[PATCH v3 2/2] Bluetooth: btnxpuart: Add GPIO support to power save feature

From: Neeraj Sanjay Kale
Date: Fri Oct 04 2024 - 08:19:17 EST


This adds support for driving the chip into sleep or wakeup with a GPIO.

If the device tree property device-wakeup-gpios is defined, the driver utilizes
this GPIO for controlling the chip's power save state, else it uses the
default UART-break method.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@xxxxxxx>
---
v3: Remove GPIO toggling in ps_init(). (Shenwei Wang)
---
drivers/bluetooth/btnxpuart.c | 34 ++++++++++++++++++++++++++++++++--
1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index 2b8a07c745c9..4b7e8b7c522a 100644
--- a/drivers/bluetooth/btnxpuart.c
+++ b/drivers/bluetooth/btnxpuart.c
@@ -16,6 +16,7 @@
#include <linux/crc8.h>
#include <linux/crc32.h>
#include <linux/string_helpers.h>
+#include <linux/gpio/consumer.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
@@ -82,6 +83,7 @@
#define WAKEUP_METHOD_BREAK 1
#define WAKEUP_METHOD_EXT_BREAK 2
#define WAKEUP_METHOD_RTS 3
+#define WAKEUP_METHOD_GPIO 4
#define WAKEUP_METHOD_INVALID 0xff

/* power save mode status */
@@ -135,6 +137,7 @@ struct ps_data {
bool driver_sent_cmd;
u16 h2c_ps_interval;
u16 c2h_ps_interval;
+ struct gpio_desc *h2c_ps_gpio;
struct hci_dev *hdev;
struct work_struct work;
struct timer_list ps_timer;
@@ -365,7 +368,7 @@ static void ps_control(struct hci_dev *hdev, u8 ps_state)
{
struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
struct ps_data *psdata = &nxpdev->psdata;
- int status;
+ int status = 0;

if (psdata->ps_state == ps_state ||
!test_bit(BTNXPUART_SERDEV_OPEN, &nxpdev->tx_state))
@@ -373,6 +376,12 @@ static void ps_control(struct hci_dev *hdev, u8 ps_state)

mutex_lock(&psdata->ps_lock);
switch (psdata->cur_h2c_wakeupmode) {
+ case WAKEUP_METHOD_GPIO:
+ if (ps_state == PS_STATE_AWAKE)
+ gpiod_set_value_cansleep(psdata->h2c_ps_gpio, 0);
+ else
+ gpiod_set_value_cansleep(psdata->h2c_ps_gpio, 1);
+ break;
case WAKEUP_METHOD_DTR:
if (ps_state == PS_STATE_AWAKE)
status = serdev_device_set_tiocm(nxpdev->serdev, TIOCM_DTR, 0);
@@ -425,8 +434,13 @@ static void ps_timeout_func(struct timer_list *t)
static void ps_setup(struct hci_dev *hdev)
{
struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
+ struct serdev_device *serdev = nxpdev->serdev;
struct ps_data *psdata = &nxpdev->psdata;

+ psdata->h2c_ps_gpio = devm_gpiod_get(&serdev->dev, "device-wakeup", GPIOD_OUT_LOW);
+ if (IS_ERR(psdata->h2c_ps_gpio))
+ psdata->h2c_wakeup_gpio = 0xff;
+
psdata->hdev = hdev;
INIT_WORK(&psdata->work, ps_work_func);
mutex_init(&psdata->ps_lock);
@@ -516,6 +530,9 @@ static int send_wakeup_method_cmd(struct hci_dev *hdev, void *data)
pcmd.c2h_wakeupmode = psdata->c2h_wakeupmode;
pcmd.c2h_wakeup_gpio = psdata->c2h_wakeup_gpio;
switch (psdata->h2c_wakeupmode) {
+ case WAKEUP_METHOD_GPIO:
+ pcmd.h2c_wakeupmode = BT_CTRL_WAKEUP_METHOD_GPIO;
+ break;
case WAKEUP_METHOD_DTR:
pcmd.h2c_wakeupmode = BT_CTRL_WAKEUP_METHOD_DSR;
break;
@@ -550,6 +567,7 @@ static void ps_init(struct hci_dev *hdev)
{
struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
struct ps_data *psdata = &nxpdev->psdata;
+ u8 default_h2c_wakeup_mode = DEFAULT_H2C_WAKEUP_MODE;

serdev_device_set_tiocm(nxpdev->serdev, 0, TIOCM_RTS);
usleep_range(5000, 10000);
@@ -561,8 +579,17 @@ static void ps_init(struct hci_dev *hdev)
psdata->c2h_wakeup_gpio = 0xff;

psdata->cur_h2c_wakeupmode = WAKEUP_METHOD_INVALID;
+ if (!IS_ERR(psdata->h2c_ps_gpio))
+ default_h2c_wakeup_mode = WAKEUP_METHOD_GPIO;
+
psdata->h2c_ps_interval = PS_DEFAULT_TIMEOUT_PERIOD_MS;
- switch (DEFAULT_H2C_WAKEUP_MODE) {
+
+ switch (default_h2c_wakeup_mode) {
+ case WAKEUP_METHOD_GPIO:
+ psdata->h2c_wakeupmode = WAKEUP_METHOD_GPIO;
+ gpiod_set_value_cansleep(psdata->h2c_ps_gpio, 0);
+ usleep_range(5000, 10000);
+ break;
case WAKEUP_METHOD_DTR:
psdata->h2c_wakeupmode = WAKEUP_METHOD_DTR;
serdev_device_set_tiocm(nxpdev->serdev, 0, TIOCM_DTR);
@@ -1279,6 +1306,9 @@ static int nxp_enqueue(struct hci_dev *hdev, struct sk_buff *skb)
psdata->c2h_wakeup_gpio = wakeup_parm.c2h_wakeup_gpio;
psdata->h2c_wakeup_gpio = wakeup_parm.h2c_wakeup_gpio;
switch (wakeup_parm.h2c_wakeupmode) {
+ case BT_CTRL_WAKEUP_METHOD_GPIO:
+ psdata->h2c_wakeupmode = WAKEUP_METHOD_GPIO;
+ break;
case BT_CTRL_WAKEUP_METHOD_DSR:
psdata->h2c_wakeupmode = WAKEUP_METHOD_DTR;
break;
--
2.25.1