Re: [RFC] Dell activity led WMI driver

[Matthew Garrett <mjg@redhat.com>]

On Mon, Feb 01, 2010 at 04:44:36PM -0600, Bob Rodgers wrote:

> This has been internally reviewed, and we are ready for outside review  
> and feedback. My colleagues have identified the dell-wmi module as a  
> suitable container in lieu of a stand-alone module specifically for this  
> driver, which makes sense, but we welcome advice. We are submitting it  
> as a stand-alone module for now because that is how we developed and  
> tested it. We would like this to be included upstream after it has been  
> reviewed.

It uses a different GUID to the event interface used by dell-wmi, so 
right now there's no inherent reason to integrate it into that rather 
than keeping it as a separate driver. On the other hand, if the GUID is 
useful for other kinds of system control rather than just the LED then 
dell-wmi may want to make use of that functionality in the future. In 
that case we'd need it to be incorporated into the dell-wmi driver.

So, really, it depends on the interface. If this GUID is specific to 
LEDs, then keep it separate. Otherwise it should be integrated.

I've got a few comments on the code...

> // Error Result Codes:

C99 style comments are usually discouraged in the kernel. 

> // Devide ID

Typo?

> // LED Commands
> #define CMD_LED_ON		16
> #define CMD_LED_OFF		17
> #define CMD_LED_BLINK	18

Use of whitespace isn't very consistent here.

> struct bios_args {
> 	unsigned char Length;
> 	unsigned char ResultCode;
> 	unsigned char DeviceId;
> 	unsigned char Command;
> 	unsigned char OnTime;
> 	unsigned char OffTime;
> 	unsigned char Reserved[122];
> };

Mm. We're also not usually big on CamelCasing in variable names - it'd 
be preferable to use underscores. That's true for the rest of this, too.

> 	// free the output ACPI object allocated by ACPI driver

Probably don't need this comment.

> static void led_on(void)
> {
> 	dell_led_perform_fn(3,		// Length of command
> 		INTERFACE_ERROR,		// Init result code to 	INTERFACE_ERROR
> 		DEVICE_ID_PANEL_BACK,	// Device ID
> 		CMD_LED_ON,				// Command
> 		0,						// not used
> 		0);						// not used
> }

Whitespace is a bit odd here, again.

Other than that, it looks good. You probably want to run it through 
Scripts/checkpatch.pl in the kernel tree to perform further style 
checks, but I can't see any functional issues.
-- 
Matthew Garrett | mjg59@srcf.ucam.org