On Wed, 31 Jul 2019 at 18:17, Ulrich Hecht <uli+renesas@xxxxxxxx> wrote: > > This fixes a clock imbalance that occurs on Renesas systems because the SD > clock is handled by both runtime PM and the hardware driver. After a > suspend/resume cycle both enable the same clock, resulting in an enable > count of 2 even if the clock is only used by one device. > > See https://www.spinics.net/lists/linux-mmc/msg44431.html for details. > > This patch removes the clock handling from the driver's runtime PM > callbacks and turns the clock off after probing if the device has a power > domain attached. > > Reported-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > Signed-off-by: Ulrich Hecht <uli+renesas@xxxxxxxx> > Tested-by: Niklas Söderlund <niklas.soderlund@xxxxxxxxxxxx> > --- > drivers/mmc/host/tmio_mmc_core.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c > index 31ffcc3..733ff96 100644 > --- a/drivers/mmc/host/tmio_mmc_core.c > +++ b/drivers/mmc/host/tmio_mmc_core.c > @@ -1260,9 +1260,14 @@ int tmio_mmc_host_probe(struct tmio_mmc_host *_host) > /* See if we also get DMA */ > tmio_mmc_request_dma(_host, pdata); > > - pm_runtime_set_active(&pdev->dev); > +#ifdef CONFIG_PM > + /* PM handles the clock; disable it so it won't be enabled twice. */ > + if (_host->clk_disable && pdev->dev.pm_domain) Hmm. This seems to work for most cases of yours, but it's fragile, because how do you know that the pm_domain above is managing the clock? You don't. > + _host->clk_disable(_host); > + pm_runtime_get_sync(&pdev->dev); > pm_runtime_set_autosuspend_delay(&pdev->dev, 50); > pm_runtime_use_autosuspend(&pdev->dev); > +#endif > > ret = mmc_add_host(mmc); > if (ret) > @@ -1325,7 +1330,8 @@ int tmio_mmc_host_runtime_suspend(struct device *dev) > if (host->clk_cache) > host->set_clock(host, 0); > > - tmio_mmc_clk_disable(host); > + if (!dev->pm_domain) > + tmio_mmc_clk_disable(host); > > return 0; > } > @@ -1340,7 +1346,9 @@ int tmio_mmc_host_runtime_resume(struct device *dev) > { > struct tmio_mmc_host *host = dev_get_drvdata(dev); > > - tmio_mmc_clk_enable(host); > + if (!dev->pm_domain) > + tmio_mmc_clk_enable(host); > + > tmio_mmc_hw_reset(host->mmc); > > if (host->clk_cache) > -- > 2.7.4 > I am going to think a bit more about this, but at this point, my gut-feeling is that may need to add some helper functions to let genpd and/or the pm_clk framework, to share some internal information with drivers. Kind regards Uffe
