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Linus Walleij d82e99a6f9 ARM: sa1100: simpad: Correct I2C GPIO offsets 
Arnd reported the following build bug bug:

In file included from arch/arm/mach-sa1100/simpad.c:20:0:
arch/arm/mach-sa1100/include/mach/SA-1100.h:1118:18: error: large
integer implicitly truncated to unsigned type [-Werror=overflow]
                      (0x00000001 << (Nb))
                      ^
include/linux/gpio/machine.h:56:16: note: in definition of macro
'GPIO_LOOKUP_IDX'
.chip_hwnum = _chip_hwnum,
              ^~~~~~~~~~~
arch/arm/mach-sa1100/include/mach/SA-1100.h:1140:21: note: in
expansion of macro 'GPIO_GPIO'
                    ^~~~~~~~~
arch/arm/mach-sa1100/simpad.c:331:27: note: in expansion of
macro 'GPIO_GPIO21'
  GPIO_LOOKUP_IDX("gpio", GPIO_GPIO21, NULL, 0,

This is what happened:

commit b2e6355559
"i2c: gpio: Convert to use descriptors"
commit 4d0ce62c0a
"i2c: gpio: Augment all boardfiles to use open drain"
together uncovered an old bug in the Simpad board
file: as theGPIO_LOOKUP_IDX() encodes GPIO offsets
on gpiochips in an u16 (see <linux/gpio/machine.h>)
these GPIO "numbers" does not fit, since in
arch/arm/mach-sa1100/include/mach/SA-1100.h it is
defined as:

  #define GPIO_GPIO(Nb) (0x00000001 << (Nb))
  (...)
  #define GPIO_GPIO21 GPIO_GPIO(21) /* GPIO [21] */

This is however provably wrong, since the i2c-gpio
driver uses proper GPIO numbers, albeit earlier from
the global number space, whereas this GPIO_GPIO21
is the local line offset in the GPIO register, which
is used in other code but certainly not in the
gpiolib GPIO driver in drivers/gpio/gpio-sa1100.c, which
has code like this:

static void sa1100_gpio_set(struct gpio_chip *chip,
                            unsigned offset, int value)
{
    int reg = value ? R_GPSR : R_GPCR;

    writel_relaxed(BIT(offset),
        sa1100_gpio_chip(chip)->membase + reg);
}

So far everything however compiled fine as an unsigned
int was used to pass the GPIO numbers in
struct i2c_gpio_platform_data. We can trace the actual error
back to

commit dbd406f9d0
"ARM: 7025/1: simpad: add GPIO based device definitions."
This added the i2c_gpio with the wrong offsets.

This commit was before the SA1100 was converted to use
the gpiolib, but as can be seen from the contemporary
gpio.c in mach-sa1100, it was already using:

static int sa1100_gpio_get(struct gpio_chip *chip,
                           unsigned offset)
{
        return GPLR & GPIO_GPIO(offset);
}

And GPIO_GPIO() is essentially the BIT() macro.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-11-10 15:48:07 +01:00
arch ARM: sa1100: simpad: Correct I2C GPIO offsets 2017-11-10 15:48:07 +01:00
block bio_copy_user_iov(): don't ignore ->iov_offset 2017-10-10 23:55:14 -04:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto Merge commit 'tags/keys-fixes-20171018' into fixes-v4.14-rc5 2017-10-19 12:28:38 +11:00
Documentation i2c: aspeed: Deassert reset in probe 2017-11-06 19:15:31 +01:00
drivers i2c: aspeed: Deassert reset in probe 2017-11-06 19:15:31 +01:00
firmware firmware: Restore support for built-in firmware 2017-09-16 10:58:48 -07:00
fs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-10-21 21:39:18 -04:00
include i2c: nuc900: remove platform_data, too 2017-11-05 12:59:22 +01:00
init Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:54:01 -07:00
ipc fix a typo in put_compat_shm_info() 2017-09-25 20:41:46 -04:00
kernel Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-22 06:54:42 -04:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-21 22:44:48 -04:00
mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-21 22:44:48 -04:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-21 22:44:48 -04:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-21 22:44:48 -04:00
scripts Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2017-10-22 16:19:12 -04:00
security commoncap: move assignment of fs_ns to avoid null pointer dereference 2017-10-19 13:09:33 +11:00
sound ALSA: hda - Fix incorrect TLV callback check introduced during set_fs() removal 2017-10-18 12:27:00 +02:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-22 06:52:53 -04:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD" 2017-09-19 08:37:17 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap Update James Hogan's email address 2017-10-04 17:11:53 -07:00
COPYING
CREDITS selinux/stable-4.14 PR 20170831 2017-09-12 13:21:00 -07:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS MAINTAINERS: new maintainer for AT24 driver 2017-11-05 13:01:40 +01:00
Makefile Linux 4.14-rc6 2017-10-23 06:49:47 -04:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README 

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.