| Message ID | 1460638414-5987-3-git-send-email-jszhang@marvell.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 04/14/2016 03:53 PM, Jisheng Zhang wrote: > If i2c_dw_probe() fail, we should call i2c_dw_plat_prepare_clk() to > disable and unprepare the clk, otherwise the clk enable and prepare > is left unbalanced. > > Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > --- > drivers/i2c/busses/i2c-designware-platdrv.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c > index 00f9e99..1488cea 100644 > --- a/drivers/i2c/busses/i2c-designware-platdrv.c > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c > @@ -268,6 +268,8 @@ rpm_disable: > pm_runtime_put_noidle(&pdev->dev); > } > > + i2c_dw_plat_prepare_clk(dev, false); > + > return r; > } > This is a bit unclear to me does devm_clk_get take care of clk disabling in case of probe error or driver removal? I see Andy's 1cb715ca4694 ("i2c-designware: move to managed functions (devm_*)") removed it but at quick look drivers/clk/clk-devres.c: devm_clk_release() calls only clk_put and I don't see disable is done down the path.
On Wed, 2016-04-20 at 15:55 +0300, Jarkko Nikula wrote: > On 04/14/2016 03:53 PM, Jisheng Zhang wrote: > > > > If i2c_dw_probe() fail, we should call i2c_dw_plat_prepare_clk() to > > disable and unprepare the clk, otherwise the clk enable and prepare > > is left unbalanced. > > > > Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > > --- > > drivers/i2c/busses/i2c-designware-platdrv.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c > > b/drivers/i2c/busses/i2c-designware-platdrv.c > > index 00f9e99..1488cea 100644 > > --- a/drivers/i2c/busses/i2c-designware-platdrv.c > > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c > > @@ -268,6 +268,8 @@ rpm_disable: > > pm_runtime_put_noidle(&pdev->dev); > > } > > > > + i2c_dw_plat_prepare_clk(dev, false); > > + > > return r; > > } > > > This is a bit unclear to me does devm_clk_get take care of clk > disabling > in case of probe error or driver removal? > > I see Andy's 1cb715ca4694 ("i2c-designware: move to managed functions > (devm_*)") removed it but at quick look drivers/clk/clk-devres.c: > devm_clk_release() calls only clk_put and I don't see disable is done > down the path. The following is a mistake of the mentioned patch. - clk_disable_unprepare(dev->clk); I did at the same mistake in dw_dmac driver which had been fixed later in the commit 8be4f523b480 ("dmaengine: dw: fix regression in dw_probe() function").
Dear Jarkko, Andy, On Wed, 20 Apr 2016 17:16:00 +0300 Andy Shevchenko wrote: > On Wed, 2016-04-20 at 15:55 +0300, Jarkko Nikula wrote: > > On 04/14/2016 03:53 PM, Jisheng Zhang wrote: > > > > > > If i2c_dw_probe() fail, we should call i2c_dw_plat_prepare_clk() to > > > disable and unprepare the clk, otherwise the clk enable and prepare > > > is left unbalanced. > > > > > > Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > > > --- > > > drivers/i2c/busses/i2c-designware-platdrv.c | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c > > > b/drivers/i2c/busses/i2c-designware-platdrv.c > > > index 00f9e99..1488cea 100644 > > > --- a/drivers/i2c/busses/i2c-designware-platdrv.c > > > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c > > > @@ -268,6 +268,8 @@ rpm_disable: > > > pm_runtime_put_noidle(&pdev->dev); > > > } > > > > > > + i2c_dw_plat_prepare_clk(dev, false); > > > + > > > return r; > > > } > > > > > This is a bit unclear to me does devm_clk_get take care of clk > > disabling > > in case of probe error or driver removal? > > > > I see Andy's 1cb715ca4694 ("i2c-designware: move to managed functions > > (devm_*)") removed it but at quick look drivers/clk/clk-devres.c: > > devm_clk_release() calls only clk_put and I don't see disable is done > > down the path. > > The following is a mistake of the mentioned patch. > - clk_disable_unprepare(dev->clk); > > I did at the same mistake in dw_dmac driver which had been fixed later > in the commit 8be4f523b480 ("dmaengine: dw: fix regression in dw_probe() > function"). > As Andy pointed out, managed devm_clk_get can only automatically put clk but doesn't unprepare and disable the clk Thanks, Jisheng
On 04/21/2016 05:40 AM, Jisheng Zhang wrote: > Dear Jarkko, Andy, > > On Wed, 20 Apr 2016 17:16:00 +0300 Andy Shevchenko wrote: > >> On Wed, 2016-04-20 at 15:55 +0300, Jarkko Nikula wrote: >>> I see Andy's 1cb715ca4694 ("i2c-designware: move to managed functions >>> (devm_*)") removed it but at quick look drivers/clk/clk-devres.c: >>> devm_clk_release() calls only clk_put and I don't see disable is done >>> down the path. >> >> The following is a mistake of the mentioned patch. >> - clk_disable_unprepare(dev->clk); >> >> I did at the same mistake in dw_dmac driver which had been fixed later >> in the commit 8be4f523b480 ("dmaengine: dw: fix regression in dw_probe() >> function"). >> > > As Andy pointed out, managed devm_clk_get can only automatically put clk > but doesn't unprepare and disable the clk > Ok, then it makes sense to move this fix first in the series and queue for stable v4.5+. Then another from you, Andy or me for kernels before b33af11de236 ("i2c: designware: Do not require clock when SSCN and FFCN are provided") that introduced the i2c_dw_plat_prepare_clk().
Dear Jarkko, On Thu, 21 Apr 2016 10:39:50 +0300 Jarkko Nikula wrote: > On 04/21/2016 05:40 AM, Jisheng Zhang wrote: > > Dear Jarkko, Andy, > > > > On Wed, 20 Apr 2016 17:16:00 +0300 Andy Shevchenko wrote: > > > >> On Wed, 2016-04-20 at 15:55 +0300, Jarkko Nikula wrote: > >>> I see Andy's 1cb715ca4694 ("i2c-designware: move to managed functions > >>> (devm_*)") removed it but at quick look drivers/clk/clk-devres.c: > >>> devm_clk_release() calls only clk_put and I don't see disable is done > >>> down the path. > >> > >> The following is a mistake of the mentioned patch. > >> - clk_disable_unprepare(dev->clk); > >> > >> I did at the same mistake in dw_dmac driver which had been fixed later > >> in the commit 8be4f523b480 ("dmaengine: dw: fix regression in dw_probe() > >> function"). > >> > > > > As Andy pointed out, managed devm_clk_get can only automatically put clk > > but doesn't unprepare and disable the clk > > > Ok, then it makes sense to move this fix first in the series and queue > for stable v4.5+. Then another from you, Andy or me for kernels before > b33af11de236 ("i2c: designware: Do not require clock when SSCN and FFCN > are provided") that introduced the i2c_dw_plat_prepare_clk(). Sounds a good idea. Will send a separate fix for this purpose soon. Thanks, Jisheng
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index 00f9e99..1488cea 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -268,6 +268,8 @@ rpm_disable: pm_runtime_put_noidle(&pdev->dev); } + i2c_dw_plat_prepare_clk(dev, false); + return r; }
If i2c_dw_probe() fail, we should call i2c_dw_plat_prepare_clk() to disable and unprepare the clk, otherwise the clk enable and prepare is left unbalanced. Signed-off-by: Jisheng Zhang <jszhang@marvell.com> --- drivers/i2c/busses/i2c-designware-platdrv.c | 2 ++ 1 file changed, 2 insertions(+)