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Date: Fri, 27 Sep 2013 11:48:57 -0500
From: Suman Anna <s-anna@...com>
To: Kumar Gala <galak@...eaurora.org>
CC: Ohad Ben-Cohen <ohad@...ery.com>, Tony Lindgren <tony@...mide.com>,
Benoit Cousson <bcousson@...libre.com>,
Paul Walmsley <paul@...an.com>, <linux-kernel@...r.kernel.org>,
<linux-omap@...r.kernel.org>, <devicetree@...r.kernel.org>
Subject: Re: [PATCHv2 1/9] hwspinlock/core: add common dt bindings and OF
helpers
Kumar,
On 09/27/2013 11:04 AM, Kumar Gala wrote:
>
> On Sep 17, 2013, at 2:30 PM, Suman Anna wrote:
>
>> All the platform-specific hwlock driver implementations need the
>> number of locks and the associated base id for registering the
>> locks present within a hwspinlock device with the driver core.
>> These two variables are represented by 'hwlock-num-locks' and
>> 'hwlock-base-id' properties. The documentation and OF helpers to
>> retrieve these common properties have been added to the driver core.
>>
>> Signed-off-by: Suman Anna <s-anna@...com>
>> ---
>> .../devicetree/bindings/hwlock/hwlock.txt | 26 +++++++++
>> drivers/hwspinlock/hwspinlock_core.c | 61 +++++++++++++++++++++-
>> include/linux/hwspinlock.h | 11 ++--
>> 3 files changed, 93 insertions(+), 5 deletions(-)
>> create mode 100644 Documentation/devicetree/bindings/hwlock/hwlock.txt
>>
>> diff --git a/Documentation/devicetree/bindings/hwlock/hwlock.txt b/Documentation/devicetree/bindings/hwlock/hwlock.txt
>> new file mode 100644
>> index 0000000..789930e
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/hwlock/hwlock.txt
>> @@ -0,0 +1,26 @@
>> +Generic hwlock bindings
>> +=======================
>> +
>> +Generic bindings that are common to all the hwlock platform specific driver
>> +implementations, the retrieved values are used for registering the device
>> +specific parameters with the hwspinlock core.
>> +
>> +The validity and need of these common properties may vary from one driver
>> +implementation to another. Look through the individual hwlock driver
>> +binding documentations for identifying which are mandatory and which are
>> +optional for that specific driver.
>> +
>> +Common properties:
>> +- hwlock-base-id: Base Id for the locks for a particular hwlock device.
>> + This property is used for representing a set of locks
>> + present in a hwlock device with a unique base id in
>> + the driver core. This property is mandatory ONLY if a
>> + SoC has several hwlock devices.
>> +
>> + See documentation on struct hwspinlock_pdata in
>> + linux/hwspinlock.h for more details.
>> +
>> +- hwlock-num-locks: Number of locks present in a hwlock device. This
>> + property is needed on hwlock devices, where the number
>> + of supported locks within a hwlock device cannot be
>> + read from a register.
>> diff --git a/drivers/hwspinlock/hwspinlock_core.c b/drivers/hwspinlock/hwspinlock_core.c
>> index 461a0d7..aec32e7 100644
>> --- a/drivers/hwspinlock/hwspinlock_core.c
>> +++ b/drivers/hwspinlock/hwspinlock_core.c
>> @@ -1,7 +1,7 @@
>> /*
>> * Hardware spinlock framework
>> *
>> - * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
>> + * Copyright (C) 2010-2013 Texas Instruments Incorporated - http://www.ti.com
>> *
>> * Contact: Ohad Ben-Cohen <ohad@...ery.com>
>> *
>> @@ -27,6 +27,7 @@
>> #include <linux/hwspinlock.h>
>> #include <linux/pm_runtime.h>
>> #include <linux/mutex.h>
>> +#include <linux/of.h>
>>
>> #include "hwspinlock_internal.h"
>>
>> @@ -308,6 +309,64 @@ out:
>> }
>>
>> /**
>> + * of_hwspin_lock_get_base_id() - OF helper to retrieve base id
>> + * @dn: device node pointer
>> + *
>> + * This is an OF helper function that can be called by the underlying
>> + * platform-specific implementations, to retrieve the base id for the
>> + * set of locks present within a hwspinlock device instance.
