From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [Patch V8] i2c: imx: add runtime pm support to improve the performance Date: Sat, 10 Oct 2015 08:30:21 +0100 Message-ID: <20151010073020.GB1619@katana> References: <1442569869-10584-1-git-send-email-b54642@freescale.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="aVD9QWMuhilNxW9f" Return-path: Received: from sauhun.de ([89.238.76.85]:57209 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751260AbbJJHaf (ORCPT ); Sat, 10 Oct 2015 03:30:35 -0400 Content-Disposition: inline In-Reply-To: <1442569869-10584-1-git-send-email-b54642@freescale.com> Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Gao Pan Cc: linux-i2c@vger.kernel.org, B20596@freescale.com, b38611@freescale.com, u.kleine-koenig@pengutronix.de, kernel@pengutronix.de, hkallweit1@gmail.com, s.hauer@pengutronix.de --aVD9QWMuhilNxW9f Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Sep 18, 2015 at 05:51:09PM +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 > 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 Uwe? Sascha? --aVD9QWMuhilNxW9f Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJWGL6MAAoJEBQN5MwUoCm2GyoP/RVOzpr58zMeS13tTHozORSi iJ9CRTPuSUa1hNvJ1HYakttd/mkxuGakHkVWvOMB1CKSDxH1c0+maRUngHLFCknk W+11N+5r+NHeHrD0UGhb40cMZ5knEeIENpvNl1uD91VxjMr5jP5sQVXuMfxgmyRz fZgRoA8WL55go2A5KYE6DW6dZDOzXR0fDPGHmWi4qw8b/tzIMrl07MMAZKH5E2sC HIPu+lESFWfM2y7/80OX9I8kLWlKbBhb9eo79WqHi7d0k6c+MC7rD6J0ZzRNTl20 OLe4eqRubU81N2gDcfBzYuHg4klmOSrzXkVPVYWPd0kdsaT9sLl2/+RknOqg/hcQ MY2widpOcbUxlp6Te22LkW3BWXgwR5G/wKL79OBgnSVO/jefYmujyxabcHkYW1Yk jIUWj5334I2sai5UcARzLYKg65ne4KrwRqUqtP7rE1bKzt/Jf0/r1fFuZrOhVsK0 LEQLERbQOqiSJvvd9fLeKyRLsUSII0uTadUPdnpD+KiOiue1lAlXvpSf1ZckauNz YR8gBYyTRxZRoQcD5jkObTJ9pO5qEwIy2Zkmjo91eq1X2U1HweBVu4f7W41f2Uoa wxgHydZQlqihZDKuy0+sIU4FF72U9yfcvl298ItowaoUkIzxuSZdAlZ87plMtTu9 IqtUPTLQ2sGxaZmu4oub =cJID -----END PGP SIGNATURE----- --aVD9QWMuhilNxW9f--