[PATCH V4 3/8] Bluetooth: btnxpuart: Add M.2 Bluetooth device support using pwrseq

["Sherry Sun (OSS)" <sherry.sun@oss.nxp.com>]

From: Sherry Sun <sherry.sun@nxp.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,
pwrseq_power_on() is called to power up the M.2 Bluetooth card. The power
sequencer descriptor is obtained via devm_pwrseq_get(), so the power-off
and cleanup are handled automatically when the device is unbound.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/bluetooth/btnxpuart.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index 6a1cffe08d5f..fc5ff23ec1cd 100644
--- a/drivers/bluetooth/btnxpuart.c
+++ b/drivers/bluetooth/btnxpuart.c
@@ -9,6 +9,8 @@
 
 #include <linux/serdev.h>
 #include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/pwrseq/consumer.h>
 #include <linux/skbuff.h>
 #include <linux/unaligned.h>
 #include <linux/firmware.h>
@@ -1872,6 +1874,18 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 		return err;
 	}
 
+	if (of_graph_is_present(dev_of_node(&serdev->ctrl->dev))) {
+		struct pwrseq_desc *pwrseq;
+
+		pwrseq = devm_pwrseq_get(&serdev->ctrl->dev, "uart");
+		if (IS_ERR(pwrseq))
+			return PTR_ERR(pwrseq);
+
+		err = pwrseq_power_on(pwrseq);
+		if (err)
+			return err;
+	}
+
 	/* Initialize and register HCI device */
 	hdev = hci_alloc_dev();
 	if (!hdev) {
-- 
2.50.1