[rtc-linux] Re: [PATCH 1/2] rtc: ds1307: fix ds1307_native_smbus_read_block_data function

[Alexandre Belloni <alexandre.belloni@free-electrons.com>]

Hi,

On 03/04/2016 at 00:10:37 +0200, Nicolas Boullis wrote :
> The i2c_smbus_read_i2c_block_data function returns 0 on success, not the 
> number of bytes written.
> 
> Hence, when there are 32 bytes or less to send, the 
> ds1307_native_smbus_write_block_data function returns 0 on success, 
> while it returns the number of bytes when there are more than 32.
> 
> The ds1307_write_block_data always returns the number of bytes on 
> success.
> 
> Signed-off-by: Nicolas Boullis <nboullis@debian.org>
> 
> ---
> 
> Should the behavior of the i2c_smbus_write_i2c_block_data function be 
> changed to be consistant with that of the i2c_smbus_read_i2c_block_data 
> function?
> 
> It might be more consistent, but the impact is certainly much larger, 
> and that's far beyond the scope of the RTC subsystem.
> 

I think it will be difficult to change it now.

Wolfram, you may have an opinion?


> diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
> index b2156ee..19e7353 100644
> --- a/drivers/rtc/rtc-ds1307.c
> +++ b/drivers/rtc/rtc-ds1307.c
> @@ -275,9 +275,13 @@ static s32 ds1307_native_smbus_write_block_data(const struct i2c_client *client,
>  {
>  	u8 suboffset = 0;
>  
> -	if (length <= I2C_SMBUS_BLOCK_MAX)
> -		return i2c_smbus_write_i2c_block_data(client,
> +	if (length <= I2C_SMBUS_BLOCK_MAX) {
> +		s32 retval = i2c_smbus_write_i2c_block_data(client,
>  					command, length, values);
> +		if (retval < 0)
> +			return retval;
> +		return length;
> +	}
>  
>  	while (suboffset < length) {
>  		s32 retval = i2c_smbus_write_i2c_block_data(client,



-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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