Re: [PATCH] phy: tegra: xusb: Fix per-pad high-speed termination calibration

Jon Hunter
2026-04-17T08:23:24Z

Hi Vinod,

On 24/03/2026 09:11, Jon Hunter wrote:
>
> On 04/03/2026 10:26, Wei-Cheng Chen wrote:
>> From: Wayne Chang <waynec@nvidia.com>
>>
>> The existing code reads a single hs_term_range_adj value from bit field
>> [10:7] of FUSE_SKU_CALIB_0 and applies it to all USB2 pads uniformly.
>> However, on SoCs that support per-pad termination, each pad has its own
>> hs_term_range_adj field: pad 0 in FUSE_SKU_CALIB_0[10:7], and pads 1-3
>> in FUSE_USB_CALIB_EXT_0 at bit offsets [8:5], [12:9], and [16:13]
>> respectively.
>>
>> Fix the calibration by reading per-pad values from the appropriate fuse
>> registers. For SoCs that do not support per-pad termination, replicate
>> pad 0's value to all pads to maintain existing behavior.
>>
>> Add a has_per_pad_term flag to the SoC data to indicate whether per-pad
>> termination values are available in FUSE_USB_CALIB_EXT_0.
>>
>> Fixes: 1ef535c6ba8e ("phy: tegra: xusb: Add Tegra194 support")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Wayne Chang <waynec@nvidia.com>
>> Signed-off-by: Wei-Cheng Chen <weichengc@nvidia.com>
>> ---
>>   drivers/phy/tegra/xusb-tegra186.c | 33 ++++++++++++++++++++++++-------
>>   drivers/phy/tegra/xusb.h          |  1 +
>>   2 files changed, 27 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/phy/tegra/xusb-tegra186.c b/drivers/phy/tegra/
>> xusb-tegra186.c
>> index bec9616c4a2..4452e73fb82 100644
>> --- a/drivers/phy/tegra/xusb-tegra186.c
>> +++ b/drivers/phy/tegra/xusb-tegra186.c
>> @@ -20,8 +20,8 @@
>>   /* FUSE USB_CALIB registers */
>>   #define HS_CURR_LEVEL_PADX_SHIFT(x)    ((x) ? (11 + (x - 1) * 6) : 0)
>>   #define HS_CURR_LEVEL_PAD_MASK        0x3f
>> -#define HS_TERM_RANGE_ADJ_SHIFT        7
>> -#define HS_TERM_RANGE_ADJ_MASK        0xf
>> +#define HS_TERM_RANGE_ADJ_PADX_SHIFT(x)    ((x) ? (5 + (x - 1) * 4) : 7)
>> +#define HS_TERM_RANGE_ADJ_PAD_MASK    0xf
>>   #define HS_SQUELCH_SHIFT        29
>>   #define HS_SQUELCH_MASK            0x7
>> @@ -253,7 +253,7 @@
>>   struct tegra_xusb_fuse_calibration {
>>       u32 *hs_curr_level;
>>       u32 hs_squelch;
>> -    u32 hs_term_range_adj;
>> +    u32 *hs_term_range_adj;
>>       u32 rpd_ctrl;
>>   };
>> @@ -930,7 +930,7 @@ static int tegra186_utmi_phy_power_on(struct phy
>> *phy)
>>       value = padctl_readl(padctl,
>> XUSB_PADCTL_USB2_OTG_PADX_CTL1(index));
>>       value &= ~TERM_RANGE_ADJ(~0);
>> -    value |= TERM_RANGE_ADJ(priv->calib.hs_term_range_adj);
>> +    value |= TERM_RANGE_ADJ(priv->calib.hs_term_range_adj[index]);
>>       value &= ~RPD_CTRL(~0);
>>       value |= RPD_CTRL(priv->calib.rpd_ctrl);
>>       padctl_writel(padctl, value,
>> XUSB_PADCTL_USB2_OTG_PADX_CTL1(index));
>> @@ -1464,17 +1464,23 @@ static const char * const
>> tegra186_usb3_functions[] = {
>>   static int
>>   tegra186_xusb_read_fuse_calibration(struct tegra186_xusb_padctl
>> *padctl)
>>   {
>> +    const struct tegra_xusb_padctl_soc *soc = padctl->base.soc;
>>       struct device *dev = padctl->base.dev;
