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author | Costa Shulyupin <costa.shul@redhat.com> | 2023-07-25 06:38:03 +0200 |
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committer | Jonathan Corbet <corbet@lwn.net> | 2023-08-18 19:03:52 +0200 |
commit | ec62a746b65363f6078fb1eefc7faffe1a4cdc38 (patch) | |
tree | f942f375b8ea431c3e7e0bf297b2e7a4685f295b /Documentation/mips/ingenic-tcu.rst | |
parent | docs: move loongarch under arch (diff) | |
download | linux-ec62a746b65363f6078fb1eefc7faffe1a4cdc38.tar.xz linux-ec62a746b65363f6078fb1eefc7faffe1a4cdc38.zip |
docs: move mips under arch
and fix all in-tree references.
Architecture-specific documentation is being moved into Documentation/arch/
as a way of cleaning up the top-level documentation directory and making
the docs hierarchy more closely match the source hierarchy.
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230725043835.2249678-1-costa.shul@redhat.com
Diffstat (limited to 'Documentation/mips/ingenic-tcu.rst')
-rw-r--r-- | Documentation/mips/ingenic-tcu.rst | 71 |
1 files changed, 0 insertions, 71 deletions
diff --git a/Documentation/mips/ingenic-tcu.rst b/Documentation/mips/ingenic-tcu.rst deleted file mode 100644 index 2ce4cb1314dc..000000000000 --- a/Documentation/mips/ingenic-tcu.rst +++ /dev/null @@ -1,71 +0,0 @@ -.. SPDX-License-Identifier: GPL-2.0 - -=============================================== -Ingenic JZ47xx SoCs Timer/Counter Unit hardware -=============================================== - -The Timer/Counter Unit (TCU) in Ingenic JZ47xx SoCs is a multi-function -hardware block. It features up to eight channels, that can be used as -counters, timers, or PWM. - -- JZ4725B, JZ4750, JZ4755 only have six TCU channels. The other SoCs all - have eight channels. - -- JZ4725B introduced a separate channel, called Operating System Timer - (OST). It is a 32-bit programmable timer. On JZ4760B and above, it is - 64-bit. - -- Each one of the TCU channels has its own clock, which can be reparented to three - different clocks (pclk, ext, rtc), gated, and reclocked, through their TCSR register. - - - The watchdog and OST hardware blocks also feature a TCSR register with the same - format in their register space. - - The TCU registers used to gate/ungate can also gate/ungate the watchdog and - OST clocks. - -- Each TCU channel works in one of two modes: - - - mode TCU1: channels cannot work in sleep mode, but are easier to - operate. - - mode TCU2: channels can work in sleep mode, but the operation is a bit - more complicated than with TCU1 channels. - -- The mode of each TCU channel depends on the SoC used: - - - On the oldest SoCs (up to JZ4740), all of the eight channels operate in - TCU1 mode. - - On JZ4725B, channel 5 operates as TCU2, the others operate as TCU1. - - On newest SoCs (JZ4750 and above), channels 1-2 operate as TCU2, the - others operate as TCU1. - -- Each channel can generate an interrupt. Some channels share an interrupt - line, some don't, and this changes between SoC versions: - - - on older SoCs (JZ4740 and below), channel 0 and channel 1 have their - own interrupt line; channels 2-7 share the last interrupt line. - - On JZ4725B, channel 0 has its own interrupt; channels 1-5 share one - interrupt line; the OST uses the last interrupt line. - - on newer SoCs (JZ4750 and above), channel 5 has its own interrupt; - channels 0-4 and (if eight channels) 6-7 all share one interrupt line; - the OST uses the last interrupt line. - -Implementation -============== - -The functionalities of the TCU hardware are spread across multiple drivers: - -=========== ===== -clocks drivers/clk/ingenic/tcu.c -interrupts drivers/irqchip/irq-ingenic-tcu.c -timers drivers/clocksource/ingenic-timer.c -OST drivers/clocksource/ingenic-ost.c -PWM drivers/pwm/pwm-jz4740.c -watchdog drivers/watchdog/jz4740_wdt.c -=========== ===== - -Because various functionalities of the TCU that belong to different drivers -and frameworks can be controlled from the same registers, all of these -drivers access their registers through the same regmap. - -For more information regarding the devicetree bindings of the TCU drivers, -have a look at Documentation/devicetree/bindings/timer/ingenic,tcu.yaml. |