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Date: Tue, 22 Sep 2015 23:15:15 +0100
From: Lee Jones <lee.jones@...aro.org>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: linux-acpi@...r.kernel.org, linux-i2c@...r.kernel.org,
linux-gpio@...r.kernel.org, Wolfram Sang <wsa@...-dreams.de>,
Linus Walleij <linus.walleij@...aro.org>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Mika Westerberg <mika.westerberg@...el.com>,
"Puustinen, Ismo" <ismo.puustinen@...el.com>,
"Pandruvada, Srinivas" <srinivas.pandruvada@...el.com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/8] mfd: core: redo ACPI matching of the children
devices
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.
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
> 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.
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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