linux-kernel - Re: [PATCH 12/15] i2c: core: Add new i2c_acpi_new

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Message-ID: <1489772231.19767.78.camel@linux.intel.com>
Date:   Fri, 17 Mar 2017 19:37:11 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Hans de Goede <hdegoede@...hat.com>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>, Wolfram Sang <wsa@...-dreams.de>,
        Lee Jones <lee.jones@...aro.org>,
        Sebastian Reichel <sre@...nel.org>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>
Cc:     linux-acpi@...r.kernel.org, Takashi Iwai <tiwai@...e.de>,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH 12/15] i2c: core: Add new i2c_acpi_new_device helper
 function

On Fri, 2017-03-17 at 10:55 +0100, Hans de Goede wrote:
> By default the i2c subsys creates an i2c-client for the first
> I2cSerialBus
> resource of an acpi_device, but some acpi_devices have multiple
> I2cSerialBus resources and the driver may need access to the others.
> 
> This commit adds a new i2c_acpi_new_device function which can be used
> by
> drivers to create an i2c-client for any (other) I2cSerialBus resource
> of
> an acpi_device.
> 
> Note that the other resources may even be on a different i2c bus, so
> just
> retrieving the client address is not enough.
> 

Looks sane to me:

Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

Nevertheless, one nit, can you update commit message with real excerpt
of DSDT?

> Signed-off-by: Hans de Goede <hdegoede@...hat.com>
> ---
>  drivers/i2c/i2c-core.c | 48
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/i2c.h    |  5 +++++
>  2 files changed, 53 insertions(+)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 32b58fb..fd45207 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -421,6 +421,54 @@ static int i2c_acpi_notify(struct notifier_block
> *nb, unsigned long value,
>  static struct notifier_block i2c_acpi_notifier = {
>  	.notifier_call = i2c_acpi_notify,
>  };
> +
> +/**
> + * i2c_acpi_new_device - Create i2c client for the Nth acpi resource
> of dev
> + * @dev:     Device owning the acpi resources to get the client from
> + * @index:   Index of acpi resource to get
> + *
> + * By default the i2c subsys creates an i2c-client for the first
> I2cSerialBus
> + * resource of an acpi_device, but some acpi_devices have multiple
> + * I2cSerialBus resources and the driver may need access to the
> others.
> + * This function can be used by drivers to create an i2c-client for
> any
> + * resource of an acpi_device.
> + *
> + * Returns a pointer to the new i2c-client, or NULL if the resource
> or
> + * adapter were not found.
> + */
> +struct i2c_client *i2c_acpi_new_device(struct device *dev, int index)
> +{
> +	struct i2c_acpi_lookup lookup;
> +	struct i2c_board_info info;
> +	struct i2c_adapter *adapter;
> +	struct acpi_device *adev;
> +	LIST_HEAD(resource_list);
> +	int ret;
> +
> +	adev = ACPI_COMPANION(dev);
> +	if (!adev)
> +		return NULL;
> +
> +	memset(&info, 0, sizeof(info));
> +	memset(&lookup, 0, sizeof(lookup));
> +	lookup.info = &info;
> +	lookup.device_handle = acpi_device_handle(adev);
> +	lookup.index = index;
> +
> +	ret = acpi_dev_get_resources(adev, &resource_list,
> +				     i2c_acpi_fill_info, &lookup);
> +	acpi_dev_free_resource_list(&resource_list);
> +
> +	if (ret < 0 || !info.addr)
> +		return NULL;
> +
> +	adapter =
> i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
> +	if (!adapter)
> +		return NULL;
> +
> +	return i2c_new_device(adapter, &info);
> +}
> +EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
>  #else /* CONFIG_ACPI */
>  static inline void i2c_acpi_register_devices(struct i2c_adapter
> *adap) { }
>  extern struct notifier_block i2c_acpi_notifier;
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index 6b18352..369ebfa 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -824,11 +824,16 @@ static inline const struct of_device_id
>  
>  #if IS_ENABLED(CONFIG_ACPI)
>  u32 i2c_acpi_find_bus_speed(struct device *dev);
> +struct i2c_client *i2c_acpi_new_device(struct device *dev, int
> index);
>  #else
>  static inline u32 i2c_acpi_find_bus_speed(struct device *dev)
>  {
>  	return 0;
>  }
> +static inline struct i2c_client *i2c_acpi_new_device(struct device
> *d, int i)
> +{
> +	return NULL;
> +}
>  #endif /* CONFIG_ACPI */
>  
>  #endif /* _LINUX_I2C_H */

-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy