On 3/10/2017 3:49 PM, Hans de Goede wrote:
Hi,
On 10-03-17 03:33, Lan Tianyu wrote:
On 2017年03月09日 23:00, Jarkko Nikula wrote:
+ Tianyu
On 03/08/17 10:47, Hans de Goede wrote:
Cherrytrail devices use the dw i2c-bus with uid 7 to access their PMIC.
Even if the i2c-bus to the PMIC is not shared with the SoC's P-Unit
and i2c-designware-baytrail.c thus does not set the pm_disabled flag,
we still need to disable pm so that ACPI PMIC opregions can access the
PMIC during late-suspend and early-resume.
This fixes errors like these blocking suspend:
i2c_designware 808622C1:06: timeout waiting for bus ready
ACPI Exception: AE_ERROR, Returned by Handler for [UserDefinedRegion]
acpi 80860F14:02: Failed to change power state to D3hot
PM: late suspend of devices failed
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/i2c/busses/i2c-designware-platdrv.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c
b/drivers/i2c/busses/i2c-designware-platdrv.c
index 8ed96dd..08d609e 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -94,7 +94,10 @@ static void dw_i2c_acpi_params(struct
platform_device *pdev, char method[],
static int dw_i2c_acpi_configure(struct platform_device *pdev)
{
struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
+ acpi_handle handle = ACPI_HANDLE(&pdev->dev);
const struct acpi_device_id *id;
+ struct acpi_device *adev;
+ const char *uid;
dev->adapter.nr = -1;
dev->tx_fifo_depth = 32;
@@ -114,6 +117,18 @@ static int dw_i2c_acpi_configure(struct
platform_device *pdev)
if (id && id->driver_data)
dev->flags |= (u32)id->driver_data;
+ if (acpi_bus_get_device(handle, &adev))
+ return -ENODEV;
+
+ /*
+ * Cherrytrail I2C7 gets used for the PMIC which gets accessed
+ * through ACPI opregions during late suspend / early resume
+ * disable pm for it.
+ */
+ uid = adev->pnp.unique_id;
+ if ((dev->flags & MODEL_CHERRYTRAIL) && !strcmp(uid, "7"))
+ dev->pm_disabled = true;
+
I'm fine with this but wondering can this be detected any other way than
hardcoded bus number.
Tianyu: You are the author of 5d98e61d337c ("I2C/ACPI: Add i2c ACPI
operation region support"). Do you know is there way to see is there a
PMIC connected to the bus?
Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>
Hi Jarkko:
PMIC device node in ACPI table should have _DEP() method to return
devices PMIC depends on.
Hmm, interesting point, but I'm afraid by the time the PMIC driver loads
(and can make say an i2c_adapter_set_syscore call) it is already too late,
as we need to request the irq in the i2c-adapter driver with certain
flags and the i2c-adapter needs to be initialized before we can
load the pmic driver.
Yes, dep_unmet field in the struct acpi_device is designed for this
case. dep_unmet will be zero after all dependent operation region
handlers are registered. Please have a look acpi_battery_add() and it
checks dep_unmet. If dep_unmet isn't equal to zero, it returns
-EPROBE_DEFER. Device core will try reprobing the device after a device
driver module is loaded. PMIC driver also should check dep_unmet in probe().
Device (PMIC)
{
Name (_ADR, Zero) // _ADR: Address
Name (_HID, "INT33FD") // _HID: Hardware ID
Name (_CID, "INT33FD") // _CID: Compatible ID
Name (_DDN, "PMIC GPIO Controller") // _DDN: DOS
Device Name
Name (_HRV, 0x02) // _HRV: Hardware Revision
Name (_UID, One) // _UID: Unique ID
Name (_DEP, Package (0x01) // _DEP: Dependencies
{
I2C7
})
...
I really think just doing this for bus number 7 is the best solution
on all cherrytrail devices I've seen the PMIC is always at bus number 7.
This seems a hack way since PMIC also may have different I2C address.
This highly depends on vendor design.
I think the general way to resolve the issue
during suspend/resume is to make sure that I2C7 is suspended/resumed
later/earlier than PMIC device.
That would also require making sure that the PMIC suspends after any
devices whose _PS0 / _PS3 methods may need access to PMIC optegions,
we do not have infrastructure in Linux to do this.
Actually, suspend/resume sequence affects by the device probing
sequence. Please have a look at deferred_probe_work_func() and
device_pm_move_last() which changes the device position in the dpm_list
during reprobing device.
Regards,
Hans
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