Date:   Fri, 6 Jul 2018 15:21:10 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Balakrishna Godavarthi <bgodavar@...eaurora.org>
Cc:     marcel@...tmann.org, johan.hedberg@...il.com,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-bluetooth@...r.kernel.org, thierry.escande@...aro.org,
        rtatiya@...eaurora.org, hemantg@...eaurora.org,
        linux-arm-msm@...r.kernel.org, Stephen Boyd <swboyd@...omium.org>
Subject: Re: [PATCH v9 7/7] Bluetooth: hci_qca: Add support for Qualcomm
 Bluetooth chip wcn3990

On Thu, Jul 05, 2018 at 10:25:15PM +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 v9:
>     * moved flow control to vendor and set_baudarte functions.
>     * removed parent regs.
> 
> 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.
> 
> ---
>  drivers/bluetooth/btqca.h   |   3 +
>  drivers/bluetooth/hci_qca.c | 387 +++++++++++++++++++++++++++++++-----
>  2 files changed, 345 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/bluetooth/btqca.h b/drivers/bluetooth/btqca.h
> index a9c2779f3e07..0c01f375fe83 100644
> --- a/drivers/bluetooth/btqca.h
> +++ b/drivers/bluetooth/btqca.h
> @@ -37,6 +37,9 @@
>  #define EDL_TAG_ID_HCI			(17)
>  #define EDL_TAG_ID_DEEP_SLEEP		(27)
>  
> +#define QCA_WCN3990_POWERON_PULSE	0xFC
> +#define QCA_WCN3990_POWEROFF_PULSE	0xC0
> +
>  enum qca_bardrate {
>  	QCA_BAUDRATE_115200 	= 0,
>  	QCA_BAUDRATE_57600,
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 7ebfaa0edf3f..d62c7785a618 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -5,7 +5,7 @@
>   *  protocol extension to H4.
>   *
>   *  Copyright (C) 2007 Texas Instruments, Inc.
> - *  Copyright (c) 2010, 2012 The Linux Foundation. All rights reserved.
> + *  Copyright (c) 2010, 2012, 2018 The Linux Foundation. All rights reserved.
>   *
>   *  Acknowledgements:
>   *  This file is based on hci_ll.c, which was...
> @@ -31,9 +31,14 @@
>  #include <linux/kernel.h>
>  #include <linux/clk.h>
>  #include <linux/debugfs.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/mod_devicetable.h>
>  #include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/serdev.h>
>  
>  #include <net/bluetooth/bluetooth.h>
> @@ -124,12 +129,46 @@ enum qca_speed_type {
>  	QCA_OPER_SPEED
>  };
>  
> +/*
> + * Voltage regulator information required for configuring the
> + * QCA Bluetooth chipset
> + */
> +struct qca_vreg {
> +	const char *name;
> +	unsigned int min_uV;
> +	unsigned int max_uV;
> +	unsigned int load_uA;
> +};
> +
> +struct qca_vreg_data {
> +	enum qca_btsoc_type soc_type;
> +	struct qca_vreg *vregs;
> +	size_t num_vregs;
> +};
> +
> +/*
> + * Platform data for the QCA Bluetooth power driver.
> + */
> +struct qca_power {
> +	struct device *dev;
> +	const struct qca_vreg_data *vreg_data;
> +	struct regulator_bulk_data *vreg_bulk;
> +	bool vregs_on;
> +};
> +
>  struct qca_serdev {
>  	struct hci_uart	 serdev_hu;
