Messages in this thread | | | From | David Brownell <> | Subject | Re: [patch/rfc 1/4] GPIO implementation framework | Date | Tue, 13 Nov 2007 20:18:22 -0800 |
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On Tuesday 13 November 2007, eric miao wrote: > Here comes the point of "struct gpio_desc" > > Subject: [PATCH 3/5] use a per GPIO "struct gpio_desc" and chain > "gpio_chip" to a list
I see what it does, but don't see the "why" ... surely you can come up with a one sentence description of why this would be better?
And I'd been so glad to *get rid of* that list, too.
> +struct gpio_desc { > + struct gpio_chip *chip; > +}; > +
> -/* gpio_lock protects modification to the table of chips and to > - * gpio_chip->requested. If a gpio is requested, its gpio_chip > - * is not removable. > - */
But it still protects data. Don't remove documentation for what locks protect ... update it! Otherwise someonels going to come by and make a change which breaks the locking model. Usually in some subtle (hard-to-debug) way.
> > - for (id = 0; id < ARRAY_SIZE(chips); id++) { > - chip = chips[id]; > - if (!chip) > - continue; > - > + list_for_each_entry(chip, &gpio_chip_list, node) { > seq_printf(s, "%sGPIOs %d-%d, %s%s:\n", > started ? "\n" : "", > chip->base, chip->base + chip->ngpio - 1,
Note that this now produces the debug info in a relatively random order ... ordered by registration rather than anything useful, and hence awkward to read.
It'd be better if you just scanned your new gpio_desc[] table in numeric order, and start a new section whenever you find a new gpio_chip.
That'd get rid of that otherwise-useless list, too.
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