[PATCH 5/7] smc911x: improve detection handle

[Sascha Hauer]

On Wed, Aug 29, 2012 at 10:36:07AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 08:52 Wed 29 Aug     , Sascha Hauer wrote:
> > On Wed, Aug 29, 2012 at 07:06:16AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > > detect if the bus is swapped and report a 32bit drivers is used on a 16bit bus
> > > 
> > > Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> > > ---
> > >  drivers/net/smc911x.c |   20 +++++++++++++++++++-
> > >  drivers/net/smc911x.h |    2 ++
> > >  2 files changed, 21 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/net/smc911x.c b/drivers/net/smc911x.c
> > > index 75a332e..17f365d 100644
> > > --- a/drivers/net/smc911x.c
> > > +++ b/drivers/net/smc911x.c
> > > @@ -470,9 +470,27 @@ static int smc911x_probe(struct device_d *dev)
> > >  	}
> > >  
> > >  	val = smc911x_reg_read(priv, BYTE_TEST);
> > > -	if(val != 0x87654321) {
> > > +	if (val == 0x43218765) {
> > > +		dev_info(dev, "BYTE_TEST looks swapped, "
> > > +			   "applying WORD_SWAP");
> > 
> > dev_dbg please. Users shouldn't be interested in this.
> > 
> > > +		smc911x_reg_write(priv, WORD_SWAP, 0xffffffff);
> > > +
> > > +		/* 1 dummy read of BYTE_TEST is needed after a write to
> > > +		 * WORD_SWAP before its contents are valid */
> > > +		val = smc911x_reg_read(priv, BYTE_TEST);
> > > +
> > > +		val = smc911x_reg_read(priv, BYTE_TEST);
> > > +	}
> > > +
> > > +	if (val != 0x87654321) {
> > >  		dev_err(dev, "no smc911x found on 0x%p (byte_test=0x%08x)\n",
> > >  			priv->base, val);
> > > +		if (((val >> 16) & 0xFFFF) == (val & 0xFFFF)) {
> > > +			dev_err(dev, "top 16 bits equal to bottom 16 bits\n");
> > > +			dev_err(dev,
> > > +				   "This may mean the chip is set "
> > > +				   "for 32 bit while the bus is reading 16 bit\n");
> > 
> > Please replace the second dev_err with a comment in the source code.
> > This is developer information only; developers will grep for the source
> > of the message anyway.
> code from the kernel prefer to keep it as is

We are not the kernel.

Sascha

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