| Message ID | 1483522697-6691-2-git-send-email-pandy.gao@nxp.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jan 04, 2017 at 05:38:17PM +0800, Gao Pan wrote: > When system enters VLLS mode, module power is turned off. As a result, > all registers are reset to HW default value. After exiting VLLS mode, > registers are still in default mode. As a result, the pinctrl settings > are incorrect, which will affect the module function. > > The patch recovers the pinctrl setting when exit VLLS mode. Why is this a change here and not in the pinctrl driver? It sounds like it's the pinctrl driver that's forgetting the settings and should be restoring them on resume but perhaps I'm missing something here.
From: Mark Brown <mailto:broonie@kernel.org> Sent: Tuesday, January 10, 2017 3:34 AM > To: Pandy Gao <pandy.gao@nxp.com> > Cc: linux-spi@vger.kernel.org > Subject: Re: [Patch V1 2/2] spi: fsl-lpspi: add VLLS mode support > > On Wed, Jan 04, 2017 at 05:38:17PM +0800, Gao Pan wrote: > > When system enters VLLS mode, module power is turned off. As a > result, > > all registers are reset to HW default value. After exiting VLLS mode, > > registers are still in default mode. As a result, the pinctrl settings > > are incorrect, which will affect the module function. > > > > The patch recovers the pinctrl setting when exit VLLS mode. > > Why is this a change here and not in the pinctrl driver? It sounds like > it's the pinctrl driver that's forgetting the settings and should be > restoring them on resume but perhaps I'm missing something here. If the pinctrl driver restores the setting on resume, then all device node should be scanned, which is irregular. Even though the pinctrl driver can handle all the child node of iomuxc, it's still difficult for the pinctrl driver to know which device node is disabled and which device node is okay. Moreover, there may be some pin conflicts among the child node of iomuxc. So it's better to do the restore in spi driver other than the pinctrl driver. Best Regards Gao Pan -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jan 17, 2017 at 07:03:28AM +0000, Pandy Gao wrote: > > > The patch recovers the pinctrl setting when exit VLLS mode. > > Why is this a change here and not in the pinctrl driver? It sounds like > > it's the pinctrl driver that's forgetting the settings and should be > > restoring them on resume but perhaps I'm missing something here. > If the pinctrl driver restores the setting on resume, then all device node > should be scanned, which is irregular. What would restoring the configuration have to do with scanning the device tree? The changelog says this is just reapplying the same settings we started out with so it's just a case of restoring the state of the device after a runtime resume which is a perfectly normal thing for a driver to do.
From: Mark Brown <mailto:broonie@kernel.org> Sent: Wednesday, January 18, 2017 3:04 AM > To: Pandy Gao <pandy.gao@nxp.com> > Cc: linux-spi@vger.kernel.org > Subject: Re: [Patch V1 2/2] spi: fsl-lpspi: add VLLS mode support > > On Tue, Jan 17, 2017 at 07:03:28AM +0000, Pandy Gao wrote: > > > > > The patch recovers the pinctrl setting when exit VLLS mode. > > > > Why is this a change here and not in the pinctrl driver? It sounds > > > like it's the pinctrl driver that's forgetting the settings and > > > should be restoring them on resume but perhaps I'm missing > something here. > > > If the pinctrl driver restores the setting on resume, then all device > > node should be scanned, which is irregular. > > What would restoring the configuration have to do with scanning the > device tree? The changelog says this is just reapplying the same > settings we started out with so it's just a case of restoring the state of > the device after a runtime resume which is a perfectly normal thing for > a driver to do. We can reapply the initial settings as the configurations defined in device node iomuxc in pinctrl driver. However, I think there are some limitations. For example, conflicts may exist between enet1grp and ecspi3grp, which is not easy for the pinctrl driver to find out. &iomuxc { pinctrl_ecspi3: ecspi3grp { ... }; pinctrl_enet1: enet1grp { ... }; } Best Regards Gao Pan -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/spi/spi-fsl-lpspi.c b/drivers/spi/spi-fsl-lpspi.c index 8ec8f55..8557728 100644 --- a/drivers/spi/spi-fsl-lpspi.c +++ b/drivers/spi/spi-fsl-lpspi.c @@ -510,10 +510,32 @@ static int fsl_lpspi_remove(struct platform_device *pdev) return 0; } +#ifdef CONFIG_PM_SLEEP +static int fsl_lpspi_suspend(struct device *dev) +{ + pinctrl_pm_select_sleep_state(dev); + + return 0; +} + +static int fsl_lpspi_resume(struct device *dev) +{ + pinctrl_pm_select_default_state(dev); + + return 0; +} + +static SIMPLE_DEV_PM_OPS(imx_lpspi_pm, fsl_lpspi_suspend, fsl_lpspi_resume); +#define IMX_LPSPI_PM (&imx_lpspi_pm) +#else +#define IMX_LPSPI_PM NULL +#endif + static struct platform_driver fsl_lpspi_driver = { .driver = { .name = DRIVER_NAME, .of_match_table = fsl_lpspi_dt_ids, + .pm = IMX_LPSPI_PM, }, .probe = fsl_lpspi_probe, .remove = fsl_lpspi_remove,
When system enters VLLS mode, module power is turned off. As a result, all registers are reset to HW default value. After exiting VLLS mode, registers are still in default mode. As a result, the pinctrl settings are incorrect, which will affect the module function. The patch recovers the pinctrl setting when exit VLLS mode. Signed-off-by: Gao Pan <pandy.gao@nxp.com> --- drivers/spi/spi-fsl-lpspi.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)