Messages in this thread | | | Date | Tue, 3 Jun 2008 08:42:03 +0200 (CEST) | From | Guennadi Liakhovetski <> | Subject | Re: [RFC] generic GPIO parameter API |
| |
On Tue, 3 Jun 2008, Ben Nizette wrote:
> On Mon, 2008-06-02 at 19:54 +0200, Guennadi Liakhovetski wrote: > > On Mon, 2 Jun 2008, Guennadi Liakhovetski wrote: > > > int gpio_register_parameter(struct gpio_chip *chip, struct gpio_parameter > > > *param); > > > struct gpio_parameter *gpio_find_parameter(struct gpio_chip *chip, char > > > *name); > > > > Actually, I think, it would be even better to just add two fields > > > > struct gpio_parameter *param; > > int param_n; > > > > to struct gpio_chip. > > I like the idea in general. The biggest worry I have is trying to find > the parameter for you to fiddle with.
Oh, this doesn't worry me - I have a driver here for a controller with switchable pullups.
> The driver which is going to want > to set the parameters is going to have the gpio number, not the > gpio_chip.
Sure, right.
> Also, the fact that the parameters are uniquely identified > by strings is a bit awkward. I can see people registering the same kind > of parameter for different chips like "pullup", "Pullup", "pu" etc > making the driver's task even harder.
Well, I thought about that too, but then I decided there would have to be too many of those macros. But we can try it that way too.
> So, I reckon if we're to do this we should stick with the current style > of gpio calls for the outside interface, maybe something more like > > int gpio_set_param(int gpio, int param, int val); > int gpio_get_param(int gpio, int param);
For the get I would rather pass it "int *val" because we don't know which values are valid and which are an error code for this specific parameter.
> with the different parameters defined as an enum in some gpio.h > somewhere. Where to keep the gpio_parameters and how to search/find > them should be up to the implementation (though the gpiolib > implementation would probably look quite like what you've got above). > > Note you'll probably want a char *name in there somewhere for the sysfs > interface, but I don't think it should be the primary mechanism for > identification. > > Anyway, that's my $0.02 :-)
Thanks for the comments Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer
| |