From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH] i2c: export bit-banging algo functions Date: Tue, 28 Feb 2012 09:08:17 +0100 Message-ID: <20120228090817.1a95c28b@endymion.delvare> References: <20120227225223.GB1050@phenom.ffwll.local> <1330385979-19406-1-git-send-email-daniel.vetter@ffwll.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1330385979-19406-1-git-send-email-daniel.vetter-/w4YWyX8dFk@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Daniel Vetter Cc: Intel Graphics Development , DRI Development , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Tue, 28 Feb 2012 00:39:39 +0100, Daniel Vetter wrote: > i915 has a hw i2c controller (gmbus) but for a bunch of stupid reasons > we need to be able to fall back to the bit-banging algo on gpio pins. > > The current code sets up a 2nd i2c controller for the same i2c bus using > the bit-banging algo. This has a bunch of issues, the major one being > that userspace can directly access this fallback i2c adaptor behind > the drivers back. > > But we need to frob a few registers before and after using fallback > gpio bit-banging, so this horribly fails. > > The new plan is to only set up one i2c adaptor and transparently fall > back to bit-banging by directly calling the xfer function of the bit- > banging algo in the i2c core. > > To make that possible, export the 2 i2c algo functions. > > v2: As suggested by Jean Delvare, simply export the i2c_bit_algo > vtable instead of the individual functions. > > Signed-off-by: Daniel Vetter > --- > drivers/i2c/algos/i2c-algo-bit.c | 3 ++- > include/linux/i2c-algo-bit.h | 1 + > 2 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c > index 525c734..ad0459c 100644 > --- a/drivers/i2c/algos/i2c-algo-bit.c > +++ b/drivers/i2c/algos/i2c-algo-bit.c > @@ -610,10 +610,11 @@ static u32 bit_func(struct i2c_adapter *adap) > > /* -----exported algorithm data: ------------------------------------- */ > > -static const struct i2c_algorithm i2c_bit_algo = { > +const struct i2c_algorithm i2c_bit_algo = { > .master_xfer = bit_xfer, > .functionality = bit_func, > }; > +EXPORT_SYMBOL(i2c_bit_algo); > > /* > * registering functions to load algorithms at runtime > diff --git a/include/linux/i2c-algo-bit.h b/include/linux/i2c-algo-bit.h > index 4f98148..584ffa0 100644 > --- a/include/linux/i2c-algo-bit.h > +++ b/include/linux/i2c-algo-bit.h > @@ -49,5 +49,6 @@ struct i2c_algo_bit_data { > > int i2c_bit_add_bus(struct i2c_adapter *); > int i2c_bit_add_numbered_bus(struct i2c_adapter *); > +extern const struct i2c_algorithm i2c_bit_algo; > > #endif /* _LINUX_I2C_ALGO_BIT_H */ Acked-by: Jean Delvare -- Jean Delvare