From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: [PATCH v2] ASoC: fsl_esai: Add ESAI CPU DAI driver Date: Fri, 10 Jan 2014 16:52:29 +0000 Message-ID: <20140110165229.GP29039@sirena.org.uk> References: <1389265078-16256-1-git-send-email-Guangyu.Chen@freescale.com> <20140109184453.GP12858@sirena.org.uk> <20140110023252.GA16467@MrMyself> <20140110023537.GB16467@MrMyself> <20140110120439.GG29039@sirena.org.uk> <20140110130338.GA17392@MrMyself> <20140110132642.GM29039@sirena.org.uk> <20140110154824.GA17609@MrMyself> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="vzUQzca511KWT6Hk" Return-path: Content-Disposition: inline In-Reply-To: <20140110154824.GA17609@MrMyself> Sender: linux-doc-owner@vger.kernel.org To: Nicolin Chen Cc: timur@tabi.org, alsa-devel@alsa-project.org, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, rob@landley.net, lgirdwood@gmail.com, perex@perex.cz, tiwai@suse.de, grant.likely@linaro.org, shawn.guo@linaro.org, devicetree@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org List-Id: alsa-devel@alsa-project.org --vzUQzca511KWT6Hk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Jan 10, 2014 at 11:48:25PM +0800, Nicolin Chen wrote: > I think I start to understand the point here: If a user only needs to playback > the default case - 44.1KHz for example, the driver can just configure all the > dividers once at the beginning, not every time, so that we can save further > register overriding operation or even complicated clock selection and divisor > calculation, which obviously makes the procedure clean and reduces the system > loading even if it might be just in a slight level. > Is this the reason, or maybe one of the reasons, to the defaults providing? The main thing is that if the DAI driver does it then it's less code in the machine drivers using it - what tends to happen otherwise is that quite a few machine drivers end up replicating the same logic. Hardware designers tend to do a lot of cut'n'paste with these things so even if the CODEC is different the clocking is often very similar. --vzUQzca511KWT6Hk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJS0CVKAAoJELSic+t+oim99IQP/08MHspLPF61FZWnYD7c/ocz umRR6MfesK+5hChKTM5MjqKhRbORurpimLy3SQgiFHuoJXHUWkDWOFyU7ARsirm4 SE93me6Ug7ARPdKtfdLJpH7xxgBsdV9YvbsZMfilEAjjLCa3UbZt7ZeDDBlOYMVE AbWOoGFjPrmvAMn5vNIUGZ2whqp9GEEzWCjrcFb2PRWNr8CCiJF+u23bX0CT/17B kxXqagbocugD3Rqjpo7EVZhaDlh8B/MARkGbnqTp53DpxRJl8xlSuM2GuyV7njhZ qedOxwUu7prtwID2HvF+xhj2cQstZaA0IXRutEoe2wj0cVBx0btGz/FHPcw85aou EQburgwdP2e63AcC8m2JcGGZ5y5QLQqMktxwgOr9RNTZj7ksL399KKpsLRiM2ABH z6gisop7cFr4BHl2H11V8W6telUgNq/TVIYAYfKASZ/3ei8BdPrT8cDm8NCShzBy aRgmxb6f2rfBwIl1xXlNYV3vP1iWhICO0TzHDKxCQ+hl1cSKB0b6Lez6OmmHzUN3 o86Hz/pfcxzRY6BdwwINgEqdiSyi0YJ91DQ8uvuISSLUVvOqx4ZwB9Mw4mhprAhV Ezpp0kEIGQuL7OhcPrjSGyJP8SeNjWMsFzZFtO3YbtPdcuw/gFIKzHvTfBL5xNbJ MBAW15HInlDLOVdc5Yga =SwMh -----END PGP SIGNATURE----- --vzUQzca511KWT6Hk-- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mezzanine.sirena.org.uk (mezzanine.sirena.org.uk [IPv6:2400:8900::f03c:91ff:fedb:4f4]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 443A72C0084 for ; Sat, 11 Jan 2014 03:53:04 +1100 (EST) Date: Fri, 10 Jan 2014 16:52:29 +0000 From: Mark Brown To: Nicolin Chen Message-ID: <20140110165229.GP29039@sirena.org.uk> References: <1389265078-16256-1-git-send-email-Guangyu.Chen@freescale.com> <20140109184453.GP12858@sirena.org.uk> <20140110023252.GA16467@MrMyself> <20140110023537.GB16467@MrMyself> <20140110120439.GG29039@sirena.org.uk> <20140110130338.GA17392@MrMyself> <20140110132642.GM29039@sirena.org.uk> <20140110154824.GA17609@MrMyself> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="vzUQzca511KWT6Hk" In-Reply-To: <20140110154824.GA17609@MrMyself> Subject: Re: [PATCH v2] ASoC: fsl_esai: Add ESAI CPU DAI driver Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, alsa-devel@alsa-project.org, shawn.guo@linaro.org, pawel.moll@arm.com, ijc+devicetree@hellion.org.uk, tiwai@suse.de, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, timur@tabi.org, lgirdwood@gmail.com, robh+dt@kernel.org, rob@landley.net, galak@codeaurora.org, grant.likely@linaro.org, perex@perex.cz, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --vzUQzca511KWT6Hk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Jan 10, 2014 at 11:48:25PM +0800, Nicolin Chen wrote: > I think I start to understand the point here: If a user only needs to playback > the default case - 44.1KHz for example, the driver can just configure all the > dividers once at the beginning, not every time, so that we can save further > register overriding operation or even complicated clock selection and divisor > calculation, which obviously makes the procedure clean and reduces the system > loading even if it might be just in a slight level. > Is this the reason, or maybe one of the reasons, to the defaults providing? The main thing is that if the DAI driver does it then it's less code in the machine drivers using it - what tends to happen otherwise is that quite a few machine drivers end up replicating the same logic. Hardware designers tend to do a lot of cut'n'paste with these things so even if the CODEC is different the clocking is often very similar. --vzUQzca511KWT6Hk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJS0CVKAAoJELSic+t+oim99IQP/08MHspLPF61FZWnYD7c/ocz umRR6MfesK+5hChKTM5MjqKhRbORurpimLy3SQgiFHuoJXHUWkDWOFyU7ARsirm4 SE93me6Ug7ARPdKtfdLJpH7xxgBsdV9YvbsZMfilEAjjLCa3UbZt7ZeDDBlOYMVE AbWOoGFjPrmvAMn5vNIUGZ2whqp9GEEzWCjrcFb2PRWNr8CCiJF+u23bX0CT/17B kxXqagbocugD3Rqjpo7EVZhaDlh8B/MARkGbnqTp53DpxRJl8xlSuM2GuyV7njhZ qedOxwUu7prtwID2HvF+xhj2cQstZaA0IXRutEoe2wj0cVBx0btGz/FHPcw85aou EQburgwdP2e63AcC8m2JcGGZ5y5QLQqMktxwgOr9RNTZj7ksL399KKpsLRiM2ABH z6gisop7cFr4BHl2H11V8W6telUgNq/TVIYAYfKASZ/3ei8BdPrT8cDm8NCShzBy aRgmxb6f2rfBwIl1xXlNYV3vP1iWhICO0TzHDKxCQ+hl1cSKB0b6Lez6OmmHzUN3 o86Hz/pfcxzRY6BdwwINgEqdiSyi0YJ91DQ8uvuISSLUVvOqx4ZwB9Mw4mhprAhV Ezpp0kEIGQuL7OhcPrjSGyJP8SeNjWMsFzZFtO3YbtPdcuw/gFIKzHvTfBL5xNbJ MBAW15HInlDLOVdc5Yga =SwMh -----END PGP SIGNATURE----- --vzUQzca511KWT6Hk--