>  	struct gpio_desc *bt_en;
>  	struct clk	 *susclk;
> +	enum qca_btsoc_type btsoc_type;
> +	struct qca_power *bt_power;
> +	u32 init_speed;
> +	u32 oper_speed;
>  };
>  
> +static int qca_power_setup(struct hci_uart *hu, bool on);
> +static void qca_power_shutdown(struct hci_uart *hu);
> +
>  static void __serial_clock_on(struct tty_struct *tty)
>  {
>  	/* TODO: Some chipset requires to enable UART clock on client
> @@ -407,6 +446,7 @@ static int qca_open(struct hci_uart *hu)
>  {
>  	struct qca_serdev *qcadev;
>  	struct qca_data *qca;
> +	int ret;
>  
>  	BT_DBG("hu %p qca_open", hu);
>  
> @@ -458,19 +498,32 @@ static int qca_open(struct hci_uart *hu)
>  
>  	hu->priv = qca;
>  
> -	timer_setup(&qca->wake_retrans_timer, hci_ibs_wake_retrans_timeout, 0);
> -	qca->wake_retrans = IBS_WAKE_RETRANS_TIMEOUT_MS;
> -
> -	timer_setup(&qca->tx_idle_timer, hci_ibs_tx_idle_timeout, 0);
> -	qca->tx_idle_delay = IBS_TX_IDLE_TIMEOUT_MS;
> -
>  	if (hu->serdev) {
>  		serdev_device_open(hu->serdev);
>  
>  		qcadev = serdev_device_get_drvdata(hu->serdev);
> -		gpiod_set_value_cansleep(qcadev->bt_en, 1);
> +		if (qcadev->btsoc_type != QCA_WCN3990) {
> +			gpiod_set_value_cansleep(qcadev->bt_en, 1);
> +		} else {
> +			hu->init_speed = qcadev->init_speed;
> +			hu->oper_speed = qcadev->oper_speed;
> +			ret = qca_power_setup(hu, true);
> +			if (ret) {
> +				destroy_workqueue(qca->workqueue);
> +				kfree_skb(qca->rx_skb);
> +				hu->priv = NULL;
> +				kfree(qca);
> +				return ret;
> +			}
> +		}
>  	}
>  
> +	timer_setup(&qca->wake_retrans_timer, hci_ibs_wake_retrans_timeout, 0);
> +	qca->wake_retrans = IBS_WAKE_RETRANS_TIMEOUT_MS;
> +
> +	timer_setup(&qca->tx_idle_timer, hci_ibs_tx_idle_timeout, 0);
> +	qca->tx_idle_delay = IBS_TX_IDLE_TIMEOUT_MS;
> +
>  	BT_DBG("HCI_UART_QCA open, tx_idle_delay=%u, wake_retrans=%u",
>  	       qca->tx_idle_delay, qca->wake_retrans);
>  
> @@ -554,10 +607,13 @@ static int qca_close(struct hci_uart *hu)
>  	qca->hu = NULL;
>  
>  	if (hu->serdev) {
> -		serdev_device_close(hu->serdev);
> -
>  		qcadev = serdev_device_get_drvdata(hu->serdev);
> -		gpiod_set_value_cansleep(qcadev->bt_en, 0);
> +		if (qcadev->btsoc_type == QCA_WCN3990)
> +			qca_power_shutdown(hu);
> +		else
> +			gpiod_set_value_cansleep(qcadev->bt_en, 0);
> +
> +		serdev_device_close(hu->serdev);
>  	}
>  
>  	kfree_skb(qca->rx_skb);
> @@ -891,6 +947,7 @@ static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
>  	struct hci_uart *hu = hci_get_drvdata(hdev);
>  	struct qca_data *qca = hu->priv;
>  	struct sk_buff *skb;
> +	struct qca_serdev *qcadev;
>  	u8 cmd[] = { 0x01, 0x48, 0xFC, 0x01, 0x00 };
>  
>  	if (baudrate > QCA_BAUDRATE_3200000)
> @@ -904,6 +961,13 @@ static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
>  		return -ENOMEM;
>  	}
>  
> +	/* Disabling hardware flow control is mandate while

