Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752749AbdLHJJH (ORCPT ); Fri, 8 Dec 2017 04:09:07 -0500 Received: from mail.free-electrons.com ([62.4.15.54]:56927 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751800AbdLHJJF (ORCPT ); Fri, 8 Dec 2017 04:09:05 -0500 Date: Fri, 8 Dec 2017 10:08:53 +0100 From: Maxime Ripard To: Chen-Yu Tsai Cc: Michael Turquette , Stephen Boyd , linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com Subject: Re: [PATCH 0/3] clk: sunxi-ng: sun8i: a83t: Use sigma-delta modulation for audio PLL Message-ID: <20171208090853.cnn52xqrpbihmpsq@flea.lan> References: <20171208083512.24080-1-wens@csie.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="nazpecrw7tte7nfl" Content-Disposition: inline In-Reply-To: <20171208083512.24080-1-wens@csie.org> User-Agent: NeoMutt/20171027 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2275 Lines: 59 --nazpecrw7tte7nfl Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Dec 08, 2017 at 04:35:09PM +0800, Chen-Yu Tsai wrote: > Hi, >=20 > This series follows previous improvements for the other Allwinner SoCs to > improve audio quality, in particular the speed and pitch of audio playbac= k. > The audio PLLs in Allwinner SoCs cannot produce the correct frequency to > match the audio sample rate families through integer factors. As such > the audio is either too fast or too flow. >=20 > This is dealt with by using sigma-delta modulation, a form of fractional-N > synthesis, on the divider. The parameters used are copied from the BSP > kernel. >=20 > As these parameters assume that one of the untracked dividers is set to > 2, we first add a fixed /2 post divider to the PLL, and force the > untracked divider to /2. Then we introduce the sigma-delta modulation > parameters. >=20 > This has been tested with SPDIF playback on the Cubietruck Plus, and an > external PCM5122 DAC from a PiFi DAC 2.0+, connected via I2S to the > Banana Pi M3. The I2C and I2S support used in this latter test will be > sent as a separate series later. Applied, thanks! Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com --nazpecrw7tte7nfl Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEE0VqZU19dR2zEVaqr0rTAlCFNr3QFAloqVqIACgkQ0rTAlCFN r3TGYA/9EMR2C950B+0QbwAx8wp+dlkLK7HU+lST5TMHg2kJsSuHO5HXRe/1uDEe 7iM0E7DczGGeDi+g0ghE7klmXAvQvWRceGhn7wOAKfnqV1iUNoQtnSnsk1JuhBBc ipVbzn9LYKFauReJ6qgonbphfmV4+UMLVxX5Hxft5xXN9BOlH4MwnEUtqjgLQ3ml vEM6KksSjQwZTOh4DDzLZOW3yu3wWclxZLz5OuvLMiNxMnxi2cK7dNVt/eiMXTk4 FHIvaeSduOBPf/upwY4K0FAbqwIQpnwHt6fwD1wyaxyU53+wgy8MZif/AKpD0qzB AFQ4jbxV3fADSi9u1nE2eUkGBPhKD47f3RSr7R2waaqYWoc2sTeDHARKIsf6UoiH cVc892kmbnawpjnzbHqcqR4G91GXGsOjORTobICaH4hd3OqY/9wT4AWr0X42dy0s gh7GtliaD5c8f6aUuuPVgXkAGCAndAE6sMR1UzYVx0R1jlzI6OdFCSe/BWLR5Snc ShZiXHtkRzWzR4ifcj4eoCXCTeWPFWRtDqkvr7b/HrvfVcgrZ10VBvnFm2Vygjky wlFtEYRAYwFy1lYs7p5/DrOYRfYMq5uBKV//Vx63niA57pQo9KMUz1cl+DpXDBxD 203BZSqFGVj/onv6QNj8y8tGPx/jVGisYQPmA66/elyFeQcOyVI= =TskE -----END PGP SIGNATURE----- --nazpecrw7tte7nfl--