linux-kernel - [PATCH next v4 2/2] Bluetooth: btnxpuart: implement powerup sequence

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Message-ID: <20250702114105.2229008-2-catalin.popescu@leica-geosystems.com>
Date: Wed,  2 Jul 2025 13:41:05 +0200
From: Catalin Popescu <catalin.popescu@...ca-geosystems.com>
To: amitkumar.karwar@....com,
	neeraj.sanjaykale@....com,
	marcel@...tmann.org,
	luiz.dentz@...il.com,
	robh@...nel.org,
	krzk+dt@...nel.org,
	conor+dt@...nel.org,
	p.zabel@...gutronix.de
Cc: linux-bluetooth@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	m.felsch@...gutronix.de,
	Catalin Popescu <catalin.popescu@...ca-geosystems.com>
Subject: [PATCH next v4 2/2] Bluetooth: btnxpuart: implement powerup sequence

NXP bluetooth chip shares power supply and reset gpio with a WLAN
chip. Add support for power supply and reset and enforce powerup
sequence:
- apply power supply
- deassert reset/powerdown

Signed-off-by: Catalin Popescu <catalin.popescu@...ca-geosystems.com>
Reviewed-by: Neeraj Sanjay Kale <neeraj.sanjaykale@....com>
---
v4:
- rebase on linux-next tag next-20250701
v3:
- rebase on linux-next tag next-20250409
- fix issue reported by CI regarding the subject
v2:
- rebase on linux-next tag next-20250227
- add reviewed-by
---
 drivers/bluetooth/btnxpuart.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index 25857919359e..b25096b8980b 100644
--- a/drivers/bluetooth/btnxpuart.c
+++ b/drivers/bluetooth/btnxpuart.c
@@ -18,6 +18,8 @@
 #include <linux/string_helpers.h>
 #include <linux/gpio/consumer.h>
 #include <linux/of_irq.h>
+#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -209,6 +211,7 @@ struct btnxpuart_dev {
 
 	struct ps_data psdata;
 	struct btnxpuart_data *nxp_data;
+	struct reset_control *pdn;
 };
 
 #define NXP_V1_FW_REQ_PKT	0xa5
@@ -1757,6 +1760,7 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 	struct hci_dev *hdev;
 	struct btnxpuart_dev *nxpdev;
 	bdaddr_t ba = {0};
+	int err;
 
 	nxpdev = devm_kzalloc(&serdev->dev, sizeof(*nxpdev), GFP_KERNEL);
 	if (!nxpdev)
@@ -1795,6 +1799,16 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 
 	crc8_populate_msb(crc8_table, POLYNOMIAL8);
 
+	nxpdev->pdn = devm_reset_control_get_optional_shared(&serdev->dev, NULL);
+	if (IS_ERR(nxpdev->pdn))
+		return PTR_ERR(nxpdev->pdn);
+
+	err = devm_regulator_get_enable(&serdev->dev, "vcc");
+	if (err) {
+		dev_err(&serdev->dev, "Failed to enable vcc regulator\n");
+		return err;
+	}
+
 	/* Initialize and register HCI device */
 	hdev = hci_alloc_dev();
 	if (!hdev) {
@@ -1802,6 +1816,8 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 		return -ENOMEM;
 	}
 
+	reset_control_deassert(nxpdev->pdn);
+
 	nxpdev->hdev = hdev;
 
 	hdev->bus = HCI_UART;
@@ -1840,6 +1856,7 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 	return 0;
 
 probe_fail:
+	reset_control_assert(nxpdev->pdn);
 	hci_free_dev(hdev);
 	return -ENODEV;
 }
@@ -1867,6 +1884,7 @@ static void nxp_serdev_remove(struct serdev_device *serdev)
 
 	ps_cleanup(nxpdev);
 	hci_unregister_dev(hdev);
+	reset_control_assert(nxpdev->pdn);
 	hci_free_dev(hdev);
 }
 
-- 
2.43.0