Am Mittwoch, dem 13.07.2022 um 10:56 +0000 schrieb Hongxing Zhu: > > -----Original Message----- > > From: Lucas Stach <l.stach@xxxxxxxxxxxxxx> > > Sent: 2022年7月13日 16:34 > > To: Hongxing Zhu <hongxing.zhu@xxxxxxx>; bhelgaas@xxxxxxxxxx; > > robh+dt@xxxxxxxxxx; broonie@xxxxxxxxxx; lorenzo.pieralisi@xxxxxxx; > > festevam@xxxxxxxxx; francesco.dolcini@xxxxxxxxxxx > > Cc: linux-pci@xxxxxxxxxxxxxxx; > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > > linux-kernel@xxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; dl-linux-imx > > <linux-imx@xxxxxxx> > > Subject: Re: [PATCH v14 10/17] PCI: imx6: Turn off regulator when > > system is in > > suspend mode > > > > Am Freitag, dem 01.07.2022 um 11:25 +0800 schrieb Richard Zhu: > > > The driver should undo any enables it did itself. The regulator > > > disable shouldn't be basing decisions on regulator_is_enabled(). > > > > > > Move the regulator_disable to the suspend function, turn off > > > regulator > > > when the system is in suspend mode. > > > > > > To keep the balance of the regulator usage counter, disable the > > > regulator in shutdown. > > > > > > Link: > > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore > > > .kernel.org%2Fr%2F1655189942-12678-6-git-send-email- > > > hongxing.z&d > > at > > > > > a=05%7C01%7Chongxing.zhu%40nxp.com%7C361c9bf365b64895482808da6 > > 4aa7cca% > > > > > 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379329806385373 > > 39%7CUnkn > > > > > own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1 > > haWwi > > > > > LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=A%2Fw6AFCddC0T%2FA > > ocBT%2F7OJZ > > > ddAeYPTbgeAxpHpPubkw%3D&reserved=0 > > > hu@xxxxxxx > > > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx> > > > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > > --- > > > drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------ > > > 1 file changed, 7 insertions(+), 12 deletions(-) > > > > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c > > > b/drivers/pci/controller/dwc/pci-imx6.c > > > index 2b42c37f1617..f72eb609769b 100644 > > > --- a/drivers/pci/controller/dwc/pci-imx6.c > > > +++ b/drivers/pci/controller/dwc/pci-imx6.c > > > @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct > > > imx6_pcie > > > *imx6_pcie) > > > > > > static void imx6_pcie_assert_core_reset(struct imx6_pcie > > > *imx6_pcie) > > > { > > > - struct device *dev = imx6_pcie->pci->dev; > > > - > > > switch (imx6_pcie->drvdata->variant) { > > > case IMX7D: > > > case IMX8MQ: > > > @@ -702,14 +700,6 @@ static void > > > imx6_pcie_assert_core_reset(struct > > imx6_pcie *imx6_pcie) > > > break; > > > } > > > > > > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie- > > > >vpcie) > 0) { > > > - int ret = regulator_disable(imx6_pcie->vpcie); > > > - > > > - if (ret) > > > - dev_err(dev, "failed to disable vpcie > > > regulator: %d\n", > > > - ret); > > > - } > > > - > > > /* Some boards don't have PCIe reset GPIO. */ > > > if (gpio_is_valid(imx6_pcie->reset_gpio)) > > > gpio_set_value_cansleep(imx6_pcie->reset_gpio, > > > @@ -722,7 +712,7 @@ static int > > > imx6_pcie_deassert_core_reset(struct > > imx6_pcie *imx6_pcie) > > > struct device *dev = pci->dev; > > > int ret; > > > > > > - if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie- > > > >vpcie)) { > > > + if (imx6_pcie->vpcie) { > > > ret = regulator_enable(imx6_pcie->vpcie); > > > if (ret) { > > > dev_err(dev, "failed to enable vpcie > > > regulator: %d\n", > > > > The regulator really has nothing to do with the core reset. Please > > move this > > regulator enable into imx6_pcie_host_init(). > Hi Lucas: > Thanks for your comments. > Got that. Had done it in the 11/17 commit. > > > > > > @@ -795,7 +785,7 @@ static int > > > imx6_pcie_deassert_core_reset(struct > > imx6_pcie *imx6_pcie) > > > return 0; > > > > > > err_clks: > > > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie- > > > >vpcie) > 0) { > > > + if (imx6_pcie->vpcie) { > > > ret = regulator_disable(imx6_pcie->vpcie); > > > if (ret) > > > dev_err(dev, "failed to disable vpcie > > > regulator: %d\n", @@ > > -1022,6 > > > +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev) > > > break; > > > } > > > > > > + if (imx6_pcie->vpcie) > > > + regulator_disable(imx6_pcie->vpcie); > > > + > > > return 0; > > > } > > > > > > @@ -1268,6 +1261,8 @@ static void imx6_pcie_shutdown(struct > > > platform_device *pdev) > > > > > > /* bring down link, so bootloader gets clean state in > > > case of reboot */ > > > imx6_pcie_assert_core_reset(imx6_pcie); > > > + if (imx6_pcie->vpcie) > > > + regulator_disable(imx6_pcie->vpcie); > > > > This looks like a separate change, not mentioned in the commit > > message. > > I'm not sure if we should do this. Shutdown is supposed to just > > stop the device, > > which is already achieved by imx6_pcie_assert_core_reset(). > > > > If we would want to do a full cleanup here we would also need to > > disable > > clocks and get the reset GPIO into asserted state. I don't think we > > want to do > > all of this here. > The regulator_disable() was contained in > imx6_pcie_assert_core_reset() before. > When refine the regulator usage, the regulator_disable() is moved out > of > imx6_pcie_assert_core_reset(). > Based on the discussion [1] with Francesco. > To keep the same behavior, the regulator_disable() is placed behind > of > imx6_pcie_assert_core_reset() in imx6_pcie_shutdown() here. > [1] > https://patchwork.ozlabs.org/project/linux-pci/patch/1644290735-3797-6-git-send-email-hongxing.zhu@xxxxxxx/ I disagree with Francesco on this. This kind of half-done cleanup doesn't help in any way. Either we care about doing a full cleanup here, which would involve clocks and reset GPIOs, or we just care about getting the core in a state where it survives a reboot, which frankly was the original intention when I added the shutdown callback. As the devices on the bus will see a full PERST reset via the reset GPIO anyways, there is no harm in keeping them powered across the reboot. Regards, Lucas
