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    SubjectRe: [PATCHv2 1/9] hwspinlock/core: add common dt bindings and OF helpers
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    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

    > +
    > + 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

    > +
    > + 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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    --
    Employee of Qualcomm Innovation Center, Inc.
    Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation



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