Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752696Ab3FXG7Q (ORCPT ); Mon, 24 Jun 2013 02:59:16 -0400 Received: from ch1ehsobe001.messaging.microsoft.com ([216.32.181.181]:8133 "EHLO ch1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752440Ab3FXG7P (ORCPT ); Mon, 24 Jun 2013 02:59:15 -0400 X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPV:NLI;H:mail.freescale.net;RD:none;EFVD:NLI X-SpamScore: 2 X-BigFish: VS2(z1039mz98dI936eI1432Izz1f42h1ee6h1de0h1fdah1202h1e76h1d1ah1d2ah1fc6hzz8275bhz2dh87h2a8h668h839h944hd25hf0ah1220h1288h12a5h12a9h12bdh137ah13b6h1441h1504h1537h153bh162dh1631h1758h18e1h1946h19b5h1ad9h1b0ah1d0ch1d2eh1d3fh1dfeh1dffh1151h1155h) X-FB-DOMAIN-IP-MATCH: fail Date: Mon, 24 Jun 2013 14:59:30 +0800 From: Shawn Guo To: Simon Pearson CC: , , Subject: Re: [PATCH 001/001] gpio-mxs: Select faster gpio-generic set methods Message-ID: <20130624065929.GC26254@S2101-09.ap.freescale.net> References: <51C497EF.1070108@acumalabs.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <51C497EF.1070108@acumalabs.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-OriginatorOrg: sigmatel.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1547 Lines: 38 On Fri, Jun 21, 2013 at 11:14:07AM -0700, Simon Pearson wrote: > From: Simon Pearson > > Kernel 3.8.4. By defining both the set and clear registers, > the speed of the gpio isimproved. gpio-generic.c, selects the > bgpio_set_with_clear() which isfaster than the current > bgpio_set_set(). This has performance implications for all > bitbang drivers (i2c, spi, etc). Slow SPI as compared to > 2.6.35.33 improved by a factor of 10 (80kHz CLK to 800kHz CLK). > > Signed-off-by: Simon Pearson The latest mainline kernel already has the improvement made by commit 90dae4e (gpio: mxs: Use set and clear capabilities of the gpio controller). Shawn > > --- > --- a/drivers/gpio/gpio-mxs.c.orig 2013-03-20 13:11:19.000000000 -0700 > +++ b/drivers/gpio/gpio-mxs.c 2013-06-21 10:02:33.000000000 -0700 > @@ -292,7 +292,8 @@ static int mxs_gpio_probe(struct platfor > > err = bgpio_init(&port->bgc, &pdev->dev, 4, > port->base + PINCTRL_DIN(port), > - port->base + PINCTRL_DOUT(port), NULL, > + port->base + PINCTRL_DOUT(port) + MXS_SET, > + port->base + PINCTRL_DOUT(port) + MXS_CLR, > port->base + PINCTRL_DOE(port), NULL, 0); > if (err) > goto out_irqdesc_free; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/