Hi,
On Saturday 01 February 2014 07:45 PM, Andrew Lunn wrote:
> Add devm_phy_optional_get, which should be used when the phy is
> optional. It does not return an error when the phy does not exist,
> rather it returns NULL, which is considered as a valid phy, but
> results in NOPs when used with the consumer API.
>
> Signed-off-by: Andrew Lunn <andrew@xxxxxxx>
> ---
> Documentation/phy.txt | 18 +++++++++++-------
> drivers/phy/phy-core.c | 27 +++++++++++++++++++++++++--
> include/linux/phy/phy.h | 7 +++++++
> 3 files changed, 43 insertions(+), 9 deletions(-)
>
> diff --git a/Documentation/phy.txt b/Documentation/phy.txt
> index 2e24b993e95f..1f34a44975ba 100644
> --- a/Documentation/phy.txt
> +++ b/Documentation/phy.txt
> @@ -76,13 +76,17 @@ 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 *devm_phy_get(struct device *dev, const char *string);
> -
> -phy_get and devm_phy_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 only difference between the two APIs is that devm_phy_get associates the
> -device with the PHY using devres on successful PHY get. On driver detach,
> -release function is invoked on the the devres data and devres data is freed.
> +struct phy *devm_phy_optional_get(struct device *dev, const char *string);
> +
> +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 the devres data and devres
> +data is freed. devm_phy_optional_get should be used when the phy is
> +optional. It does not return an error when the phy cannot be found, it
> +returns NULL.
>
> 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,
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index 74d34b5cc75c..4992523111b5 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -390,13 +390,13 @@ struct phy *phy_get(struct device *dev, const char *string)
> string);
> phy = of_phy_get(dev, index);
> if (IS_ERR(phy)) {
> - dev_err(dev, "unable to find phy\n");
> + dev_dbg(dev, "unable to find phy\n");
> return phy;
> }
> } else {
> phy = phy_lookup(dev, string);
> if (IS_ERR(phy)) {
> - dev_err(dev, "unable to find phy\n");
> + dev_dbg(dev, "unable to find phy\n");
> return phy;
> }
Hans de Goede has a patch [1] that deals with this. You might want to have a
look at it.
[1] -> https://groups.google.com/forum/#!msg/linux-sunxi/NfWi6rWcGsA/nw2jUw8KVOEJ
> }
> @@ -441,6 +441,29 @@ struct phy *devm_phy_get(struct device *dev, const char *string)
> EXPORT_SYMBOL_GPL(devm_phy_get);
>
> /**
> + * devm_phy_optional_get() - lookup and obtain a reference to an optional phy.
> + * @dev: device that requests this phy
> + * @string: the phy name as given in the dt data or phy device name
> + * for non-dt case
> + *
> + * Gets the phy using phy_get(), and associates a device with it using
> + * devres. On driver detach, release function is invoked on the devres data,
> + * then, devres data is freed. This differs to devm_phy_get() in that if the
> + * phy does not exist, it is not considered an error. Instead the NULL phy
> + * is returned, which can be passed to all other phy consumer calls.
It doesn't explain how devm_phy_optional_get is different from phy_get :-s
> + */
> +struct phy *devm_phy_optional_get(struct device *dev, const char *string)
> +{
> + struct phy *phy = devm_phy_get(dev, string);
> +
> + if (PTR_ERR(phy) == -ENODEV)
> + phy = NULL;
Do we need an API in phy-core to handle this? Can't this be done in the
controller driver itself?
Cheers
Kishon
--
To unsubscribe from this list: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
