linux-kernel - Re: [PATCH v5 2/4] ACPI / scan: Create platform device for fwnodes with multiple i2c devices

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Date:   Thu, 09 Aug 2018 13:08:05 +0300
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>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Darren Hart <dvhart@...radead.org>,
        Wolfram Sang <wsa@...-dreams.de>
Cc:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        linux-acpi@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        linux-i2c@...r.kernel.org
Subject: Re: [PATCH v5 2/4] ACPI / scan: Create platform device for fwnodes
 with multiple i2c devices

On Thu, 2018-08-09 at 11:15 +0200, Hans de Goede wrote:
> Some devices have multiple I2cSerialBus resources and for things to
> work
> an i2c-client must be instantiated for each, each with its own
> i2c_device_id.
> 
> Normally we only instantiate an i2c-client for the first resource,
> using
> the ACPI HID as id.
> 
> This commit adds a list of HIDs of devices, which need multiple i2c-
> clients
> instantiated from a single fwnode, to
> acpi_device_enumeration_by_parent and
> makes acpi_device_enumeration_by_parent return false for these devices
> so
> that a platform device will be instantiated.
> 
> This allows the drivers/platform/x86/i2c-multi-instantiate.c driver,
> which
> knows which i2c_device_id to use for each resource, to bind to the
> fwnode
> and initiate an i2c-client for each resource.
> 

I like this approach

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


> Signed-off-by: Hans de Goede <hdegoede@...hat.com>
> ---
> Changes in v3:
> -New patch in v3 of this patch-set
> 
> Changes in v4:
> -Some small code-style fixes
> ---
>  drivers/acpi/scan.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 6799d00dd790..b51913372e21 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -1540,6 +1540,18 @@ static bool
> acpi_device_enumeration_by_parent(struct acpi_device *device)
>  {
>  	struct list_head resource_list;
>  	bool is_serial_bus_slave = false;
> +	/*
> +	 * These devices have multiple I2cSerialBus resources and an
> i2c-client
> +	 * must be instantiated for each, each with its own
> i2c_device_id.
> +	 * Normally we only instantiate an i2c-client for the first
> resource,
> +	 * using the ACPI HID as id. These special cases are handled by
> the
> +	 * drivers/platform/x86/i2c-multi-instantiate.c driver, which
> knows
> +	 * which i2c_device_id to use for each resource.
> +	 */
> +	static const struct acpi_device_id i2c_multi_instantiate_ids[] =
> {
> +		{"BSG1160", },
> +		{}
> +	};
>  
>  	if (acpi_is_indirect_io_slave(device))
>  		return true;
> @@ -1551,6 +1563,10 @@ static bool
> acpi_device_enumeration_by_parent(struct acpi_device *device)
>  	     fwnode_property_present(&device->fwnode, "baud")))
>  		return true;
>  
> +	/* Instantiate a pdev for the i2c-multi-instantiate drv to bind
> to */
> +	if (!acpi_match_device_ids(device, i2c_multi_instantiate_ids))
> +		return false;
> +
>  	INIT_LIST_HEAD(&resource_list);
>  	acpi_dev_get_resources(device, &resource_list,
>  			       acpi_check_serial_bus_slave,

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