >>> + return -EOPNOTSUPP; >>> +} >> Always returning the same value doesn't make much sense. Are you trying >> to save space on the call sites? > Please elaborate. I think it does. If a quirk matches, we report that we > don't support this transfer. OK, but what's the point of having this function return *int* if it always returns the same value? AFAIU, you're trying to save the code space on the call sites of this function by not having *return* -EOPNOTSUPP there each time? >> [...] >>> @@ -2080,6 +2130,9 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) >>> unsigned long orig_jiffies; >>> int ret, try; >>> >>> + if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) >> So, you only check for non-zero result of this function? Perhaps it makes >> sense to return true/false instead? > Could be done, but what would be the advantage? A lot of functions > return errno or 0. It would have been OK if you were actually caring about the result, e.g. returning it from __i2c_transfer(). Since you don't, IMO it would make more sense to return true from i2c_check_for_quirks() (making it *bool*) iff it did find/apply a quirk. WBR, Sergei From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 09 Jan 2015 22:05:18 +0100 (CET) Received: from mail-la0-f52.google.com ([209.85.215.52]:42806 "EHLO mail-la0-f52.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S27010751AbbAIVFQFVEi7 (ORCPT ); Fri, 9 Jan 2015 22:05:16 +0100 Received: by mail-la0-f52.google.com with SMTP id hs14so17051196lab.11 for ; Fri, 09 Jan 2015 13:05:10 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:message-id:date:from:organization:user-agent :mime-version:to:cc:subject:references:in-reply-to:content-type :content-transfer-encoding; bh=ecMGYd0JPndrsydtkTkh4ImHNtfJrQkuFC3tHQp4vBE=; b=AWWgzyf4WjcEOzfrXosgcTsl41MxuqLKqRaEGO7GsVkOAql42dXGOb3ehz3B28Nphu 1mex4QFUQrq5+Cd086pJEwpboVpuBN5LYThA9iVSL+jBDyMAPrBDv2i00k699vCxa7NC VgHwjFkNuMGB0Ag8jgdbnCthnGhCXzxBZrI0/ZIobRifqq7nXMksEfyVM2Vev3GgBaw0 mtGZvayYImqjauCOr/1zU6W12BkEF+r/eioWligB1CcrYzftrAoNjdcwdi0UftsxAC0r KpYQ+VxI/Ss9aYef+DKFrL++sfrqUQTZAUxbP8TqOPqdK7Ei6M2BLvoAZWApLG7pTCUD bV7w== X-Gm-Message-State: ALoCoQkyQY2DlceFyDYwU/rfzUauYjophHcNf13EjFSm1Aw9mtI1lZioWK3FLqhfqdrB0dZfXAuB X-Received: by 10.152.26.201 with SMTP id n9mr24091032lag.50.1420837510625; Fri, 09 Jan 2015 13:05:10 -0800 (PST) Received: from wasted.cogentembedded.com (ppp20-191.pppoe.mtu-net.ru. [81.195.20.191]) by mx.google.com with ESMTPSA id r5sm2095015lae.34.2015.01.09.13.05.08 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 09 Jan 2015 13:05:09 -0800 (PST) Message-ID: <54B04283.5070705@cogentembedded.com> Date: Sat, 10 Jan 2015 00:05:07 +0300 From: Sergei Shtylyov Organization: Cogent Embedded User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Wolfram Sang CC: linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-mips@linux-mips.org, Benjamin Herrenschmidt , Ludovic Desroches , Yingjoe Chen , linux-kernel@vger.kernel.org Subject: Re: [RFC 02/11] i2c: add quirk checks to core References: <1420824103-24169-1-git-send-email-wsa@the-dreams.de> <1420824103-24169-3-git-send-email-wsa@the-dreams.de> <54B02D7F.7040501@cogentembedded.com> <20150109204522.GB1904@katana> In-Reply-To: <20150109204522.GB1904@katana> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 45044 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: sergei.shtylyov@cogentembedded.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips Hello. On 01/09/2015 11:45 PM, Wolfram Sang wrote: >>> Let the core do the checks if HW quirks prevent a transfer. Saves code >> >from drivers and adds consistency. >>> Signed-off-by: Wolfram Sang >>> --- >>> drivers/i2c/i2c-core.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 53 insertions(+) >>> >>> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c >>> index 39d25a8cb1ad..7b10a19abf5b 100644 >>> --- a/drivers/i2c/i2c-core.c >>> +++ b/drivers/i2c/i2c-core.c >>> @@ -2063,6 +2063,56 @@ module_exit(i2c_exit); >>> * ---------------------------------------------------- >>> */ >>> >>> +/* Check if val is exceeding the quirk IFF quirk is non 0 */ >>> +#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) >>> + >>> +static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) >>> +{ >>> + dev_err(&adap->dev, "quirk: %s (addr 0x%04x, size %u)\n", err_msg, msg->addr, msg->len); >>> + return -EOPNOTSUPP; >>> +} >> Always returning the same value doesn't make much sense. Are you trying >> to save space on the call sites? > Please elaborate. I think it does. If a quirk matches, we report that we > don't support this transfer. OK, but what's the point of having this function return *int* if it always returns the same value? AFAIU, you're trying to save the code space on the call sites of this function by not having *return* -EOPNOTSUPP there each time? >> [...] >>> @@ -2080,6 +2130,9 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) >>> unsigned long orig_jiffies; >>> int ret, try; >>> >>> + if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) >> So, you only check for non-zero result of this function? Perhaps it makes >> sense to return true/false instead? > Could be done, but what would be the advantage? A lot of functions > return errno or 0. It would have been OK if you were actually caring about the result, e.g. returning it from __i2c_transfer(). Since you don't, IMO it would make more sense to return true from i2c_check_for_quirks() (making it *bool*) iff it did find/apply a quirk. WBR, Sergei From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f43.google.com (mail-la0-f43.google.com [209.85.215.43]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id C009E1A0FA7 for ; Sat, 10 Jan 2015 08:05:14 +1100 (AEDT) Received: by mail-la0-f43.google.com with SMTP id s18so16511471lam.2 for ; Fri, 09 Jan 2015 13:05:10 -0800 (PST) Message-ID: <54B04283.5070705@cogentembedded.com> Date: Sat, 10 Jan 2015 00:05:07 +0300 From: Sergei Shtylyov MIME-Version: 1.0 To: Wolfram Sang Subject: Re: [RFC 02/11] i2c: add quirk checks to core References: <1420824103-24169-1-git-send-email-wsa@the-dreams.de> <1420824103-24169-3-git-send-email-wsa@the-dreams.de> <54B02D7F.7040501@cogentembedded.com> <20150109204522.GB1904@katana> In-Reply-To: <20150109204522.GB1904@katana> Content-Type: text/plain; charset=windows-1252; format=flowed Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, Ludovic Desroches , linux-i2c@vger.kernel.org, Yingjoe Chen , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hello. On 01/09/2015 11:45 PM, Wolfram Sang wrote: >>> Let the core do the checks if HW quirks prevent a transfer. Saves code >> >from drivers and adds consistency. >>> Signed-off-by: Wolfram Sang >>> --- >>> drivers/i2c/i2c-core.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 53 insertions(+) >>> >>> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c >>> index 39d25a8cb1ad..7b10a19abf5b 100644 >>> --- a/drivers/i2c/i2c-core.c >>> +++ b/drivers/i2c/i2c-core.c >>> @@ -2063,6 +2063,56 @@ module_exit(i2c_exit); >>> * ---------------------------------------------------- >>> */ >>> >>> +/* Check if val is exceeding the quirk IFF quirk is non 0 */ >>> +#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) >>> + >>> +static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) >>> +{ >>> + dev_err(&adap->dev, "quirk: %s (addr 0x%04x, size %u)\n", err_msg, msg->addr, msg->len); >>> + return -EOPNOTSUPP; >>> +} >> Always returning the same value doesn't make much sense. Are you trying >> to save space on the call sites? > Please elaborate. I think it does. If a quirk matches, we report that we > don't support this transfer. OK, but what's the point of having this function return *int* if it always returns the same value? AFAIU, you're trying to save the code space on the call sites of this function by not having *return* -EOPNOTSUPP there each time? >> [...] >>> @@ -2080,6 +2130,9 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) >>> unsigned long orig_jiffies; >>> int ret, try; >>> >>> + if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) >> So, you only check for non-zero result of this function? Perhaps it makes >> sense to return true/false instead? > Could be done, but what would be the advantage? A lot of functions > return errno or 0. It would have been OK if you were actually caring about the result, e.g. returning it from __i2c_transfer(). Since you don't, IMO it would make more sense to return true from i2c_check_for_quirks() (making it *bool*) iff it did find/apply a quirk. WBR, Sergei From mboxrd@z Thu Jan 1 00:00:00 1970 From: sergei.shtylyov@cogentembedded.com (Sergei Shtylyov) Date: Sat, 10 Jan 2015 00:05:07 +0300 Subject: [RFC 02/11] i2c: add quirk checks to core In-Reply-To: <20150109204522.GB1904@katana> References: <1420824103-24169-1-git-send-email-wsa@the-dreams.de> <1420824103-24169-3-git-send-email-wsa@the-dreams.de> <54B02D7F.7040501@cogentembedded.com> <20150109204522.GB1904@katana> Message-ID: <54B04283.5070705@cogentembedded.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hello. On 01/09/2015 11:45 PM, Wolfram Sang wrote: >>> Let the core do the checks if HW quirks prevent a transfer. Saves code >> >from drivers and adds consistency. >>> Signed-off-by: Wolfram Sang >>> --- >>> drivers/i2c/i2c-core.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 53 insertions(+) >>> >>> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c >>> index 39d25a8cb1ad..7b10a19abf5b 100644 >>> --- a/drivers/i2c/i2c-core.c >>> +++ b/drivers/i2c/i2c-core.c >>> @@ -2063,6 +2063,56 @@ module_exit(i2c_exit); >>> * ---------------------------------------------------- >>> */ >>> >>> +/* Check if val is exceeding the quirk IFF quirk is non 0 */ >>> +#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk))) >>> + >>> +static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg) >>> +{ >>> + dev_err(&adap->dev, "quirk: %s (addr 0x%04x, size %u)\n", err_msg, msg->addr, msg->len); >>> + return -EOPNOTSUPP; >>> +} >> Always returning the same value doesn't make much sense. Are you trying >> to save space on the call sites? > Please elaborate. I think it does. If a quirk matches, we report that we > don't support this transfer. OK, but what's the point of having this function return *int* if it always returns the same value? AFAIU, you're trying to save the code space on the call sites of this function by not having *return* -EOPNOTSUPP there each time? >> [...] >>> @@ -2080,6 +2130,9 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) >>> unsigned long orig_jiffies; >>> int ret, try; >>> >>> + if (adap->quirks && i2c_check_for_quirks(adap, msgs, num)) >> So, you only check for non-zero result of this function? Perhaps it makes >> sense to return true/false instead? > Could be done, but what would be the advantage? A lot of functions > return errno or 0. It would have been OK if you were actually caring about the result, e.g. returning it from __i2c_transfer(). Since you don't, IMO it would make more sense to return true from i2c_check_for_quirks() (making it *bool*) iff it did find/apply a quirk. WBR, Sergei