[PATCH v2 6/9] Bluetooth: hci_qca: Add M.2 Bluetooth device support using pwrseq

[Manivannan Sadhasivam via B4 Relay <devnull+manivannan.sadhasivam.oss.qualcomm.com@kernel.org>]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

Power supply to the M.2 Bluetooth device attached to the host using M.2
connector is controlled using the 'uart' pwrseq device. So add support for
getting the pwrseq device if the OF graph link is present. Once obtained,
the existing pwrseq APIs can be used to control the power supplies of the
M.2 card.

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/bluetooth/hci_qca.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index cd1834246b47..c83fe72bc549 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -26,6 +26,7 @@
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_graph.h>
 #include <linux/acpi.h>
 #include <linux/platform_device.h>
 #include <linux/pwrseq/consumer.h>
@@ -2443,6 +2444,18 @@ static int qca_serdev_probe(struct serdev_device *serdev)
 	case QCA_WCN6750:
 	case QCA_WCN6855:
 	case QCA_WCN7850:
+		/*
+		 * OF graph link is only present for BT devices attached through
+		 * the M.2 Key E connector.
+		 */
+		if (of_graph_is_present(dev_of_node(&serdev->ctrl->dev))) {
+			qcadev->bt_power->pwrseq = devm_pwrseq_get(&serdev->ctrl->dev,
+								   "uart");
+			if (IS_ERR(qcadev->bt_power->pwrseq))
+				return PTR_ERR(qcadev->bt_power->pwrseq);
+			break;
+		}
+
 		if (!device_property_present(&serdev->dev, "enable-gpios")) {
 			/*
 			 * Backward compatibility with old DT sources. If the

-- 
2.51.0