Re: [PATCH v7 8/8] Bluetooth: hci_qca: Add support for Qualcomm Bluetooth chip wcn3990

[Matthias Kaehlcke <mka@chromium.org>]

Hi Balakrishna,

On Thu, Jun 21, 2018 at 07:30:25PM +0530, Balakrishna Godavarthi wrote:
> Hi Matthias,
> 
> On 2018-06-20 03:23, Matthias Kaehlcke wrote:
> > On Sat, Jun 16, 2018 at 11:57:18AM +0530, Balakrishna Godavarthi wrote:
> > > Add support to set voltage/current of various regulators
> > > to power up/down Bluetooth chip wcn3990.
> > > 
> > > Signed-off-by: Balakrishna Godavarthi <bgodavar@codeaurora.org>
> > > ---
> > > diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> > > index 28ae6a17a595..1961e313aae7 100644
> > > --- a/drivers/bluetooth/hci_qca.c
> > > +++ b/drivers/bluetooth/hci_qca.c
> > >
> > >  static int qca_setup(struct hci_uart *hu)
> > >  {
> > >  	struct hci_dev *hdev = hu->hdev;
> > >  	struct qca_data *qca = hu->priv;
> > > +	struct qca_serdev *qcadev;
> > >  	unsigned int speed, qca_baudrate = QCA_BAUDRATE_115200;
> > >  	int ret;
> > >  	int soc_ver = 0;
> > > 
> > > -	bt_dev_info(hdev, "ROME setup");
> > > +	qcadev = serdev_device_get_drvdata(hu->serdev);
> > > 
> > >  	/* Patch downloading has to be done without IBS mode */
> > >  	clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
> > > -
> > > -	/* Setup initial baudrate */
> > >  	qca_set_init_speed(hu);
> > > +
> > > +	if (qcadev->btsoc_type == QCA_WCN3990) {
> > > +		bt_dev_dbg(hdev, "setting up wcn3990");
> > > +		hci_uart_set_flow_control(hu, true);
> > > +		ret = qca_send_vendor_cmd(hdev, CHEROKEE_POWERON_PULSE);
> > > +		if (ret) {
> > > +			bt_dev_err(hdev, "failed to send power on command");
> > > +			return ret;
> > > +		}
> > > +		serdev_device_close(hu->serdev);
> > > +		ret = serdev_device_open(hu->serdev);
> > > +		if (ret) {
> > > +			bt_dev_err(hdev, "failed to open port");
> > > +			return ret;
> > > +		}
> > > +		msleep(100);
> > > +		qca_set_init_speed(hu);
> > > +		hci_uart_set_flow_control(hu, false);
> > > +		ret = qca_read_soc_version(hdev, &soc_ver);
> > > +		if (ret < 0 || soc_ver == 0) {
> > > +			bt_dev_err(hdev, "Failed to get version %d", ret);
> > 
> > serdev_device_close() ?
> > 
> > Also applies to other error paths in this function.
> > 
> [Bala]: sorry, i didn't get you.

A few lines above serdev_device_open() is called, in the error paths
the device should be closed.

> > >  static int qca_serdev_probe(struct serdev_device *serdev)
> > >  {
> > >  	struct qca_serdev *qcadev;
> > > +	const struct qca_vreg_data *data;
> > >  	int err;
> > > 
> > >  	qcadev = devm_kzalloc(&serdev->dev, sizeof(*qcadev), GFP_KERNEL);
> > > @@ -1041,47 +1264,85 @@ static int qca_serdev_probe(struct
> > > serdev_device *serdev)
> > >  		return -ENOMEM;
> > > 
> > >  	qcadev->serdev_hu.serdev = serdev;
> > > +	data = of_device_get_match_data(&serdev->dev);
> > > +	if (data && data->soc_type == QCA_WCN3990)
> > > +		qcadev->btsoc_type = QCA_WCN3990;
> > > +	else
> > > +		qcadev->btsoc_type = QCA_ROME;
> > > +
> > >  	serdev_device_set_drvdata(serdev, qcadev);
> > > +	if (qcadev->btsoc_type == QCA_WCN3990) {
> > 
> > nit: the double "if (soc_type == QCA_WCN3990)" is a bit odd. Consider
> > changing this condition to "if (data && data->soc_type == QCA_WCN3990)"
> > and assign qcadev->btsoc_type in the corresponding branch.
> 
> [bala]: will update.
> 
> I have idea of removing flow control from qca_setup() and use them in
> qca_set_speed()
> "i need to disable hardware flow control when sending change baudrate
> request to WCN3990.
> enabling it after setting host baudrate. this is only for wcn3990.
> "

I definitely think it's positive to hide the
hci_uart_set_flow_control() call in qca_set_speed(). A few comments
inline.


> static int qca_set_speed(struct hci_uart *hu, unsigned int speed,
>                          enum qca_speed_type speed_type,
>                          enum qca_btsoc_type soc_type)
> {

That's a lot of parameters, in particular 'soc_type' seems a bit
off-topic in a function called qca_set_speed(). Passing struct
qca_serdev instead of struct hci_uart would make the 'soc_type'
parameter unnecessary.

>         unsigned int qca_baudrate;
>         int ret;
> 
>         if (speed_type == QCA_INIT_SPEED)
>                 goto change_host_baudrate;

If the order of setting host and chip baudrate can't be changed I
think it's preferable to set the init speed right here in the if
branch instead of doing the goto. I earlier mentioned the short cut of
a return (if possible) to save a level of indentation, but a goto
IMO doesn't improve readability and it's the first level of
indentation anyway.

>         if (soc_type == QCA_WCN3990)
>                 hci_uart_set_flow_control(hu, true);
> 
>         qca_baudrate = qca_get_baudrate_value(speed);
>         bt_dev_info(hu->hdev, "Set UART speed to %d", speed);
>         ret = qca_set_baudrate(hu->hdev, qca_baudrate);
>         if (ret) {
>                 bt_dev_err(hu->hdev, "Failed to change the baudrate (%d)",
> ret);
>                 return ret;
>         }
> 
> change_host_baudrate:
> 
>         host_set_baudrate(hu, speed);
>         if (soc_type == QCA_WCN3990)
>                 hci_uart_set_flow_control(hu, false);
> 
>         return ret;
> }
> 
> 
> is it good idea?

In general I think it is.