Re: [PATCH] ACPI / LPSS: Add device link for CHT SD card dependency on I2C

[Adrian Hunter]

On 04/12/17 15:48, Hans de Goede wrote:
> Hi,
> 
> Wouldn't it be easier to use the ACPI _DEP tracking for this, e.g.

It is using _DEP, see acpi_lpss_dep()

> add something like this to the the probe function:
> 
> ÂÂÂÂstruct acpi_device = ACPI_COMPANION(device);
> 
> ÂÂÂÂif (acpi_device->dep_unmet)
> ÂÂÂÂÂÂÂ return -EPROBE_DEFER;
> 
> No idea if this will work, but if it does work, using the deps described
> in the ACPI tables seems like a better solution then hardcoding this.

That would not work because there are other devices listed in the _DEP
method so dep_unmet is always true.  So we are left checking _DEP but only
for specific device dependencies.

> 
> Regards,
> 
> Hans
> 
> 
> 
> On 04-12-17 13:32, Adrian Hunter wrote:
>> 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@xxxxxxxxx>
>> ---
>> Â drivers/acpi/acpi_lpss.c | 139
>> +++++++++++++++++++++++++++++++++++++++++++++++
>> Â 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)
>> ÂÂÂÂÂ {}
>> Â };
>> Â +static const struct x86_cpu_id cht_cpu[] = {
>> +ÂÂÂ ICPU(INTEL_FAM6_ATOM_AIRMONT),ÂÂÂ /* Braswell, Cherry Trail */
>> +ÂÂÂ {}
>> +};
>> +
>> Â #else
>> Â Â #define LPSS_ADDR(desc) (0UL)
>> @@ -427,6 +432,139 @@ static int register_device_clock(struct acpi_device
>> *adev,
>> ÂÂÂÂÂ return 0;
>> Â }
>> Â +struct lpss_device_links {
>> +ÂÂÂ const char *supplier_hid;
>> +ÂÂÂ const char *supplier_uid;
>> +ÂÂÂ const char *consumer_hid;
>> +ÂÂÂ const char *consumer_uid;
>> +ÂÂÂ const struct x86_cpu_id *cpus;
>> +ÂÂÂ u32 flags;
>> +};
>> +
>> +static const struct lpss_device_links lpss_device_links[] = {
>> +ÂÂÂ {"808622C1", "7", "80860F14", "3", cht_cpu, DL_FLAG_PM_RUNTIME},
>> +};
>> +
>> +static bool hid_uid_match(const char *hid1, const char *uid1,
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂ const char *hid2, const char *uid2)
>> +{
>> +ÂÂÂ return !strcmp(hid1, hid2) && uid1 && uid2 && !strcmp(uid1, uid2);
>> +}
>> +
>> +static bool acpi_lpss_is_supplier(struct acpi_device *adev,
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ const struct lpss_device_links *link)
>> +{
>> +ÂÂÂ return hid_uid_match(acpi_device_hid(adev), acpi_device_uid(adev),
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ link->supplier_hid, link->supplier_uid);
>> +}
>> +
>> +static bool acpi_lpss_is_consumer(struct acpi_device *adev,
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ const struct lpss_device_links *link)
>> +{
>> +ÂÂÂ return hid_uid_match(acpi_device_hid(adev), acpi_device_uid(adev),
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ link->consumer_hid, link->consumer_uid);
>> +}
>> +
>> +struct hid_uid {
>> +ÂÂÂ const char *hid;
>> +ÂÂÂ const char *uid;
>> +};
>> +
>> +static int match_hid_uid(struct device *dev, void *data)
>> +{
>> +ÂÂÂ struct acpi_device *adev = ACPI_COMPANION(dev);
>> +ÂÂÂ struct hid_uid *id = data;
>> +
>> +ÂÂÂ if (!adev)
>> +ÂÂÂÂÂÂÂ return 0;
>> +
>> +ÂÂÂ return hid_uid_match(acpi_device_hid(adev), acpi_device_uid(adev),
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ id->hid, id->uid);