>> + *
>> + * Returns the base id value on success, -ENODEV on generic failure or
>> + * an appropriate error code as returned by the OF layer
>> + */
>> +int of_hwspin_lock_get_base_id(struct device_node *dn)
>> +{
>> + unsigned int val;
>> + int ret = -ENODEV;
>> +
>> +#ifdef CONFIG_OF
>> + if (!dn)
>> + return -ENODEV;
>
> Checking !dn is done in of_property_read_u32, so you don't need to duplicate
I have added this specifically since my intention is to differentiate
the validity of the node vs the presence of the property within a node.
This property may be optional for some platforms and a must for some
others, and differentiating would allow the individual driver
implementations to make the distinction.
>
>> +
>> + ret = of_property_read_u32(dn, "hwlock-base-id", &val);
>> + if (!ret)
>> + ret = val;
>> +#endif
>> +
>> + return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(of_hwspin_lock_get_base_id);
>> +
>> +/**
>> + * of_hwspin_lock_get_num_locks() - OF helper to retrieve number of locks
>> + * @dn: device node pointer
>> + *
>> + * This is an OF helper function that can be called by the underlying
>> + * platform-specific implementations, to retrieve the number of locks
>> + * present within a hwspinlock device instance.
>> + *
>> + * Returns a positive number of locks on success, -ENODEV on generic
>> + * failure or an appropriate error code as returned by the OF layer
>> + */
>> +int of_hwspin_lock_get_num_locks(struct device_node *dn)
>> +{
>> + unsigned int val;
>> + int ret = -ENODEV;
>> +
>> +#ifdef CONFIG_OF
>> + if (!dn)
>> + return -ENODEV;
>
> Checking !dn is done in of_property_read_u32, so you don't need to duplicate
Same comment as above.
regards
Suman
>
>> +
>> + ret = of_property_read_u32(dn, "hwlock-num-locks", &val);
>> + if (!ret)
>> + ret = val ? val : -ENODEV;
>> +#endif
>> +
>> + return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(of_hwspin_lock_get_num_locks);
>> +
>> +/**
>> * hwspin_lock_register() - register a new hw spinlock device
>> * @bank: the hwspinlock device, which usually provides numerous hw locks
>> * @dev: the backing device
>> diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h
>> index 3343298..1f6a5b8 100644
>> --- a/include/linux/hwspinlock.h
>> +++ b/include/linux/hwspinlock.h
>> @@ -1,7 +1,7 @@
>> /*
>> * Hardware spinlock public header
>> *
>> - * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com
>> + * Copyright (C) 2010-2013 Texas Instruments Incorporated - http://www.ti.com
>> *
>> * Contact: Ohad Ben-Cohen <ohad@...ery.com>
>> *
>> @@ -26,6 +26,7 @@
>> #define HWLOCK_IRQ 0x02 /* Disable interrupts, don't save state */
>>
>> struct device;
>> +struct device_node;
>> struct hwspinlock;
>> struct hwspinlock_device;
>> struct hwspinlock_ops;
>> @@ -60,6 +61,8 @@ struct hwspinlock_pdata {
>>
>> #if defined(CONFIG_HWSPINLOCK) || defined(CONFIG_HWSPINLOCK_MODULE)
>>
>> +int of_hwspin_lock_get_base_id(struct device_node *dn);
>> +int of_hwspin_lock_get_num_locks(struct device_node *dn);
>> int hwspin_lock_register(struct hwspinlock_device *bank, struct device *dev,
>> const struct hwspinlock_ops *ops, int base_id, int num_locks);
>> int hwspin_lock_unregister(struct hwspinlock_device *bank);
>> @@ -80,9 +83,9 @@ void __hwspin_unlock(struct hwspinlock *, int, unsigned long *);
>> * code path get compiled away. This way, if CONFIG_HWSPINLOCK is not
>> * required on a given setup, users will still work.
>> *
>> - * The only exception is hwspin_lock_register/hwspin_lock_unregister, with which
>> - * we _do_ want users to fail (no point in registering hwspinlock instances if
>> - * the framework is not available).
>> + * The only exception is hwspin_lock_register/hwspin_lock_unregister and
>> + * associated OF helpers, with which we _do_ want users to fail (no point
>> + * in registering hwspinlock instances if the framework is not available).
>> *
>> * Note: ERR_PTR(-ENODEV) will still be considered a success for NULL-checking
>> * users. Others, which care, can still check this with IS_ERR.
>> --
>> 1.8.3.3
>>
>> --
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