Hi,
On 12/19/22 12:20, Richard Fitzgerald wrote:
> Ensure that i2c_mark_adapter_suspended() is always balanced by a call to
> i2c_mark_adapter_resumed().
>
> dw_i2c_plat_resume() must always be called, so that
> i2c_mark_adapter_resumed() is called. This is not compatible with
> DPM_FLAG_MAY_SKIP_RESUME, so remove the flag.
>
> Since the controller is always resumed on system resume the
> dw_i2c_plat_complete() callback is redundant and has been removed.
>
> The unbalanced suspended flag was introduced by
> commit c57813b8b288 ("i2c: designware: Lock the adapter while setting the
> suspended flag")
>
> Before that commit, the system and runtime PM used the same functions. The
> DPM_FLAG_MAY_SKIP_RESUME was used to skip the system resume if the driver
> had been in runtime-suspend. If system resume was skipped, the suspended
> flag would be cleared by the next runtime resume. The check of the
> suspended flag was _after_ the call to pm_runtime_get_sync() in
> i2c_dw_xfer(). So either a system resume or a runtime resume would clear
> the flag before it was checked.
>
> Having introduced the unbalanced suspended flag with that commit, a further
> commit 80704a84a9f8 ("i2c: designware: Use the
> i2c_mark_adapter_suspended/resumed() helpers")
>
> changed from using a local suspended flag to using the
> i2c_mark_adapter_suspended/resumed() functions. These use a flag that is
> checked by I2C core code before issuing the transfer to the bus driver, so
> there was no opportunity for the bus driver to runtime resume itself before
> the flag check.
>
> Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
> Fixes: c57813b8b288 ("i2c: designware: Lock the adapter while setting the suspended flag")
Thanks, patch looks good to me:
Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Regards,
Hans
> ---
> drivers/i2c/busses/i2c-designware-platdrv.c | 20 ++------------------
> 1 file changed, 2 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> index ba043b547393..74182db03a88 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -351,13 +351,11 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
>
> if (dev->flags & ACCESS_NO_IRQ_SUSPEND) {
> dev_pm_set_driver_flags(&pdev->dev,
> - DPM_FLAG_SMART_PREPARE |
> - DPM_FLAG_MAY_SKIP_RESUME);
> + DPM_FLAG_SMART_PREPARE);
> } else {
> dev_pm_set_driver_flags(&pdev->dev,
> DPM_FLAG_SMART_PREPARE |
> - DPM_FLAG_SMART_SUSPEND |
> - DPM_FLAG_MAY_SKIP_RESUME);
> + DPM_FLAG_SMART_SUSPEND);
> }
>
> device_enable_async_suspend(&pdev->dev);
> @@ -419,21 +417,8 @@ static int dw_i2c_plat_prepare(struct device *dev)
> */
> return !has_acpi_companion(dev);
> }
> -
> -static void dw_i2c_plat_complete(struct device *dev)
> -{
> - /*
> - * The device can only be in runtime suspend at this point if it has not
> - * been resumed throughout the ending system suspend/resume cycle, so if
> - * the platform firmware might mess up with it, request the runtime PM
> - * framework to resume it.
> - */
> - if (pm_runtime_suspended(dev) && pm_resume_via_firmware())
> - pm_request_resume(dev);
> -}
> #else
> #define dw_i2c_plat_prepare NULL
> -#define dw_i2c_plat_complete NULL
> #endif
>
> #ifdef CONFIG_PM
> @@ -483,7 +468,6 @@ static int __maybe_unused 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,
> SET_LATE_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume)
> SET_RUNTIME_PM_OPS(dw_i2c_plat_runtime_suspend, dw_i2c_plat_runtime_resume, NULL)
> };
