1 .. SPDX-License-Identifier: GPL-2.0
2
3 ==============================================
4 Ingenic JZ47xx SoCs Timer/Counter Unit hardwar
5 ==============================================
6
7 The Timer/Counter Unit (TCU) in Ingenic JZ47xx
8 hardware block. It features up to eight channe
9 counters, timers, or PWM.
10
11 - JZ4725B, JZ4750, JZ4755 only have six TCU ch
12 have eight channels.
13
14 - JZ4725B introduced a separate channel, calle
15 (OST). It is a 32-bit programmable timer. On
16 64-bit.
17
18 - Each one of the TCU channels has its own clo
19 different clocks (pclk, ext, rtc), gated, an
20
21 - The watchdog and OST hardware blocks als
22 format in their register space.
23 - The TCU registers used to gate/ungate ca
24 OST clocks.
25
26 - Each TCU channel works in one of two modes:
27
28 - mode TCU1: channels cannot work in sleep
29 operate.
30 - mode TCU2: channels can work in sleep mo
31 more complicated than with TCU1 channels
32
33 - The mode of each TCU channel depends on the
34
35 - On the oldest SoCs (up to JZ4740), all o
36 TCU1 mode.
37 - On JZ4725B, channel 5 operates as TCU2,
38 - On newest SoCs (JZ4750 and above), chann
39 others operate as TCU1.
40
41 - Each channel can generate an interrupt. Some
42 line, some don't, and this changes between S
43
44 - on older SoCs (JZ4740 and below), channe
45 own interrupt line; channels 2-7 share t
46 - On JZ4725B, channel 0 has its own interr
47 interrupt line; the OST uses the last in
48 - on newer SoCs (JZ4750 and above), channe
49 channels 0-4 and (if eight channels) 6-7
50 the OST uses the last interrupt line.
51
52 Implementation
53 ==============
54
55 The functionalities of the TCU hardware are sp
56
57 =========== =====
58 clocks drivers/clk/ingenic/tcu.c
59 interrupts drivers/irqchip/irq-ingenic-tcu.c
60 timers drivers/clocksource/ingenic-timer
61 OST drivers/clocksource/ingenic-ost.c
62 PWM drivers/pwm/pwm-jz4740.c
63 watchdog drivers/watchdog/jz4740_wdt.c
64 =========== =====
65
66 Because various functionalities of the TCU tha
67 and frameworks can be controlled from the same
68 drivers access their registers through the sam
69
70 For more information regarding the devicetree
71 have a look at Documentation/devicetree/bindin
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