From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: [PATCH 1/2] spi/rockchip: fix bug that case spi can't go as fast as slave request Date: Thu, 16 Oct 2014 12:26:36 +0200 Message-ID: <20141016102636.GE2200@sirena.org.uk> References: <1413372311-4203-1-git-send-email-addy.ke@rock-chips.com> <1413372349-4254-1-git-send-email-addy.ke@rock-chips.com> <20141015130452.GD27755@sirena.org.uk> <543F8CD2.1010302@rock-chips.com> <20141016093410.GB2200@sirena.org.uk> <543F96DB.40403@rock-chips.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="3O1VwFp74L81IIeR" Cc: heiko@sntech.de, dianders@chromium.org, grant.likely@linaro.org, robh+dt@kernel.org, amstan@google.com, sonnyrao@google.com, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, devicetree@vger.kernel.org, olof@lixom.net, hj@rock-chips.com, kever.yang@rock-chips.com, xjq@rock-chips.com, huangtao@rock-chips.com, zyw@rock-chips.com, yzq@rock-chips.com, zhenfu.fang@rock-chips.com, cf@rock-chips.com, zhangqing@rock-chips.com, hl@rock-chips.com, wei.luo@rock-chips.com To: addy ke Return-path: Content-Disposition: inline In-Reply-To: <543F96DB.40403@rock-chips.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org --3O1VwFp74L81IIeR Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, Oct 16, 2014 at 05:58:51PM +0800, addy ke wrote: Please fix your mailer to word wrap within paragraphs. > On 2014/10/16 17:34, Mark Brown wrote: > >> If we set the rate unconditionally here, clk_set_rate() will be executed in each spi transfer. > > Is that really such a high cost? > Not high cost, but I think if the default spi_clk is enough, we do not need to set spi_clk again. > Maybe we can only set spi_clk as (2 * MAX_SCLK_OUT) in probe(). It's not too bad to do it where it is, it just seems better to be simpler. --3O1VwFp74L81IIeR Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBAgAGBQJUP51bAAoJECTWi3JdVIfQsqUIAIBGJkL6Jkve/Hu047z7xaaz iNtIkYoYq8em30yzbYyH2YKXog+D4HRng6bR1rI/Pil0bfPliYMFiHJBz3l3XfrO TgNcyZE3Lm1CWOOuADLmmvtzz+z70tSXJRVPPplFPXU9OQrZBdzo3ZRSMMOyzXfl UFMIndIcr0A6hDkPNsldHLrpkVitI7ceZjG86nDu/uPtqQRj1Nzl0J67w5EzmNLN oByideJoYAv0oYWnUHe/EPpRQz7JYlilZ5DoCpNUP0HKWeYhtgU51r37vzB5glg0 SyUHKqp94ysx3ZDsUMm9pSUvQz3y8KJxj8wiszqkbnw4Nohz2f+B3+6UpMoYQn0= =9p8j -----END PGP SIGNATURE----- --3O1VwFp74L81IIeR--