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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 782C1C433F5 for ; Sat, 8 Jan 2022 17:48:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230249AbiAHRsN (ORCPT ); Sat, 8 Jan 2022 12:48:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229928AbiAHRsL (ORCPT ); Sat, 8 Jan 2022 12:48:11 -0500 Received: from mail-ed1-x530.google.com (mail-ed1-x530.google.com [IPv6:2a00:1450:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8140C06173F; Sat, 8 Jan 2022 09:48:10 -0800 (PST) Received: by mail-ed1-x530.google.com with SMTP id j6so35265213edw.12; Sat, 08 Jan 2022 09:48:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=HKLi8ROSD1N0wXToisA4xUpZ4tz7KIbvKJEjlY+zaMA=; b=PcqwM7NAXcRYpLPiEYfz8ZW5rmZxpmtXiai7y6zR+n4NY3My0rbQigrJBCedZ/3eOu wI/l1T+lA0cMqcOenXQCOSVOVy8wUMIn4j+kys9sbU01qzjmrSNfk9Hx4u2VN5PktxSd s9h1Ztclpvqx0V8qlFfWyJiE0OilijmlZ9tpsRiiyz4MX+XLIR+Kss1QFd6RU/ETrANN /j7PuJmGhgKufed9GjyC7hJlcDPe7gfnPWde1f7ZRcU+qxKOP8JgKGDMdf4d7rP7DOq8 kWXs9BnYca0Kvhu+hztSbUUswZ/0Z6YzQfMw0aKfnRqsG6nB/vs2qo4EnhJ6ia+mxe7l NHKg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=HKLi8ROSD1N0wXToisA4xUpZ4tz7KIbvKJEjlY+zaMA=; b=a5oQaB6GJPLnysoScdF2s3l3BdWuanLFO9R57h2/4vSN6Pv4aW/N4mnu4q6TtmeNaw ueizkgOaP4VCmyOLdesqQ2BTCMDUK9czMesZxVIgSl+a/pCJeVkrMbkOtAP2WRgbgis5 jbgE9+WmS/K7wWDhPlgWFkOS2D+7LIprgFdzTHofN/Tqa3HNihtRo2cI9/JJ79EL/OvX vleENNF16rNoXHyt5lXXPB1SLwrqgUREcmZBG2i150aU93dORlV5JmK3y4GZ8oZ7AqpY DzsqBFNA90rq0xWKECACmE0cQSW8i2LW8zNfdZNLFxFB7O6qsoVE70oLWLYqlrZgr2Xv IIgA== X-Gm-Message-State: AOAM530ZsT4/ihUpEpwsxHUOR/SLFVpFjShqBmNCOmjeOz7uggwIAJ/r sFNBv2Fl0Xw9+n92dsTgjwPW0zdjDW9lF/2Jd+c= X-Google-Smtp-Source: ABdhPJyanEkx9eiDlQV1xTggUJn4Revs/1UtDujKoh9WRgpTMrFstm6S1BQMKo9gsk+Y+tQTRTagKlu9TPLuX8AsFnk= X-Received: by 2002:a17:906:3ed0:: with SMTP id d16mr52555537ejj.636.1641664089284; Sat, 08 Jan 2022 09:48:09 -0800 (PST) MIME-Version: 1.0 References: <20220107233458.2326512-1-gsomlo@gmail.com> <20220107233458.2326512-4-gsomlo@gmail.com> In-Reply-To: From: Andy Shevchenko Date: Sat, 8 Jan 2022 19:47:32 +0200 Message-ID: Subject: Re: [PATCH v8 3/3] mmc: Add driver for LiteX's LiteSDCard interface To: "Gabriel L. Somlo" Cc: "linux-kernel@vger.kernel.org" , "robh+dt@kernel.org" , "devicetree@vger.kernel.org" , "ulf.hansson@linaro.org" , "linux-mmc@vger.kernel.org" , "kgugala@antmicro.com" , "mholenko@antmicro.com" , "krakoczy@antmicro.com" , "mdudek@internships.antmicro.com" , "paulus@ozlabs.org" , "joel@jms.id.au" , "shorne@gmail.com" , "geert@linux-m68k.org" , "david.abdurachmanov@sifive.com" , "florent@enjoy-digital.fr" , "rdunlap@infradead.org" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 8, 2022 at 3:20 PM Gabriel L. Somlo wrote: > On Sat, Jan 08, 2022 at 01:26:08PM +0200, Andy Shevchenko wrote: > > On Sat, Jan 8, 2022 at 3:57 AM Gabriel L. Somlo wrote: > > > On Sat, Jan 08, 2022 at 01:54:07AM +0200, Andy Shevchenko wrote: > > > > On Saturday, January 8, 2022, Gabriel Somlo wrote: ... > > > > + u32 div; > > > > + > > > > + div = freq ? host->ref_clk / freq : 256U; > > > > > > > > + div = roundup_pow_of_two(div); > > > > + div = clamp(div, 2U, 256U); > > > > > > > > Logically seems to me that you may join these two together, because clamped > > > > range is power-of-2 one. > > > > > > `div` needs to be a power-of-2 when written to the LITEX_PHY_CLOCKERDIV > > > register (below). And clamp() will just enforce a min/max range, so if > > > (div = ref_clk / freq) ends up e.g., 5, I need both roundup_pow_of_two() > > > to bump it to 8, and clamp() to enforce that it's between 2 and 256. > > > > > > Unless you mean I should simply write it like: > > > > > > div = clamp(roundup_pow_of_two(div), 2U, 256U); > > > > > > ... as a single line? > > > > Yes, that's what I meant. > > Turns out, clamp really hates being passed roundup_pow_of_two() > directly (see below). I think it's probably better if we leave > them as-is, to avoid going the explicit cast route which Geert > recommended against. I see, then ignore my comment on this matter in v9. Perhaps add a comment in the code explaining that roundup_pow_of_two() may not be unified with clamp()? -- With Best Regards, Andy Shevchenko