[PATCH] Added i2c support for mc13xxx-core

[Uwe Kleine-König]

Hello,

On Wed, Dec 08, 2010 at 07:07:55PM +1100, Marc Reilly wrote:
> Hi Yong,
> 
> > It's better to use git format-patch to gernerate patch for review, by
> > which you can add some commit information and s-o-b stuff.
> 
> I've submitted a (slightly) better patch earlier today. (although this was 
> generated via format-patch, I forgot the sob.). 
> 
> My main hope was to get some indication that I was progressing along the right 
> path.
> 
> > Please see inline comments.
> Thanks, replies also in-line.
> 
> snip...
> 
> > > +               if (usespi) {
> > > +                       const struct spi_device_id *devid =
> > > +                               spi_get_device_id(mc13xxx->spidev);
> > > +                       if (!devid || devid->driver_data !=
> > > mc13xxx->icid) +                               dev_warn(mc13xxx->pdev,
> > > "device id doesn't " +                                              
> > > "match auto detection!\n"); +               } else {
> > > +                       /* TODO */
> > 
> > todo what? remove this or add real code here.
> > 
> 
> I wasn't immediately sure of what the equivalent way to do this via the i2c 
> subsystem is. I'm not sure how useful it would be anyway, so I'll leave it out 
> in future.
I think this is OK to post the patch with TODO for review if you don't
know what to do (maybe specify a question here, then though).  For a
final patch that should be fixed of course.

> 
> snip ...
> 
> > > +       mutex_init(&mc13xxx->lock);
> > > +       mc13xxx_lock(mc13xxx);
> > > +
> > > +       ret = mc13xxx_identify(mc13xxx, 0);
> > > +       if (ret || (mc13xxx->icid == MC13XXX_ID_INVALID))
> > > +               goto err_revision;
> > > +
> > > +       /* mask all irqs */
> > > +       ret = mc13xxx_reg_write(mc13xxx, MC13XXX_IRQMASK0, 0x00ffffff);
> > > +       if (ret)
> > > +               goto err_mask;
> > > +
> > > +       ret = mc13xxx_reg_write(mc13xxx, MC13XXX_IRQMASK1, 0x00ffffff);
> > > +       if (ret)
> > > +               goto err_mask;
> > > +
> > > +       ret = request_threaded_irq(mc13xxx->irq, NULL,
> > > mc13xxx_irq_thread, +                       IRQF_ONESHOT |
> > > IRQF_TRIGGER_HIGH, "mc13xxx", mc13xxx); +
> > > +       if (ret) {
> > > +err_mask:
> > 
> > > +err_revision:
> > Why two labels here?
> 
> Copied from existing code. 
I consider this to be OK, too (actually it's my code, so it would be
surprising if not ...)  There are two different errors that just share
the place the goto should point to.  Technically a single name would do
it, but I learned that for one the code is easier to verify with useful
label names and sometimes when code needs to be reshuffled the patch
becomes slightly less intrusive.

> > Also, if ret == 0, the lock will not be released.
> 
> The lock is released in mc13xxx_common_probe. 
> Yes, it would be better in this function, before common_probe is called.
ack

> 
> > 
> > > +               mutex_unlock(&mc13xxx->lock);
> > > +               kfree(mc13xxx);
> > > +               return ret;
> > > +       }
> > > +
> > > +       return mc13xxx_common_probe(mc13xxx,pdata);
> > > +}
> > > +
> > > +static int __devexit mc13xxx_i2c_remove(struct i2c_client *client)
> > > +{
> > > +       struct mc13xxx *mc13xxx = dev_get_drvdata(&client->dev);
> > > +
> > > +       free_irq(mc13xxx->irq, mc13xxx);
> > > +
> > > +       mfd_remove_devices(&client->dev);
> > > +
> > > +       kfree(mc13xxx);
> > > +
> > > +       return 0;
> > > +}
> > > +
> > > +static const struct i2c_device_id mc13xxx_i2c_idtable[] = {
> > > +       { "mc13892", MC13XXX_ID_MC13892},
> > > +       { }
> > 
> > you may want to remove empty '{}'
> 
> Again, mimicking the existing spi device table.
This must not go away, as it's the sentinel to mark the end of the
array.

Uwe

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