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[85.228.174.190]) by smtp.gmail.com with ESMTPSA id l1sm2212934ljc.65.2020.06.29.05.51.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Jun 2020 05:51:03 -0700 (PDT) Received: from johan by xi.terra with local (Exim 4.93.0.4) (envelope-from ) id 1jptFW-0006wJ-Se; Mon, 29 Jun 2020 14:51:03 +0200 Date: Mon, 29 Jun 2020 14:51:02 +0200 From: Johan Hovold To: Lee Jones Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Johan Hovold Subject: Re: [PATCH 2/5] mfd: lm3533-ctrlbank: Cap BRIGHTNESS_MAX to 127 since API uses u8 as carrier Message-ID: <20200629125102.GT3334@localhost> References: <20200629123215.1014747-1-lee.jones@linaro.org> <20200629123215.1014747-3-lee.jones@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200629123215.1014747-3-lee.jones@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 29, 2020 at 01:32:12PM +0100, Lee Jones wrote: > Since its conception in 2012 brightness has been artificially capped > at 127 since the variable carrying the value is u8. We could go to > the trouble of changing the whole API (crossing 3 different subsystems), > but clearly this hasn't bothered anyone in the best part of a decade. > > Simply, cap BRIGHTNESS_MAX to 127 instead (for now at least). Hmm. This patch is clearly broken and would contrary to the claim be introducing an artificial cap at half brightness. u8 can hold the max brightness value 255 just fine. > Fixes the following W=1 warning(s): > > drivers/mfd/lm3533-ctrlbank.c: In function ‘lm3533_ctrlbank_set_brightness’: > drivers/mfd/lm3533-ctrlbank.c:98:10: warning: comparison is always false due to limited range of data type [-Wtype-limits] > 98 | if (val > LM3533_##_NAME##_MAX) | ^ > drivers/mfd/lm3533-ctrlbank.c:125:1: note: in expansion of macro ‘lm3533_ctrlbank_set’ > 125 | lm3533_ctrlbank_set(brightness, BRIGHTNESS); > | ^~~~~~~~~~~~~~~~~~~ This warning is benign. The same macro is used to defined two function where in one case the max value coincides with U8_MAX so that the sanity check becomes redundant. > Cc: Johan Hovold > Signed-off-by: Lee Jones > --- > drivers/mfd/lm3533-ctrlbank.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mfd/lm3533-ctrlbank.c b/drivers/mfd/lm3533-ctrlbank.c > index 34fba06ec7057..348ce67453092 100644 > --- a/drivers/mfd/lm3533-ctrlbank.c > +++ b/drivers/mfd/lm3533-ctrlbank.c > @@ -17,7 +17,7 @@ > #define LM3533_MAX_CURRENT_MAX 29800 > #define LM3533_MAX_CURRENT_STEP 800 > > -#define LM3533_BRIGHTNESS_MAX 255 > +#define LM3533_BRIGHTNESS_MAX 127 /* Capped by API - could be up to 255 */ > #define LM3533_PWM_MAX 0x3f > > #define LM3533_REG_PWM_BASE 0x14 Johan From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13407C433DF for ; Mon, 29 Jun 2020 12:52:44 