Date:   Fri, 29 Jun 2018 23:07:22 +0530
From:   Balakrishna Godavarthi <bgodavar@...eaurora.org>
To:     Matthias Kaehlcke <mka@...omium.org>
Cc:     marcel@...tmann.org, johan.hedberg@...il.com,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-bluetooth@...r.kernel.org, rtatiya@...eaurora.org,
        hemantg@...eaurora.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v8 7/7] Bluetooth: hci_qca: Add support for Qualcomm
 Bluetooth chip wcn3990

Hi Matthias,

On 2018-06-26 06:35, Matthias Kaehlcke wrote:
> On Mon, Jun 25, 2018 at 07:10:13PM +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@...eaurora.org>
>> ---
>> changes in v8:
>>     * closing qca buffer, if qca_power_setup fails
>>     * chnaged ibs start timer function call location.
>>     * updated review comments.
>> 
>> changes in v7:
>>     * addressed review comments.
>> 
>> changes in v6:
>>     * Hooked up qca_power to qca_serdev.
>>     * renamed all the naming inconsistency functions with qca_*
>>     * leveraged common code of ROME for wcn3990.
>>     * created wrapper functions for re-usable blocks.
>>     * updated function of _*regulator_enable and _*regualtor_disable.
>>     * removed redundant comments and functions.
>>     * addressed review comments.
>> 
>> Changes in v5:
>>     * updated regulator vddpa min_uV to 1304000.
>>       * addressed review comments.
>> 
>> Changes in v4:
>>     * Segregated the changes of btqca from hci_qca
>>     * rebased all changes on top of bluetooth-next.
>>     * addressed review comments.
>> 
>> ---
>> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
>> index 28187a89b850..bd4c9a78716f 100644
>> --- a/drivers/bluetooth/hci_qca.c
>> +++ b/drivers/bluetooth/hci_qca.c
>> ...
>> +static int qca_send_vendor_cmd(struct hci_dev *hdev, u8 cmd)
>> +{
>> +	struct hci_uart *hu = hci_get_drvdata(hdev);
>> +	struct qca_data *qca = hu->priv;
>> +	struct sk_buff *skb;
>> +
>> +	bt_dev_dbg(hdev, "sending command %02x to SoC", cmd);
>> +
>> +	skb = bt_skb_alloc(sizeof(cmd), GFP_KERNEL);
>> +	if (!skb) {
>> +		bt_dev_err(hdev, "Failed to allocate memory for vendor packet");
> 
> As mentioned on v7, custom OOM messages should be avoided.
> 

[Bala]: sry i might have missed it, will update.

>>  static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type 
>> speed_type)
>>  {
>> +	struct qca_serdev *qcadev;
>>  	unsigned int speed, qca_baudrate;
>>  	int ret;
>> 
>> @@ -971,6 +1054,13 @@ static int qca_set_speed(struct hci_uart *hu, 
>> enum qca_speed_type speed_type)
>>  		return 0;
>>  	}
>> 
>> +	qcadev = serdev_device_get_drvdata(hu->serdev);
>> +	/* Disabling hardware flow control is preferred while
>> +	 * sending change baud rate command to SoC.
>> +	 */
> 
> Is it only preferred or must be?
> 

[Bala]: must be. will update.

>> +	if (qcadev->btsoc_type == QCA_WCN3990)
>> +		hci_uart_set_flow_control(hu, true);
>> +
> 
> nit: consider doing this just before qca_set_baudrate(). It doesn't
> make a difference but leaves it clearer what exactly needs to be
> 'protected' (analogy to locking).

[Bala] : will do it.

> 
>>  	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);
>> @@ -980,8 +1070,10 @@ static int qca_set_speed(struct hci_uart *hu, 
>> enum qca_speed_type speed_type)
>>  	}
>> 
>>  	host_set_baudrate(hu, speed);
>> +	if (qcadev->btsoc_type == QCA_WCN3990)
>> +		hci_uart_set_flow_control(hu, false);
> 
>>  static int qca_setup(struct hci_uart *hu)
>> @@ -989,10 +1081,11 @@ static int qca_setup(struct hci_uart *hu)
>>  	struct hci_dev *hdev = hu->hdev;
>>  	struct qca_data *qca = hu->priv;
>>  	unsigned int speed, qca_baudrate = QCA_BAUDRATE_115200;
>> +	struct qca_serdev *qcadev;
>>  	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);
>> @@ -1000,6 +1093,35 @@ static int qca_setup(struct hci_uart *hu)
>>  	/* Setup initial baudrate */
>>  	qca_set_speed(hu, QCA_INIT_SPEED);
>> 
>> +	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, QCA_WCN3990_POWERON_PULSE);
>> +		if (ret)
>> +			return ret;
>> +
>> +		hci_uart_set_flow_control(hu, false);
>> +		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);
> 
> Is the sleep really related with _open() or is it rather that the
> device needs to settle after the power on pulse? In the latter case
> I'd suggest to do the sleep before _open(), if it doesn't make a
> functional difference (makes the code a bit more self documenting).
> 
>> +		/* Setup initial baudrate */
>> +		qca_set_speed(hu, QCA_INIT_SPEED);
>> +		hci_uart_set_flow_control(hu, false);
> 
> This is still a bit noisy with all the open/close and flow control
> stuff. If I understand correctly this essentially switches the
> controller on (or resets it?) and brings it (and the driver) into a
> sane state. Would it make sense to move the above block into a
> wcn3990_init/reset() or so?

[Bala]: It is very good idea, may be future chips also will flow same 
functions with some initial setup changes.
         will group these functions into a common functions.


-- 
Regards
Balakrishna.

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