Hi Sakari, > -----Original Message----- > From: Sakari Ailus [mailto:sakari.ailus@xxxxxxxxxxxxxxx] > Sent: Tuesday, June 26, 2018 2:48 PM > To: Chiang, AlanX <alanx.chiang@xxxxxxxxx> > Cc: linux-i2c@xxxxxxxxxxxxxxx; Yeh, Andy <andy.yeh@xxxxxxxxx>; > Shevchenko, Andriy <andriy.shevchenko@xxxxxxxxx>; Mani, Rajmohan > <rajmohan.mani@xxxxxxxxx>; andy.shevchenko@xxxxxxxxx; brgl@xxxxxxxx; > robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx; arnd@xxxxxxxx; > gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > 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, alanx.chiang@xxxxxxxxx wrote: > > From: "alanx.chiang" <alanx.chiang@xxxxxxxxx> > > > > 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 <alanx.chiang@xxxxxxxxx> > > Signed-off-by: Andy Yeh <andy.yeh@xxxxxxxxx> > > > > --- > > 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; > > + break; > > + case 16: > > + chip->flags |= AT24_FLAG_ADDR16; > > + break; > > + default: > > + dev_warn(dev, "Bad \"address-width\" property: > %u\n", > > + val); > > + } > > + } > > + > > err = device_property_read_u32(dev, "size", &val); > > if (!err) > > chip->byte_len = val; > > -- > Regards, > > Sakari Ailus > sakari.ailus@xxxxxxxxxxxxxxx