Re: [PATCH] drivers: PMC MSP71xx LED driver

Andrew Morton
2007-03-10T06:17:15Z

> On Fri, 9 Mar 2007 14:20:56 -0800 Marc St-Jean <Marc_St-Jean@pmc-sierra.com> wrote:
>
>
> > > +typedef enum {
> > > + MSP_LED_INPUT = 0,
> > > + MSP_LED_OUTPUT,
> > > +} msp_led_direction_t;
> >
> > No typedefs, please. Convert this to
> >
> > enum msp_led_direction {
> > ...
> > };
>
> Alright I'll change it but it wasn't mentioned in the review of
> the previous drivers and they've been resubmitted with some.
> A quick search shows several drivers typedef'ing enums with and
> without *_t suffixes.

Poeple do bad things, and it sometimes gets missed.

> Is there a new style rule or are only core kernel types allowed to
> use _t?

The general rule is: no typedefs.

typedefs make sense when the underlying type can change: u64, size_t,
resource_size_t, etc. We also use them for really hairy definitions like
filler_t. Nothing else. Please don't use them just to save typing.

>
> > > +/* Output modes */
> > > +typedef enum {
> > > + MSP_LED_OFF = 0, /* Off steady */
> > > + MSP_LED_ON, /* On steady */
> > > + MSP_LED_BLINK, /* On for initialPeriod, off
> > for finalPeriod */
> > > + MSP_LED_BLINK_INVERT, /* Off for initialPeriod, on for
> > finalPeriod */
> > > +} msp_led_mode_t;
> >
> > Ditto.
> >
> > > +/* For non-LED pins, these macros set HI and LO accordingly */
> > > +#define msp_led_pin_hi msp_led_turn_off
> > > +#define msp_led_pin_lo msp_led_turn_on
> >
> > eww.
> >
> > static inline wrapper functions are preferred. Write code in C, not cpp
> > where possible.
>
> I agree the wrappers are cleaner but don't understand how this relates
> to C++.

cpp == C preprocessor.

It would be better to do

/*
* nice comment goes here
*/
static inline void msp_led_pin_hi(...)
{
msp_led_turn_off(...);
}