On Tue, Jun 26, 2018 at 07:11:54AM +0000, Chiang, AlanX wrote:
> Hi Sakari,
> 
> > -----Original Message-----
> > From: Sakari Ailus [mailto:[email protected]]
> > Sent: Tuesday, June 26, 2018 2:48 PM
> > To: Chiang, AlanX <[email protected]>
> > Cc: [email protected]; Yeh, Andy <[email protected]>;
> > Shevchenko, Andriy <[email protected]>; Mani, Rajmohan
> > <[email protected]>; [email protected]; [email protected];
> > [email protected]; [email protected]; [email protected];
> > [email protected]; [email protected]
> > Subject: Re: [PATCH v2 2/2] eeprom: at24: Add support for address-width
> > property
> > 
> > Hi Alan,
> > 
> > On Tue, Jun 26, 2018 at 02:22:08PM +0800, [email protected] wrote:
> > > From: "alanx.chiang" <[email protected]>
> > >
> > > Provide a flexible way to determine the addressing bits of eeprom.
> > > Pass the addressing bits to driver through address-width property.
> > >
> > > Signed-off-by: Alan Chiang <[email protected]>
> > > Signed-off-by: Andy Yeh <[email protected]>
> > >
> > > ---
> > > since v1
> > > -- Add a warn message for 8-bit addressing.
> > >
> > > ---
> > >  drivers/misc/eeprom/at24.c | 16 ++++++++++++++++
> > >  1 file changed, 16 insertions(+)
> > >
> > > diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> > > index 0c125f2..231afcd 100644
> > > --- a/drivers/misc/eeprom/at24.c
> > > +++ b/drivers/misc/eeprom/at24.c
> > > @@ -478,6 +478,22 @@ static void at24_properties_to_pdata(struct device
> > *dev,
> > >   if (device_property_present(dev, "no-read-rollover"))
> > >           chip->flags |= AT24_FLAG_NO_RDROL;
> > >
> > > + err = device_property_read_u32(dev, "address-width", &val);
> > > + if (!err) {
> > > +         switch (val) {
> > > +         case 8:
> > > +                 chip->flags &= ~AT24_FLAG_ADDR16;
> > > +                 dev_warn(dev, "address-width is 8, clear the ADD16
> > bit\n");
> > 
> > Even though the default is 8 address bits, I don't see a need to issue a
> > warning if the address-width property sets that to 8 explicitly. I.e. only 
> > warn
> > if the flag was set.
> > 
> 
> Do you mean I have to add a statement for checking if the bit has been set 
> before?
> For example:
> 
> If (chip->flags & AT24_FLAG_ADDR16)
>       dev_warn(dev, "address-width is 8, clear the ADD16 bit\n");
> 
> If it is, I would like to modify it as below:
> 
> case 8:
>       If (chip->flags & AT24_FLAG_ADDR16) {
>               chip->flags &= ~AT24_FLAG_ADDR16;
>               dev_warn(dev, "address-width is 8, clear the ADDR16 bit\n");
>       }
>       break;

Seems good to me.

-- 
Sakari Ailus
[email protected]

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