Re: [PATCH v6 5/5] Bluetooth: hci_qca: Add support for Qualcomm Bluetooth chip wcn3990.

[Matthias Kaehlcke <mka@chromium.org>]

On Thu, May 24, 2018 at 09:30:51PM +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>
> ---
> 
> 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 cb1034998040..e235be0e5202 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> ...
> +static void qca_set_init_speed(struct hci_uart *hu)
> +{
> +	unsigned int speed = 0;
>  
> -	/* Setup initial baudrate */
> -	speed = 0;
>  	if (hu->init_speed)
>  		speed = hu->init_speed;
>  	else if (hu->proto->init_speed)
> @@ -946,29 +1015,136 @@ static int qca_setup(struct hci_uart *hu)
>  
>  	if (speed)
>  		host_set_baudrate(hu, speed);
> +}
> +
> +static int qca_set_operating_speed(struct hci_uart *hu, u32 *qca_baudrate)
> +{

This is a bit convoluted, with the function setting the speed and
returning it. I would suggest a qca_get_oper_speed() and
qca_get_init_speed(), and just have them return the value instead of
passing it through a pointer. You could then have a qca_set_speed()
which converts the baudrate to the value the chip understands, calls
qca_set_baudrate() and host_set_baudrate()

> +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;
> +
> +	qcadev = serdev_device_get_drvdata(hu->serdev);
> +
> +	switch (qcadev->btsoc_type) {
> +	case BTQCA_CHEROKEE:
> +		bt_dev_dbg(hdev, "setting up wcn3990");
> +		/* Patch downloading has to be done without IBS mode */
> +		clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
> +		qca_set_init_speed(hu);
> +		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;
> +		}
> +
> +		/* Close and re-open the port */

As mentioned earlier, this comment doesn't provide any useful
information, it's evident from the code. Rather explain *why* the
close/open is needed.

> +		serdev_device_close(hu->serdev);
> +		ret = serdev_device_open(hu->serdev);
> +		if (ret) {
> +			bt_dev_err(hdev, "failed to open port");
> +			return ret;
> +		}
> +
> +		qca_set_init_speed(hu);
> +		hci_uart_set_flow_control(hu, false);
> +		msleep(100);

Which step makes the delay necessary? I guess it's not enabling flow
control but probably sending the power on command. If that is correct
the delay should be done after the corresponding command.

> +		ret = qca_patch_ver_req(hdev, &soc_ver);
> +		if (ret < 0 || soc_ver == 0) {
> +			bt_dev_err(hdev, "Failed to get version 0x%x", ret);

Probably better: "Failed to get version: %d" since ret contains an
errno and the problem wasn't that we couldn't get "version 0x<errno>".

> +			return ret;
> +		}
> +
> +		bt_dev_info(hdev, "wcn3990 controller version 0x%08x", soc_ver);
> +		hci_uart_set_flow_control(hu, true);

Repeatedly switching on and off of flow control is a bit noisy, I
wonder if it could be hidden in a wrapper. From the code it seems that
flow control is disabled (true) for init speed and and enabled (false)
for operating speed. If this is correct the hci_uart_set_flow_control()
calls could be moved inside qca_set_oper/init_speed(). struct qca_serdev
could have a flag indicating if flow control is supported at all to
skip the hci_uart_set_flow_control() calls for Rome.

Just an idea, no objections if you prefer to leave it as is and Marcel
is ok with it.

> +		ret = qca_set_operating_speed(hu, &qca_baudrate);
> +		if (ret)
> +			return ret;
> +		hci_uart_set_flow_control(hu, false);
> +		/* Setup patch and NVM configurations */
> +		ret = qca_uart_setup_cherokee(hdev, qca_baudrate, &soc_ver);
> +
> +		break;
> +
> +	default:
> +		bt_dev_info(hdev, "ROME setup");
> +
> +		/* Patch downloading has to be done without IBS mode */
> +		clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
> +
> +		/* Setup initial baudrate */
> +		speed = 0;
> +		if (hu->init_speed)
> +			speed = hu->init_speed;
> +		else if (hu->proto->init_speed)
> +			speed = hu->proto->init_speed;

If you introduce helpers to determine the init/oper speed these should
also be used here. Probably best to do this in a separate patch.

