Re: [PATCH V1 8/9] phy: tegra: p2u: Set ENABLE_L2_EXIT_RATE_CHANGE in calibration

From: Vinod Koul
Date: Tue Sep 20 2022 - 02:11:55 EST


On 19-09-22, 20:06, Vidya Sagar wrote:
> Set ENABLE_L2_EXIT_RATE_CHANGE to request UPHY PLL rate change to Gen1
> during initialization. This helps in the below surprise down cases,
> - Surprise down happens at Gen3/Gen4 link speed
> - Surprise down happens and external REFCLK is cut off which causes
> UPHY PLL rate to deviate to an invalid rate
>
> ENABLE_L2_EXIT_RATE_CHANGE needs to be set to bring the UPHY PLL rate
> back to Gen1 during controller initialization for the link up.
>
> Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
> ---
> 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..fb710e89acac 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;
> }
>
> +int tegra_p2u_calibrate(struct phy *x)

why not static?

> +{
> + 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