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    SubjectRe: [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@ti.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@wizery.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@wizery.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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    >



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