From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Ujfalusi Subject: Re: [RESEND 2/2] clk: Add driver for Palmas clk32kg and clk32kgaudio clocks Date: Mon, 30 Jun 2014 08:56:55 +0300 Message-ID: <53B0FC27.5040002@ti.com> References: <1403848871-26519-1-git-send-email-peter.ujfalusi@ti.com> <1403848871-26519-3-git-send-email-peter.ujfalusi@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-doc-owner@vger.kernel.org To: Javier Martinez Canillas Cc: Mike Turquette , Grant Likely , "devicetree@vger.kernel.org" , Linux Kernel , "linux-omap@vger.kernel.org" , ldewangan@nvidia.com, linux-doc@vger.kernel.org, Nishanth Menon , Rob Herring List-Id: devicetree@vger.kernel.org Hi Javier, On 06/27/2014 09:23 PM, Javier Martinez Canillas wrote: > Hello Peter, >=20 > On Fri, Jun 27, 2014 at 8:01 AM, Peter Ujfalusi wrote: >> Palmas class of devices can provide 32K clock(s) to be used by other= devices >> on the board. Depending on the actual device the provided clocks can= be: >> CLK32K_KG and CLK32K_KGAUDIO >> or only one: >> CLK32K_KG (TPS659039 for example) >> >> Use separate compatible flags for the two 32K clock. >> A system which needs or have only one of the 32k clock from >> Palmas will need to add node(s) for each clock as separate section >> in the dts file. >> The two compatible property is: >> "ti,palmas-clk32kg" for clk32kg clock >> "ti,palmas-clk32kgaudio" for clk32kgaudio clock >> >> Apart from the register control of the clocks - which is done via >> the clock API there is a posibility to enable the external sleep >> control. In this way the clock can be enabled/disabled on demand by = the >> user of the clock. >> >> See the documentation for more details. >> >> Signed-off-by: Peter Ujfalusi >> Reviewed-by: Nishanth Menon >> +static unsigned long palmas_clks_recalc_rate(struct clk_hw *hw, >> + unsigned long parent_ra= te) >> +{ >> + return 32768; >> +} >=20 > I see that other clock drivers using a constant rate return 0 if the > clock has not been enabled. and there are examples when similar fixed clock drivers returns only th= e clock value, like clk-max77686. I can not find clear guidelines neither in th= e documentation or around the header/c files for this. Mike, what is the appropriate way of handling the recalc_rate? > So maybe is more correct to have something > like the following? >=20 > if (__clk_is_enabled(hw->clk)) > return 32768; > else > return 0; >=20 > Best regards, > Javier >=20 --=20 P=C3=A9ter