[Linux-stm32] [PATCH v2 2/2] usb: typec: mux: gpio-sbu: enable when only used for orientation

[Fabrice Gasnier]

When used as orientation-switch only (no mode-switch, e.g. no altmode),
the optional enable gpio remains disabled.
Enable it from the switch_set() routine, in this case, when the
orientation is set and the enable-gpios property has been provided.
Move enable GPIO configuration after the swapped configuration has
been done, to avoid possible glitches in case both signals are changed.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier at foss.st.com>
---
Changes in v2
- fix issues reported by Sashiko: probe mode-switch property before
  registering Type-C switch, to avoid possible race. Configure enable
  GPIO after swapp GPIO has been configured, in case both transition.
---
 drivers/usb/typec/mux/gpio-sbu-mux.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/typec/mux/gpio-sbu-mux.c b/drivers/usb/typec/mux/gpio-sbu-mux.c
index 1834f1a2dd9d..120f1ab5dbcb 100644
--- a/drivers/usb/typec/mux/gpio-sbu-mux.c
+++ b/drivers/usb/typec/mux/gpio-sbu-mux.c
@@ -17,6 +17,7 @@ struct gpio_sbu_mux {
 
 	struct typec_switch_dev *sw;
 	struct typec_mux_dev *mux;
+	bool mode_switch;
 
 	struct mutex lock; /* protect enabled and swapped */
 	bool enabled;
@@ -40,19 +41,24 @@ static int gpio_sbu_switch_set(struct typec_switch_dev *sw,
 		enabled = false;
 		break;
 	case TYPEC_ORIENTATION_NORMAL:
+		if (!sbu_mux->mode_switch)
+			enabled = true;
 		swapped = false;
 		break;
 	case TYPEC_ORIENTATION_REVERSE:
+		if (!sbu_mux->mode_switch)
+			enabled = true;
 		swapped = true;
 		break;
 	}
 
-	if (enabled != sbu_mux->enabled)
-		gpiod_set_value_cansleep(sbu_mux->enable_gpio, enabled);
-
 	if (swapped != sbu_mux->swapped)
 		gpiod_set_value_cansleep(sbu_mux->select_gpio, swapped);
 
+	/* If both enabled and swapped transition, set enable GPIO after to avoid glitches */
+	if (enabled != sbu_mux->enabled)
+		gpiod_set_value_cansleep(sbu_mux->enable_gpio, enabled);
+
 	sbu_mux->enabled = enabled;
 	sbu_mux->swapped = swapped;
 
@@ -125,6 +131,8 @@ static int gpio_sbu_mux_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, PTR_ERR(sbu_mux->sw),
 				     "failed to register typec switch\n");
 
+	sbu_mux->mode_switch = device_property_read_bool(dev, "mode-switch");
+
 	mux_desc.drvdata = sbu_mux;
 	mux_desc.fwnode = dev_fwnode(dev);
 	mux_desc.set = gpio_sbu_mux_set;

-- 
2.43.0