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Commit e6ce0ce3 authored by Adrian Hunter's avatar Adrian Hunter Committed by Rafael J. Wysocki
Browse files

ACPI / LPSS: Add device link for CHT SD card dependency on I2C 



Some Cherry Trail boards have a dependency between the SDHCI host
controller used for SD cards and an external PMIC accessed via I2C. Add a
device link between the SDHCI host controller (consumer) and the I2C
adapter (supplier).

This patch depends on a fix to devices links, namely commit 0ff26c66
("driver core: Fix device link deferred probe"). And also either,
commit 126dbc6b ("PM: i2c-designware-platdrv: Clean up PM handling in
probe"), or patch "PM / runtime: Fix handling of suppliers with disabled
runtime PM".

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 50c4c4e2

drivers/acpi/acpi_lpss.c

+137 −0
Original line number Diff line number Diff line
@@ -427,6 +427,142 @@ static int register_device_clock(struct acpi_device *adev, 
	return 0;

}



struct lpss_device_links {

	const char *supplier_hid;

	const char *supplier_uid;

	const char *consumer_hid;

	const char *consumer_uid;

	u32 flags;

};



/*

 * The _DEP method is used to identify dependencies but instead of creating

 * device links for every handle in _DEP, only links in the following list are

 * created. That is necessary because, in the general case, _DEP can refer to

 * devices that might not have drivers, or that are on different buses, or where

 * the supplier is not enumerated until after the consumer is probed.

 */

static const struct lpss_device_links lpss_device_links[] = {

	{"808622C1", "7", "80860F14", "3", DL_FLAG_PM_RUNTIME},

};



static bool hid_uid_match(const char *hid1, const char *uid1,

			  const char *hid2, const char *uid2)

{

	return !strcmp(hid1, hid2) && uid1 && uid2 && !strcmp(uid1, uid2);

}



static bool acpi_lpss_is_supplier(struct acpi_device *adev,

				  const struct lpss_device_links *link)

{

	return hid_uid_match(acpi_device_hid(adev), acpi_device_uid(adev),

			     link->supplier_hid, link->supplier_uid);

}



static bool acpi_lpss_is_consumer(struct acpi_device *adev,

				  const struct lpss_device_links *link)

{

	return hid_uid_match(acpi_device_hid(adev), acpi_device_uid(adev),

			     link->consumer_hid, link->consumer_uid);

}



struct hid_uid {

	const char *hid;

	const char *uid;

};



static int match_hid_uid(struct device *dev, void *data)

{

	struct acpi_device *adev = ACPI_COMPANION(dev);

	struct hid_uid *id = data;



	if (!adev)

		return 0;



	return hid_uid_match(acpi_device_hid(adev), acpi_device_uid(adev),

			     id->hid, id->uid);

}



static struct device *acpi_lpss_find_device(const char *hid, const char *uid)

{

	struct hid_uid data = {

		.hid = hid,

		.uid = uid,

	};



	return bus_find_device(&platform_bus_type, NULL, &data, match_hid_uid);

}



static bool acpi_lpss_dep(struct acpi_device *adev, acpi_handle handle)

{

	struct acpi_handle_list dep_devices;

	acpi_status status;

	int i;



	if (!acpi_has_method(adev->handle, "_DEP"))

		return false;



	status = acpi_evaluate_reference(adev->handle, "_DEP", NULL,

					 &dep_devices);

	if (ACPI_FAILURE(status)) {

		dev_dbg(&adev->dev, "Failed to evaluate _DEP.\n");

		return false;

	}



	for (i = 0; i < dep_devices.count; i++) {

		if (dep_devices.handles[i] == handle)

			return true;

	}



	return false;

}



static void acpi_lpss_link_consumer(struct device *dev1,

				    const struct lpss_device_links *link)

{

	struct device *dev2;



	dev2 = acpi_lpss_find_device(link->consumer_hid, link->consumer_uid);

	if (!dev2)

		return;



	if (acpi_lpss_dep(ACPI_COMPANION(dev2), ACPI_HANDLE(dev1)))

		device_link_add(dev2, dev1, link->flags);



	put_device(dev2);

}



static void acpi_lpss_link_supplier(struct device *dev1,

				    const struct lpss_device_links *link)

{

	struct device *dev2;



	dev2 = acpi_lpss_find_device(link->supplier_hid, link->supplier_uid);

	if (!dev2)

		return;



	if (acpi_lpss_dep(ACPI_COMPANION(dev1), ACPI_HANDLE(dev2)))

		device_link_add(dev1, dev2, link->flags);



	put_device(dev2);

}



static void acpi_lpss_create_device_links(struct acpi_device *adev,

					  struct platform_device *pdev)

{

	int i;



	for (i = 0; i < ARRAY_SIZE(lpss_device_links); i++) {

		const struct lpss_device_links *link = &lpss_device_links[i];



		if (acpi_lpss_is_supplier(adev, link))

			acpi_lpss_link_consumer(&pdev->dev, link);



		if (acpi_lpss_is_consumer(adev, link))

			acpi_lpss_link_supplier(&pdev->dev, link);

	}

}



static int acpi_lpss_create_device(struct acpi_device *adev,

				   const struct acpi_device_id *id)

{
@@ -500,6 +636,7 @@ static int acpi_lpss_create_device(struct acpi_device *adev, 
	adev->driver_data = pdata;

	pdev = acpi_create_platform_device(adev, dev_desc->properties);

	if (!IS_ERR_OR_NULL(pdev)) {

		acpi_lpss_create_device_links(adev, pdev);

		return 1;

	}