Re: [PATCH v1 2/8] mfd: core: redo ACPI matching of the children devices

[Andy Shevchenko]

On Tue, 2015-09-22 at 23:15 +0100, Lee Jones wrote:
> On Tue, 22 Sep 2015, Andy Shevchenko wrote:
> 
> > There is at least one board on the market, i.e. Intel Galileo Gen2, 
> > that uses
> > _ADR to distinguish the devices under one actual device. Due to 
> > this we have to
> > improve the quirk in the MFD core to handle that board.
> 
> This will require an ACPI Ack.

Rafael is Cc'ed, so, I hope he will comment on this.

> 
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > ---
> >  Documentation/acpi/enumeration.txt | 11 +++++---
> >  drivers/mfd/mfd-core.c             | 52 ++++++++++++++++++++++++++
> > ------------
> >  include/linux/mfd/core.h           | 10 ++++++--
> >  3 files changed, 52 insertions(+), 21 deletions(-)
> > 
> > diff --git a/Documentation/acpi/enumeration.txt 
> > b/Documentation/acpi/enumeration.txt
> > index b731b29..a91ec5a 100644
> > --- a/Documentation/acpi/enumeration.txt
> > +++ b/Documentation/acpi/enumeration.txt
> > @@ -347,13 +347,18 @@ For the first case, the MFD drivers do not 
> > need to do anything. The
> >  resulting child platform device will have its ACPI_COMPANION() set 
> > to point
> >  to the parent device.
> >  
> > -If the ACPI namespace has a device that we can match using an ACPI 
> > id,
> > -the id should be set like:
> > +If the ACPI namespace has a device that we can match using an ACPI 
> > id or ACPI
> > +adr, the cell should be set like:
> > +
> > +	static struct mfd_cell_acpi_match 
> > my_subdevice_cell_acpi_match = {
> > +		.pnpid = "XYZ0001",
> > +		.adr = 0,
> > +	};
> >  
> >  	static struct mfd_cell my_subdevice_cell = {
> >  		.name = "my_subdevice",
> >  		/* set the resources relative to the parent */
> > -		.acpi_pnpid = "XYZ0001",
> > +		.acpi_match = &my_subdevice_cell_acpi_match,
> >  	};
> >  
> >  The ACPI id "XYZ0001" is then used to lookup an ACPI device 
> > directly under
> > diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
> > index c17635d..60b60dc 100644
> > --- a/drivers/mfd/mfd-core.c
> > +++ b/drivers/mfd/mfd-core.c
> > @@ -82,29 +82,49 @@ static int mfd_platform_add_cell(struct 
> > platform_device *pdev,
> >  static void mfd_acpi_add_device(const struct mfd_cell *cell,
> >  				struct platform_device *pdev)
> >  {
> > -	struct acpi_device *parent_adev;
> > +	const struct mfd_cell_acpi_match *match = cell
> > ->acpi_match;
> > +	struct acpi_device *parent, *child;
> >  	struct acpi_device *adev;
> >  
> > -	parent_adev = ACPI_COMPANION(pdev->dev.parent);
> > -	if (!parent_adev)
> > +	parent = ACPI_COMPANION(pdev->dev.parent);
> > +	if (!parent)
> >  		return;
> >  
> >  	/*
> > -	 * MFD child device gets its ACPI handle either from the 
> > ACPI
> > -	 * device directly under the parent that matches the 
> > acpi_pnpid or
> > -	 * it will use the parent handle if is no acpi_pnpid is 
> > given.
> > +	 * MFD child device gets its ACPI handle either from the 
> > ACPI device
> > +	 * directly under the parent that matches the either _HID 
> > or _CID, or
> > +	 * _ADR or it will use the parent handle if is no ID is 
> > given.
> > +	 *
> > +	 * Note that use of _ADR is a grey area in the ACPI 
> > specification,
> > +	 * though Intel Galileo Gen2 is using it to distinguish 
> > the children
> > +	 * devices.
> >  	 */
> > -	adev = parent_adev;
> > -	if (cell->acpi_pnpid) {
> > -		struct acpi_device_id ids[2] = {};
> > -		struct acpi_device *child_adev;
> > -
> > -		strlcpy(ids[0].id, cell->acpi_pnpid, 
> > sizeof(ids[0].id));
> > -		list_for_each_entry(child_adev, &parent_adev
> > ->children, node)
> > -			if (acpi_match_device_ids(child_adev, 
> > ids)) {
> > -				adev = child_adev;
> > -				break;
> > +	adev = parent;
> > +	if (match) {
> > +		if (match->pnpid) {
> > +			struct acpi_device_id ids[2] = {};
> > +
> > +			strlcpy(ids[0].id, match->pnpid, 
> > sizeof(ids[0].id));
> > +			list_for_each_entry(child, &parent
> > ->children, node) {
> > +				if (acpi_match_device_ids(child, 
> > ids)) {
> > +					adev = child;
> > +					break;
> > +				}
> > +			}
> > +		} else {
> > +			unsigned long long adr;
> > +			acpi_status status;
> > +
> > +			list_for_each_entry(child, &parent
> > ->children, node) {
> > +				status = 
> > acpi_evaluate_integer(child->handle,
> > +							      
> >  "_ADR", NULL,
> > +							      
> >  &adr);
> > +				if (ACPI_SUCCESS(status) && match
> > ->adr == adr) {
> > +					adev = child;
> > +					break;
> > +				}
> >  			}
> > +		}
> >  	}
> >  
> >  	ACPI_COMPANION_SET(&pdev->dev, adev);
> > diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
> > index a76bc10..27dac3f 100644
> > --- a/include/linux/mfd/core.h
> > +++ b/include/linux/mfd/core.h
> > @@ -18,6 +18,12 @@
> >  
> >  struct irq_domain;
> >  
> > +/* Matches ACPI PNP id, either _HID or _CID, or ACPI _ADR */
> > +struct mfd_cell_acpi_match {
> > +	const char			*pnpid;
> > +	const unsigned long long	adr;
> > +};
> > +
> >  /*
> >   * This struct describes the MFD part ("cell").
> >   * After registration the copy of this structure will become the 
> > platform data
> > @@ -44,8 +50,8 @@ struct mfd_cell {
> >  	 */
> >  	const char		*of_compatible;
> >  
> > -	/* Matches ACPI PNP id, either _HID or _CID */
> > -	const char		*acpi_pnpid;
> > +	/* Matches ACPI */
> > +	const struct mfd_cell_acpi_match	*acpi_match;
> >  
> >  	/*
> >  	 * These resources can be specified relative to the parent 
> > device.
> 

-- 
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy
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