>> +}
>> +
>> +static struct device *acpi_lpss_find_device(const char *hid, const char
>> *uid)
>> +{
>> +ÂÂÂ struct hid_uid data = {
>> +ÂÂÂÂÂÂÂ .hid = hid,
>> +ÂÂÂÂÂÂÂ .uid = uid,
>> +ÂÂÂ };
>> +
>> +ÂÂÂ return bus_find_device(&platform_bus_type, NULL, &data, match_hid_uid);
>> +}
>> +
>> +static bool acpi_lpss_dep(struct acpi_device *adev, acpi_handle handle)
>> +{
>> +ÂÂÂ struct acpi_handle_list dep_devices;
>> +ÂÂÂ acpi_status status;
>> +ÂÂÂ int i;
>> +
>> +ÂÂÂ if (!acpi_has_method(adev->handle, "_DEP"))
>> +ÂÂÂÂÂÂÂ return false;
>> +
>> +ÂÂÂ status = acpi_evaluate_reference(adev->handle, "_DEP", NULL,
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ &dep_devices);
>> +ÂÂÂ if (ACPI_FAILURE(status)) {
>> +ÂÂÂÂÂÂÂ dev_dbg(&adev->dev, "Failed to evaluate _DEP.\n");
>> +ÂÂÂÂÂÂÂ return false;
>> +ÂÂÂ }
>> +
>> +ÂÂÂ for (i = 0; i < dep_devices.count; i++) {
>> +ÂÂÂÂÂÂÂ if (dep_devices.handles[i] == handle)
>> +ÂÂÂÂÂÂÂÂÂÂÂ return true;
>> +ÂÂÂ }
>> +
>> +ÂÂÂ return false;
>> +}
>> +
>> +static void acpi_lpss_link_consumer(struct device *dev1,
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ const struct lpss_device_links *link)
>> +{
>> +ÂÂÂ struct device *dev2;
>> +
>> +ÂÂÂ dev2 = acpi_lpss_find_device(link->consumer_hid, link->consumer_uid);
>> +ÂÂÂ if (!dev2)
>> +ÂÂÂÂÂÂÂ return;
>> +
>> +ÂÂÂ if (acpi_lpss_dep(ACPI_COMPANION(dev2), ACPI_HANDLE(dev1)))
>> +ÂÂÂÂÂÂÂ device_link_add(dev2, dev1, link->flags);
>> +
>> +ÂÂÂ put_device(dev2);
>> +}
>> +
>> +static void acpi_lpss_link_supplier(struct device *dev1,
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ const struct lpss_device_links *link)
>> +{
>> +ÂÂÂ struct device *dev2;
>> +
>> +ÂÂÂ dev2 = acpi_lpss_find_device(link->supplier_hid, link->supplier_uid);
>> +ÂÂÂ if (!dev2)
>> +ÂÂÂÂÂÂÂ return;
>> +
>> +ÂÂÂ if (acpi_lpss_dep(ACPI_COMPANION(dev1), ACPI_HANDLE(dev2)))
>> +ÂÂÂÂÂÂÂ device_link_add(dev1, dev2, link->flags);
>> +
>> +ÂÂÂ put_device(dev2);
>> +}
>> +
>> +static void acpi_lpss_create_device_links(struct acpi_device *adev,
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct platform_device *pdev)
>> +{
>> +ÂÂÂ int i;
>> +
>> +ÂÂÂ for (i = 0; i < ARRAY_SIZE(lpss_device_links); i++) {
>> +ÂÂÂÂÂÂÂ const struct lpss_device_links *link = &lpss_device_links[i];
>> +
>> +ÂÂÂÂÂÂÂ if (link->cpus && !x86_match_cpu(link->cpus))
>> +ÂÂÂÂÂÂÂÂÂÂÂ continue;
>> +
>> +ÂÂÂÂÂÂÂ if (acpi_lpss_is_supplier(adev, link))
>> +ÂÂÂÂÂÂÂÂÂÂÂ acpi_lpss_link_consumer(&pdev->dev, link);
>> +
>> +ÂÂÂÂÂÂÂ if (acpi_lpss_is_consumer(adev, link))
>> +ÂÂÂÂÂÂÂÂÂÂÂ acpi_lpss_link_supplier(&pdev->dev, link);
>> +ÂÂÂ }
>> +}
>> +
>> Â static int acpi_lpss_create_device(struct acpi_device *adev,
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ const struct acpi_device_id *id)
>> Â {
>> @@ -500,6 +638,7 @@ static int acpi_lpss_create_device(struct acpi_device
>> *adev,
>> ÂÂÂÂÂ adev->driver_data = pdata;
>> ÂÂÂÂÂ pdev = acpi_create_platform_device(adev, dev_desc->properties);
>> ÂÂÂÂÂ if (!IS_ERR_OR_NULL(pdev)) {
>> +ÂÂÂÂÂÂÂ acpi_lpss_create_device_links(adev, pdev);
>> ÂÂÂÂÂÂÂÂÂ return 1;
>> ÂÂÂÂÂ }
>> Â
>