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    Subject[PATCH v2 07/15] Bluetooth: hci_bcm: Use "txco" and "extclk" to get clock reference
    Date
    Originally the device tree binding only specified one clock reference,
    with the name "extclk". The driver simply retrieves the clock without
    bothering to specify a name.

    Since we added a second clock to the binding, we need to fetch the
    clocks by name now. First we try the new name "txco", then fall back
    to the old name "extclk", and finally try retrieving a clock without
    using any name, to cover any instances where a bad device tree or
    firmware worked by accident.

    In the last case, we should take care that we don't get the same
    clock twice when we add support for the "lpo" clock.

    Signed-off-by: Chen-Yu Tsai <wens@csie.org>
    ---
    drivers/bluetooth/hci_bcm.c | 41 +++++++++++++++++++++++++++----------
    1 file changed, 30 insertions(+), 11 deletions(-)

    diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
    index ff73ecb8215f..1584c95c9c34 100644
    --- a/drivers/bluetooth/hci_bcm.c
    +++ b/drivers/bluetooth/hci_bcm.c
    @@ -71,8 +71,8 @@
    * @btlp: Apple ACPI method to toggle BT_WAKE pin ("Bluetooth Low Power")
    * @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")
    - * @clk: clock used by Bluetooth device
    - * @clk_enabled: whether @clk is prepared and enabled
    + * @txco_clk: external reference frequency clock used by Bluetooth device
    + * @clk_enabled: whether @txco_clk is 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
    @@ -102,7 +102,7 @@ struct bcm_device {
    int gpio_int_idx;
    #endif

    - struct clk *clk;
    + struct clk *txco_clk;
    bool clk_enabled;

    u32 init_speed;
    @@ -215,7 +215,7 @@ static int bcm_gpio_set_power(struct bcm_device *dev, bool powered)
    int err;

    if (powered && !dev->clk_enabled) {
    - err = clk_prepare_enable(dev->clk);
    + err = clk_prepare_enable(dev->txco_clk);
    if (err)
    return err;
    }
    @@ -229,7 +229,7 @@ static int bcm_gpio_set_power(struct bcm_device *dev, bool powered)
    goto err_revert_shutdown;

    if (!powered && dev->clk_enabled)
    - clk_disable_unprepare(dev->clk);
    + clk_disable_unprepare(dev->txco_clk);

    dev->clk_enabled = powered;

    @@ -239,7 +239,7 @@ static int bcm_gpio_set_power(struct bcm_device *dev, bool powered)
    dev->set_shutdown(dev, !powered);
    err_clk_disable:
    if (powered && !dev->clk_enabled)
    - clk_disable_unprepare(dev->clk);
    + clk_disable_unprepare(dev->txco_clk);
    return err;
    }

    @@ -896,6 +896,25 @@ static int bcm_gpio_set_shutdown(struct bcm_device *dev, bool powered)
    return 0;
    }

    +/* Try a bunch of names for TXCO */
    +static struct clk *bcm_get_txco(struct device *dev)
    +{
    + struct clk *clk;
    +
    + /* New explicit name */
    + clk = devm_clk_get(dev, "txco");
    + if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
    + return clk;
    +
    + /* Deprecated name */
    + clk = devm_clk_get(dev, "extclk");
    + if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
    + return clk;
    +
    + /* Original code used no name at all */
    + return devm_clk_get(dev, NULL);
    +}
    +
    static int bcm_get_resources(struct bcm_device *dev)
    {
    const struct dmi_system_id *dmi_id;
    @@ -905,15 +924,15 @@ static int bcm_get_resources(struct bcm_device *dev)
    if (x86_apple_machine && !bcm_apple_get_resources(dev))
    return 0;

    - dev->clk = devm_clk_get(dev->dev, NULL);
    + dev->txco_clk = bcm_get_txco(dev->dev);

    /* Handle deferred probing */
    - if (dev->clk == ERR_PTR(-EPROBE_DEFER))
    - return PTR_ERR(dev->clk);
    + if (dev->txco_clk == ERR_PTR(-EPROBE_DEFER))
    + return PTR_ERR(dev->txco_clk);

    /* Ignore all other errors as before */
    - if (IS_ERR(dev->clk))
    - dev->clk = NULL;
    + if (IS_ERR(dev->txco_clk))
    + dev->txco_clk = NULL;

    dev->device_wakeup = devm_gpiod_get_optional(dev->dev, "device-wakeup",
    GPIOD_OUT_LOW);
    --
    2.19.1
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