From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
After commit a23318feeff6 (i2c: designware: Fix system suspend)
the i2c-designware-platdrv driver always resumes the device in its
system sleep ->suspend callback which isn't particularly nice,
even though it is technically correct.
A better approach would be to make the driver track the PM state of
the device so that it doesn't need to resume it in ->suspend and
to drop its ->prepare and ->complete callbacks which are only
marginally useful, so implement that.
First, drop dw_i2c_plat_suspend() added by commit a23318feeff6 and
rename dw_i2c_plat_runtime_suspend() back to dw_i2c_plat_suspend().
Second, point the driver's ->late_suspend and ->early_resume
callbacks, rather than its ->suspend and ->resume callbacks,
to dw_i2c_plat_suspend() and dw_i2c_plat_resume(), respectively,
so that they are not executed in parallel with each other, for
example if runtime resume of the device takes place during system
suspend.
Next, add "suspended" and "skip_resume" flags to struct dw_i2c_dev
and make dw_i2c_plat_suspend() and dw_i2c_plat_resume() use them to
avoid suspending or resuming the device twice in a row and to avoid
resuming a previously runtime-suspended device during system resume.
Finally, drop the driver's ->prepare and ->complete PM callbacks,
because returning "true" from ->prepare for runtime-suspended
devices is marginally useful (the PM core may still ignore that
return value and invoke the driver's ->suspend callback anyway)
and ->complete is only needed because of what ->prepare does.
Overrides: a23318feeff6 (i2c: designware: Fix system suspend)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
-> v2: Add the "suspended" flag, which is needed, because
dw_i2c_plat_suspend() doesn't update the runtime PM
status of the device, so dw_i2c_plat_resume() can't
rely on the pm_runtime_status_suspended() check
during system resume.
---
drivers/i2c/busses/i2c-designware-core.h | 2 +
drivers/i2c/busses/i2c-designware-platdrv.c | 51 ++++++++++------------------
2 files changed, 22 insertions(+), 31 deletions(-)
Index: linux-pm/drivers/i2c/busses/i2c-designware-core.h
===================================================================
--- linux-pm.orig/drivers/i2c/busses/i2c-designware-core.h
+++ linux-pm/drivers/i2c/busses/i2c-designware-core.h
@@ -280,6 +280,8 @@ struct dw_i2c_dev {
int (*acquire_lock)(struct dw_i2c_dev *dev);
void (*release_lock)(struct dw_i2c_dev *dev);
bool pm_disabled;
+ bool suspended;
+ bool skip_resume;
void (*disable)(struct dw_i2c_dev *dev);
void (*disable_int)(struct dw_i2c_dev *dev);
int (*init)(struct dw_i2c_dev *dev);
Index: linux-pm/drivers/i2c/busses/i2c-designware-platdrv.c
===================================================================
--- linux-pm.orig/drivers/i2c/busses/i2c-designware-platdrv.c
+++ linux-pm/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -434,31 +434,22 @@ static const struct of_device_id dw_i2c_
MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
#endif
-#ifdef CONFIG_PM_SLEEP
-static int dw_i2c_plat_prepare(struct device *dev)
-{
- return pm_runtime_suspended(dev);
-}
-
-static void dw_i2c_plat_complete(struct device *dev)
-{
- if (dev->power.direct_complete)
- pm_request_resume(dev);
-}
-#else
-#define dw_i2c_plat_prepare NULL
-#define dw_i2c_plat_complete NULL
-#endif
-
#ifdef CONFIG_PM
-static int dw_i2c_plat_runtime_suspend(struct device *dev)
+static int dw_i2c_plat_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
+ if (i_dev->suspended) {
+ i_dev->skip_resume = true;
+ return 0;
+ }
+
i_dev->disable(i_dev);
i2c_dw_plat_prepare_clk(i_dev, false);
+ i_dev->suspended = true;
+
return 0;
}
@@ -467,27 +458,25 @@ static int dw_i2c_plat_resume(struct dev
struct platform_device *pdev = to_platform_device(dev);
struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
+ if (!i_dev->suspended)
+ return 0;
+
+ if (i_dev->skip_resume) {
+ i_dev->skip_resume = false;
+ return 0;
+ }
+
i2c_dw_plat_prepare_clk(i_dev, true);
i_dev->init(i_dev);
- return 0;
-}
+ i_dev->suspended = false;
-#ifdef CONFIG_PM_SLEEP
-static int dw_i2c_plat_suspend(struct device *dev)
-{
- pm_runtime_resume(dev);
- return dw_i2c_plat_runtime_suspend(dev);
+ return 0;
}
-#endif
static const struct dev_pm_ops dw_i2c_dev_pm_ops = {
- .prepare = dw_i2c_plat_prepare,
- .complete = dw_i2c_plat_complete,
- SET_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume)
- SET_RUNTIME_PM_OPS(dw_i2c_plat_runtime_suspend,
- dw_i2c_plat_resume,
- NULL)
+ 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)
};
#define DW_I2C_DEV_PMOPS (&dw_i2c_dev_pm_ops)
--
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