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D2F5523CD4 for ; Mon, 29 Jun 2020 12:52:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="EfDBy8Jb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D2F5523CD4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=xt3XonjNoXDN+7lQ0m+aNZ17FoqR5+kKjL+YFj/jfvE=; b=EfDBy8Jbr9QQVJqWp0jTNFnrN aCp3n70vgdd+DO3TkCAW/q0xgSQvCIjNip8yNy9b+WLAQhR36vHQj4Z0/uWmGhCRCPHgaZUzdiLMQ vffddHy7+YRKdKcfP/A6JZ2k5bRGFSKMxmjcSGxAsGjpCIdEsVXomjfdo9uZadEhlDpyHlg7lrBFv fgtL9m7t29wd5xDThPcWHXQKD2CleIHurtNsuEy+DP2bXoebh1ihzKkzkKv/Nyb85TgG0nvkXWWno WTL1GaBmEtigSXtX0WmxT3uW0LByhAB2o7+g26/3Y6jGttpx+v7/C3Xw1Rx6+N6h/Q3RXg4T6qGqk R5yEyohug==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jptFf-00035j-RQ; Mon, 29 Jun 2020 12:51:11 +0000 Received: from mail-lj1-f193.google.com ([209.85.208.193]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jptFb-00033N-5i for linux-arm-kernel@lists.infradead.org; Mon, 29 Jun 2020 12:51:08 +0000 Received: by mail-lj1-f193.google.com with SMTP id f8so5609798ljc.2 for ; Mon, 29 Jun 2020 05:51:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=0LrwryG62eUyl2zqUjhBe++Y1D3GieTqe72DllAUzwU=; b=qBhV6juSBwi9tkdjnhNsNreUa9BrBfOfnlTs1z5gVejXTg4R0AXLZCPdxxfCPGDE/p DydtFiVB4+WLF8DWFtzd3pSo1hVMhfGlHrJmtCSRTRciMLbj8SLShNyA8NozPb6dRr3n xLIMWTjDAz0e2+luY1/Z5f+nZIh2FwJr2yN+YdkepGbMxcPySq55ds2gdDmX4jz3lqWw O2fXVHFdtQtNEG6Ov4NAVHKYN8obauEKumJNpBnpg1COKlhmYzfLkwZt1eX5mW5uWXj4 WW0z5/ZOp5fPRMtV+/rGxMmrPLU0reEdwfHCVgw9/am4w7HvvZkVm69xKalNX0Zv4v/P JiLg== X-Gm-Message-State: AOAM530Cj0AtHuFjHR/bgPOu3Fn6/Ca0re5Lhl4uz9YNV2I8ngYEFDmd VclZ3lC5u6haBLtSxFrssKI= X-Google-Smtp-Source: ABdhPJy1Oa+sFlJzr/Lrmq06b2ZzNN4W8IFLJhckyKTLVnMrowOCwFnL7cGHxQlWRfjiLHud6wIsow== X-Received: by 2002:a2e:3316:: with SMTP id d22mr1714816ljc.18.1593435064220; Mon, 29 Jun 2020 05:51:04 -0700 (PDT) Received: from xi.terra (c-beaee455.07-184-6d6c6d4.bbcust.telenor.se. [85.228.174.190]) by smtp.gmail.com with ESMTPSA id l1sm2212934ljc.65.2020.06.29.05.51.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Jun 2020 05:51:03 -0700 (PDT) Received: from johan by xi.terra with local (Exim 4.93.0.4) (envelope-from ) id 1jptFW-0006wJ-Se; Mon, 29 Jun 2020 14:51:03 +0200 Date: Mon, 29 Jun 2020 14:51:02 +0200 From: Johan Hovold To: Lee Jones Subject: Re: [PATCH 2/5] mfd: lm3533-ctrlbank: Cap BRIGHTNESS_MAX to 127 since API uses u8 as carrier Message-ID: <20200629125102.GT3334@localhost> References: <20200629123215.1014747-1-lee.jones@linaro.org> <20200629123215.1014747-3-lee.jones@linaro.