From mboxrd@z Thu Jan 1 00:00:00 1970 From: lee.jones@linaro.org (Lee Jones) Date: Thu, 25 Apr 2013 09:13:38 +0100 Subject: [PATCH 03/32 v3] dmaengine: ste_dma40: Use the BIT macro to replace ugly '(1 << x)'s In-Reply-To: References: <1366279934-30761-1-git-send-email-lee.jones@linaro.org> <1366279934-30761-4-git-send-email-lee.jones@linaro.org> <20130424151145.GH9652@gmail.com> Message-ID: <20130425081338.GB4623@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, 24 Apr 2013, Rabin Vincent wrote: > 2013/4/24 Lee Jones : > > The aim is to make the code that little more readable. > > > > Acked-by: Vinod Koul > > Acked-by: Arnd Bergmann > > Signed-off-by: Lee Jones > > Please pay closer attention to the semantics of each usage instead of > just replacing all x left shifts of 1 by BIT(x) for "readability". > > > if (seg_max > STEDMA40_MAX_SEG_SIZE) > > - seg_max -= (1 << max_w); > > + seg_max -= BIT(max_w); > > > > - if (!IS_ALIGNED(size, 1 << max_w)) > > + if (!IS_ALIGNED(size, BIT(max_w))) > > return -EINVAL; > > Here and in all other places where the values are from cfg->data_width, > the semantic purpose of the shift is not for setting a particular bit > but instead for converting the data_width field into the data width > value in bytes. You should not change these usages to BIT(). > > It would be instead better to just make the cfg->data_width as the > number of bytes and convert them to the appropriate hardware field > values when the descriptors are constructed. That of course should be > in another patch. I'll do that. Thanks for the pointer. -- Lee Jones Linaro ST-Ericsson Landing Team Lead Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog