[PATCH v6 3/3] Bluetooth: hci_qca: Add serdev support

From: Thierry Escande
Date: Wed Mar 28 2018 - 05:52:20 EST


Add support for Qualcomm serial slave devices. Probe the serial device,
retrieve its maximum speed and register a new hci uart device.

Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---

v6:
- Fix gpio name in error message

v5:
- Use gpio new name 'enable'

v4:
- Rename divclk4 as susclk (its name in the bt chip)
- Use gpiod_set_value_cansleep()
- Replace #include <linux/of.h> with <linux/mod_devicetable.h>
- Restore dependency on BT_HCIUART

v3:
- Remove redundant call to gpiod_set_value() after devm_gpiod_get()
- Check returned values for clk_set_rate() and clk_prepare_enable()
- Use clk_disable_unprepare()

v2:
- Fix author email

drivers/bluetooth/Kconfig | 1 +
drivers/bluetooth/hci_qca.c | 109 +++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 108 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
index 07e55cd8f8c8..e0f1a6609b68 100644
--- a/drivers/bluetooth/Kconfig
+++ b/drivers/bluetooth/Kconfig
@@ -196,6 +196,7 @@ config BT_HCIUART_BCM
config BT_HCIUART_QCA
bool "Qualcomm Atheros protocol support"
depends on BT_HCIUART
+ depends on BT_HCIUART_SERDEV
select BT_HCIUART_H4
select BT_QCA
help
diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index 05ec530b8a3a..1c4475d0707c 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -29,7 +29,11 @@
*/

#include <linux/kernel.h>
+#include <linux/clk.h>
#include <linux/debugfs.h>
+#include <linux/gpio/consumer.h>
+#include <linux/mod_devicetable.h>
+#include <linux/serdev.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
@@ -50,6 +54,9 @@
#define IBS_TX_IDLE_TIMEOUT_MS 2000
#define BAUDRATE_SETTLE_TIMEOUT_MS 300

+/* susclk rate */
+#define SUSCLK_RATE_32KHZ 32768
+
/* HCI_IBS transmit side sleep protocol states */
enum tx_ibs_states {
HCI_IBS_TX_ASLEEP,
@@ -111,6 +118,12 @@ struct qca_data {
u64 votes_off;
};

+struct qca_serdev {
+ struct hci_uart serdev_hu;
+ struct gpio_desc *bt_en;
+ struct clk *susclk;
+};
+
static void __serial_clock_on(struct tty_struct *tty)
{
/* TODO: Some chipset requires to enable UART clock on client
@@ -386,6 +399,7 @@ static void hci_ibs_wake_retrans_timeout(struct timer_list *t)
/* Initialize protocol */
static int qca_open(struct hci_uart *hu)
{
+ struct qca_serdev *qcadev;
struct qca_data *qca;

BT_DBG("hu %p qca_open", hu);
@@ -444,6 +458,13 @@ static int qca_open(struct hci_uart *hu)
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);
+ }
+
BT_DBG("HCI_UART_QCA open, tx_idle_delay=%u, wake_retrans=%u",
qca->tx_idle_delay, qca->wake_retrans);

@@ -512,6 +533,7 @@ static int qca_flush(struct hci_uart *hu)
/* Close protocol */
static int qca_close(struct hci_uart *hu)
{
+ struct qca_serdev *qcadev;
struct qca_data *qca = hu->priv;

BT_DBG("hu %p qca close", hu);
@@ -525,6 +547,13 @@ static int qca_close(struct hci_uart *hu)
destroy_workqueue(qca->workqueue);
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);
+ }
+
kfree_skb(qca->rx_skb);

hu->priv = NULL;
@@ -885,6 +914,14 @@ static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
return 0;
}

+static inline void host_set_baudrate(struct hci_uart *hu, unsigned int speed)
+{
+ if (hu->serdev)
+ serdev_device_set_baudrate(hu->serdev, speed);
+ else
+ hci_uart_set_baudrate(hu, speed);
+}
+
static int qca_setup(struct hci_uart *hu)
{
struct hci_dev *hdev = hu->hdev;
@@ -905,7 +942,7 @@ static int qca_setup(struct hci_uart *hu)
speed = hu->proto->init_speed;

if (speed)
- hci_uart_set_baudrate(hu, speed);
+ host_set_baudrate(hu, speed);

/* Setup user speed if needed */
speed = 0;
@@ -924,7 +961,7 @@ static int qca_setup(struct hci_uart *hu)
ret);
return ret;
}
- hci_uart_set_baudrate(hu, speed);
+ host_set_baudrate(hu, speed);
}

/* Setup patch / NVM configurations */
@@ -958,12 +995,80 @@ static struct hci_uart_proto qca_proto = {
.dequeue = qca_dequeue,
};

+static int qca_serdev_probe(struct serdev_device *serdev)
+{
+ struct qca_serdev *qcadev;
+ int err;
+
+ qcadev = devm_kzalloc(&serdev->dev, sizeof(*qcadev), GFP_KERNEL);
+ if (!qcadev)
+ return -ENOMEM;
+
+ qcadev->serdev_hu.serdev = serdev;
+ serdev_device_set_drvdata(serdev, qcadev);
+
+ 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);
+ }
+
+ err = clk_set_rate(qcadev->susclk, SUSCLK_RATE_32KHZ);
+ 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);
+
+ return err;
+}
+
+static void qca_serdev_remove(struct serdev_device *serdev)
+{
+ struct qca_serdev *qcadev = serdev_device_get_drvdata(serdev);
+
+ hci_uart_unregister_device(&qcadev->serdev_hu);
+
+ clk_disable_unprepare(qcadev->susclk);
+}
+
+static const struct of_device_id qca_bluetooth_of_match[] = {
+ { .compatible = "qcom,qca6174-bt" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, qca_bluetooth_of_match);
+
+static struct serdev_device_driver qca_serdev_driver = {
+ .probe = qca_serdev_probe,
+ .remove = qca_serdev_remove,
+ .driver = {
+ .name = "hci_uart_qca",
+ .of_match_table = qca_bluetooth_of_match,
+ },
+};
+
int __init qca_init(void)
{
+ serdev_device_driver_register(&qca_serdev_driver);
+
return hci_uart_register_proto(&qca_proto);
}

int __exit qca_deinit(void)
{
+ serdev_device_driver_unregister(&qca_serdev_driver);
+
return hci_uart_unregister_proto(&qca_proto);
}
--
2.14.1