Mon, 12 May 2014 12:38:50 +0200 от Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>:
> On Sun, May 11, 2014 at 10:49:26PM +0400, Alexander Shiyan wrote:
> > Thu, 8 May 2014 09:31:36 +0200 от Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>:
> > > SPI is often used by other devices, so make sure it's initialized
> > > early.
> > >
> > > Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> > > ---
> > > drivers/spi/imx_spi.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/spi/imx_spi.c b/drivers/spi/imx_spi.c
> > > index e07cf1a..3146339 100644
> > > --- a/drivers/spi/imx_spi.c
> > > +++ b/drivers/spi/imx_spi.c
> > > @@ -586,4 +586,4 @@ static struct driver_d imx_spi_driver = {
> > > .of_compatible = DRV_OF_COMPAT(imx_spi_dt_ids),
> > > .id_table = imx_spi_ids,
> > > };
> > > -device_platform_driver(imx_spi_driver);
> > > +coredevice_platform_driver(imx_spi_driver);
> > > --
> >
> > Maybe we should put all drivers in a single runlevel and implement
> > handle of EPROBE_DEFER?
>
> I think about EPROBE_DEFER for longer now. What has hold me back was
> that we would have to release all resources before returning
> EPROBE_DEFER. Most drivers don't have proper error pathes implemented
> and I don't see much gain in fixing this. For a bootloader the error
> release pathes are unnecessary overhead, because nobody will ever
> use the same resources again (at least without EPROBE_DEFER).
> My recent idea to work around that issue is this:
>
> - put the drivers private data into dev->priv
> - when returning an error from probe, instead of freeing the data
> keep it.
> - when probing again re-use the data.
>
> With this drivers could be written like:
>
> priv = dev->priv;
> if (!priv) {
> priv = xzalloc(sizeof(priv));
> dev->priv = priv;
> }
>
> if (!priv->clk) {
> clk = clk_get(dev, NULL);
> if (IS_ERR(clk))
> return PTR_ERR(clk);
> priv->clk = clk;
> clk_enable(priv->clk);
> }
>
> if (!priv->regulator) {
> regulator = regulator_get(dev, "vmmc");
> if (IS_ERR(regulator))
> return PTR_ERR(regulator);
> priv->regulator = regulator;
> }
>
> This way drivers could allocate the missing resources as needed without
> freeing them between different calls to probe().
The idea is good, but I think that it will not be so easy to do.
In addition, we obtain additional incompatibility with the kernel code.
---
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