diff options
| author | Chen-Yu Tsai <wens@csie.org> | 2018-12-17 12:04:42 +0800 |
|---|---|---|
| committer | Marcel Holtmann <marcel@holtmann.org> | 2018-12-19 00:28:38 +0100 |
| commit | 90bc07cc59ac32f37d6de78a501246575c8866bf (patch) | |
| tree | a34f38ca72d4e2dd2318417a61a90c66729622a2 | |
| parent | 55dbfcd0f621a745acfd8e3221c41be181b5b128 (diff) | |
Bluetooth: hci_bcm: Add support for LPO clock
The Broadcom Bluetooth controllers support a secondary LPO clock at
32.768 kHz. This external clock provides low power timing, and also
a way to detect the frequency of the main reference clock. On many
designs without NVRAM and a non-default reference clock, this must
be used or the controller will not function correctly.
Tested-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
| -rw-r--r-- | drivers/bluetooth/hci_bcm.c | 41 |
1 files changed, 36 insertions, 5 deletions
diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c index 1584c95c9c34..345d728a5434 100644 --- a/drivers/bluetooth/hci_bcm.c +++ b/drivers/bluetooth/hci_bcm.c @@ -72,7 +72,8 @@ * @btpu: Apple ACPI method to drive BT_REG_ON pin high ("Bluetooth Power Up") * @btpd: Apple ACPI method to drive BT_REG_ON pin low ("Bluetooth Power Down") * @txco_clk: external reference frequency clock used by Bluetooth device - * @clk_enabled: whether @txco_clk is prepared and enabled + * @lpo_clk: external LPO clock used by Bluetooth device + * @clk_enabled: whether clocks are prepared and enabled * @init_speed: default baudrate of Bluetooth device; * the host UART is initially set to this baudrate so that * it can configure the Bluetooth device for @oper_speed @@ -103,6 +104,7 @@ struct bcm_device { #endif struct clk *txco_clk; + struct clk *lpo_clk; bool clk_enabled; u32 init_speed; @@ -215,21 +217,34 @@ static int bcm_gpio_set_power(struct bcm_device *dev, bool powered) int err; if (powered && !dev->clk_enabled) { - err = clk_prepare_enable(dev->txco_clk); + /* LPO clock needs to be 32.768 kHz */ + err = clk_set_rate(dev->lpo_clk, 32768); + if (err) { + dev_err(dev->dev, "Could not set LPO clock rate\n"); + return err; + } + + err = clk_prepare_enable(dev->lpo_clk); if (err) return err; + + err = clk_prepare_enable(dev->txco_clk); + if (err) + goto err_lpo_clk_disable; } err = dev->set_shutdown(dev, powered); if (err) - goto err_clk_disable; + goto err_txco_clk_disable; err = dev->set_device_wakeup(dev, powered); if (err) goto err_revert_shutdown; - if (!powered && dev->clk_enabled) + if (!powered && dev->clk_enabled) { clk_disable_unprepare(dev->txco_clk); + clk_disable_unprepare(dev->lpo_clk); + } dev->clk_enabled = powered; @@ -237,9 +252,12 @@ static int bcm_gpio_set_power(struct bcm_device *dev, bool powered) err_revert_shutdown: dev->set_shutdown(dev, !powered); -err_clk_disable: +err_txco_clk_disable: if (powered && !dev->clk_enabled) clk_disable_unprepare(dev->txco_clk); +err_lpo_clk_disable: + if (powered && !dev->clk_enabled) + clk_disable_unprepare(dev->lpo_clk); return err; } @@ -934,6 +952,19 @@ static int bcm_get_resources(struct bcm_device *dev) if (IS_ERR(dev->txco_clk)) dev->txco_clk = NULL; + dev->lpo_clk = devm_clk_get(dev->dev, "lpo"); + if (dev->lpo_clk == ERR_PTR(-EPROBE_DEFER)) + return PTR_ERR(dev->lpo_clk); + + if (IS_ERR(dev->lpo_clk)) + dev->lpo_clk = NULL; + + /* Check if we accidentally fetched the lpo clock twice */ + if (dev->lpo_clk && clk_is_match(dev->lpo_clk, dev->txco_clk)) { + devm_clk_put(dev->dev, dev->txco_clk); + dev->txco_clk = NULL; + } + dev->device_wakeup = devm_gpiod_get_optional(dev->dev, "device-wakeup", GPIOD_OUT_LOW); if (IS_ERR(dev->device_wakeup)) |