Messages in this thread |  | | Subject | Re: [PATCH] ACPI / LPSS: Add device link for CHT SD card dependency on I2C | From | Hans de Goede <> | Date | Mon, 4 Dec 2017 15:33:29 +0100 |
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Hi,
On 04-12-17 15:30, Adrian Hunter wrote: > 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: >> >> struct acpi_device = ACPI_COMPANION(device); >> >> if (acpi_device->dep_unmet) >> 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.
Ugh, understood thank you for explaining this. Perhaps it is a good idea to mention in the commit message why acpi_dev->dep_unmet cannot be used here?
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@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; >>> } >>> >> >
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