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200629123215.1014747-3-lee.jones@linaro.org> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Johan Hovold , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gTW9uLCBKdW4gMjksIDIwMjAgYXQgMDE6MzI6MTJQTSArMDEwMCwgTGVlIEpvbmVzIHdyb3Rl Ogo+IFNpbmNlIGl0cyBjb25jZXB0aW9uIGluIDIwMTIgYnJpZ2h0bmVzcyBoYXMgYmVlbiBhcnRp ZmljaWFsbHkgY2FwcGVkCj4gYXQgMTI3IHNpbmNlIHRoZSB2YXJpYWJsZSBjYXJyeWluZyB0aGUg dmFsdWUgaXMgdTguICBXZSBjb3VsZCBnbyB0bwo+IHRoZSB0cm91YmxlIG9mIGNoYW5naW5nIHRo ZSB3aG9sZSBBUEkgKGNyb3NzaW5nIDMgZGlmZmVyZW50IHN1YnN5c3RlbXMpLAo+IGJ1dCBjbGVh cmx5IHRoaXMgaGFzbid0IGJvdGhlcmVkIGFueW9uZSBpbiB0aGUgYmVzdCBwYXJ0IG9mIGEgZGVj YWRlLgo+IAo+IFNpbXBseSwgY2FwIEJSSUdIVE5FU1NfTUFYIHRvIDEyNyBpbnN0ZWFkIChmb3Ig bm93IGF0IGxlYXN0KS4KCkhtbS4gVGhpcyBwYXRjaCBpcyBjbGVhcmx5IGJyb2tlbiBhbmQgd291 bGQgY29udHJhcnkgdG8gdGhlIGNsYWltIGJlCmludHJvZHVjaW5nIGFuIGFydGlmaWNpYWwgY2Fw IGF0IGhhbGYgYnJpZ2h0bmVzcy4gdTggY2FuIGhvbGQgdGhlIG1heApicmlnaHRuZXNzIHZhbHVl IDI1NSBqdXN0IGZpbmUuCgo+IEZpeGVzIHRoZSBmb2xsb3dpbmcgVz0xIHdhcm5pbmcocyk6Cj4g Cj4gIGRyaXZlcnMvbWZkL2xtMzUzMy1jdHJsYmFuay5jOiBJbiBmdW5jdGlvbiDigJhsbTM1MzNf Y3RybGJhbmtfc2V0X2JyaWdodG5lc3PigJk6Cj4gIGRyaXZlcnMvbWZkL2xtMzUzMy1jdHJsYmFu ay5jOjk4OjEwOiB3YXJuaW5nOiBjb21wYXJpc29uIGlzIGFsd2F5cyBmYWxzZSBkdWUgdG8gbGlt aXRlZCByYW5nZSBvZiBkYXRhIHR5cGUgWy1XdHlwZS1saW1pdHNdCj4gIDk4IHwgaWYgKHZhbCA+ IExNMzUzM18jI19OQU1FIyNfTUFYKSB8IF4KPiAgZHJpdmVycy9tZmQvbG0zNTMzLWN0cmxiYW5r LmM6MTI1OjE6IG5vdGU6IGluIGV4cGFuc2lvbiBvZiBtYWNybyDigJhsbTM1MzNfY3RybGJhbmtf c2V04oCZCj4gIDEyNSB8IGxtMzUzM19jdHJsYmFua19zZXQoYnJpZ2h0bmVzcywgQlJJR0hUTkVT Uyk7Cj4gIHwgXn5+fn5+fn5+fn5+fn5+fn5+fgoKVGhpcyB3YXJuaW5nIGlzIGJlbmlnbi4gVGhl IHNhbWUgbWFjcm8gaXMgdXNlZCB0byBkZWZpbmVkIHR3byBmdW5jdGlvbgp3aGVyZSBpbiBvbmUg Y2FzZSB0aGUgbWF4IHZhbHVlIGNvaW5jaWRlcyB3aXRoIFU4X01BWCBzbyB0aGF0IHRoZSBzYW5p dHkKY2hlY2sgYmVjb21lcyByZWR1bmRhbnQuCgo+IENjOiBKb2hhbiBIb3ZvbGQgPGpob3ZvbGRA Z21haWwuY29tPgo+IFNpZ25lZC1vZmYtYnk6IExlZSBKb25lcyA8bGVlLmpvbmVzQGxpbmFyby5v cmc+Cj4gLS0tCj4gIGRyaXZlcnMvbWZkL2xtMzUzMy1jdHJsYmFuay5jIHwgMiArLQo+ICAxIGZp bGUgY2hhbmdlZCwgMSBpbnNlcnRpb24oKyksIDEgZGVsZXRpb24oLSkKPiAKPiBkaWZmIC0tZ2l0 IGEvZHJpdmVycy9tZmQvbG0zNTMzLWN0cmxiYW5rLmMgYi9kcml2ZXJzL21mZC9sbTM1MzMtY3Ry bGJhbmsuYwo+IGluZGV4IDM0ZmJhMDZlYzcwNTcuLjM0OGNlNjc0NTMwOTIgMTAwNjQ0Cj4gLS0t IGEvZHJpdmVycy9tZmQvbG0zNTMzLWN0cmxiYW5rLmMKPiArKysgYi9kcml2ZXJzL21mZC9sbTM1 MzMtY3RybGJhbmsuYwo+IEBAIC0xNyw3ICsxNyw3IEBACj4gICNkZWZpbmUgTE0zNTMzX01BWF9D VVJSRU5UX01BWAkJMjk4MDAKPiAgI2RlZmluZSBMTTM1MzNfTUFYX0NVUlJFTlRfU1RFUAkJODAw Cj4gIAo+IC0jZGVmaW5lIExNMzUzM19CUklHSFRORVNTX01BWAkJMjU1Cj4gKyNkZWZpbmUgTE0z NTMzX0JSSUdIVE5FU1NfTUFYCQkxMjcgIC8qIENhcHBlZCBieSBBUEkgLSBjb3VsZCBiZSB1cCB0 byAyNTUgKi8KPiAgI2RlZmluZSBMTTM1MzNfUFdNX01BWAkJCTB4M2YKPiAgCj4gICNkZWZpbmUg TE0zNTMzX1JFR19QV01fQkFTRQkJMHgxNAoKSm9oYW4KCl9fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fCmxpbnV4LWFybS1rZXJuZWwgbWFpbGluZyBsaXN0Cmxp bnV4LWFybS1rZXJuZWxAbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5mcmFkZWFk Lm9yZy9tYWlsbWFuL2xpc3RpbmZvL2xpbnV4LWFybS1rZXJuZWwK