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References: <20210119085546.725005-1-jckuo@nvidia.com> <20210119085546.725005-2-jckuo@nvidia.com>
Subject: Re: [PATCH v6 01/15] clk: tegra: Add PLLE HW power sequencer control
From:   Stephen Boyd <sboyd@kernel.org>
Cc:     linux-tegra@vger.kernel.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        nkristam@nvidia.com, JC Kuo <jckuo@nvidia.com>,
        Thierry Reding <treding@nvidia.com>
To:     JC Kuo <jckuo@nvidia.com>, gregkh@linuxfoundation.org,
        jonathanh@nvidia.com, kishon@ti.com, robh@kernel.org,
        thierry.reding@gmail.com
Date:   Wed, 10 Feb 2021 19:06:25 -0800
Message-ID: <161301278546.1254594.2076696450962679318@swboyd.mtv.corp.google.com>
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Quoting JC Kuo (2021-01-19 00:55:32)
> PLLE has a hardware power sequencer logic which is a state machine
> that can power on/off PLLE without any software intervention. The
> sequencer has two inputs, one from XUSB UPHY PLL and the other from
> SATA UPHY PLL. PLLE provides reference clock to XUSB and SATA UPHY
> PLLs. When both of the downstream PLLs are powered-off, PLLE hardware
> power sequencer will automatically power off PLLE for power saving.
>=20
> XUSB and SATA UPHY PLLs also have their own hardware power sequencer
> logic. XUSB UPHY PLL is shared between XUSB SuperSpeed ports and PCIE
> controllers. The XUSB UPHY PLL hardware power sequencer has inputs
> from XUSB and PCIE. When all of the XUSB SuperSpeed ports and PCIE
> controllers are in low power state, XUSB UPHY PLL hardware power
> sequencer automatically power off PLL and flags idle to PLLE hardware
> power sequencer. Similar applies to SATA UPHY PLL.
>=20
> PLLE hardware power sequencer has to be enabled after both downstream
> sequencers are enabled.
>=20
> This commit adds two helper functions:
> 1. tegra210_plle_hw_sequence_start() for XUSB PADCTL driver to enable
>    PLLE hardware sequencer at proper time.
>=20
> 2. tegra210_plle_hw_sequence_is_enabled() for XUSB PADCTL driver to
>    check whether PLLE hardware sequencer has been enabled or not.
>=20
> Signed-off-by: JC Kuo <jckuo@nvidia.com>
> Acked-by: Thierry Reding <treding@nvidia.com>
> ---

Acked-by: Stephen Boyd <sboyd@kernel.org>