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97689a1a3f
Add documentation about the Timer/Counter Unit (TCU) present in the
Ingenic JZ47xx SoCs.
The Timer/Counter Unit (TCU) in Ingenic JZ47xx SoCs is a multi-function
hardware block. It features up to 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 JZ4770 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.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Mathieu Malaterre <malat@debian.org>
Tested-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: linux-clk@vger.kernel.org
Cc: od@zcrc.me
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| .. | ||
| ABI | ||
| accounting | ||
| acpi/dsd | ||
| admin-guide | ||
| arm | ||
| arm64 | ||
| auxdisplay | ||
| block | ||
| bpf | ||
| cdrom | ||
| core-api | ||
| cpu-freq | ||
| crypto | ||
| dev-tools | ||
| devicetree | ||
| doc-guide | ||
| driver-api | ||
| EDID | ||
| fault-injection | ||
| fb | ||
| features | ||
| filesystems | ||
| firmware_class | ||
| firmware-guide | ||
| fpga | ||
| gpu | ||
| hid | ||
| hwmon | ||
| i2c | ||
| ia64 | ||
| ide | ||
| iio | ||
| infiniband | ||
| input | ||
| ioctl | ||
| isdn | ||
| kbuild | ||
| kernel-hacking | ||
| leds | ||
| livepatch | ||
| locking | ||
| m68k | ||
| maintainer | ||
| media | ||
| mic | ||
| mips | ||
| misc-devices | ||
| netlabel | ||
| networking | ||
| nios2 | ||
| openrisc | ||
| parisc | ||
| PCI | ||
| pcmcia | ||
| power | ||
| powerpc | ||
| process | ||
| RCU | ||
| riscv | ||
| s390 | ||
| scheduler | ||
| scsi | ||
| security | ||
| sh | ||
| sound | ||
| sparc | ||
| sphinx | ||
| sphinx-static | ||
| spi | ||
| target | ||
| thermal | ||
| timers | ||
| trace | ||
| translations | ||
| usb | ||
| userspace-api | ||
| virtual | ||
| vm | ||
| w1 | ||
| watchdog | ||
| wimax | ||
| x86 | ||
| xtensa | ||
| .gitignore | ||
| atomic_bitops.txt | ||
| atomic_t.txt | ||
| bus-virt-phys-mapping.txt | ||
| Changes | ||
| CodingStyle | ||
| conf.py | ||
| COPYING-logo | ||
| crc32.txt | ||
| debugging-modules.txt | ||
| debugging-via-ohci1394.txt | ||
| digsig.txt | ||
| DMA-API-HOWTO.txt | ||
| DMA-API.txt | ||
| DMA-attributes.txt | ||
| DMA-ISA-LPC.txt | ||
| docutils.conf | ||
| dontdiff | ||
| futex-requeue-pi.txt | ||
| hwspinlock.txt | ||
| index.rst | ||
| io_ordering.txt | ||
| io-mapping.txt | ||
| IPMI.txt | ||
| IRQ-affinity.txt | ||
| IRQ-domain.txt | ||
| IRQ.txt | ||
| irqflags-tracing.txt | ||
| Kconfig | ||
| kobject.txt | ||
| kprobes.txt | ||
| kref.txt | ||
| logo.gif | ||
| lzo.txt | ||
| mailbox.txt | ||
| Makefile | ||
| memory-barriers.txt | ||
| nommu-mmap.txt | ||
| packing.txt | ||
| padata.txt | ||
| percpu-rw-semaphore.txt | ||
| pi-futex.txt | ||
| preempt-locking.txt | ||
| rbtree.txt | ||
| remoteproc.txt | ||
| robust-futex-ABI.txt | ||
| robust-futexes.txt | ||
| rpmsg.txt | ||
| speculation.txt | ||
| static-keys.txt | ||
| SubmittingPatches | ||
| tee.txt | ||
| this_cpu_ops.txt | ||
| unaligned-memory-access.txt | ||
| xz.txt | ||
