Re: [PATCH 3/3] serial: sh-sci: Add reset support for RZ/G2L SoC
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2021-11-08 16:40:13
Also in:
linux-devicetree, linux-renesas-soc, lkml
Hi Prabhakar, On Wed, Nov 3, 2021 at 6:31 PM Lad Prabhakar [off-list ref] wrote:
On RZ/G2L devices should be explicitly pulled out of reset for it to work. This patch adds support to read the "resets" property and performs 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@bp.renesas.com> Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Thanks for your patch!
--- Hi Geert, For handling the resets I was in dual mind whether to perform reset based on compatible strings or soc-id, let me know your thoughts. Currently no SoC's use "renesas,sci" so using the same for performing the reset operation for SCI.
We do, on H8/300.
quoted hunk ↗ jump to hunk
--- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c@@ -3203,23 +3204,58 @@ 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; struct plat_sci_port *p; struct sci_port *sp; const void *data; int id; 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); + if (!strcmp(of_id->compatible, "renesas,scif-r9a07g044") || + !strcmp(of_id->compatible, "renesas,sci")) {
This will match on H8/300, too, which doesn't have resets. Please match against "renesas,sci-r9a07g044" instead. Please don't use explicit strcmp() calls here, but add a flag to of_sci_match[].data.
+ struct reset_control *rstc;
+ int ret;
+
+ rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+ if (IS_ERR(rstc)) {
+ dev_err(&pdev->dev, "Error: missing reset ctrl\n");
+ return ERR_PTR(PTR_ERR(rstc));
+ }
+
+ ret = reset_control_deassert(rstc);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to deassert %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;
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
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