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Date: Fri, 27 Sep 2013 11:04:22 -0500
From: Kumar Gala <galak@...eaurora.org>
To: Suman Anna <s-anna@...com>
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
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
> +
> + 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@...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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