> +
> +		if (speed)
> +			host_set_baudrate(hu, speed);
> +
> +		/* Setup user speed if needed */
> +		speed = 0;
> +		if (hu->oper_speed)
> +			speed = hu->oper_speed;
> +		else if (hu->proto->oper_speed)
> +			speed = hu->proto->oper_speed;

ditto

> +static void qca_disable_regulator(struct qca_vreg vregs,
> +				  struct regulator *regulator)
> +{
> +	/* Disable the regulator if requested by user
> +	 * or when fault to enable any regulator.
> +	 */

This comment is not useful. The following code simply disables the
regulator, why this is done is a question of the caller.

> +	regulator_disable(regulator);
> +	regulator_set_voltage(regulator, 0, vregs.max_uV);
> +	if (vregs.load_uA)
> +		regulator_set_load(regulator, 0);
> +
> +}
> +
> +int qca_btsoc_power_setup(struct hci_uart *hu, bool on)
> +{
> +	struct qca_vreg *vregs;
> +	struct regulator_bulk_data *vreg_bulk;
> +	struct qca_serdev *qcadev;
> +	int i, num_vregs, ret = 0;
> +
> +	qcadev = serdev_device_get_drvdata(hu->serdev);
> +	if (!qcadev || !qcadev->bt_power || !qcadev->bt_power->vreg_data ||
> +	    !qcadev->bt_power->vreg_bulk)
> +		return -EINVAL;
> +
> +	vregs = qcadev->bt_power->vreg_data->vregs;
> +	vreg_bulk = qcadev->bt_power->vreg_bulk;
> +	num_vregs = qcadev->bt_power->vreg_data->num_vregs;
> +	BT_DBG("on: %d", on);
> +	if (on  && !qcadev->bt_power->vregs_on) {
> +		for (i = 0; i < num_vregs; i++) {
> +			ret = qca_enable_regulator(vregs[i],
> +						   vreg_bulk[i].consumer);
> +			if (ret)
> +				break;
> +		}
> +		/* regulators failed */

Comment is not useful, BT_ERR below leaves things clear.

> +		if (ret) {
> +			BT_ERR("failed to enable regulator:%s", vregs[i].name);
> +			/* turn off regulators which are enabled */
> +			for (i = i - 1; i >= 0; i--)
> +				qca_disable_regulator(vregs[i],
> +						      vreg_bulk[i].consumer);
> +		} else {
> +			qcadev->bt_power->vregs_on = true;
> +		}
> +	} else if (!on && qcadev->bt_power->vregs_on) {
> +		/* turn off regulator in reverse order */
> +		i = qcadev->bt_power->vreg_data->num_vregs - 1;
> +		for ( ; i >= 0; i--)
> +			qca_disable_regulator(vregs[i], vreg_bulk[i].consumer);
> +		qcadev->bt_power->vregs_on = false;
> +	}
> +
> +	return ret;
> +}
> +
> +static int qca_init_regulators(struct qca_power *qca,
> +			       const struct qca_vreg *vregs, size_t num_vregs)
> +{
> +	int i;
> +
> +	qca->vreg_bulk = devm_kzalloc(qca->dev, num_vregs *
> +				      sizeof(struct regulator_bulk_data),
> +				      GFP_KERNEL);
> +	if (!qca->vreg_bulk)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < num_vregs; i++)
> +		qca->vreg_bulk[i].supply = vregs[i].name;
> +
> +	return devm_regulator_bulk_get(qca->dev, num_vregs, qca->vreg_bulk);
> +}
> +
>  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);
> @@ -1014,34 +1301,72 @@ 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 == BTQCA_CHEROKEE)
> +		qcadev->btsoc_type = BTQCA_CHEROKEE;
> +	else
> +		qcadev->btsoc_type = BTQCA_ROME;
> +
>  	serdev_device_set_drvdata(serdev, qcadev);
> +	if (qcadev->btsoc_type == BTQCA_CHEROKEE) {
> +		qcadev->bt_power = devm_kzalloc(&serdev->dev,
> +						sizeof(struct qca_power),
> +						GFP_KERNEL);
> +		if (!qcadev->bt_power)
> +			return -ENOMEM;
> +
> +		qcadev->bt_power->dev = &serdev->dev;
> +		qcadev->bt_power->vreg_data = data;
> +		err = qca_init_regulators(qcadev->bt_power, data->vregs,
> +					  data->num_vregs);
> +		if (err) {
> +			BT_ERR("Failed to init regulators:%d", err);
> +			devm_kfree(&serdev->dev, qcadev->bt_power->vreg_bulk);
> +			devm_kfree(&serdev->dev, qcadev->bt_power);

