From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Ujfalusi Subject: Re: [PATCH] sound/tlv320dac33: Add device tree support Date: Wed, 31 Jan 2018 11:24:34 +0200 Message-ID: <571fedb5-0449-eb6f-04c5-e14252e055aa@ti.com> References: <20180129230539.GA18280@amd> <20180129232031.GA7695@lenoch> <20180129233301.GA18104@amd> <20180130083446.GA13498@lenoch> <20180130085314.GA4585@amd> <1141b126-b883-a246-85ad-c5a69acb90bb@gmail.com> <20180130093838.GA15195@lenoch> <20180130100023.GB18104@amd> <20180130101046.GA16474@lenoch> <20180130103538.GD18104@amd> <20180130113829.GA18464@lenoch> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: quoted-printable Return-path: Received: from fllnx209.ext.ti.com (fllnx209.ext.ti.com [198.47.19.16]) by alsa0.perex.cz (Postfix) with ESMTP id 28B6B266A74 for ; Wed, 31 Jan 2018 10:24:15 +0100 (CET) In-Reply-To: <20180130113829.GA18464@lenoch> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Ladislav Michl , Pavel Machek Cc: mark.rutland@arm.com, alsa-devel@alsa-project.org, tony@atomide.com, abcloriens@gmail.com, lgirdwood@gmail.com, martijn@brixit.nl, =?UTF-8?Q?Filip_Matijevi=c4=87?= , patrikbachan@gmail.com, ivo.g.dimitrov.75@gmail.com, khilman@kernel.org, tiwai@suse.com, serge@hallyn.com, devicetree@vger.kernel.org, broonie@kernel.org, sre@kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel , aaro.koskinen@iki.fi, linux-kernel@vger.kernel.org, robh+dt@kernel.org, clayton@craftyguy.net, sakari.ailus@linux.intel.com, pali.rohar@gmail.com, bhumirks@gmail.com List-Id: alsa-devel@alsa-project.org On 2018-01-30 13:38, Ladislav Michl wrote: > On Tue, Jan 30, 2018 at 11:35:38AM +0100, Pavel Machek wrote: >> On Tue 2018-01-30 11:10:46, Ladislav Michl wrote: >>> On Tue, Jan 30, 2018 at 11:00:23AM +0100, Pavel Machek wrote: >>>> On Tue 2018-01-30 10:38:38, Ladislav Michl wrote: >>>>> On Tue, Jan 30, 2018 at 10:11:02AM +0100, Filip Matijevi=E6 wrote: >>>>>> Hi, >>>>>> >>>> >>>>>>> Well, notice I'm converting existing driver to device tree. And that >>>>>>> one already has GPIO dependency. It is possible that more work needs >>>>>>> to be done there, but that should not be a reason to delay this. Fe= el >>>>>>> free to help. >>>>> >>>>> Adding DT properties that need to be maintained for compatibility rea= sons >>>>> is a bad idea and very good reason to delay merging unfinished stuff. >>>>> And meanwhile it turned out it is not power-gpio :) >>>> >>>> I believe reset-gpios and power-gpios are commonly used like >>>> this... and that's what the old code does. >>> >>> Why do you care about old code when introducing new DT property? >>> Either it is reset, then lets call it reset-gpios or it is power supply >>> and then voltage regulator should be used (VAUX4.OUT is such a regulator >>> although it is unclear to me how it is controlled (*)). >> >> power gpio =3D !reset gpio. Difference is only in polarity. > = > Quick grep: > Documentation/devicetree/bindings/net/smsc-lan91c111.txt > - power-gpios: GPIO to control the PWRDWN pin > - reset-gpios: GPIO to control the RESET pin > Documentation/devicetree/bindings/net/wireless/ti,wl1251.txt > - ti,power-gpio : GPIO connected to chip's PMEN pin > Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt > - power-gpios : Specification for the pin connected to the gs= l1680's > shutdown input. This needs to be driven high = to take the > gsl1680 out of its low power state > Documentation/devicetree/bindings/input/touchscreen/ektf2127.txt > - power-gpios : GPIO specification for the pin connected to t= he > ektf2127's wake input. This needs to be drive= n high > to take ektf2127 out of it's low power state > = > As you can see others are using it to drive pins different from nRESET. As > stated in datasheet: > "The TLV320DAC32 requires a hardware reset after power-up for proper oper= ation. > After all power supplies are at their specified values, the nRESET pin mu= st be > driven low for at least 10ns. If this reset sequence is not performed, th= e DAC32 > may not respond properly to register reads/writes". That does not sound l= ike > anything to do with power. > = > (It seems the only difference between TLV320DAC33 and TLV320DAC32 is uses= a ball > grid array package vs QFN32) Note that tlv320dac32 !=3D tlv320dac33, they are not even register compatible devices... dac33 was created _for_ Nokia back in the days and as far as I know there is no publicly available documentation for dac33. And yes, my pick to use power_gpio in the code was wrong, it should have been named as reset_gpio. > = >>>> You are not helping. >>> >>> The only way I can help here is to resend your patch with "reset-gpios" >>> used, which I'm pretty sure you can handle yourself. >> >> Well, you can do that, and then you can argue with the next person who >> feels one of the properties has to get his preferred color. Hard part >> is not changing code :-(. > = > Indeed, hard part is not to break DT compatibility later. Consider someone > will have to add regulator support later, which you omitted to do - having > both power supply and power gpio is a bit confusing, don't you think? > = > Anyway, time to stop arguing, feel free to do what you think is right, I = do > not have anything important to add :) > = > ladis > _______________________________________________ > Alsa-devel mailing list > Alsa-devel@alsa-project.org > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel > = - P=E9ter Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki