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From: Yong Li <sdliyong@gmail.com>
Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] gpio: pca953x: Use correct u16 value for register word write
Date: Tue, 29 Mar 2016 20:53:58 +0800	[thread overview]
Message-ID: <CADO9-pdhTOmg9OMgz+K++Gc3mCxbi7KF23kA8zsftVeDTR3SSw@mail.gmail.com> (raw)
In-Reply-To: <56FA6FB6.4040003@electromag.com.au>

Thanks for your comment, I think I can change it to val[0] | (val[1]
<< 8), is it okay ?

2016-03-29 20:06 GMT+08:00 Phil Reid <preid@electromag.com.au>:
> G'day Yong,
>
> One comment below.
>
> On 29/03/2016 2:27 PM, Yong Li wrote:
>>
>> The current implementation only uses the first byte in *val,
>> the second data is always 0. Change it to *(u16 *)val
>> to write the two bytes into the register
>>
>> Signed-off-by: Yong Li <sdliyong@gmail.com>
>> ---
>>   drivers/gpio/gpio-pca953x.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
>> index d0d3065..cf3d410 100644
>> --- a/drivers/gpio/gpio-pca953x.c
>> +++ b/drivers/gpio/gpio-pca953x.c
>> @@ -159,7 +159,7 @@ static int pca953x_write_regs(struct pca953x_chip
>> *chip, int reg, u8 *val)
>>                 switch (chip->chip_type) {
>>                 case PCA953X_TYPE:
>>                         ret = i2c_smbus_write_word_data(chip->client,
>> -                                                       reg << 1, (u16)
>> *val);
>> +                                                       reg << 1, *(u16
>> *)val);
>
> I don't think this is safe for systems that don't support unaligned memory
> access.
>
>
>>                         break;
>>                 case PCA957X_TYPE:
>>                         ret = i2c_smbus_write_byte_data(chip->client, reg
>> << 1,
>>
>
>
> --
> Regards
> Phil Reid
>

  reply	other threads:[~2016-03-29 12:54 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-29  6:27 [PATCH] gpio: pca953x: Use correct u16 value for register word write Yong Li
2016-03-29 12:06 ` Phil Reid
2016-03-29 12:53   ` Yong Li [this message]
2016-03-29 14:39     ` Alexander Stein
2016-03-29 16:33       ` Phil Reid
2016-03-30  2:46         ` Yong Li
     [not found]         ` <CADO9-pdxpQRQQ8RFtjT6rz28GteL3u+at0EGVdNwG8VV48SGEw@mail.gmail.com>
2016-03-30  5:01           ` Yong Li
2016-03-30  5:14             ` Phil Reid

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