linux-kernel - Re: [PATCH v7 14/19] phy: sun4i-usb: Introduce port2 SIDDQ quirk

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Date:   Mon, 21 Jun 2021 10:06:31 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     Andre Przywara <andre.przywara@....com>
Cc:     Maxime Ripard <mripard@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Rob Herring <robh@...nel.org>, Icenowy Zheng <icenowy@...c.io>,
        Samuel Holland <samuel@...lland.org>,
        linux-arm-kernel@...ts.infradead.org, linux-sunxi@...glegroups.com,
        linux-sunxi@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Ondrej Jirman <megous@...ous.com>,
        Kishon Vijay Abraham I <kishon@...com>,
        linux-phy@...ts.infradead.org, linux-usb@...r.kernel.org
Subject: Re: [PATCH v7 14/19] phy: sun4i-usb: Introduce port2 SIDDQ quirk

On 15-06-21, 12:06, Andre Przywara wrote:
> At least the Allwinner H616 SoC requires a weird quirk to make most
> USB PHYs work: Only port2 works out of the box, but all other ports
> need some help from this port2 to work correctly: The CLK_BUS_PHY2 and
> RST_USB_PHY2 clock and reset need to be enabled, and the SIDDQ bit in
> the PMU PHY control register needs to be cleared. For this register to
> be accessible, CLK_BUS_ECHI2 needs to be ungated. Don't ask ....
> 
> Instead of disguising this as some generic feature, do exactly that
> in our PHY init:
> If the quirk bit is set, and we initialise a PHY other than PHY2, ungate
> this one special clock, and clear the SIDDQ bit. We can pull in the
> other required clocks via the DT.
> 
> Signed-off-by: Andre Przywara <andre.przywara@....com>
> ---
>  drivers/phy/allwinner/phy-sun4i-usb.c | 59 +++++++++++++++++++++++++++
>  1 file changed, 59 insertions(+)
> 
> diff --git a/drivers/phy/allwinner/phy-sun4i-usb.c b/drivers/phy/allwinner/phy-sun4i-usb.c
> index 126ef74d013c..316ef5fca831 100644
> --- a/drivers/phy/allwinner/phy-sun4i-usb.c
> +++ b/drivers/phy/allwinner/phy-sun4i-usb.c
> @@ -120,6 +120,7 @@ struct sun4i_usb_phy_cfg {
>  	u8 phyctl_offset;
>  	bool dedicated_clocks;
>  	bool phy0_dual_route;
> +	bool needs_phy2_siddq;
>  	int missing_phys;
>  };
>  
> @@ -289,6 +290,50 @@ static int sun4i_usb_phy_init(struct phy *_phy)
>  		return ret;
>  	}
>  
> +	/* Some PHYs on some SoCs need the help of PHY2 to work. */
> +	if (data->cfg->needs_phy2_siddq && phy->index != 2) {
> +		struct sun4i_usb_phy *phy2 = &data->phys[2];
> +
> +		ret = clk_prepare_enable(phy2->clk);
> +		if (ret) {
> +			reset_control_assert(phy->reset);
> +			clk_disable_unprepare(phy->clk2);
> +			clk_disable_unprepare(phy->clk);
> +			return ret;
> +		}
> +
> +		ret = reset_control_deassert(phy2->reset);
> +		if (ret) {
> +			clk_disable_unprepare(phy2->clk);
> +			reset_control_assert(phy->reset);
> +			clk_disable_unprepare(phy->clk2);
> +			clk_disable_unprepare(phy->clk);
> +			return ret;
> +		}

no delay between deassert and assert... ?


-- 
~Vinod