mainlining shenanigans
93d2725aff
The RaspberryPi4 firmware actually exposes more clocks than are currently handled by the driver and we will need to change some of them directly based on the pixel rate for the display related clocks, or the load for the GPU. Since the firmware implements DVFS, this rate change can have a number of side-effects, including adjusting the various PLL voltages or the PLL parents. The firmware also implements thermal throttling, so even some thermal pressure can change those parameters behind Linux back. DVFS is currently implemented on the arm, core, h264, v3d, isp and hevc clocks, so updating any of them using the MMIO driver (and thus behind the firmware's back) can lead to troubles, the arm clock obviously being the most problematic. In order to make Linux play as nice as possible with those constraints, it makes sense to rely on the firmware clocks as much as possible. However, the firmware doesn't seem to provide some equivalents to their MMIO counterparts, so we can't really replace that driver entirely. Fortunately, the firmware has an interface to discover the clocks it exposes. Let's use it to discover, register the clocks in the clocks framework and then expose them through the device tree for consumers to use them. Cc: Michael Turquette <mturquette@baylibre.com> Cc: Stephen Boyd <sboyd@kernel.org> Cc: linux-clk@vger.kernel.org Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Reviewed-by: Stephen Boyd <sboyd@kernel.org> Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Signed-off-by: Maxime Ripard <maxime@cerno.tech> Link: https://lore.kernel.org/r/438d73962741a8c5f7c689319b7443b930a87fde.1592210452.git-series.maxime@cerno.tech Signed-off-by: Stephen Boyd <sboyd@kernel.org> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.