Re: [RFC 2.6.27 1/1] gpiolib: add support for batch set of pins

From: Jaya Kumar
Date: Tue Dec 30 2008 - 23:58:58 EST


On Tue, Dec 30, 2008 at 11:55 PM, Robin Getz <rgetz@xxxxxxxxxxxxxxxxxxxx> wrote:
> Yeah, I hadn't thought about spanning more than one gpio_chip. That's a good
> point.

The currently posted code already supports spanning more than one gpio_chip.

+ do {
+ chip = gpio_to_chip(gpio + i);
+ WARN_ON(extra_checks && chip->can_sleep);
+
+ if (!chip->set_bus) {
+ while (((gpio + i) < (chip->base + chip->ngpio))
+ && bitwidth) {
+ value = values & (1 << i);
+ chip->set(chip, gpio + i - chip->base, value);
+ i++;
+ bitwidth--;
+ }
+ } else {
+ value = values >> i; /* shift off the used stuff */
+ remwidth = ((chip->base + (int) chip->ngpio) -
+ ((int) gpio + i));
+ width = min(bitwidth, remwidth);
+
+ chip->set_bus(chip, gpio + i - chip->base, value,
+ width);
+ i += width;
+ bitwidth -= width;
+ }
+ } while (bitwidth);
--
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