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.
> + 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().
> + 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.
BTW, ERR_CAST() is a shorthand for ERR_PTR(PTR_ERR()).
> + }
> +
> + 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.
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
