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From: Thierry Reding <thierry.reding@gmail.com>
To: JC Kuo <jckuo@nvidia.com>
Cc: gregkh@linuxfoundation.org, robh@kernel.org,
	jonathanh@nvidia.com, kishon@ti.com, linux-tegra@vger.kernel.org,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org, nkristam@nvidia.com
Subject: Re: [PATCH v3 04/15] phy: tegra: xusb: tegra210: Do not reset UPHY PLL
Date: Mon, 28 Sep 2020 15:06:18 +0200
Message-ID: <20200928130618.GE3065790@ulmo> (raw)
In-Reply-To: <20200909081041.3190157-5-jckuo@nvidia.com>


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On Wed, Sep 09, 2020 at 04:10:30PM +0800, JC Kuo wrote:
> Once UPHY PLL hardware power sequencer is enabled, do not assert
> reset to PEX/SATA PLLs, otherwise UPHY PLL operation will be broken.
> This commit removes reset_control_assert(pcie->rst) and
> reset_control_assert(sata->rst) from PEX/SATA UPHY disable procedure.
> 
> Signed-off-by: JC Kuo <jckuo@nvidia.com>
> ---
> v3:
>    new, was a part of "phy: tegra: xusb: Rearrange UPHY init on Tegra210"
> 
>  drivers/phy/tegra/xusb-tegra210.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/phy/tegra/xusb-tegra210.c b/drivers/phy/tegra/xusb-tegra210.c
> index f06e7bc7a51b..ef4bbcbed60b 100644
> --- a/drivers/phy/tegra/xusb-tegra210.c
> +++ b/drivers/phy/tegra/xusb-tegra210.c
> @@ -504,7 +504,6 @@ static void tegra210_pex_uphy_disable(struct tegra_xusb_padctl *padctl)
>  	if (--pcie->enable > 0)
>  		goto unlock;
>  
> -	reset_control_assert(pcie->rst);
>  	clk_disable_unprepare(pcie->pll);
>  
>  unlock:
> @@ -746,7 +745,6 @@ static void tegra210_sata_uphy_disable(struct tegra_xusb_padctl *padctl)
>  	if (--sata->enable > 0)
>  		goto unlock;
>  
> -	reset_control_assert(sata->rst);
>  	clk_disable_unprepare(sata->pll);
>  
>  unlock:

Does this mean that we can no longer reset these PLLs anymore? Is that
safe? Would we ever need to reset them for recovery or similar? For
power saving, is disabling the clock enough, or could we save some extra
power by putting the PLLs into reset?

Thierry

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  reply index

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-09  8:10 [PATCH v3 00/15] Tegra XHCI controller ELPG support JC Kuo
2020-09-09  8:10 ` [PATCH v3 01/15] clk: tegra: Add PLLE HW power sequencer control JC Kuo
2020-09-28 12:51   ` Thierry Reding
2020-09-09  8:10 ` [PATCH v3 02/15] clk: tegra: Don't enable PLLE HW sequencer at init JC Kuo
2020-09-28 12:52   ` Thierry Reding
2020-09-09  8:10 ` [PATCH v3 03/15] phy: tegra: xusb: Move usb3 port init for Tegra210 JC Kuo
2020-09-28 13:03   ` Thierry Reding
2020-09-09  8:10 ` [PATCH v3 04/15] phy: tegra: xusb: tegra210: Do not reset UPHY PLL JC Kuo
2020-09-28 13:06   ` Thierry Reding [this message]
2020-10-14  3:21     ` JC Kuo
2020-09-09  8:10 ` [PATCH v3 05/15] phy: tegra: xusb: Rearrange UPHY init on Tegra210 JC Kuo
2020-09-28 13:08   ` Thierry Reding
2020-09-09  8:10 ` [PATCH v3 06/15] phy: tegra: xusb: Add Tegra210 lane_iddq operation JC Kuo
2020-09-28 13:10   ` Thierry Reding
2020-09-09  8:10 ` [PATCH v3 07/15] phy: tegra: xusb: Add sleepwalk and suspend/resume JC Kuo
2020-09-28 13:11   ` Thierry Reding
2020-09-09  8:10 ` [PATCH v3 08/15] soc/tegra: pmc: Provide usb sleepwalk register map JC Kuo
2020-09-28 13:17   ` Thierry Reding
2020-10-14  4:08     ` JC Kuo
2020-09-09  8:10 ` [PATCH v3 09/15] arm64: tegra210: XUSB PADCTL add "nvidia,pmc" prop JC Kuo
2020-09-28 13:18   ` Thierry Reding
2020-10-14  4:15     ` JC Kuo
2020-09-09  8:10 ` [PATCH v3 10/15] phy: tegra: xusb: Add wake/sleepwalk for Tegra210 JC Kuo
2020-09-28 13:40   ` Thierry Reding
2020-10-14  8:37     ` JC Kuo
2020-09-09  8:10 ` [PATCH v3 11/15] phy: tegra: xusb: Tegra210 host mode VBUS control JC Kuo
2020-09-28 13:42   ` Thierry Reding
2020-09-09  8:10 ` [PATCH v3 12/15] phy: tegra: xusb: Add wake/sleepwalk for Tegra186 JC Kuo
2020-09-28 13:50   ` Thierry Reding
2020-10-15  8:08     ` JC Kuo
2020-09-09  8:10 ` [PATCH v3 13/15] arm64: tegra210/tegra186/tegra194: XUSB PADCTL irq JC Kuo
2020-09-09  8:10 ` [PATCH v3 14/15] usb: host: xhci-tegra: Unlink power domain devices JC Kuo
2020-09-28 13:53   ` Thierry Reding
2020-10-15  8:09     ` JC Kuo
2020-09-09  8:10 ` [PATCH v3 15/15] xhci: tegra: Enable ELPG for runtime/system PM JC Kuo
2020-09-28 14:06   ` Thierry Reding
2020-10-15  8:12     ` JC Kuo
2020-09-28 12:54 ` [PATCH v3 00/15] Tegra XHCI controller ELPG support Thierry Reding
2020-10-14  2:26   ` JC Kuo

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