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From: eddie.huang@mediatek.com (Eddie Huang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v5 2/3] I2C: mediatek: Add driver for MediaTek I2C controller
Date: Wed, 1 Apr 2015 10:11:17 +0800	[thread overview]
Message-ID: <1427854277.21285.15.camel@mtksdaap41> (raw)
In-Reply-To: <20150331175234.GK9742@pengutronix.de>

Hi Sascha,

On Tue, 2015-03-31 at 19:52 +0200, Sascha Hauer wrote:
> On Tue, Mar 31, 2015 at 07:50:58PM +0800, Eddie Huang wrote:
> > Hi Sascha,
> > 
> > On Tue, 2015-03-31 at 15:08 +0800, Eddie Huang wrote:
> > > Hi Sascha,
> > > 
> > > > > > speed <= 400000 here to make this more obvious?
> > > > > There are two cases, not only speed<=400000, but I2C_MASTER_WRRD. I tend
> > > > > to keep it.
> > > >
> > > > Still it looks strange. You only ever write this default value to the
> > > > register. Putting this register write under an if() seems bogus since
> > > > the same value will be in the register the next time this code is
> > > > executed. It looks like you should move this register write to some
> > > > initialization function.
> > > OK, move to mtk_i2c_init_hw function
> > > 
> > Sorry for my negligence. Write-then-read (I2C_MASTER_WRRD) decides
> > according to each I2C transfer, so I still need to judge whether set
> > I2C_CONTROL_RS and DELAY_LEN here. Other control setting can move to
> > init function.
> 
> You need to decide whether you have to set the I2C_CONTROL_RS bit, but
> you don't need to write the same value to the DELAY_LEN register each
> time. It won't change under your hood.
> 
Yes, you are right. DELAY_LEN should only be set one time in init
function. Thanks your correction.

Eddie

  reply	other threads:[~2015-04-01  2:11 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-21  6:05 [PATCH v5 0/3] ARM: mediatek: Add driver for Mediatek I2C controller Eddie Huang
2015-03-21  6:05 ` [PATCH v5 1/3] dt-bindings: Add I2C bindings for mt65xx/mt81xx Eddie Huang
2015-03-23  8:45   ` Sascha Hauer
2015-03-21  6:05 ` [PATCH v5 2/3] I2C: mediatek: Add driver for MediaTek I2C controller Eddie Huang
2015-03-23  8:42   ` Sascha Hauer
2015-03-30  8:14     ` Eddie Huang
2015-03-30 17:23       ` Sascha Hauer
2015-03-31  7:08         ` Eddie Huang
2015-03-31 11:50           ` Eddie Huang
2015-03-31 17:52             ` Sascha Hauer
2015-04-01  2:11               ` Eddie Huang [this message]
2015-03-21  6:05 ` [PATCH v5 3/3] I2C: mediatek: Add driver for MediaTek MT8173 " Eddie Huang
2015-03-23  7:39   ` Sascha Hauer
2015-03-30  8:05     ` Eddie Huang

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