Re: [PATCH] ACPI / LPSS: Add device link for CHT SD card dependency on I2C
From: Hans de Goede
Date: Mon Dec 04 2017 - 09:33:37 EST
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:
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.
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@xxxxxxxxx>
---
 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)
ÂÂÂÂÂ {}
 };
 +static const struct x86_cpu_id cht_cpu[] = {
+ÂÂÂ ICPU(INTEL_FAM6_ATOM_AIRMONT),ÂÂÂ /* Braswell, Cherry Trail */
+ÂÂÂ {}
+};
+
 #else
  #define LPSS_ADDR(desc) (0UL)
@@ -427,6 +432,139 @@ static int register_device_clock(struct acpi_device
*adev,
ÂÂÂÂÂ return 0;
 }
 +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 }
+}
+
 static int acpi_lpss_create_device(struct acpi_device *adev,
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ const struct acpi_device_id *id)
 {
@@ -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 }