From mboxrd@z Thu Jan 1 00:00:00 1970 From: grant.likely@secretlab.ca (Grant Likely) Date: Sat, 09 Feb 2013 09:20:38 +0000 Subject: [PATCH 1/9] gpiolib: link all gpio_chips using a list In-Reply-To: References: <1359822572-26009-1-git-send-email-acourbot@nvidia.com> <1359822572-26009-3-git-send-email-acourbot@nvidia.com> Message-ID: <20130209092039.0C5D23E2548@localhost> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, 5 Feb 2013 18:00:56 +0100, Linus Walleij wrote: > On Sat, Feb 2, 2013 at 5:29 PM, Alexandre Courbot wrote: > > > Add a list member to gpio_chip that allows all chips to be parsed > > quickly. The current method requires parsing the entire GPIO integer > > space, which is painfully slow. Using a list makes many chip operations > > that involve lookup or parsing faster, and also simplifies the code. It > > is also necessary to eventually get rid of the global gpio_desc[] array. > > > > The list of gpio_chips is always ordered by base GPIO number to ensure > > chips traversal is done in the right order. > > > > Signed-off-by: Alexandre Courbot > > OK! > > > + * Return -EBUSY if the new chip overlaps with some other chip's integer > > + * space. > (...) > > + /* are we stepping on the chip right before? */ > > + if (pos != &gpio_chips && pos->prev != &gpio_chips) { > > + _chip = list_entry(pos->prev, struct gpio_chip, list); > > + if (_chip->base + _chip->ngpio > chip->base) { > > + dev_err(chip->dev, > > + "GPIO integer space overlap, cannot add chip\n"); > > + err = -EBUSY; > > + } > > + } > > This robustness change on its own is a merit for merging the patch. > And keeping a list of gpiochips available is great for stuff like > debugfs. > > Reviewed-by: Linus Walleij Applied, thanks. g.