From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: PWM DMA interface Date: Wed, 18 Jun 2014 00:54:05 +0200 Message-ID: <20140617225401.GA25525@mithrandir> References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="sdtB3X0nJg68CQEu" Return-path: Received: from mail-wg0-f46.google.com ([74.125.82.46]:60554 "EHLO mail-wg0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755944AbaFQWyI (ORCPT ); Tue, 17 Jun 2014 18:54:08 -0400 Received: by mail-wg0-f46.google.com with SMTP id y10so23393wgg.29 for ; Tue, 17 Jun 2014 15:54:07 -0700 (PDT) Content-Disposition: inline In-Reply-To: Sender: linux-pwm-owner@vger.kernel.org List-Id: linux-pwm@vger.kernel.org To: Gordon Hollingworth Cc: "linux-pwm@vger.kernel.org" --sdtB3X0nJg68CQEu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jun 09, 2014 at 10:49:46AM +0000, Gordon Hollingworth wrote: > Hi, >=20 > I've been writing a driver that uses the PWM to talk to devices that > communicate through a pwm like signal. To achieve this some devices have > a dma interface that you can stream data at to the pwm... >=20 > We use something similar to this on Raspberry Pi to do audio output, we > use the PWM interface to output a 'stream' of audio data which is > subsequently filtered (RC filter) to give an audio output. What kind of audio data is this? Is it able to play back any arbitrary audio signal? Thierry --sdtB3X0nJg68CQEu Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJToMcJAAoJEN0jrNd/PrOhiwwP/2wR9adHBx8esQuZ3F32F0O1 G1Vs2UV8Vm+r+2ZJlUuuKvIUIWLqfvs+NhXzsPzm8UUHlex7Kt1reE3W8fuB4nZ+ H5oxnrZbYKBBHZ10c8s/upI+hzjYYL1dzVbQKFpl8LXAaM9PIRnZGKAgpvmnxbrE nq56RnHLFkgQSZx0fuCd6LXOwPyMvXQAXHKu0yN3BgGiXvx9BJwCPcO9c7ZuVsBv 2x5V/eqH29gF96WITvdjjmLUD+0WDWgeQERgE7RbzBAAJdDnjgD6Cxavx0ldyIEw T8jw1LW7OPCEfZ9qbMOQ/XDgGJFnurj8y0qQpX/YYB07o0MI2Kw3QIVnI8VkLYec p82SEkZ/D7QtQYVi8nDnbBo/cJntuwakIny9W5K/oU1TgV1zvnDwvNmZuuaZUtzu 1gpcs1Xipw4RMjKxd+/2KWORDVvgKUBmp28H3bcVBjan+GZWub6ZH8VnM3AGfthl df0WZe8o4t3jv7HcPd+TYiMosLkbkQK//6mUFqnU5XNisNQB2p5T47rcjBPj0YLx bTVeMFdQJjM8uGnvG+lq0RH1R8YGzKqXhQa6eIMlBvMsW/0xu5kleuFtO0ivdcuL RL6UH1o9mRG38/NC+zxN7QLRLJ0ddrJdWzT9oeJ7MJ+6zNvzbymEOofDG0jDnDye KNdZvDVbtl4F1vvzZom/ =zZ5f -----END PGP SIGNATURE----- --sdtB3X0nJg68CQEu--