lkml.org 
[lkml]   [2012]   [May]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: mc13xxx-core: kernel hangs after 'regmap_read'
On Thu, May 24, 2012 at 09:22:29PM +1000, Marc Reilly wrote:

> > > map->reg_shift = config->pad_bits % 8;
> > > map->format.buf_size = (config->reg_bits
> > >
> > > + config->val_bits
> > >
> > > + map->reg_shift) / 8;

> > Yes, that's been missed in the addition of padding. We should also be
> > using DIV_ROUND_UP() which we aren't at the minute.

> That would break, in _regmap_read_raw():

> ret = map->bus->read(map->bus_context, map->work_buf,
> map->format.reg_bytes + map->format.pad_bytes,
> val, val_len);

> If pad_bytes was 1 here, then the register size would end up being 2 bytes.

The above is about buf_size... pad_bytes isn't in the quoted text which
is the issue.

> The way I understood the pad_bytes field was it was the number of _complete_
> padding bytes (ie, full 8 bits) between the register address and value. Any
> remainder of padding bits is incorporated into the register and shifted by
> shift bits.

Yes.

> > We could also do
> > reg_bytes + pad_bytes + val_bytes which should cover everything I think?

> If we want to cover everything, we could do reg_bytes + pad_bytes + val_bytes
> + 3 ... :) (I'm not seriously suggesting that).

Yes, but the above should be the total that goes onto the wire.


\
 
 \ /
  Last update: 2012-05-24 15:01    [from the cache]
©2003-2011 Jasper Spaans