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authorHans de Goede <hdegoede@redhat.com>2021-12-03 13:28:44 +0300
committerHans de Goede <hdegoede@redhat.com>2021-12-13 13:44:47 +0300
commit9d9bcae47fd5a0b827521f65ab7d10a218eacc37 (patch)
tree88a2f13b2fbc49a6137897ac87ee943023f86891 /include/acpi
parentfa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf (diff)
downloadlinux-9d9bcae47fd5a0b827521f65ab7d10a218eacc37.tar.xz
ACPI: delay enumeration of devices with a _DEP pointing to an INT3472 device
The clk and regulator frameworks expect clk/regulator consumer-devices to have info about the consumed clks/regulators described in the device's fw_node. To work around cases where this info is not present in the firmware tables, which is often the case on x86/ACPI devices, both frameworks allow the provider-driver to attach info about consumers to the clks/regulators when registering these. This causes problems with the probe ordering wrt drivers for consumers of these clks/regulators. Since the lookups are only registered when the provider-driver binds, trying to get these clks/regulators before then results in a -ENOENT error for clks and a dummy regulator for regulators. One case where we hit this issue is camera sensors such as e.g. the OV8865 sensor found on the Microsoft Surface Go. The sensor uses clks, regulators and GPIOs provided by a TPS68470 PMIC which is described in an INT3472 ACPI device. There is special platform code handling this and setting platform_data with the necessary consumer info on the MFD cells instantiated for the PMIC under: drivers/platform/x86/intel/int3472. For this to work properly the ov8865 driver must not bind to the I2C-client for the OV8865 sensor until after the TPS68470 PMIC gpio, regulator and clk MFD cells have all been fully setup. The OV8865 on the Microsoft Surface Go is just one example, all X86 devices using the Intel IPU3 camera block found on recent Intel SoCs have similar issues where there is an INT3472 HID ACPI-device, which describes the clks and regulators, and the driver for this INT3472 device must be fully initialized before the sensor driver (any sensor driver) binds for things to work properly. On these devices the ACPI nodes describing the sensors all have a _DEP dependency on the matching INT3472 ACPI device (there is one per sensor). This allows solving the probe-ordering problem by delaying the enumeration (instantiation of the I2C-client in the ov8865 example) of ACPI-devices which have a _DEP dependency on an INT3472 device. The new acpi_dev_ready_for_enumeration() helper used for this is also exported because for devices, which have the enumeration_by_parent flag set, the parent-driver will do its own scan of child ACPI devices and it will try to enumerate those during its probe(). Code doing this such as e.g. the i2c-core-acpi.c code must call this new helper to ensure that it too delays the enumeration until all the _DEP dependencies are met on devices which have the new honor_deps flag set. Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Link: https://lore.kernel.org/r/20211203102857.44539-2-hdegoede@redhat.com
Diffstat (limited to 'include/acpi')
-rw-r--r--include/acpi/acpi_bus.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 480f9207a4c6..2f93ecf05dac 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -202,7 +202,8 @@ struct acpi_device_flags {
u32 coherent_dma:1;
u32 cca_seen:1;
u32 enumeration_by_parent:1;
- u32 reserved:19;
+ u32 honor_deps:1;
+ u32 reserved:18;
};
/* File System */
@@ -285,6 +286,7 @@ struct acpi_dep_data {
struct list_head node;
acpi_handle supplier;
acpi_handle consumer;
+ bool honor_dep;
};
/* Performance Management */
@@ -693,6 +695,7 @@ static inline bool acpi_device_can_poweroff(struct acpi_device *adev)
bool acpi_dev_hid_uid_match(struct acpi_device *adev, const char *hid2, const char *uid2);
void acpi_dev_clear_dependencies(struct acpi_device *supplier);
+bool acpi_dev_ready_for_enumeration(const struct acpi_device *device);
struct acpi_device *acpi_dev_get_first_consumer_dev(struct acpi_device *supplier);
struct acpi_device *
acpi_dev_get_next_match_dev(struct acpi_device *adev, const char *hid, const char *uid, s64 hrv);