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Diffstat (limited to 'Documentation/arm/sunxi')
| -rw-r--r-- | Documentation/arm/sunxi/README | 52 | ||||
| -rw-r--r-- | Documentation/arm/sunxi/clocks.txt | 56 |
2 files changed, 108 insertions, 0 deletions
diff --git a/Documentation/arm/sunxi/README b/Documentation/arm/sunxi/README new file mode 100644 index 00000000000..7945238453e --- /dev/null +++ b/Documentation/arm/sunxi/README @@ -0,0 +1,52 @@ +ARM Allwinner SoCs +================== + +This document lists all the ARM Allwinner SoCs that are currently +supported in mainline by the Linux kernel. This document will also +provide links to documentation and/or datasheet for these SoCs. + +SunXi family +------------ + Linux kernel mach directory: arch/arm/mach-sunxi + + Flavors: + * ARM926 based SoCs + - Allwinner F20 (sun3i) + + Not Supported + + * ARM Cortex-A8 based SoCs + - Allwinner A10 (sun4i) + + Datasheet + http://dl.linux-sunxi.org/A10/A10%20Datasheet%20-%20v1.21%20%282012-04-06%29.pdf + + User Manual + http://dl.linux-sunxi.org/A10/A10%20User%20Manual%20-%20v1.20%20%282012-04-09%2c%20DECRYPTED%29.pdf + + - Allwinner A10s (sun5i) + + Datasheet + http://dl.linux-sunxi.org/A10s/A10s%20Datasheet%20-%20v1.20%20%282012-03-27%29.pdf + + - Allwinner A13 (sun5i) + + Datasheet + http://dl.linux-sunxi.org/A13/A13%20Datasheet%20-%20v1.12%20%282012-03-29%29.pdf + + User Manual + http://dl.linux-sunxi.org/A13/A13%20User%20Manual%20-%20v1.2%20%282013-01-08%29.pdf + + * Dual ARM Cortex-A7 based SoCs + - Allwinner A20 (sun7i) + + User Manual + http://dl.linux-sunxi.org/A20/A20%20User%20Manual%202013-03-22.pdf + + - Allwinner A23 + + Not Supported + + * Quad ARM Cortex-A7 based SoCs + - Allwinner A31 (sun6i) + + Datasheet + http://dl.linux-sunxi.org/A31/A31%20Datasheet%20-%20v1.00%20(2012-12-24).pdf + + - Allwinner A31s (sun6i) + + Not Supported + + * Quad ARM Cortex-A15, Quad ARM Cortex-A7 based SoCs + - Allwinner A80 + + Not Supported
\ No newline at end of file diff --git a/Documentation/arm/sunxi/clocks.txt b/Documentation/arm/sunxi/clocks.txt new file mode 100644 index 00000000000..e09a88aa313 --- /dev/null +++ b/Documentation/arm/sunxi/clocks.txt @@ -0,0 +1,56 @@ +Frequently asked questions about the sunxi clock system +======================================================= + +This document contains useful bits of information that people tend to ask +about the sunxi clock system, as well as accompanying ASCII art when adequate. + +Q: Why is the main 24MHz oscillator gatable? Wouldn't that break the + system? + +A: The 24MHz oscillator allows gating to save power. Indeed, if gated + carelessly the system would stop functioning, but with the right + steps, one can gate it and keep the system running. Consider this + simplified suspend example: + + While the system is operational, you would see something like + + 24MHz 32kHz + | + PLL1 + \ + \_ CPU Mux + | + [CPU] + + When you are about to suspend, you switch the CPU Mux to the 32kHz + oscillator: + + 24Mhz 32kHz + | | + PLL1 | + / + CPU Mux _/ + | + [CPU] + + Finally you can gate the main oscillator + + 32kHz + | + | + / + CPU Mux _/ + | + [CPU] + +Q: Were can I learn more about the sunxi clocks? + +A: The linux-sunxi wiki contains a page documenting the clock registers, + you can find it at + + http://linux-sunxi.org/A10/CCM + + The authoritative source for information at this time is the ccmu driver + released by Allwinner, you can find it at + + https://github.com/linux-sunxi/linux-sunxi/tree/sunxi-3.0/arch/arm/mach-sun4i/clock/ccmu |