Re: [RFC PATCH v4 1/1] serial: core: Start managing serial controllers to enable runtime PM
From: Andy Shevchenko
Date: Wed Dec 07 2022 - 15:28:32 EST
On Wed, Dec 07, 2022 at 10:22:11PM +0200, Andy Shevchenko wrote:
> On Wed, Dec 07, 2022 at 02:43:05PM +0200, Tony Lindgren wrote:
...
> > +int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
> > +{
>
> > + bool allocated = false;
>
> Not sure why this is needed.
Okay, I got it.
Still, see below.
> > + struct device *ctrl_dev;
> > + int ret;
> > +
> > + ret = serial_core_add_one_port(drv, port);
> > + if (ret)
> > + return ret;
> > +
> > + mutex_lock(&port_mutex);
> > +
> > + /* Inititalize a serial core controller device if needed */
> > + ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
> > + if (!ctrl_dev) {
> > + ctrl_dev = serial_core_ctrl_device_add(port);
> > + if (!ctrl_dev)
> > + goto err_remove_port;
> > + allocated = true;
> > + }
>
> Wouldn't be slightly better
>
> ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
> if (!ctrl_dev)
> ctrl_dev = serial_core_ctrl_device_add(port);
> if (!ctrl_dev)
> goto err_remove_port;
>
> ?
>
> > + /* Initialize a serial core port device */
> > + ret = serial_core_port_device_add(ctrl_dev, port);
> > + if (ret)
> > + goto err_del_ctrl_dev;
> > +
> > + mutex_unlock(&port_mutex);
> > +
> > + return 0;
> > +
> > +err_del_ctrl_dev:
> > + if (allocated)
We can avoid this check by caching the platform device.
struct platform_device *ctrl_pdev = NULL;
if (...) {
ctrl_pdev = to_platform_device(ctrl_dev);
}
platform_device_del(ctrl_pdev);
> > + platform_device_del(to_platform_device(ctrl_dev));
>
> Shouldn't you call platform_device_unregister()?
>
> > +err_remove_port:
> > + mutex_unlock(&port_mutex);
> > +
> > + return serial_core_remove_one_port(drv, port);
> > +}
--
With Best Regards,
Andy Shevchenko