nit: s/mandate/mandatory|required/

> +	 * sending change baudrate request to wcn3990 SoC.
> +	 */
> +	qcadev = serdev_device_get_drvdata(hu->serdev);
> +	if (qcadev->btsoc_type == QCA_WCN3990)
> +		hci_uart_set_flow_control(hu, true);
> +
>  	/* Assign commands to change baudrate and packet type. */
>  	skb_put_data(skb, cmd, sizeof(cmd));
>  	hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;
> @@ -919,6 +983,9 @@ static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
>  	schedule_timeout(msecs_to_jiffies(BAUDRATE_SETTLE_TIMEOUT_MS));
>  	set_current_state(TASK_RUNNING);
>  
> +	if (qcadev->btsoc_type == QCA_WCN3990)
> +		hci_uart_set_flow_control(hu, false);
> +
>  	return 0;
>  }
>  
> @@ -930,6 +997,36 @@ static inline void host_set_baudrate(struct hci_uart *hu, unsigned int speed)
>  		hci_uart_set_baudrate(hu, speed);
>  }
>  
> +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)
> +		return -ENOMEM;
> +
> +	/* Disabling hardware flow control is mandate while

Same nit as above

> +	 * sending vendor power on and off pulse to SoC.
> +	 */

The function is called qca_send_vendor_cmd(), the comment about power
on/off pulses seems misplaced here. Are there other 'vendor commands'
that require a different flow control behavior?

Perhaps the function should have a different name or we need another
wrapper.

> +	hci_uart_set_flow_control(hu, true);

Should the changing of the flow control be limited to wcn3990? As of
now the function is only called for wcn3990, however this is not
stated as a requirement and might change in the future.

> +	skb_put_u8(skb, cmd);
> +	hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;
> +
> +	skb_queue_tail(&qca->txq, skb);
> +	hci_uart_tx_wakeup(hu);
> +
> +	/* Wait for 100 uS for SoC to settle down */
> +	usleep_range(100, 200);

Is this needed for any 'vendor command' or directly related with the
power on/off pulses?

> +	hci_uart_set_flow_control(hu, false);
> +
> +	return 0;
> +}
> +
>  static unsigned int qca_get_speed(struct hci_uart *hu,
>  				  enum qca_speed_type speed_type)
>  {
> @@ -952,10 +1049,19 @@ static unsigned int qca_get_speed(struct hci_uart *hu,
>  
>  static int qca_check_speeds(struct hci_uart *hu)
>  {
> -	/* One or the other speeds should be non zero. */
> -	if (!qca_get_speed(hu, QCA_INIT_SPEED) &&
> -	    !qca_get_speed(hu, QCA_OPER_SPEED))
> +	struct qca_serdev *qcadev;
> +
> +	qcadev = serdev_device_get_drvdata(hu->serdev);
> +	if ((qcadev->btsoc_type == QCA_WCN3990 &&
> +	    !qca_get_speed(hu, QCA_INIT_SPEED)) ||
> +	    !qca_get_speed(hu, QCA_OPER_SPEED)) {
> +		/* Both INIT and OPER speed should be non zero. */
>  		return -EINVAL;
> +	} else if (!qca_get_speed(hu, QCA_INIT_SPEED) &&
> +		    !qca_get_speed(hu, QCA_OPER_SPEED)) {
> +		/* One or the other speeds should be non zero. */
> +		return -EINVAL;
> +	}

It is questionable if the comments are useful, they are basically
stating the same as the conditions.

if-else statements with a single statement in all branches shouldn't
use curly braces. Personally I don't dislike them in this case with
the multi-line conditions, but in principle they shoulnd't be there.

nit: this would be easier to read with nested if statements:

	if (qcadev->btsoc_type == QCA_WCN3990)
		if (!qca_get_speed(hu, QCA_INIT_SPEED)) ||
		    !qca_get_speed(hu, QCA_OPER_SPEED))
			return -EINVAL;
	else
		if (!qca_get_speed(hu, QCA_INIT_SPEED) &&
		    !qca_get_speed(hu, QCA_OPER_SPEED)) {
			return -EINVAL;

>  	return 0;
>  }
> @@ -986,15 +1092,40 @@ static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type)
>  	return 0;
>  }
>  
> +static int qca_wcn3990_init(struct hci_uart *hu)
> +{
> +	int ret;
> +
> +	ret = qca_send_vendor_cmd(hu->hdev, QCA_WCN3990_POWERON_PULSE);
> +	if (ret)
> +		return ret;
> +
> +	/* Wait for 100 ms for SoC to boot up */
> +	msleep(100);
> +	serdev_device_close(hu->serdev);
> +	ret = serdev_device_open(hu->serdev);
> +	if (ret) {
> +		bt_dev_err(hu->hdev, "failed to open port");
> +		return ret;
> +	}
> +
> +	/* Setup initial baudrate */
> +	qca_set_speed(hu, QCA_INIT_SPEED);

The comment is a bit redundant.

