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    Subject[PATCH] ACPI / LPSS: Add device link for CHT SD card dependency on I2C
    Date
    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 0ff26c662d5f
    ("driver core: Fix device link deferred probe"). And also either,
    commit 126dbc6b49c8 ("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: Adrian Hunter <adrian.hunter@intel.com>
    ---
    drivers/acpi/acpi_lpss.c | 139 +++++++++++++++++++++++++++++++++++++++++++++++
    1 file changed, 139 insertions(+)

    diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
    index 7f2b02cc8ea1..9d82f2f6c327 100644
    --- a/drivers/acpi/acpi_lpss.c
    +++ b/drivers/acpi/acpi_lpss.c
    @@ -290,6 +290,11 @@ static void bsw_pwm_setup(struct lpss_private_data *pdata)
    {}
    };

    +static const struct x86_cpu_id cht_cpu[] = {
    + ICPU(INTEL_FAM6_ATOM_AIRMONT), /* Braswell, Cherry Trail */
    + {}
    +};
    +
    #else

    #define LPSS_ADDR(desc) (0UL)
    @@ -427,6 +432,139 @@ 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;
    + const struct x86_cpu_id *cpus;
    + u32 flags;
    +};
    +
    +static const struct lpss_device_links lpss_device_links[] = {
    + {"808622C1", "7", "80860F14", "3", cht_cpu, 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 (link->cpus && !x86_match_cpu(link->cpus))
    + continue;
    +
    + 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 +638,7 @@ 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;
    }

    --
    1.9.1
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