Hi Geert,
Thank you for the review.
On Tue, Nov 9, 2021 at 12:58 PM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
>
> Hi Prabhakar,
>
> On Tue, Nov 9, 2021 at 1:17 PM Lad Prabhakar
> <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> wrote:
> > On RZ/G2L SoC we need to explicitly deassert the reset line
> > for the device to work, use this opportunity to deassert/assert
> > reset line in sh-sci driver.
> >
> > This patch adds support to read the "resets" property (if available)
> > from DT and perform deassert/assert when required.
> >
> > Also, propagate the error to the caller of sci_parse_dt() instead of
> > returning NULL in case of failure.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > Reviewed-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > ---
> > v1->v2
> > * deassert/assert reset line if available on all SoC's
> > * Updated commit message
>
> Thanks for the update!
>
> > --- a/drivers/tty/serial/sh-sci.c
> > +++ b/drivers/tty/serial/sh-sci.c
> > @@ -37,6 +37,7 @@
> > #include <linux/of_device.h>
> > #include <linux/platform_device.h>
> > #include <linux/pm_runtime.h>
> > +#include <linux/reset.h>
> > #include <linux/scatterlist.h>
> > #include <linux/serial.h>
> > #include <linux/serial_sci.h>
> > @@ -3203,23 +3204,53 @@ static const struct of_device_id of_sci_match[] = {
> > };
> > MODULE_DEVICE_TABLE(of, of_sci_match);
> >
> > +static void sci_reset_control_assert(void *data)
> > +{
> > + reset_control_assert(data);
> > +}
> > +
> > static struct plat_sci_port *sci_parse_dt(struct platform_device *pdev,
> > unsigned int *dev_id)
> > {
> > struct device_node *np = pdev->dev.of_node;
> > + const struct of_device_id *of_id;
>
> Not needed.
>
Agreed.
> > + struct reset_control *rstc;
> > struct plat_sci_port *p;
> > struct sci_port *sp;
> > const void *data;
> > - int id;
> > + int id, ret;
> >
> > if (!IS_ENABLED(CONFIG_OF) || !np)
> > - return NULL;
> > + return ERR_PTR(-EINVAL);
> > +
> > + of_id = of_match_device(of_sci_match, &pdev->dev);
> > + if (!of_id)
> > + return ERR_PTR(-EINVAL);
> >
> > - data = of_device_get_match_data(&pdev->dev);
>
> Please keep the old construct using of_device_get_match_data().
>
OK.
> > + rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
> > + if (IS_ERR(rstc)) {
> > + dev_err(&pdev->dev, "failed to get reset ctrl %ld\n", PTR_ERR(rstc));
> > + return ERR_PTR(PTR_ERR(rstc));
>
> The error might be -EPROBE_DEFER, so please use
> "return ERR_PTR(dev_err_probe(...))", to avoid printing the message
> in case of probe deferral.
>
Agreed, will use dev_err_probe().
> BTW, ERR_CAST() is a shorthand for ERR_PTR(PTR_ERR()).
>
Thanks for the pointer.
> > + }
> > +
> > + ret = reset_control_deassert(rstc);
> > + if (ret) {
> > + dev_err(&pdev->dev, "failed to deassert reset %d\n", ret);
> > + return ERR_PTR(ret);
> > + }
> > +
> > + ret = devm_add_action_or_reset(&pdev->dev, sci_reset_control_assert, rstc);
> > + if (ret) {
> > + dev_err(&pdev->dev, "failed to register assert devm action, %d\n",
> > + ret);
> > + return ERR_PTR(ret);
> > + }
> > +
> > + data = of_id->data;
> >
> > p = devm_kzalloc(&pdev->dev, sizeof(struct plat_sci_port), GFP_KERNEL);
> > if (!p)
> > - return NULL;
> > + return ERR_PTR(-ENOMEM);
> >
> > /* Get the line number from the aliases node. */
> > id = of_alias_get_id(np, "serial");
>
> I gave this a try on Salvator-XS, and noticed no regressions.
> I will test this on more SCIF variants later.
>
Thanks, I will re-spin a v3 just for this lone patch. I hope that's OK.
Cheers,
Prabhakar
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds
