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Message-ID: <45a44e480812302058k365eddcfxf902095657b78534@mail.gmail.com>
Date: Tue, 30 Dec 2008 23:58:44 -0500
From: "Jaya Kumar" <jayakumar.lkml@gmail.com>
To: "Robin Getz" <rgetz@blackfin.uclinux.org>
Subject: Re: [RFC 2.6.27 1/1] gpiolib: add support for batch set of pins
Cc: "David Brownell" <david-b@pacbell.net>,
       "Eric Miao" <eric.y.miao@gmail.com>, "Sam Ravnborg" <sam@ravnborg.org>,
       "Eric Miao" <eric.miao@marvell.com>,
       "Haavard Skinnemoen" <hskinnemoen@atmel.com>,
       "Philipp Zabel" <philipp.zabel@gmail.com>,
       "Russell King" <rmk@arm.linux.org.uk>,
       "Ben Gardner" <bgardner@wabtec.com>, "Greg KH" <greg@kroah.com>,
       linux-arm-kernel@lists.arm.linux.org.uk,
       linux-fbdev-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org,
       linux-embedded@vger.kernel.org
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	 <200812281346.56703.rgetz@blackfin.uclinux.org>
	 <200812291156.12230.david-b@pacbell.net>
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On Tue, Dec 30, 2008 at 11:55 PM, Robin Getz <rgetz@blackfin.uclinux.org> 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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