From: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
To: Eddie Huang <eddie.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
Cc: Sascha Hauer <kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>,
srv_heupstream-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org,
Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>,
Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
Ian Campbell
<ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>,
Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
Matthias Brugger
<matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Xudong Chen <xudong.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>,
Liguo Zhang <liguo.zhang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>,
linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH v7 2/3] I2C: mediatek: Add driver for MediaTek I2C controller
Date: Mon, 18 May 2015 08:37:42 +0200 [thread overview]
Message-ID: <20150518063742.GA1545@katana> (raw)
In-Reply-To: <1431928701.22349.22.camel@mtksdaap41>
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> > > + rpaddr = dma_map_single(i2c->adap.dev.parent, msgs->buf,
> > > + msgs->len, DMA_FROM_DEVICE);
> >
> > I think you shouldn't use the adapter device here and later, but the dma
> > channel device.
> >
> In MTK SoC, each I2C controller has its own DMA, and this DMA can't be
> used by other hardware.
> So I tend to use DMA directly, not through DMA channel.
> Even so, "i2c->adap.dev.parent" is not suitable here. I will change to
> use i2c->dev here. (Reference i2c-at91.c).
The better reference would be i2c-sh_mobile.c, especially commit
8cfcae9f0595bf0d145a67cfaa1051804a301d7c ("i2c: sh_mobile: use proper
device for mapping DMA memory") ;) The request to use the DMA channel
device came from the DMA folks, so if there is no real reason for an
exception, please use the channel device.
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next prev parent reply other threads:[~2015-05-18 6:37 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-06 8:37 [PATCH v7 0/3] ARM: mediatek: Add driver for Mediatek I2C Eddie Huang
[not found] ` <1430901427-65146-1-git-send-email-eddie.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2015-05-06 8:37 ` [PATCH v7 1/3] dt-bindings: Add I2C bindings for mt65xx/mt81xx Eddie Huang
[not found] ` <1430901427-65146-2-git-send-email-eddie.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2015-05-12 12:37 ` wsa-z923LK4zBo2bacvFa/9K2g
[not found] ` <20150512123709.GA4447-oo5tB6JMkjKRinMKxDlMNPwbnWRJjS81@public.gmane.org>
2015-05-12 12:45 ` Sascha Hauer
2015-05-06 8:37 ` [PATCH v7 2/3] I2C: mediatek: Add driver for MediaTek I2C controller Eddie Huang
[not found] ` <1430901427-65146-3-git-send-email-eddie.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2015-05-12 12:58 ` wsa-z923LK4zBo2bacvFa/9K2g
[not found] ` <20150512125832.GB4447-oo5tB6JMkjKRinMKxDlMNPwbnWRJjS81@public.gmane.org>
2015-05-18 5:58 ` Eddie Huang
2015-05-18 6:37 ` Wolfram Sang [this message]
2015-05-18 7:42 ` Eddie Huang
2015-05-18 9:05 ` Wolfram Sang
2015-05-06 8:37 ` [PATCH v7 3/3] I2C: mediatek: Add driver for MediaTek MT8173 " Eddie Huang
[not found] ` <1430901427-65146-4-git-send-email-eddie.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
2015-05-12 13:00 ` wsa-z923LK4zBo2bacvFa/9K2g
2015-05-07 7:39 ` [PATCH v7 0/3] ARM: mediatek: Add driver for Mediatek I2C Lee Jones
2015-05-07 7:54 ` Eddie Huang
2015-05-07 8:27 ` Lee Jones
2015-05-12 12:45 ` Sascha Hauer
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