linux-kernel - [PATCH 1/3] usb: typec: ps883x: Cache register settings, not Type-C mode

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Message-Id: <20251014-topic-ps883x_usb4-v1-1-e6adb1a4296e@oss.qualcomm.com>
Date: Tue, 14 Oct 2025 18:06:45 +0200
From: Konrad Dybcio <konradybcio@...nel.org>
To: Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>, 
 Bjorn Andersson <bjorn.andersson@....qualcomm.com>, 
 Wesley Cheng <wesley.cheng@....qualcomm.com>, 
 Jack Pham <jack.pham@....qualcomm.com>, 
 Raghavendra Thoorpu <rthoorpu@....qualcomm.com>, linux-usb@...r.kernel.org, 
 linux-kernel@...r.kernel.org, 
 Konrad Dybcio <konrad.dybcio@....qualcomm.com>
Subject: [PATCH 1/3] usb: typec: ps883x: Cache register settings, not
 Type-C mode

From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>

Certain Type-C mode configurations may result in identical settings of
the PS8830. Check if the latter have changed instead of assuming
there's always a difference.

ps883x_set() is changed to accept a typec_retimer_state in preparation
for more work and the ps883x_sw_set() (which only handles orientation
switching) is changed to use regmap_assign_bits(), which itself does
not perform any writes if the desired value is already set.

Reviewed-by: Jack Pham <jack.pham@....qualcomm.com>
Signed-off-by: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
---
 drivers/usb/typec/mux/ps883x.c | 41 ++++++++++++++++++++++-------------------
 1 file changed, 22 insertions(+), 19 deletions(-)

diff --git a/drivers/usb/typec/mux/ps883x.c b/drivers/usb/typec/mux/ps883x.c
index ad59babf7cce..68f172df7be3 100644
--- a/drivers/usb/typec/mux/ps883x.c
+++ b/drivers/usb/typec/mux/ps883x.c
@@ -54,8 +54,9 @@ struct ps883x_retimer {
 	struct mutex lock; /* protect non-concurrent retimer & switch */
 
 	enum typec_orientation orientation;
-	unsigned long mode;
-	unsigned int svid;
+	u8 cfg0;
+	u8 cfg1;
+	u8 cfg2;
 };
 
 static int ps883x_configure(struct ps883x_retimer *retimer, int cfg0,
@@ -64,6 +65,9 @@ static int ps883x_configure(struct ps883x_retimer *retimer, int cfg0,
 	struct device *dev = &retimer->client->dev;
 	int ret;
 
+	if (retimer->cfg0 == cfg0 && retimer->cfg1 == cfg1 && retimer->cfg2 == cfg2)
+		return 0;
+
 	ret = regmap_write(retimer->regmap, REG_USB_PORT_CONN_STATUS_0, cfg0);
 	if (ret) {
 		dev_err(dev, "failed to write conn_status_0: %d\n", ret);
@@ -82,27 +86,31 @@ static int ps883x_configure(struct ps883x_retimer *retimer, int cfg0,
 		return ret;
 	}
 
+	retimer->cfg0 = cfg0;
+	retimer->cfg1 = cfg1;
+	retimer->cfg2 = cfg2;
+
 	return 0;
 }
 
-static int ps883x_set(struct ps883x_retimer *retimer)
+static int ps883x_set(struct ps883x_retimer *retimer, struct typec_retimer_state *state)
 {
 	int cfg0 = CONN_STATUS_0_CONNECTION_PRESENT;
 	int cfg1 = 0x00;
 	int cfg2 = 0x00;
 
 	if (retimer->orientation == TYPEC_ORIENTATION_NONE ||
-	    retimer->mode == TYPEC_STATE_SAFE) {
+	    state->mode == TYPEC_STATE_SAFE) {
 		return ps883x_configure(retimer, cfg0, cfg1, cfg2);
 	}
 
-	if (retimer->mode != TYPEC_STATE_USB && retimer->svid != USB_TYPEC_DP_SID)
+	if (state->alt && state->alt->svid != USB_TYPEC_DP_SID)
 		return -EINVAL;
 
 	if (retimer->orientation == TYPEC_ORIENTATION_REVERSE)
 		cfg0 |= CONN_STATUS_0_ORIENTATION_REVERSED;
 
-	switch (retimer->mode) {
+	switch (state->mode) {
 	case TYPEC_STATE_USB:
 		cfg0 |= CONN_STATUS_0_USB_3_1_CONNECTED;
 		break;
@@ -149,7 +157,13 @@ static int ps883x_sw_set(struct typec_switch_dev *sw,
 	if (retimer->orientation != orientation) {
 		retimer->orientation = orientation;
 
-		ret = ps883x_set(retimer);
+		ret = regmap_assign_bits(retimer->regmap, REG_USB_PORT_CONN_STATUS_0,
+					 CONN_STATUS_0_ORIENTATION_REVERSED,
+					 orientation == TYPEC_ORIENTATION_REVERSE);
+		if (ret) {
+			dev_err(&retimer->client->dev, "failed to set orientation: %d\n", ret);
+			return ret;
+		}
 	}
 
 	mutex_unlock(&retimer->lock);
@@ -165,18 +179,7 @@ static int ps883x_retimer_set(struct typec_retimer *rtmr,
 	int ret = 0;
 
 	mutex_lock(&retimer->lock);
-
-	if (state->mode != retimer->mode) {
-		retimer->mode = state->mode;
-
-		if (state->alt)
-			retimer->svid = state->alt->svid;
-		else
-			retimer->svid = 0;
-
-		ret = ps883x_set(retimer);
-	}
-
+	ret = ps883x_set(retimer, state);
 	mutex_unlock(&retimer->lock);
 
 	if (ret)

-- 
2.51.0