Date:   Thu, 2 Aug 2018 12:57:33 -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
Subject: Re: [PATCH v13 7/7] Bluetooth: hci_qca: Add support for Qualcomm
 Bluetooth chip wcn3990

On Fri, Aug 03, 2018 at 12:37:32AM +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>
> Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
> ---
> Changes in v13:
>    * updated review comments.
> 
> Changes in v12:
>     * removed retrying iteration loop in qca_wcn3990_init.
>  
> Changes in v11:
>     * removed support to read regulator currents from dts.
>     * updated review comments.
> 
> Changes in v10:
>     * added support to read regulator currents from dts.
>     * added support to try to connect with chip if it fails to respond to initial commands
>     * updated review comments.
> 
> 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 | 402 +++++++++++++++++++++++++++++++-----
>  2 files changed, 358 insertions(+), 47 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 a6e7d38ef931..66f36527e4dd 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_dev *hdev);
> +
>  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->hdev);
> +		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 mandatory while
> +	 * 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 +997,43 @@ static inline void host_set_baudrate(struct hci_uart *hu, unsigned int speed)
>  		hci_uart_set_baudrate(hu, speed);
>  }
>  
> +static int qca_send_power_pulse(struct hci_dev *hdev, u8 cmd)
> +{
> +	struct hci_uart *hu = hci_get_drvdata(hdev);
> +	struct qca_data *qca = hu->priv;
> +	struct sk_buff *skb;
> +
> +	/* These power pulses are single byte command which are sent
> +	 * at required baudrate to wcn3990. On wcn3990, we have an external
> +	 * circuit at Tx pin which decodes the pulse sent at specific baudrate.
> +	 * For example, wcn3990 supports RF COEX antenna for both Wi-Fi/BT
> +	 * and also we use the same power inputs to turn on and off for
> +	 * Wi-Fi/BT. Powering up the power sources will not enable BT, until
> +	 * we send a power on pulse at 115200 bps. This algorithm will help to
> +	 * save power. Disabling hardware flow control is mandatory while
> +	 * sending power pulses to SoC.
> +	 */
> +	bt_dev_dbg(hdev, "sending power pulse %02x to SoC", cmd);
> +
> +	skb = bt_skb_alloc(sizeof(cmd), GFP_KERNEL);
> +	if (!skb)
> +		return -ENOMEM;
> +
> +	hci_uart_set_flow_control(hu, true);
> +
> +	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);
> +	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)
>  {
> @@ -952,9 +1056,18 @@ static unsigned int qca_get_speed(struct hci_uart *hu,
>  
>  static int qca_check_speeds(struct hci_uart *hu)
>  {
> -	if (!qca_get_speed(hu, QCA_INIT_SPEED) ||
> -	    !qca_get_speed(hu, QCA_OPER_SPEED))
> -		return -EINVAL;
> +	struct qca_serdev *qcadev;
> +
> +	qcadev = serdev_device_get_drvdata(hu->serdev);
> +	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;
>  }
> @@ -974,7 +1087,7 @@ static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type)
>  			return 0;
>  
>  		qca_baudrate = qca_get_baudrate_value(speed);
> -		bt_dev_info(hu->hdev, "Set UART speed to %d", speed);
> +		bt_dev_dbg(hu->hdev, "Set UART speed to %d", speed);
>  		ret = qca_set_baudrate(hu->hdev, qca_baudrate);
>  		if (ret)
>  			return ret;
> @@ -985,15 +1098,51 @@ 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, u32 *soc_ver)
> +{

I focussed more on other things in the last review rounds and
overlooked that qca_read_soc_version() and the soc_ver pointer slipped
in here with v10 (v9: https://patchwork.kernel.org/patch/10510029/).

In a similar line as in an earlier discussion about reading the SoC
version in qca_uart_setup() (https://patchwork.kernel.org/patch/10467903/)
I don't think the init function is the right place and it shouldn't
receive this soc_ver parameter about which it doesn't really
care. Please switch back as it was in v9 and read the SoC version in
qca_setup() (like it is done for Rome).

Then we should be done from my side.

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