Not necessary, the memory is allocated with devm_kzalloc(&serdev->dev,
...), therefore it is freed if probe() fails.

> +			goto out;
> +		}
>  
> -	qcadev->bt_en = devm_gpiod_get(&serdev->dev, "enable",
> -				       GPIOD_OUT_LOW);
> -	if (IS_ERR(qcadev->bt_en)) {
> -		dev_err(&serdev->dev, "failed to acquire enable gpio\n");
> -		return PTR_ERR(qcadev->bt_en);
> -	}
> +		qcadev->bt_power->vregs_on = false;
> +		device_property_read_u32(&serdev->dev, "max-speed",
> +					 &qcadev->oper_speed);
> +		if (!qcadev->oper_speed)
> +			BT_INFO("UART will pick default operating speed");
> +		err = hci_uart_register_device(&qcadev->serdev_hu, &qca_proto);
> +		if (err) {
> +			BT_ERR("wcn3990 serdev registration failed");
> +			devm_kfree(&serdev->dev, qcadev->bt_power->vreg_bulk);
> +			devm_kfree(&serdev->dev, qcadev->bt_power);

no need to free memory.

> +			goto out;
> +		}
> +	} else {
> +		qcadev->bt_en = devm_gpiod_get(&serdev->dev, "enable",
> +					       GPIOD_OUT_LOW);
> +		if (IS_ERR(qcadev->bt_en)) {
> +			dev_err(&serdev->dev, "failed to acquire enable gpio\n");
> +			return PTR_ERR(qcadev->bt_en);
> +		}
>  
> -	qcadev->susclk = devm_clk_get(&serdev->dev, NULL);
> -	if (IS_ERR(qcadev->susclk)) {
> -		dev_err(&serdev->dev, "failed to acquire clk\n");
> -		return PTR_ERR(qcadev->susclk);
> -	}
> +		qcadev->susclk = devm_clk_get(&serdev->dev, NULL);
> +		if (IS_ERR(qcadev->susclk)) {
> +			dev_err(&serdev->dev, "failed to acquire clk\n");
> +			return PTR_ERR(qcadev->susclk);
> +		}
>  
> -	err = clk_set_rate(qcadev->susclk, SUSCLK_RATE_32KHZ);
> -	if (err)
> -		return err;
> +		err = clk_set_rate(qcadev->susclk, SUSCLK_RATE_32KHZ);
> +		if (err)
> +			return err;
>  
> -	err = clk_prepare_enable(qcadev->susclk);
> -	if (err)
> -		return err;
> +		err = clk_prepare_enable(qcadev->susclk);
> +		if (err)
> +			return err;
>  
> -	err = hci_uart_register_device(&qcadev->serdev_hu, &qca_proto);
> -	if (err)
> -		clk_disable_unprepare(qcadev->susclk);
> +		err = hci_uart_register_device(&qcadev->serdev_hu, &qca_proto);
> +		if (err)
> +			clk_disable_unprepare(qcadev->susclk);
> +	}
> +
> +out:	return err;
>  
> -	return err;
>  }
>  
>  static void qca_serdev_remove(struct serdev_device *serdev)
> @@ -1050,11 +1375,17 @@ static void qca_serdev_remove(struct serdev_device *serdev)
>  
>  	hci_uart_unregister_device(&qcadev->serdev_hu);
>  
> -	clk_disable_unprepare(qcadev->susclk);
> +	if (qcadev->btsoc_type == BTQCA_CHEROKEE) {
> +		devm_kfree(&serdev->dev, qcadev->bt_power->vreg_bulk);
> +		devm_kfree(&serdev->dev, qcadev->bt_power);

no need to free memory