Re: [PATCH REVIEW] e4000: convert DVB tuner to I2C driver model

[Antti Palosaari <crope@iki.fi>]

On 16.10.2013 20:19, Michael Krufky wrote:
> On Wed, Oct 16, 2013 at 1:09 PM, Jean Delvare <khali@linux-fr.org> wrote:
>> Hi Michael,
>>
>> On Wed, 16 Oct 2013 13:04:42 -0400, Michael Krufky wrote:
>>> YIKES!!  i2c_new_probed_device() does indeed probe the hardware --
>>> this is unacceptable, as such an action can damage the ic.
>>>
>>> Is there some additional information that I'm missing that lets this
>>> perform an attach without probe?
>>
>> Oh, i2c_new_probed_device() probes the device, what a surprise! :D
>>
>> Try, I don't know, i2c_new_device() maybe if you don't want the
>> probe? ;)
>>
>> --
>> Jean Delvare
>
> OK, so to confirm that I follow correctly, one can use
> i2c_new_device() to attach the sub-driver without probing, and the
> line that ensures that the correct sub-driver gets attached is
> "strlcpy(info.type, "e4000", I2C_NAME_SIZE);"  ??
>
> We're matching based on a string?  I think that's kinda yucky, but if
> that's what we're doing in i2c nowadays then I'm OK with it.
>
> If not, what prevents the wrong sub-driver from attaching to a device?
>   ...or conversely, how does the right sub-driver know which device to
> attach to?

Yes, it is that string. Driver has that string as a ID table entry. Then 
you issue i2c_new_device() call with string and it attachs driver when 
strings match.

> Again, if I'm asking "stupid questions" just point me to the documentation.
>
> -Mike
>

regards
Antti

-- 
http://palosaari.fi/