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

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Message-Id: <20241004113557.2851060-2-catalin.popescu@leica-geosystems.com>
Date: Fri,  4 Oct 2024 13:35:57 +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,
	bsp-development.geo@...ca-geosystems.com,
	Catalin Popescu <catalin.popescu@...ca-geosystems.com>
Subject: [PATCH 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:
1. apply power supply
2. deassert reset/powerdown

Signed-off-by: Catalin Popescu <catalin.popescu@...ca-geosystems.com>
---
 drivers/bluetooth/btnxpuart.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index 4f493be763b8..e58e7ac7999f 100644
--- a/drivers/bluetooth/btnxpuart.c
+++ b/drivers/bluetooth/btnxpuart.c
@@ -16,6 +16,8 @@
 #include <linux/crc8.h>
 #include <linux/crc32.h>
 #include <linux/string_helpers.h>
+#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -188,6 +190,7 @@ struct btnxpuart_dev {
 
 	struct ps_data psdata;
 	struct btnxpuart_data *nxp_data;
+	struct reset_control *pdn;
 };
 
 #define NXP_V1_FW_REQ_PKT	0xa5
@@ -1458,6 +1461,7 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 {
 	struct hci_dev *hdev;
 	struct btnxpuart_dev *nxpdev;
+	int err;
 
 	nxpdev = devm_kzalloc(&serdev->dev, sizeof(*nxpdev), GFP_KERNEL);
 	if (!nxpdev)
@@ -1485,6 +1489,16 @@ 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) {
@@ -1492,6 +1506,8 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 		return -ENOMEM;
 	}
 
+	reset_control_deassert(nxpdev->pdn);
+
 	nxpdev->hdev = hdev;
 
 	hdev->bus = HCI_UART;
@@ -1509,6 +1525,7 @@ static int nxp_serdev_probe(struct serdev_device *serdev)
 
 	if (hci_register_dev(hdev) < 0) {
 		dev_err(&serdev->dev, "Can't register HCI device\n");
+		reset_control_assert(nxpdev->pdn);
 		hci_free_dev(hdev);
 		return -ENODEV;
 	}
@@ -1540,6 +1557,7 @@ 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);
 }
 
-- 
2.34.1