After recent kernel changes Bay and Cherry Trail devices where the I2C bus
to the PMIC is shared with PUNIT properly reach S0ix states when suspended.
As explained in detail in the commit message of commit 9d9a152ebaa8 ("i2c:
designware: Re-init controllers with pm_disabled set on resume"), the
I2C controller for this bus has an effectively empty _PS3 ACPI method and
thus is left in D0 during suspend. It seems to somehow automatically
powerdown once S0i3 is reached, which means that it needs to be
reinitialized on resume for us to be able to use it again.
The referred commit adds the necessary code to re-init the controller
to the drivers resume_early method. It turns out that for some devices
this is too late. On a Peaq C1010 2-in-1 tablet/laptop doing the re-init
from resume_early leads to the device rebooting on resume.
This commit moves the re-init to resume_noirq, fixing this. Note this
means that the controller re-init now happens before the early_resume
handler from drivers/acpi/acpi_lpss.c runs. Which means that the
controller was not put in D0 yet when we re-init, this is not a problem
since the controller was never put in D3 in the first place.
This has been tested on the Peaq C1010 and one other Bay Trail device and
Cherry Trail device, both of which have an I2C bus shared with the PUNIT
too.
Fixes: 9d9a152ebaa8 ("i2c: designware: Re-init controllers with ...")
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/i2c/busses/i2c-designware-platdrv.c | 22 ++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index e92fdb46b5a0..3f96d048ce2d 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -429,8 +429,27 @@ static int dw_i2c_plat_resume(struct device *dev)
{
struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
+ if (i_dev->shared_with_punit)
+ return 0;
+
+ i2c_dw_prepare_clk(i_dev, true);
+ i_dev->init(i_dev);
+
+ return 0;
+}
+
+/*
+ * This is only for (Intel BYT/CHT) devices where the I2C bus to the PMIC
+ * is shared with the SoC's PUNIT. On these devices the controller is never
+ * turned off by us, but is automatically powered down in hardware. So we
+ * need to re-init it and we need to do this as early as possible.
+ */
+static int dw_i2c_plat_resume_noirq(struct device *dev)
+{
+ struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
+
if (!i_dev->shared_with_punit)
- i2c_dw_prepare_clk(i_dev, true);
+ return 0;
i_dev->init(i_dev);
@@ -440,6 +459,7 @@ static int dw_i2c_plat_resume(struct device *dev)
static const struct dev_pm_ops dw_i2c_dev_pm_ops = {
.prepare = dw_i2c_plat_prepare,
.complete = dw_i2c_plat_complete,
+ .resume_noirq = dw_i2c_plat_resume_noirq,
SET_LATE_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume)
SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL)
};
--
2.19.0.rc0
