From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiner Kallweit Subject: Re: [PATCH 1/9] mmc: meson-gx: fix setting f_min Date: Wed, 1 Feb 2017 21:14:00 +0100 Message-ID: <6085c3ea-0a85-458d-bf15-8dcdd2d83186@gmail.com> References: <476265c8-b7e8-acdb-1964-5663c629caa3@gmail.com> <1e55512d-1dc3-bd57-82e1-888553ab3a9e@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wm0-f65.google.com ([74.125.82.65]:34700 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751076AbdBAUON (ORCPT ); Wed, 1 Feb 2017 15:14:13 -0500 Received: by mail-wm0-f65.google.com with SMTP id c85so7970661wmi.1 for ; Wed, 01 Feb 2017 12:14:12 -0800 (PST) In-Reply-To: <1e55512d-1dc3-bd57-82e1-888553ab3a9e@samsung.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Jaehoon Chung , Ulf Hansson , Kevin Hilman Cc: Carlo Caione , linux-mmc@vger.kernel.org Am 01.02.2017 um 12:49 schrieb Jaehoon Chung: > On 02/01/2017 05:57 AM, Heiner Kallweit wrote: >> Currently f_min is set to 4 MHz whilst the comment states 400 MHz. >> I think the itention is to set f_min to 400 kHz. >> Change value and comment accordingly. >> >> Signed-off-by: Heiner Kallweit >> --- >> drivers/mmc/host/meson-gx-mmc.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c >> index 5eca88bc..da3cce31 100644 >> --- a/drivers/mmc/host/meson-gx-mmc.c >> +++ b/drivers/mmc/host/meson-gx-mmc.c >> @@ -268,7 +268,7 @@ static int meson_mmc_clk_init(struct meson_host *host) >> if (f_min != UINT_MAX) >> f_min = DIV_ROUND_UP(CLK_SRC_XTAL_RATE, CLK_DIV_MAX); >> else >> - f_min = 4000000; /* default min: 400 MHz */ >> + f_min = 400000; /* default min: 400 kHz */ > > I'm not sure but f_min can be 100KHz by default, not 400KHz. > Because mmc-core should be try to find frequency from 400KHz to "f_min" value. > Actually I wonder how we can ever reach this part of the if clause. If at least one parent clock is defined and we can get its clock rate then f_min != UINT_MAX. Can we think of a case where no parent clock is defined? And would it make sense at all to proceed in this case? > Best Regards, > Jaehoon Chung > >> host->mmc->f_min = f_min; >> >> /* create the mux */ >> > >