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Diffstat (limited to 'Documentation/driver-api/phy/phy.rst')
| -rw-r--r-- | Documentation/driver-api/phy/phy.rst | 49 |
1 files changed, 38 insertions, 11 deletions
diff --git a/Documentation/driver-api/phy/phy.rst b/Documentation/driver-api/phy/phy.rst index 8fc1ce0bb905..81785c084f3e 100644 --- a/Documentation/driver-api/phy/phy.rst +++ b/Documentation/driver-api/phy/phy.rst @@ -94,7 +94,8 @@ Inorder to dereference the private data (in phy_ops), the phy provider driver can use phy_set_drvdata() after creating the PHY and use phy_get_drvdata() in phy_ops to get back the private data. -4. Getting a reference to the PHY +Getting a reference to the PHY +============================== Before the controller can make use of the PHY, it has to get a reference to it. This framework provides the following APIs to get a reference to the PHY. @@ -102,27 +103,31 @@ it. This framework provides the following APIs to get a reference to the PHY. :: struct phy *phy_get(struct device *dev, const char *string); - struct phy *phy_optional_get(struct device *dev, const char *string); struct phy *devm_phy_get(struct device *dev, const char *string); struct phy *devm_phy_optional_get(struct device *dev, const char *string); + struct phy *devm_of_phy_get(struct device *dev, struct device_node *np, + const char *con_id); + struct phy *devm_of_phy_optional_get(struct device *dev, + struct device_node *np, + const char *con_id); struct phy *devm_of_phy_get_by_index(struct device *dev, struct device_node *np, int index); -phy_get, phy_optional_get, devm_phy_get and devm_phy_optional_get can -be used to get the PHY. In the case of dt boot, the string arguments +phy_get, devm_phy_get and devm_phy_optional_get can be used to get the PHY. +In the case of dt boot, the string arguments should contain the phy name as given in the dt data and in the case of non-dt boot, it should contain the label of the PHY. The two devm_phy_get associates the device with the PHY using devres on successful PHY get. On driver detach, release function is invoked on -the devres data and devres data is freed. phy_optional_get and -devm_phy_optional_get should be used when the phy is optional. These -two functions will never return -ENODEV, but instead returns NULL when -the phy cannot be found.Some generic drivers, such as ehci, may use multiple -phys and for such drivers referencing phy(s) by name(s) does not make sense. In -this case, devm_of_phy_get_by_index can be used to get a phy reference based on -the index. +the devres data and devres data is freed. +The _optional_get variants should be used when the phy is optional. These +functions will never return -ENODEV, but instead return NULL when +the phy cannot be found. +Some generic drivers, such as ehci, may use multiple phys. In this case, +devm_of_phy_get or devm_of_phy_get_by_index can be used to get a phy +reference based on name or index. It should be noted that NULL is a valid phy reference. All phy consumer calls on the NULL phy become NOPs. That is the release calls, @@ -130,6 +135,28 @@ the phy_init() and phy_exit() calls, and phy_power_on() and phy_power_off() calls are all NOP when applied to a NULL phy. The NULL phy is useful in devices for handling optional phy devices. +Order of API calls +================== + +The general order of calls should be:: + + [devm_][of_]phy_get() + phy_init() + phy_power_on() + [phy_set_mode[_ext]()] + ... + phy_power_off() + phy_exit() + [[of_]phy_put()] + +Some PHY drivers may not implement :c:func:`phy_init` or :c:func:`phy_power_on`, +but controllers should always call these functions to be compatible with other +PHYs. Some PHYs may require :c:func:`phy_set_mode <phy_set_mode_ext>`, while +others may use a default mode (typically configured via devicetree or other +firmware). For compatibility, you should always call this function if you know +what mode you will be using. Generally, this function should be called after +:c:func:`phy_power_on`, although some PHY drivers may allow it at any time. + Releasing a reference to the PHY ================================ |