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

Wei-Cheng Chen
2026-03-04T10:27:08Z

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 {
--
2.43.0