While using GPIO library API we might get into troubles in the future, because we can't rely on label name in the driver since vendor firmware might provide any GPIO pin there, e.g. "reset", and even mark it in _DSD (in which case the request will fail). To avoid inconsistency and potential issues we have two options: a) generate GPIO ACPI mapping table and supply it via acpi_dev_add_driver_gpios(), or b) just pass NULL as connection ID. The b) approach is much simpler and would work since the driver relies on GPIO indices only. Moreover, the _CRS fallback mechanism, when requesting GPIO, is going to be stricter, and supplying non-NULL connection ID when neither _DSD, nor GPIO ACPI mapping is present, will make request fail. See https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git/commit/?h=for-next&id=ed7fcf1ed5ea4ea01243995ae085757a77cf0f3e for more background. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org> |
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Documentation | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
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.