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Date:   Fri, 28 Oct 2022 17:12:10 +0530
From:   Vinod Koul <vkoul@kernel.org>
To:     Vidya Sagar <vidyas@nvidia.com>
Cc:     lpieralisi@kernel.org, robh@kernel.org, kw@linux.com,
        bhelgaas@google.com, thierry.reding@gmail.com,
        jonathanh@nvidia.com, kishon@ti.com, mani@kernel.org,
        Sergey.Semin@baikalelectronics.ru, ffclaire1224@gmail.com,
        linux-pci@vger.kernel.org, linux-tegra@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org,
        kthota@nvidia.com, mmaddireddy@nvidia.com, sagar.tv@gmail.com
Subject: Re: [PATCH V3 08/21] phy: tegra: p2u: Set ENABLE_L2_EXIT_RATE_CHANGE
 in calibration
Message-ID: <Y1vAEh3NRiB5mrM7@matsya>
References: <20221013183854.21087-1-vidyas@nvidia.com>
 <20221013183854.21087-9-vidyas@nvidia.com>
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On 14-10-22, 00:08, Vidya Sagar wrote:
> Set ENABLE_L2_EXIT_RATE_CHANGE register bit to request UPHY PLL rate change
> to Gen1 during initialization. This helps in the below surprise link down
> cases,
>   - Surprise link down happens at Gen3/Gen4 link speed.
>   - Surprise link down happens and external REFCLK is cut off, which causes
> UPHY PLL rate to deviate to an invalid rate.

This looks okay to me and I can go ahead and apply, PCI patches can come
thru PCI tree and whenever ready use .calibrate() ?

> 
> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
> ---
> V3:
> * Removed "Reported-by: kernel test robot <lkp@intel.com>" based on Bjorn's review comment
> * Reworded the commit message
> 
> V2:
> * Addressed review comment from test bot and Vinod
> 
>  drivers/phy/tegra/phy-tegra194-p2u.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/phy/tegra/phy-tegra194-p2u.c b/drivers/phy/tegra/phy-tegra194-p2u.c
> index 1415ca71de38..633e6b747275 100644
> --- a/drivers/phy/tegra/phy-tegra194-p2u.c
> +++ b/drivers/phy/tegra/phy-tegra194-p2u.c
> @@ -15,6 +15,7 @@
>  #include <linux/phy/phy.h>
>  
>  #define P2U_CONTROL_CMN			0x74
> +#define P2U_CONTROL_CMN_ENABLE_L2_EXIT_RATE_CHANGE		BIT(13)
>  #define P2U_CONTROL_CMN_SKP_SIZE_PROTECTION_EN			BIT(20)
>  
>  #define P2U_PERIODIC_EQ_CTRL_GEN3	0xc0
> @@ -85,8 +86,21 @@ static int tegra_p2u_power_on(struct phy *x)
>  	return 0;
>  }
>  
> +static int tegra_p2u_calibrate(struct phy *x)
> +{
> +	struct tegra_p2u *phy = phy_get_drvdata(x);
> +	u32 val;
> +
> +	val = p2u_readl(phy, P2U_CONTROL_CMN);
> +	val |= P2U_CONTROL_CMN_ENABLE_L2_EXIT_RATE_CHANGE;
> +	p2u_writel(phy, val, P2U_CONTROL_CMN);
> +
> +	return 0;
> +}
> +
>  static const struct phy_ops ops = {
>  	.power_on = tegra_p2u_power_on,
> +	.calibrate = tegra_p2u_calibrate,
>  	.owner = THIS_MODULE,
>  };
>  
> -- 
> 2.17.1

-- 
~Vinod