Re: [PATCH RESEND v2 1/2] Input: touchscreen: ads7846: keep copy of pdata in private struct

[Daniel Mack <zonque@gmail.com>]

On 01.07.2013 09:09, Dmitry Torokhov wrote:
> Hi Daniel,
> 
> On Mon, Jul 01, 2013 at 08:48:50AM +0200, Daniel Mack wrote:
>> Hi Dmitry,
>>
>> On 01.07.2013 03:33, Dmitry Torokhov wrote:
>>> On Sun, Jun 30, 2013 at 11:09:14PM +0200, Daniel Mack wrote:
>>>> +
>>>> +	if (!pdata->model)
>>>> +		pdata->model = 7846;
>>>> +
>>>> +	if (!pdata->vref_delay_usecs)
>>>> +		pdata->vref_delay_usecs = 100;
>>>> +
>>>> +	if (!pdata->x_plate_ohms)
>>>> +		pdata->x_plate_ohms = 400;
>>>> +
>>>> +	if (!pdata->pressure_max)
>>>> +		pdata->pressure_max = ~0;
>>>
>>> We should not be changing the platform data as the device does not own
>>> it and it may well be declared as a constant structure.
>>
>> We don't change the platform data that is passed in via the driver core.
>> We keep a copy of it in our private strucz (that's what the subject
>> says) and in case of DT, we modify that copy. The passed pdata is left
>> untouched.
>>
> 
> That might have been the intent but the patch only stores a _pointer_ to
> the platform data in the main structure, so in non-DT case you end up
> modifying the original structure.

Eh, ok. I'll change that to always make a copy. Somehow though, I like
the first approach (v1 of the set) better, which stored all data that is
modified inside the private struct directly.

Anyway, I'll submit v3 later.


Thanks,
Daniel