Date:   Mon, 6 Mar 2023 08:49:27 +0200
From:   Tony Lindgren <tony@atomide.com>
To:     Andy Shevchenko <andriy.shevchenko@intel.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        Ilpo =?utf-8?B?SsOkcnZpbmVu?= <ilpo.jarvinen@linux.intel.com>,
        Johan Hovold <johan@kernel.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-serial@vger.kernel.org
Subject: Re: [PATCH v5 1/1] serial: core: Start managing serial controllers
 to enable runtime PM
Message-ID: <20230306064927.GA7501@atomide.com>
References: <20230116080002.47315-1-tony@atomide.com>
 <ZADJm+co4goPgr7u@smile.fi.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ZADJm+co4goPgr7u@smile.fi.intel.com>
Precedence: bulk

* Andy Shevchenko <andriy.shevchenko@intel.com> [230302 16:07]:
> On Mon, Jan 16, 2023 at 09:59:58AM +0200, Tony Lindgren wrote:
> > We want to enable runtime PM for serial port device drivers in a generic
> > way. To do this, we want to have the serial core layer manage the
> > registered physical serial controller devices.
> > 
> > To do this, let's set up a struct device for the serial core controller
> > as suggested by Greg and Jiri. The serial core controller devices are
> > children of the physical serial port device. The serial core controller
> > device is needed to support multiple different kind of ports connected
> > to single physical serial port device.
> > 
> > Let's also set up a struct device for the serial core port. The serial
> > core port instances are children of the serial core controller device.
> > 
> > With the serial core port device we can now flush pending TX on the
> > runtime PM resume as suggested by Johan.
> 
> A side note. Perhaps it makes sense to also clean up documentation somehow
> related to this change. For example, I found that
> Documentation/firmware-guide/acpi/enumeration.rst has this:
> 
>   "Note that standard UARTs are not busses so there is no struct uart_device,
>    although some of them may be represented by struct serdev_device."

OK good point, will update that for the next version.

FYI, I replaced the serial core platform bus with just struct device and
bus, need to clean-up a bit before posting though.

Regards,

Tony