From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756022AbaIQQKF (ORCPT ); Wed, 17 Sep 2014 12:10:05 -0400 Received: from mail-ie0-f177.google.com ([209.85.223.177]:45339 "EHLO mail-ie0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755688AbaIQQKD (ORCPT ); Wed, 17 Sep 2014 12:10:03 -0400 Date: Wed, 17 Sep 2014 09:09:58 -0700 From: Lee Jones To: Doug Anderson Cc: Chris Zhong , Heiko Stuebner , linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, Sonny Rao , sameo@linux.intel.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mfd: RK808: Add register caching Message-ID: <20140917160958.GI30918@lee--X1> References: <1410303964-6943-1-git-send-email-dianders@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1410303964-6943-1-git-send-email-dianders@chromium.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 09 Sep 2014, Doug Anderson wrote: > Let's define the voltatile registers (those that can't be cached) and > enable caching. The rk808 is accessed almost constantly with cpufreq > so this is really nice. > > As measured by ftrace: > before this change: cpu0_set_target() => ~2200us > after this change: cpu0_set_target() => ~500us > > Signed-off-by: Doug Anderson > --- > drivers/mfd/rk808.c | 30 ++++++++++++++++++++++++++++++ > 1 file changed, 30 insertions(+) Applied with Chris' Reviewed-by. > diff --git a/drivers/mfd/rk808.c b/drivers/mfd/rk808.c > index 0324422..bd02150 100644 > --- a/drivers/mfd/rk808.c > +++ b/drivers/mfd/rk808.c > @@ -29,10 +29,40 @@ struct rk808_reg_data { > int value; > }; > > +static bool rk808_is_volatile_reg(struct device *dev, unsigned int reg) > +{ > + /* > + * Notes: > + * - Technically the ROUND_30s bit makes RTC_CTRL_REG volatile, but > + * we don't use that feature. It's better to cache. > + * - It's unlikely we care that RK808_DEVCTRL_REG is volatile since > + * bits are cleared in case when we shutoff anyway, but better safe. > + */ > + > + switch (reg) { > + case RK808_SECONDS_REG ... RK808_WEEKS_REG: > + case RK808_RTC_STATUS_REG: > + case RK808_VB_MON_REG: > + case RK808_THERMAL_REG: > + case RK808_DCDC_UV_STS_REG: > + case RK808_LDO_UV_STS_REG: > + case RK808_DCDC_PG_REG: > + case RK808_LDO_PG_REG: > + case RK808_DEVCTRL_REG: > + case RK808_INT_STS_REG1: > + case RK808_INT_STS_REG2: > + return true; > + } > + > + return false; > +} > + > static const struct regmap_config rk808_regmap_config = { > .reg_bits = 8, > .val_bits = 8, > .max_register = RK808_IO_POL_REG, > + .cache_type = REGCACHE_RBTREE, > + .volatile_reg = rk808_is_volatile_reg, > }; > > static struct resource rtc_resources[] = { -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog