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SubjectRe: [PATCH v3 2/7] serdev: add dev_pm_domain_attach|detach()
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On Thu, 2018-06-14 at 10:58 +0200, Ulf Hansson wrote:
> On Thu, 14 Jun 2018 at 09:14, <sean.wang@mediatek.com> wrote:
> >
> > From: Sean Wang <sean.wang@mediatek.com>
> >
> > In order to open up the required power gate before any operation can be
> > effectively performed over the serial bus between CPU and serdev, it's
> > clearly essential to add common attach functions for PM domains to serdev
> > at the probe phase.
> >
> > Similarly, the relevant dettach function for the PM domains should be
> > properly and reversely added at the remove phase.
> >
> > Signed-off-by: Sean Wang <sean.wang@mediatek.com>
> > Cc: Rob Herring <robh@kernel.org>
> > Cc: Ulf Hansson <ulf.hansson@linaro.org>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: Jiri Slaby <jslaby@suse.com>
> > Cc: linux-serial@vger.kernel.org
> > ---
> > drivers/tty/serdev/core.c | 14 +++++++++++++-
> > 1 file changed, 13 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
> > index df93b72..c93d8ee 100644
> > --- a/drivers/tty/serdev/core.c
> > +++ b/drivers/tty/serdev/core.c
> > @@ -13,6 +13,7 @@
> > #include <linux/module.h>
> > #include <linux/of.h>
> > #include <linux/of_device.h>
> > +#include <linux/pm_domain.h>
> > #include <linux/serdev.h>
> > #include <linux/slab.h>
> >
> > @@ -330,8 +331,16 @@ EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
> > static int serdev_drv_probe(struct device *dev)
> > {
> > const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
> > + int ret;
> > +
> > + ret = dev_pm_domain_attach(dev, true);
> > + if (ret != -EPROBE_DEFER) {
>
> From 4.18 rc1 via commit 919b7308fcc4, dev_pm_domain_attach() will
> return better error codes.
>
> I suggest to change the above error path to:
> if (ret)
> return ret;
>
> Then continue with the probing below.

Thanks for sharing me the information. I'll happily respin using the
patch because it makes the most sense.

>
> > + ret = sdrv->probe(to_serdev_device(dev));
> > + if (ret)
> > + dev_pm_domain_detach(dev, true);
> > + }
> >
> > - return sdrv->probe(to_serdev_device(dev));
> > + return ret;
> > }
> >
> > static int serdev_drv_remove(struct device *dev)
> > @@ -339,6 +348,9 @@ static int serdev_drv_remove(struct device *dev)
> > const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
> > if (sdrv->remove)
> > sdrv->remove(to_serdev_device(dev));
> > +
> > + dev_pm_domain_detach(dev, true);
> > +
> > return 0;
> > }
> >
> > --
> > 2.7.4
> >
>
> Otherwise, this makes sense to me!
>

really thanks for your review!

> Kind regards
> Uffe


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