From: Kevin Hilman <khilman@kernel.org>
To: Tony Lindgren <tony@atomide.com>
Cc: Nishanth Menon <nm@ti.com>, Vignesh Raghavendra <vigneshr@ti.com>,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
Dhruva Gole <d-gole@ti.com>
Subject: Re: [PATCH v2 1/1] arm64: dts: ti: k3-am62-wakeup: Configure ti-sysc for wkup_uart0
Date: Fri, 08 Dec 2023 09:13:43 -0800 [thread overview]
Message-ID: <7hedfwd3co.fsf@baylibre.com> (raw)
In-Reply-To: <20231207060854.GQ5169@atomide.com>
Tony Lindgren <tony@atomide.com> writes:
> * Kevin Hilman <khilman@kernel.org> [231205 18:14]:
>> I'm a little confused why these power-domain and clocks stay here and
>> are not moved under the wkup_uart0 node...
>
> The resources are also needed by the interconnect target module. It's the
> wrapper IP for the child device(s). In this case there's one chip 8250 IP
> instance. In some other devices there can be multiple child IP devices
> wired to one target module.
>
>> > - clock-names = "fclk";
>> > - status = "disabled";
>> > + clock-names = "fck";
>> > + #address-cells = <1>;
>> > + #size-cells = <1>;
>> > + ranges = <0 0 0x2b300000 0x100000>;
>> > +
>> > + wkup_uart0: serial@2b300000 {
>> > + compatible = "ti,am64-uart", "ti,am654-uart";
>> > + reg = <0 0x100>;
>> > + interrupts = <GIC_SPI 186 IRQ_TYPE_LEVEL_HIGH>;
>> > + status = "disabled";
>>
>> ...here.
>>
>> The SCI device ID 114 is specifically for wkup_uart0[1], so it seems to
>> me those should be in the wkup_uart0 node.
>
> Those resources are also needed for the parent target module for revision
> detection, quirks, reset, idle register configuration, and to probe the
> child devices.
>
> Here the 8250 IP can be set to status = "reserved" when used by the
> firmware, and 8250 not touched by Linux. However, the parent interconnect
> target module still needs to be configured for idle registers and wake-up
> path register bit so the wake-up from deeper suspend states works.
OK, makes sense. Thanks for the clarification.
In that case, shouldn't the same be done for the other wakeup sources
there (e.g. wkup_rtc0) ?
Kevin
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next prev parent reply other threads:[~2023-12-08 17:14 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-14 7:32 [PATCH v2 1/1] arm64: dts: ti: k3-am62-wakeup: Configure ti-sysc for wkup_uart0 Tony Lindgren
2023-12-05 18:13 ` Kevin Hilman
2023-12-07 6:08 ` Tony Lindgren
2023-12-08 17:13 ` Kevin Hilman [this message]
2023-12-09 3:59 ` Tony Lindgren
2023-12-13 15:41 ` Kevin Hilman
2023-12-15 16:00 ` Nishanth Menon
2023-12-18 7:28 ` Tony Lindgren
2023-12-18 16:19 ` Nishanth Menon
2023-12-19 7:06 ` Tony Lindgren
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