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    Subject[PATCH v3 06/11] staging: typec: fusb302: Add support for USB2 charger detection through extcon
    Date
    The fusb302 port-controller relies on an external device doing USB2
    charger-type detection.

    The Intel Whiskey Cove PMIC with which the fusb302 is combined on some
    X86/ACPI platforms already has a charger-type detection driver which
    uses extcon to communicate the detected charger-type.

    Rather then inventing a new API for USB2 charger-type detection
    specifically for use with the tcpm code, this commit simply re-uses the
    existing extcon API and uses that do USB2 charger detection.

    Note that the "fcs,extcon-name" property name is only for kernel internal
    use by X86/ACPI platform code and as such is NOT documented in
    the fusb302 devicetree bindings.

    Cc: "Yueyao (Nathan) Zhu" <yueyao@google.com>
    Signed-off-by: Hans de Goede <hdegoede@redhat.com>
    ---
    Changes in v2:
    -Put extcon code directly in fusb302.c rather then introducing helpers
    which are only used by fusb302.c

    Changes in v3:
    -Improve commit message
    ---
    drivers/staging/typec/fusb302/fusb302.c | 49 +++++++++++++++++++++++++++++++++
    1 file changed, 49 insertions(+)

    diff --git a/drivers/staging/typec/fusb302/fusb302.c b/drivers/staging/typec/fusb302/fusb302.c
    index 675161cf4f3a..6f007f66d597 100644
    --- a/drivers/staging/typec/fusb302/fusb302.c
    +++ b/drivers/staging/typec/fusb302/fusb302.c
    @@ -17,6 +17,7 @@
    #include <linux/debugfs.h>
    #include <linux/delay.h>
    #include <linux/errno.h>
    +#include <linux/extcon.h>
    #include <linux/gpio.h>
    #include <linux/i2c.h>
    #include <linux/interrupt.h>
    @@ -96,6 +97,7 @@ struct fusb302_chip {

    int gpio_int_n;
    int gpio_int_n_irq;
    + struct extcon_dev *extcon;

    struct workqueue_struct *wq;
    struct delayed_work bc_lvl_handler;
    @@ -516,6 +518,38 @@ static int tcpm_get_vbus(struct tcpc_dev *dev)
    return ret;
    }

    +static int tcpm_get_current_limit(struct tcpc_dev *dev)
    +{
    + struct fusb302_chip *chip = container_of(dev, struct fusb302_chip,
    + tcpc_dev);
    + int current_limit = 0;
    + unsigned long timeout;
    +
    + if (!chip->extcon)
    + return 0;
    +
    + /*
    + * USB2 Charger detection may still be in progress when we get here,
    + * this can take upto 600ms, wait 800ms max.
    + */
    + timeout = jiffies + msecs_to_jiffies(800);
    + do {
    + if (extcon_get_state(chip->extcon, EXTCON_CHG_USB_SDP) == 1)
    + current_limit = 500;
    +
    + if (extcon_get_state(chip->extcon, EXTCON_CHG_USB_CDP) == 1 ||
    + extcon_get_state(chip->extcon, EXTCON_CHG_USB_ACA) == 1)
    + current_limit = 1500;
    +
    + if (extcon_get_state(chip->extcon, EXTCON_CHG_USB_DCP) == 1)
    + current_limit = 2000;
    +
    + msleep(50);
    + } while (current_limit == 0 && time_before(jiffies, timeout));
    +
    + return current_limit;
    +}
    +
    static int fusb302_set_cc_pull(struct fusb302_chip *chip,
    bool pull_up, bool pull_down)
    {
    @@ -1201,6 +1235,7 @@ static void init_tcpc_dev(struct tcpc_dev *fusb302_tcpc_dev)
    {
    fusb302_tcpc_dev->init = tcpm_init;
    fusb302_tcpc_dev->get_vbus = tcpm_get_vbus;
    + fusb302_tcpc_dev->get_current_limit = tcpm_get_current_limit;
    fusb302_tcpc_dev->set_cc = tcpm_set_cc;
    fusb302_tcpc_dev->get_cc = tcpm_get_cc;
    fusb302_tcpc_dev->set_polarity = tcpm_set_polarity;
    @@ -1685,6 +1720,7 @@ static int fusb302_probe(struct i2c_client *client,
    struct fusb302_chip *chip;
    struct i2c_adapter *adapter;
    struct device *dev = &client->dev;
    + const char *name;
    int ret = 0;
    u32 v;

    @@ -1717,6 +1753,19 @@ static int fusb302_probe(struct i2c_client *client,
    if (!device_property_read_u32(dev, "fcs,operating-sink-microwatt", &v))
    chip->tcpc_config.operating_snk_mw = v / 1000;

    + /*
    + * Devicetree platforms should get extcon via phandle (not yet
    + * supported). On ACPI platforms, we get the name from a device prop.
    + * This device prop is for kernel internal use only and is expected
    + * to be set by the platform code which also registers the i2c client
    + * for the fusb302.
    + */
    + if (device_property_read_string(dev, "fcs,extcon-name", &name) == 0) {
    + chip->extcon = extcon_get_extcon_dev(name);
    + if (!chip->extcon)
    + return -EPROBE_DEFER;
    + }
    +
    ret = fusb302_debugfs_init(chip);
    if (ret < 0)
    return ret;
    --
    2.13.4
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