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SubjectRe: [PATCH v4 5/5] Bluetooth: btusb: Use the hw_reset method to allow resetting the BT chip
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Hi Rajat,

> If the platform provides it, use the reset gpio to reset the BT
> chip (requested by the HCI core if needed). This has been found helpful
> on some of Intel bluetooth controllers where the firmware gets stuck and
> the only way out is a hard reset pin provided by the platform.
>
> Signed-off-by: Rajat Jain <rajatja@google.com>
> ---
> v4: Use data->flags instead of clearing the quirk in btusb_hw_reset()
> v3: Better error handling for gpiod_get_optional()
> v2: Handle the EPROBE_DEFER case.
>
> drivers/bluetooth/btusb.c | 45 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 45 insertions(+)
>
> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
> index 59869643cc29..7cf1e4f749e9 100644
> --- a/drivers/bluetooth/btusb.c
> +++ b/drivers/bluetooth/btusb.c
> @@ -29,6 +29,7 @@
> #include <linux/of_device.h>
> #include <linux/of_irq.h>
> #include <linux/suspend.h>
> +#include <linux/gpio/consumer.h>
> #include <asm/unaligned.h>
>
> #include <net/bluetooth/bluetooth.h>
> @@ -439,6 +440,7 @@ static const struct dmi_system_id btusb_needs_reset_resume_table[] = {
> #define BTUSB_BOOTING 9
> #define BTUSB_DIAG_RUNNING 10
> #define BTUSB_OOB_WAKE_ENABLED 11
> +#define BTUSB_HW_RESET_DONE 12

I think you mean BTUSB_HW_RESET_ACTIVE or BTUSB_HW_RESET_IN_PROGRESS.

>
> struct btusb_data {
> struct hci_dev *hdev;
> @@ -476,6 +478,8 @@ struct btusb_data {
> struct usb_endpoint_descriptor *diag_tx_ep;
> struct usb_endpoint_descriptor *diag_rx_ep;
>
> + struct gpio_desc *reset_gpio;
> +
> __u8 cmdreq_type;
> __u8 cmdreq;
>
> @@ -491,6 +495,30 @@ struct btusb_data {
> int oob_wake_irq; /* irq for out-of-band wake-on-bt */
> };
>
> +
> +static void btusb_hw_reset(struct hci_dev *hdev)
> +{
> + struct btusb_data *data = hci_get_drvdata(hdev);
> + struct gpio_desc *reset_gpio = data->reset_gpio;
> +
> + /*
> + * Toggle the hard reset line if the platform provides one. The reset
> + * is going to yank the device off the USB and then replug. So doing
> + * once is enough. The cleanup is handled correctly on the way out
> + * (standard USB disconnect), and the new device is detected cleanly
> + * and bound to the driver again like it should be.
> + */
> + if (test_and_set_bit(BTUSB_HW_RESET_DONE, &data->flags)) {
> + bt_dev_warn(hdev, "last reset failed? Not resetting again\n");
> + return;
> + }
> +
> + bt_dev_dbg(hdev, "Initiating HW reset via gpio\n”);

The bt_dev_ functions don’t need the \n at the end.

> + gpiod_set_value(reset_gpio, 1);
> + mdelay(100);
> + gpiod_set_value(reset_gpio, 0);
> +}
> +
> static inline void btusb_free_frags(struct btusb_data *data)
> {
> unsigned long flags;
> @@ -2915,6 +2943,7 @@ static int btusb_probe(struct usb_interface *intf,
> const struct usb_device_id *id)
> {
> struct usb_endpoint_descriptor *ep_desc;
> + struct gpio_desc *reset_gpio;
> struct btusb_data *data;
> struct hci_dev *hdev;
> unsigned ifnum_base;
> @@ -3028,6 +3057,16 @@ static int btusb_probe(struct usb_interface *intf,
>
> SET_HCIDEV_DEV(hdev, &intf->dev);
>
> + reset_gpio = gpiod_get_optional(&data->udev->dev, "reset",
> + GPIOD_OUT_LOW);
> + if (IS_ERR(reset_gpio)) {
> + err = PTR_ERR(reset_gpio);
> + goto out_free_dev;
> + } else if (reset_gpio) {
> + data->reset_gpio = reset_gpio;
> + hdev->hw_reset = btusb_hw_reset;
> + }
> +
> hdev->open = btusb_open;
> hdev->close = btusb_close;
> hdev->flush = btusb_flush;
> @@ -3083,6 +3122,7 @@ static int btusb_probe(struct usb_interface *intf,
> set_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks);
> set_bit(HCI_QUIRK_SIMULTANEOUS_DISCOVERY, &hdev->quirks);
> set_bit(HCI_QUIRK_NON_PERSISTENT_DIAG, &hdev->quirks);
> + set_bit(HCI_QUIRK_HW_RESET_ON_TIMEOUT, &hdev->quirks);
>
> if (id->driver_info & BTUSB_INTEL) {
> hdev->setup = btusb_setup_intel;
> @@ -3223,6 +3263,8 @@ static int btusb_probe(struct usb_interface *intf,
> return 0;
>
> out_free_dev:
> + if (data->reset_gpio)
> + gpiod_put(data->reset_gpio);
> hci_free_dev(hdev);
> return err;
> }
> @@ -3266,6 +3308,9 @@ static void btusb_disconnect(struct usb_interface *intf)
> if (data->oob_wake_irq)
> device_init_wakeup(&data->udev->dev, false);
>
> + if (data->reset_gpio)
> + gpiod_put(data->reset_gpio);
> +
> hci_free_dev(hdev);
> }

Regards

Marcel

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