Re: [PATCH 1/2] Input: DaVinci Keypad Driver

From: Miguel Aguilar <miguel.aguilar@ridgerun.com>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: nsnehaprabha@ti.com,
	davinci-linux-open-source@linux.davincidsp.com,
	linux-input@vger.kernel.org, todd.fischer@ridgerun.com,
	diego.dompe@ridgerun.com, clark.becker@ridgerun.com,
	santiago.nunez@ridgerun.com, David Brownell <david-b@pacbell.net>
Subject: Re: [PATCH 1/2] Input: DaVinci Keypad Driver
Date: Wed, 23 Sep 2009 12:15:24 -0600	[thread overview]
Message-ID: <4ABA65BC.7040404@ridgerun.com> (raw)
In-Reply-To: <20090923174130.GD13435@core.coreip.homeip.net>

Dmitry Torokhov wrote:
> On Wed, Sep 23, 2009 at 11:25:59AM -0600, Miguel Aguilar wrote:
>>>>>> Please kopy keymap into the davinci_kp stucture and use it so that
>>>>>> platform data is never changed and can be declared const.
>>>>> Do you mean something like this?
>>>>>
>>>>> struct davinci_kp {
>>>>>     ...
>>>>>     const int    *keymap;
>>>>>     ...
>>>>> };
>>>>>
>>>> More like:
>>>>
>>>> struct davinci_kp {
>>>>     ...
>>>>     unsgned char keymap[];
>>>>     ...
>>>> };
>>>>
>>> [MA] Ok.
>> [MA] Why usigned char with no pointer and not u32 as most of the keypad 
>> driver as defined?
> 
> Sorry, meant to say "unsigned short keymap[...]", we not going to have
> more than 64K keycodes. You need to fill the array dimension, if the
> size is not known before hand (and if upper bound is too jigh to always
> allocate max) then you'll have to allocate it separately. Hm, well, if
> you make it the last element of the davinci_kp structure you can alwqays
> allocate the needed amount of memory, like this:
> 
> struct davinci_kp {
> 	...
> 	...
> 	unsigned short keymap[];
> };
> 
> ...
> 
> kp = kzalloc(sizeof(struct davinci_kp) +
> 			sizeof(unsigned short) * pdata->keymap_size,
> 	     GFP_KERNEL);
> 

Why do I need to use keymap[]; instead of *keymap? If I use keypad[] how is the 
proper way to assign the platform keymap to the private keymap of the driver?