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Date: Tue, 4 Jun 2013 17:56:01 +0530
From: Kishon Vijay Abraham I <kishon@...com>
To: Sylwester Nawrocki <s.nawrocki@...sung.com>
CC: <grant.likely@...aro.org>, <tony@...mide.com>, <balbi@...com>,
<arnd@...db.de>, <swarren@...dia.com>,
<linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-usb@...r.kernel.org>, <rob.herring@...xeda.com>,
<rob@...dley.net>, <b-cousson@...com>, <linux@....linux.org.uk>,
<gregkh@...uxfoundation.org>, <benoit.cousson@...aro.org>,
<mchehab@...hat.com>, <akpm@...ux-foundation.org>,
<cesarb@...arb.net>, <davem@...emloft.net>, <rnayak@...com>,
<shawn.guo@...aro.org>, <santosh.shilimkar@...com>,
<devicetree-discuss@...ts.ozlabs.org>, <linux-doc@...r.kernel.org>,
<nsekhar@...com>
Subject: Re: [PATCH v6 1/9] drivers: phy: add generic PHY framework
Hi,
On Tuesday 04 June 2013 03:51 PM, Sylwester Nawrocki wrote:
> On 04/29/2013 12:03 PM, Kishon Vijay Abraham I wrote:
>> The PHY framework provides a set of APIs for the PHY drivers to
>> create/destroy a PHY and APIs for the PHY users to obtain a reference to the
>> PHY with or without using phandle. For dt-boot, the PHY drivers should
>> also register *PHY provider* with the framework.
>>
>> PHY drivers should create the PHY by passing id and ops like init, exit,
>> power_on and power_off. This framework is also pm runtime enabled.
>>
>> The documentation for the generic PHY framework is added in
>> Documentation/phy.txt and the documentation for dt binding can be found at
>> Documentation/devicetree/bindings/phy/phy-bindings.txt
>>
>> Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
>> ---
>> .../devicetree/bindings/phy/phy-bindings.txt | 66 +++
>> Documentation/phy.txt | 123 +++++
>> MAINTAINERS | 7 +
>> drivers/Kconfig | 2 +
>> drivers/Makefile | 2 +
>> drivers/phy/Kconfig | 13 +
>> drivers/phy/Makefile | 5 +
>> drivers/phy/phy-core.c | 539 ++++++++++++++++++++
>> include/linux/phy/phy.h | 248 +++++++++
>> 9 files changed, 1005 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/phy/phy-bindings.txt
>> create mode 100644 Documentation/phy.txt
>> create mode 100644 drivers/phy/Kconfig
>> create mode 100644 drivers/phy/Makefile
>> create mode 100644 drivers/phy/phy-core.c
>> create mode 100644 include/linux/phy/phy.h
>
>> +static inline int phy_init(struct phy *phy)
>> +{
>> + pm_runtime_get_sync(&phy->dev);
>
> Hmm, no need to check return value here ? Also it looks a bit unexpected to
I purposely dint check the return values in order to support platforms
that don’t enable pm_runtime.
> possibly have runtime_resume callback of a PHY device called before ops->init()
> call ? It seems a bit unclear what the purpose of init() callback is.
Not really. Anything that is used to initialize the PHY (internal
configuration) can go in phy_init. Usually in runtime_resume callback,
optional functional clocks are enabled and also in some cases context
restore is done. So it really makes sense to enable clocks/module
(pm_runtime_get_sync) before doing a PHY configuration (phy_init).
>
>> + if (phy->ops->init)
>> + return phy->ops->init(phy);
>> +
>> + return -EINVAL;
>> +}
>> +
>> +static inline int phy_exit(struct phy *phy)
>> +{
>> + int ret = -EINVAL;
>> +
>> + if (phy->ops->exit)
>> + ret = phy->ops->exit(phy);
>> +
>> + pm_runtime_put_sync(&phy->dev);
>> +
>> + return ret;
>> +}
>
> Do phy_init/phy_exit need to be mandatory ? What if there is really
No. phy_init/phy_exit is not mandatory at all.
> nothing to do in those callbacks ? Perhaps -ENOIOCTLCMD should be
> returned if a callback is not implemented, so PHY users can recognize
> such situation and proceed ?
So currently these APIs return -EINVAL if these callbacks are not
populated which is good enough IMHO.
>
>> +static inline int phy_power_on(struct phy *phy)
>> +{
>> + if (phy->ops->power_on)
>> + return phy->ops->power_on(phy);
>> +
>> + return -EINVAL;
>> +}
>> +
>> +static inline int phy_power_off(struct phy *phy)
>> +{
>> + if (phy->ops->power_off)
>> + return phy->ops->power_off(phy);
>> +
>> + return -EINVAL;
>> +}
>> +
>> +static inline int phy_pm_runtime_get(struct phy *phy)
>> +{
>> + if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
>> + return -EINVAL;
>> +
>> + return pm_runtime_get(&phy->dev);
>> +}
>> +
>> +static inline int phy_pm_runtime_get_sync(struct phy *phy)
>> +{
>> + if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
>> + return -EINVAL;
>> +
>> + return pm_runtime_get_sync(&phy->dev);
>> +}
>> +
>> +static inline int phy_pm_runtime_put(struct phy *phy)
>> +{
>> + if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
>> + return -EINVAL;
>> +
>> + return pm_runtime_put(&phy->dev);
>> +}
>> +
>> +static inline int phy_pm_runtime_put_sync(struct phy *phy)
>> +{
>> + if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
>> + return -EINVAL;
>> +
>> + return pm_runtime_put_sync(&phy->dev);
>> +}
>> +
>> +static inline void phy_pm_runtime_allow(struct phy *phy)
>> +{
>> + if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
>> + return;
>> +
>> + pm_runtime_allow(&phy->dev);
>> +}
>> +
>> +static inline void phy_pm_runtime_forbid(struct phy *phy)
>> +{
>> + if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
>> + return;
>> +
>> + pm_runtime_forbid(&phy->dev);
>> +}
>
> Do we need to have all these runtime PM wrappers ? I guess you
> intended to avoid referencing phy->dev from the PHY consumers ?
Yeah.. I dint want pm_runtime of phy core device to be called from PHY
consumers.
Thanks
Kishon
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