From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [Patch V10] i2c: imx: add runtime pm support to improve the performance Date: Sun, 3 Jan 2016 19:10:10 +0100 Message-ID: <20160103181009.GA1522@katana> References: <1449800649-32763-1-git-send-email-b54642@freescale.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="ew6BAiZeqk4r7MaW" Return-path: Received: from sauhun.de ([89.238.76.85]:55760 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751221AbcACSKR (ORCPT ); Sun, 3 Jan 2016 13:10:17 -0500 Content-Disposition: inline In-Reply-To: <1449800649-32763-1-git-send-email-b54642@freescale.com> Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Gao Pan Cc: u.kleine-koenig@pengutronix.de, linux-i2c@vger.kernel.org, B20596@freescale.com, b38611@freescale.com, kernel@pengutronix.de, Heiner Kallweit --ew6BAiZeqk4r7MaW Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Dec 11, 2015 at 10:24:09AM +0800, Gao Pan wrote: > In our former i2c driver, i2c clk is enabled and disabled in > xfer function, which contributes to power saving. However, > the clk enable process brings a busy wait delay until the core > is stable. As a result, the performance is sacrificed. >=20 > To weigh the power consumption and i2c bus performance, runtime > pm is the good solution for it. The clk is enabled when a i2c > transfer starts, and disabled after a specifically defined delay. >=20 > If CONFIG_PM is disabled the net result of this patch is that the > clock is never disabled. >=20 > Without the patch the test case (many eeprom reads) executes with approx: > real 1m7.735s > user 0m0.488s > sys 0m20.040s >=20 > With the patch the same test case (many eeprom reads) executes with appro= x: > real 0m54.241s > user 0m0.440s > sys 0m5.920s >=20 > Signed-off-by: Fugang Duan > Signed-off-by: Gao Pan > Acked-by: Uwe Kleine-K=C3=B6nig Applied to for-next, thanks! Also much thanks to Uwe and Heiner for the reviews of all these versions! --ew6BAiZeqk4r7MaW Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJWiWQBAAoJEBQN5MwUoCm2B9sP/0smOXR5RH9/T0ZcgVb/PPvI 69du33GEnDdXvCfDlNO/MTaEmuwiqhrtTNO+IuDNPmpXVTymFb1uIwdarMAS+tA9 Zz4flC5ZhC/svUQkMOXbLDdKwPTMKtwe0r6/rjnRsVRpD+0/0vSPp/nbemvFVqEy zBiz09XP1wXlSboN2BimCUSM4OD1Pjpt+PoaeBuHD/FL++657HAKDlM2OU/Lie2r iW+lWSaYk5bsqOiWlTZRQ9rOjYilmSGGjx9rivvlG5ivyWSx8u4IzmZnMNtBWei6 Rj26BI6jnSmxruLL2iDq1wRFfC7m3or58amuFsHv+VKRdfzYI1MKbAUo30dsQkrI s2zY3WCYc5kEyCB8JphjLJse0Wc3BCOKaDxqz4In1oePCGLOrdJSQfd52hH/0qOz l2rgS8CWVKkZfkOrpqQkq5T3BjLXDh3Jhpc+Y4pMjoiTnOfNTpEDlBd6Wx0TDKT3 7oMQeBuOBRn6c1/JOGcxuE3Qp+4lbA6tDMiTlslyBOR893DAFEdNyYMIAahxWIJ7 PiYwcVdYYlOkQAqs2g4npg1KKlgtrOrOU3fnaUy2MSoU/DBm8PYwIocEBTz1W8JW JwPtMGooeVgrrCATv3kItgc1AsmlesSwzb3rb1psfWixFzLYWPWgF0+4i788jLsv teLkfVV6syB1RcO7rMUl =Uy8+ -----END PGP SIGNATURE----- --ew6BAiZeqk4r7MaW--