>>       unsigned int i, count;
>>       u32 value, *level;
>> +    u32 *hs_term_range_adj;
>>       int err;
>> -    count = padctl->base.soc->ports.usb2.count;
>> +    count = soc->ports.usb2.count;
>>       level = devm_kcalloc(dev, count, sizeof(u32), GFP_KERNEL);
>>       if (!level)
>>           return -ENOMEM;
>> +    hs_term_range_adj = devm_kcalloc(dev, count, sizeof(u32),
>> GFP_KERNEL);
>> +    if (!hs_term_range_adj)
>> +        return -ENOMEM;
>> +
>>       err = tegra_fuse_readl(TEGRA_FUSE_SKU_CALIB_0, &value);
>>       if (err)
>>           return dev_err_probe(dev, err,
>> @@ -1490,8 +1496,8 @@ tegra186_xusb_read_fuse_calibration(struct
>> tegra186_xusb_padctl *padctl)
>>       padctl->calib.hs_squelch = (value >> HS_SQUELCH_SHIFT) &
>>                       HS_SQUELCH_MASK;
>> -    padctl->calib.hs_term_range_adj = (value >>
>> HS_TERM_RANGE_ADJ_SHIFT) &
>> -                        HS_TERM_RANGE_ADJ_MASK;
>> +    hs_term_range_adj[0] = (value >> HS_TERM_RANGE_ADJ_PADX_SHIFT(0)) &
>> +                HS_TERM_RANGE_ADJ_PAD_MASK;
>>       err = tegra_fuse_readl(TEGRA_FUSE_USB_CALIB_EXT_0, &value);
>>       if (err) {
>> @@ -1503,6 +1509,17 @@ tegra186_xusb_read_fuse_calibration(struct
>> tegra186_xusb_padctl *padctl)
>>       padctl->calib.rpd_ctrl = (value >> RPD_CTRL_SHIFT) & RPD_CTRL_MASK;
>> +    for (i = 1; i < count; i++) {
>> +        if (soc->has_per_pad_term)
>> +            hs_term_range_adj[i] =
>> +                (value >> HS_TERM_RANGE_ADJ_PADX_SHIFT(i)) &
>> +                HS_TERM_RANGE_ADJ_PAD_MASK;
>> +        else
>> +            hs_term_range_adj[i] = hs_term_range_adj[0];
>> +    }
>> +
>> +    padctl->calib.hs_term_range_adj = hs_term_range_adj;
>> +
>>       return 0;
>>   }
>> @@ -1708,6 +1725,7 @@ const struct tegra_xusb_padctl_soc
>> tegra194_xusb_padctl_soc = {
>>       .num_supplies = ARRAY_SIZE(tegra194_xusb_padctl_supply_names),
>>       .supports_gen2 = true,
>>       .poll_trk_completed = true,
>> +    .has_per_pad_term = true,
>>   };
>>   EXPORT_SYMBOL_GPL(tegra194_xusb_padctl_soc);
>> @@ -1732,6 +1750,7 @@ const struct tegra_xusb_padctl_soc
>> tegra234_xusb_padctl_soc = {
>>       .trk_hw_mode = false,
>>       .trk_update_on_idle = true,
>>       .supports_lp_cfg_en = true,
>> +    .has_per_pad_term = true,
>>   };
>>   EXPORT_SYMBOL_GPL(tegra234_xusb_padctl_soc);
>>   #endif
>> diff --git a/drivers/phy/tegra/xusb.h b/drivers/phy/tegra/xusb.h
>> index d2b5f956513..810b410672f 100644
>> --- a/drivers/phy/tegra/xusb.h
>> +++ b/drivers/phy/tegra/xusb.h
>> @@ -436,6 +436,7 @@ struct tegra_xusb_padctl_soc {
>>       bool trk_hw_mode;
>>       bool trk_update_on_idle;
>>       bool supports_lp_cfg_en;
>> +    bool has_per_pad_term;
>>   };
>>   struct tegra_xusb_padctl {
>
> Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
> Tested-by: Jon Hunter <jonathanh@nvidia.com>

I guess this was missed for Linux v7.1. If you don't have any concerns
can you pick this up for v7.2 once v7.1-rc1 is out?

Thanks!
Jon

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nvpublic