> +	hci_uart_set_flow_control(hu, false);
> +
> +	return 0;
> +}
> +
>  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);
>  
>  	ret = qca_check_speeds(hu);
>  	if (ret)
> @@ -1006,6 +1137,21 @@ 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");

Seems like this should be bt_dev_info() for consistency with Rome.

> +		ret = qca_wcn3990_init(hu);
> +		if (ret)
> +			return ret;
> +
> +		ret = qca_read_soc_version(hdev, &soc_ver);
> +		if (ret < 0 || soc_ver == 0) {
> +			bt_dev_err(hdev, "Failed to get version %d", ret);
> +			return ret;
> +		}
> +	} else {
> +		bt_dev_info(hdev, "ROME setup");
> +	}
> +
>  	/* Setup user speed if needed */
>  	speed = qca_get_speed(hu, QCA_OPER_SPEED);
>  	if (speed) {
> @@ -1016,16 +1162,18 @@ static int qca_setup(struct hci_uart *hu)
>  		qca_baudrate = qca_get_baudrate_value(speed);
>  	}
>  
> -	/* Get QCA version information */
> -	ret = qca_read_soc_version(hdev, &soc_ver);
> -	if (ret < 0 || soc_ver == 0) {
> -		bt_dev_err(hdev, "QCA Failed to get version (%d)", ret);
> -		return ret;
> +	if (!soc_ver) {


The following would probably be clearer:

  	if (qcadev->btsoc_type != QCA_WCN3990) {

> +		/* Get QCA version information */
> +		ret = qca_read_soc_version(hdev, &soc_ver);
> +		if (ret < 0 || soc_ver == 0) {
> +			bt_dev_err(hdev, "QCA Failed to get version (%d)", ret);
> +			return ret;
> +		}
> +		bt_dev_info(hdev, "QCA controller version 0x%08x", soc_ver);

Couldn't we hide some of this in qca_read_soc_version()?

qca_read_soc_version() could at least do the logging in the error case
(the 'soc_ver == 0' case could be handled there as well), which would
leave us with:


	ret = qca_read_soc_version(hdev, &soc_ver);
	if (ret)
		return ret;

And the same above.

The controller version can be logged outside of the branch for both
wcn3990 and Rome.

>  	}
> -	bt_dev_info(hdev, "QCA controller version 0x%08x", soc_ver);
>  
>  	/* Setup patch / NVM configurations */
> -	ret = qca_uart_setup(hdev, qca_baudrate, QCA_ROME, soc_ver);
> +	ret = qca_uart_setup(hdev, qca_baudrate, qcadev->btsoc_type, soc_ver);
>  	if (!ret) {
>  		set_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
>  		qca_debugfs_init(hdev);
> @@ -1061,9 +1209,123 @@ static struct hci_uart_proto qca_proto = {
>  	.dequeue	= qca_dequeue,
>  };
>  
> +static const struct qca_vreg_data qca_soc_data = {
> +	.soc_type = QCA_WCN3990,
> +	.vregs = (struct qca_vreg []) {
> +		{ "vddio",   1800000, 1800000,  0 },
> +		{ "vddxo",   1800000, 1800000,  1 },
> +		{ "vddrf",   1304000, 1304000,  1 },
> +		{ "vddch0",  3000000, 3312000,  1 },
> +	},
> +	.num_vregs = 4,
> +};

I didn't chime in earlier in the discussion with Stephen on the
regulators (https://patchwork.kernel.org/patch/10467911/), however I
agree with him that specifying at load of 1uA doesn't seem to make
much sense. What would happen if the load remained unspecified (or 0)?

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