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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Wed, 12 Jan 2022 17:13:53 +0100
Message-ID: <CAJZ5v0hW-i8+hqkQtHG2H3X7zotABEx_bKei9OFkjBuFbL6JKw@mail.gmail.com>
Subject: Re: [PATCH v2 1/3] device property: Add device_irq_get_byname
To:     Akhil R <akhilrajeev@nvidia.com>
Cc:     Andy Shevchenko <andy.shevchenko@gmail.com>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        Dmitry Osipenko <digetx@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jon Hunter <jonathanh@nvidia.com>,
        Laxman Dewangan <ldewangan@nvidia.com>,
        linux-i2c <linux-i2c@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-tegra <linux-tegra@vger.kernel.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Wolfram Sang <wsa@kernel.org>, Len Brown <lenb@kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>
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On Wed, Jan 12, 2022 at 3:14 PM Akhil R <akhilrajeev@nvidia.com> wrote:
>
> Get interrupt by name from ACPI table as well.
>
> Add option to use 'interrupt-names' in _DSD which can map to interrupt by
> index. The implementation is similar to 'interrupt-names' in devicetree.
> Also add a common routine to get irq by name from devicetree and ACPI
> table.
>
> Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
> ---
>  drivers/base/property.c  | 35 +++++++++++++++++++++++++++++++++++
>  include/linux/property.h |  3 +++
>  2 files changed, 38 insertions(+)
>
> diff --git a/drivers/base/property.c b/drivers/base/property.c
> index cbe4fa2..414c316 100644
> --- a/drivers/base/property.c
> +++ b/drivers/base/property.c
> @@ -920,6 +920,41 @@ int fwnode_irq_get(const struct fwnode_handle *fwnode, unsigned int index)
>  EXPORT_SYMBOL(fwnode_irq_get);
>
>  /**
> + * fwnode_irq_get_byname - Get IRQ from a fwnode using its name
> + * @fwnode:    Pointer to the firmware node
> + * @name:      IRQ name in interrupt-names property in fwnode
> + *
> + * Returns Linux IRQ number on success, errno otherwise.
> + */
> +int fwnode_irq_get_byname(const struct fwnode_handle *fwnode, const char *name)
> +{
> +       int index;
> +
> +       if (unlikely(!name))
> +               return -EINVAL;
> +
> +       index = fwnode_property_match_string(fwnode, "interrupt-names",  name);
> +       if (index < 0)
> +               return index;
> +
> +       return fwnode_irq_get(fwnode, index);
> +}
> +EXPORT_SYMBOL(fwnode_irq_get_byname);
> +
> +/**
> + * device_irq_get_byname - Get IRQ of a device using interrupt name
> + * @dev:       Device to get the interrupt
> + * @name:      IRQ name in interrupt-names property in fwnode

Which fwnode?

> + *
> + * Returns Linux IRQ number on success, errno otherwise.
> + */
> +int device_irq_get_byname(struct device *dev, const char *name)
> +{
> +       return fwnode_irq_get_byname(dev_fwnode(dev), name);
> +}
> +EXPORT_SYMBOL_GPL(device_irq_get_byname);

This can be confusing, because it pretends to be super-generic and in
fact it depends on an fwnode to be there.

I guess I'd rather not have it at all, or use a more precise name for it.

> +
> +/**
>   * fwnode_graph_get_next_endpoint - Get next endpoint firmware node
>   * @fwnode: Pointer to the parent firmware node
>   * @prev: Previous endpoint node or %NULL to get the first
> diff --git a/include/linux/property.h b/include/linux/property.h
> index 16f736c..bc49350 100644
> --- a/include/linux/property.h
> +++ b/include/linux/property.h
> @@ -121,6 +121,9 @@ struct fwnode_handle *fwnode_handle_get(struct fwnode_handle *fwnode);
>  void fwnode_handle_put(struct fwnode_handle *fwnode);
>
>  int fwnode_irq_get(const struct fwnode_handle *fwnode, unsigned int index);
> +int fwnode_irq_get_byname(const struct fwnode_handle *fwnode, const char *name);
> +
> +int device_irq_get_byname(struct device *dev, const char *name);
>
>  unsigned int device_get_child_node_count(struct device *dev);
>
> --
> 2.7.4
>