driver/bluetooth/h4_ifx_cyw43xxx: Allow CBUCK regulator to discharge

Problem:
re-plug USB (e.g cy8cproto_062_4343w kit) can cause that
CY43xx device become unresponsive (cy8cproto_062_4343w).
As result we catch ASSERTION FAIL (timeout) on HCI_Reset command.

that BT CBUCK regulator to discharge.

Tested on:
cy8cproto_062_4343w, cy8ckit_062s2_ai and cy8ckit_062s2_43012 kits.

(cherry picked from commit 41c9ec3)

Original-Fix: added delay (BT_POWER_CBUCK_DISCHARGE_TIME_MS) to be sure
Original-Signed-off-by: Nazar Palamar <[email protected]>
GitOrigin-RevId: 41c9ec3
Change-Id: Ifae85657472fd7b437eef83df23b2e1d3bb917b6
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/5650214
Reviewed-by: Ting Shen <[email protected]>
Tested-by: ChromeOS Prod (Robot) <[email protected]>
Tested-by: Ting Shen <[email protected]>
Commit-Queue: Ting Shen <[email protected]>

Author: npal-cy

drivers/bluetooth/hci/h4_ifx_cyw43xxx.c

@@ -32,6 +32,7 @@ BUILD_ASSERT(DT_PROP(DT_INST_GPARENT(0), hw_flow_control) == 1,
 
 /* BT settling time after power on */
 #define BT_POWER_ON_SETTLING_TIME_MS      (500u)
+#define BT_POWER_CBUCK_DISCHARGE_TIME_MS  (300u)
 
 /* Stabilization delay after FW loading */
 #define BT_STABILIZATION_DELAY_MS         (250u)
@@ -230,12 +231,16 @@ int bt_h4_vnd_setup(const struct device *dev)
 	}
 
 	/* Configure bt_reg_on as output  */
-	err = gpio_pin_configure_dt(&bt_reg_on, GPIO_OUTPUT);
+	err = gpio_pin_configure_dt(&bt_reg_on, GPIO_OUTPUT_LOW);
 	if (err) {
 		LOG_ERR("Error %d: failed to configure bt_reg_on %s pin %d",
 			err, bt_reg_on.port->name, bt_reg_on.pin);
 		return err;
 	}
+
+	/* Allow BT CBUCK regulator to discharge */
+	(void)k_msleep(BT_POWER_CBUCK_DISCHARGE_TIME_MS);
+
 	err = gpio_pin_set_dt(&bt_reg_on, 1);
 	if (err) {
 		return err;