From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ulf Hansson Subject: Re: [PATCH v2 01/11] dt-bindings: mmc: arasan: Update documentation for SD Card Clock Date: Thu, 25 Jul 2019 15:00:53 +0200 Message-ID: References: <1561958991-21935-1-git-send-email-manish.narani@xilinx.com> <1561958991-21935-2-git-send-email-manish.narani@xilinx.com> <20190722215404.GA28292@bogus> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Manish Narani Cc: "mark.rutland@arm.com" , "kernel@esmil.dk" , "viresh.kumar@linaro.org" , "linux-kernel@vger.kernel.org" , Jolly Shah , "tony.xie@rock-chips.com" , "philipp.tomsich@theobroma-systems.com" , "heiko@sntech.de" , Rob Herring , "linux-rockchip@lists.infradead.org" , Rajan Vaja , Michal Simek , "devicetree@vger.kernel.org" , Nava kishore Manne , "scott.branden@broadcom.com" , "ayaka@soulik.info" , "mdf@kernel.org" , "linux-arm-kernel@lists.infradead.org" List-Id: devicetree@vger.kernel.org On Tue, 23 Jul 2019 at 10:23, Manish Narani wrote: > > Hi Rob, > > Thanks a lot for the review! > > > > -----Original Message----- > > From: Rob Herring > > Sent: Tuesday, July 23, 2019 3:24 AM > > To: Manish Narani > > Cc: ulf.hansson@linaro.org; mark.rutland@arm.com; heiko@sntech.de; Michal > > Simek ; adrian.hunter@intel.com; > > christoph.muellner@theobroma-systems.com; philipp.tomsich@theobroma- > > systems.com; viresh.kumar@linaro.org; scott.branden@broadcom.com; > > ayaka@soulik.info; kernel@esmil.dk; tony.xie@rock-chips.com; Rajan Vaja > > ; Jolly Shah ; Nava kishore Manne > > ; mdf@kernel.org; olof@lixom.net; linux- > > mmc@vger.kernel.org; devicetree@vger.kernel.org; linux- > > kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux- > > rockchip@lists.infradead.org > > Subject: Re: [PATCH v2 01/11] dt-bindings: mmc: arasan: Update > > documentation for SD Card Clock > > > > On Mon, Jul 01, 2019 at 10:59:41AM +0530, Manish Narani wrote: > > > The clock handling is to be updated in the Arasan SDHCI. As the > > > 'devm_clk_register' is deprecated in the clock framework, this needs to > > > specify one more clock named 'clk_sdcard' to get the clock in the driver > > > via 'devm_clk_get()'. This clock represents the clock from controller to > > > the card. > > > > Please explain why in terms of the binding, not some driver calls. > Okay. > > > > > > > > Signed-off-by: Manish Narani > > > --- > > > Documentation/devicetree/bindings/mmc/arasan,sdhci.txt | 15 ++++++++++- > > ---- > > > 1 file changed, 10 insertions(+), 5 deletions(-) > > > > > > diff --git a/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt > > b/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt > > > index 1edbb04..15c6397 100644 > > > --- a/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt > > > +++ b/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt > > > @@ -23,6 +23,10 @@ Required Properties: > > > - reg: From mmc bindings: Register location and length. > > > - clocks: From clock bindings: Handles to clock inputs. > > > - clock-names: From clock bindings: Tuple including "clk_xin" and "clk_ahb" > > > + Apart from these two there is one more optional clock which > > > + is "clk_sdcard". This clock represents output clock from > > > + controller and card. This must be specified when #clock-cells > > > + is specified. > > > - interrupts: Interrupt specifier > > > > > > Required Properties for "arasan,sdhci-5.1": > > > @@ -36,9 +40,10 @@ Optional Properties: > > > - clock-output-names: If specified, this will be the name of the card clock > > > which will be exposed by this device. Required if #clock-cells is > > > specified. > > > - - #clock-cells: If specified this should be the value <0>. With this property > > > - in place we will export a clock representing the Card Clock. This clock > > > - is expected to be consumed by our PHY. You must also specify > > > + - #clock-cells: If specified this should be the value <0>. With this > > > + property in place we will export one clock representing the Card > > > + Clock. This clock is expected to be consumed by our PHY. You must also > > > + specify > > > > specify what? > I think this line was already there, I missed to correct it, Will update in v3. > > > > > The 3rd clock input I assume? This statement means any existing users > > with 2 clock inputs and #clock-cells are in error now. Is that correct? > Yes, this is correct. So far there was only one vendor using '#clock-cells' which is Rockchip. I have sent DT patch (02/11) for that also. > Here this is needed as earlier implementation isn't correct as suggested by Uffe. (https://lkml.org/lkml/2019/6/20/486) . I am not sure how big of a problem the backwards compatible thingy with DT is, in general we must not break it. What do you say Manish? As a workaround, would it be possible to use of_clk_get_from_provider() somehow to address the compatibility issue? Or maybe there is another clock API that can help. Kind regards Uffe