From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: [PATCH v2] gpio: pca953x: remove incorrect le16_to_cpu calls Date: Wed, 19 Jul 2017 15:14:52 +0300 Message-ID: <1500466492.29303.112.camel@linux.intel.com> References: <20170718155116.88531-1-andriy.shevchenko@linux.intel.com> <871spc7i7v.fsf@free-electrons.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: Received: from mga11.intel.com ([192.55.52.93]:25668 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751228AbdGSMR4 (ORCPT ); Wed, 19 Jul 2017 08:17:56 -0400 In-Reply-To: <871spc7i7v.fsf@free-electrons.com> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Gregory CLEMENT Cc: Linus Walleij , linux-gpio@vger.kernel.org, Sebastian Reichel , Yong Li , Phil Reid On Wed, 2017-07-19 at 13:56 +0200, Gregory CLEMENT wrote: > Hi Andy, >   >  On mar., juil. 18 2017, Andy Shevchenko l.com> wrote: > > > i2c_smbus commands handle the correct byte order for smbus > > transactions > > I am not sure of this claim, I didn't find any cpu_to_lexx in the > sbmus > function. Of course you didn't (I didn't either on the first glance, then I read the code more carefully). It does that byte-by-byte. That explains why people do not notice it AFAIU Sebastian's claim. > > > internally. This will currently result in incorrect operation on big > > endian systems. > > Did you managed to test this driver in a big endian system and to > check > that with this patch the driver worked as expected? Unfortunately no. I have big endian systems, though I have no such device connected to them. > > Thanks, > > Gregory > > > > > > Suggested-by: Sebastian Reichel > > Reviewed-by: Sebastian Reichel > > Signed-off-by: Andy Shevchenko > > --- > > - add RB tag > >  drivers/gpio/gpio-pca953x.c | 8 +++----- > >  1 file changed, 3 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio- > > pca953x.c > > index 4c9e21300a26..1b9dbf691ae7 100644 > > --- a/drivers/gpio/gpio-pca953x.c > > +++ b/drivers/gpio/gpio-pca953x.c > > @@ -187,10 +187,9 @@ static int pca953x_write_regs_8(struct > > pca953x_chip *chip, int reg, u8 *val) > >   > >  static int pca953x_write_regs_16(struct pca953x_chip *chip, int > > reg, u8 *val) > >  { > > - __le16 word = cpu_to_le16(get_unaligned((u16 *)val)); > > + u16 word = get_unaligned((u16 *)val); > >   > > - return i2c_smbus_write_word_data(chip->client, > > -  reg << 1, (__force > > u16)word); > > + return i2c_smbus_write_word_data(chip->client, reg << 1, > > word); > >  } > >   > >  static int pca957x_write_regs_16(struct pca953x_chip *chip, int > > reg, u8 *val) > > @@ -241,8 +240,7 @@ static int pca953x_read_regs_16(struct > > pca953x_chip *chip, int reg, u8 *val) > >   int ret; > >   > >   ret = i2c_smbus_read_word_data(chip->client, reg << 1); > > - val[0] = (u16)ret & 0xFF; > > - val[1] = (u16)ret >> 8; > > + put_unaligned(ret, (u16 *)val); > >   > >   return ret; > >  } > > --  > > 2.11.0 > > > > -- Andy Shevchenko Intel Finland Oy