linux-kernel - Re: [PATCH v4 3/3] Bluetooth: hci_qca: Enable power off/on support during hci down/up for QCA Rome

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Date:   Wed, 15 Jan 2020 10:02:14 -0800
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Rocky Liao <rjliao@...eaurora.org>
Cc:     marcel@...tmann.org, johan.hedberg@...il.com,
        linux-kernel@...r.kernel.org, linux-bluetooth@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, bgodavar@...eaurora.org,
        hemantg@...eaurora.org
Subject: Re: [PATCH v4 3/3] Bluetooth: hci_qca: Enable power off/on support
 during hci down/up for QCA Rome

On Wed, Jan 15, 2020 at 04:55:52PM +0800, Rocky Liao wrote:
> This patch registers hdev->shutdown() callback and also sets
> HCI_QUIRK_NON_PERSISTENT_SETUP for QCA Rome. It will power-off the BT chip
> during hci down and power-on/initialize the chip again during hci up. As
> wcn399x already enabled this, this patch also removed the callback register
> and QUIRK setting in qca_setup() for wcn399x and uniformly do this in the
> probe() routine.
> 
> Signed-off-by: Rocky Liao <rjliao@...eaurora.org>
> ---
> 
> Changes in v2: None
> Changes in v3: 
>   -moved the quirk and callback register to probe()
> Changes in v4:
>   -rebased the patch with latest code
>   -moved the quirk and callback register to probe() for wcn399x
>   -updated commit message
> 
>  drivers/bluetooth/hci_qca.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 1139142e8eed..3c6c6bd20177 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -1569,12 +1569,7 @@ static int qca_setup(struct hci_uart *hu)
>  		return ret;
>  
>  	if (qca_is_wcn399x(soc_type)) {
> -		/* Enable NON_PERSISTENT_SETUP QUIRK to ensure to execute
> -		 * setup for every hci up.
> -		 */
> -		set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
>  		set_bit(HCI_QUIRK_USE_BDADDR_PROPERTY, &hdev->quirks);

I guess this should also move to _probe() eventually, but it's not really
the scope of this patch.

> -		hu->hdev->shutdown = qca_power_off;
>  
>  		ret = qca_read_soc_version(hdev, &soc_ver, soc_type);
>  		if (ret)
> @@ -1813,6 +1808,7 @@ static int qca_init_regulators(struct qca_power *qca,
>  static int qca_serdev_probe(struct serdev_device *serdev)
>  {
>  	struct qca_serdev *qcadev;
> +	struct hci_dev *hdev;
>  	const struct qca_vreg_data *data;
>  	int err;
>  
> @@ -1881,7 +1877,13 @@ static int qca_serdev_probe(struct serdev_device *serdev)
>  			clk_disable_unprepare(qcadev->susclk);
>  	}
>  
> -out:	return err;
> +out:
> +	if (!err) {
> +		hdev = qcadev->serdev_hu.hdev;
> +		set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
> +		hdev->shutdown = qca_power_off;
> +	}
> +	return err;

Since there is no unwinding in case of an error I would suggest to
change the jumps to the 'out' label further above to 'return err;'
and change the above lines to:

	hdev = qcadev->serdev_hu.hdev;
	set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
	hdev->shutdown = qca_power_off;

	return 0;

This will also require to return directly when hci_uart_register_device()
fails.