From: Alexandre Courbot <acourbot@nvidia.com>
To: Grant Likely <grant.likely@secretlab.ca>,
Linus Walleij <linus.walleij@linaro.org>,
Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, gnurou@gmail.com,
Alexandre Courbot <acourbot@nvidia.com>
Subject: [PATCH 5/9] gpiolib: use gpio_chips list in gpiochip_find_base
Date: Sun, 3 Feb 2013 01:29:28 +0900 [thread overview]
Message-ID: <1359822572-26009-7-git-send-email-acourbot@nvidia.com> (raw)
In-Reply-To: <1359822572-26009-1-git-send-email-acourbot@nvidia.com>
Re-implement gpiochip_find_base using the list of chips instead of the
global gpio_desc[] array. This makes it both simpler and more efficient,
and is needed to remove the global descriptors array.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
drivers/gpio/gpiolib.c | 37 ++++++++++++++++---------------------
1 file changed, 16 insertions(+), 21 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e473ded..af4c350 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -126,30 +126,25 @@ struct gpio_chip *gpio_to_chip(unsigned gpio)
/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
static int gpiochip_find_base(int ngpio)
{
- int i;
- int spare = 0;
- int base = -ENOSPC;
-
- for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) {
- struct gpio_desc *desc = &gpio_desc[i];
- struct gpio_chip *chip = desc->chip;
-
- if (!chip) {
- spare++;
- if (spare == ngpio) {
- base = i;
- break;
- }
- } else {
- spare = 0;
- if (chip)
- i -= chip->ngpio - 1;
- }
+ struct gpio_chip *chip;
+ int base = ARCH_NR_GPIOS - ngpio;
+
+ list_for_each_entry_reverse(chip, &gpio_chips, list) {
+ /* found a free space? */
+ if (chip->base + chip->ngpio <= base)
+ break;
+ else
+ /* nope, check the space right before the chip */
+ base = chip->base - ngpio;
}
- if (gpio_is_valid(base))
+ if (gpio_is_valid(base)) {
pr_debug("%s: found new base at %d\n", __func__, base);
- return base;
+ return base;
+ } else {
+ pr_err("%s: cannot find free range\n", __func__);
+ return -ENOSPC;
+ }
}
/* caller ensures gpio is valid and requested, chip->get_direction may sleep */
--
1.8.1.1
next prev parent reply other threads:[~2013-02-02 16:29 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-02 16:29 [PATCH 0/9] gpiolib: remove gpio_desc[] static array Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot
2013-02-02 16:29 ` [PATCH 1/9] gpiolib: link all gpio_chips using a list Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot
2013-02-05 17:00 ` Linus Walleij
2013-02-09 9:20 ` Grant Likely
2013-02-09 9:20 ` Grant Likely
2013-02-02 16:29 ` [PATCH 2/9] gpiolib: use gpio_chips list in gpiolib_sysfs_init Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot
2013-02-05 17:04 ` Linus Walleij
2013-02-09 9:22 ` Grant Likely
2013-02-09 9:22 ` Grant Likely
2013-02-02 16:29 ` [PATCH 3/9] gpiolib: use gpio_chips list in gpiochip_find Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot
2013-02-05 17:05 ` Linus Walleij
2013-02-09 9:25 ` Grant Likely
2013-02-09 9:25 ` Grant Likely
2013-02-02 16:29 ` [PATCH 4/9] gpiolib: use gpio_chips list in sysfs ops Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot
2013-02-05 17:15 ` Linus Walleij
2013-02-05 17:15 ` Linus Walleij
2013-02-09 9:37 ` Grant Likely
2013-02-09 9:37 ` Grant Likely
2013-02-09 13:53 ` Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot [this message]
2013-02-02 16:29 ` [PATCH 5/9] gpiolib: use gpio_chips list in gpiochip_find_base Alexandre Courbot
2013-02-05 17:21 ` Linus Walleij
2013-02-06 4:48 ` Alex Courbot
2013-02-09 9:47 ` Grant Likely
2013-02-09 9:47 ` Grant Likely
2013-02-02 16:29 ` [PATCH 6/9] gpiolib: use descriptors internally Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot
2013-02-05 17:53 ` Linus Walleij
2013-02-07 6:57 ` Alexandre Courbot
2013-02-09 9:17 ` Grant Likely
2013-02-09 9:17 ` Grant Likely
2013-02-11 14:09 ` Linus Walleij
2013-02-11 15:40 ` Paul Mundt
2013-02-11 15:40 ` Paul Mundt
2013-02-11 17:39 ` Stephen Warren
2013-02-12 12:29 ` Linus Walleij
2013-02-12 15:59 ` Paul Mundt
2013-02-12 17:18 ` Arnd Bergmann
2013-02-09 13:11 ` Grant Likely
2013-02-09 13:11 ` Grant Likely
2013-02-09 14:15 ` Alexandre Courbot
2013-02-09 13:24 ` Grant Likely
2013-02-09 13:24 ` Grant Likely
2013-02-09 14:18 ` Alexandre Courbot
2013-02-02 16:29 ` [PATCH 7/9] gpiolib: let gpio_chip reference its descriptors Alexandre Courbot
2013-02-05 18:00 ` Linus Walleij
2013-02-09 13:28 ` Grant Likely
2013-02-02 16:29 ` [PATCH 8/9] gpiolib: use gpio_chips list in gpio_to_desc Alexandre Courbot
2013-02-05 18:01 ` Linus Walleij
2013-02-05 18:01 ` Linus Walleij
2013-02-09 9:58 ` Grant Likely
2013-02-09 9:58 ` Grant Likely
2013-02-09 14:21 ` Alexandre Courbot
2013-02-09 14:21 ` Alexandre Courbot
2013-02-09 14:37 ` Grant Likely
2013-02-02 16:29 ` [PATCH 9/9] gpiolib: dynamically allocate descriptors array Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot
2013-02-05 18:02 ` Linus Walleij
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