clocksource/drivers/renesas-ostm: Add RZ/G2L OSTM support

RZ/G2L SoC has Generic Timer Module(a.k.a OSTM) which needs to
deassert the reset line before accessing any registers.

This patch adds an entry point for RZ/G2L so that we can deassert
the reset line in probe callback.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20211112184413.4391-4-biju.das.jz@bp.renesas.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

diff --git a/drivers/clocksource/renesas-ostm.c b/drivers/clocksource/renesas-ostm.c
index 3d06ba6..21d1392 100644 (file)
--- a/drivers/clocksource/renesas-ostm.c
+++ b/drivers/clocksource/renesas-ostm.c
@@ -9,6 +9,8 @@
 #include <linux/clk.h>
 #include <linux/clockchips.h>
 #include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
 #include <linux/sched_clock.h>
 #include <linux/slab.h>
 
@@ -159,6 +161,7 @@ static int __init ostm_init_clkevt(struct timer_of *to)
 
 static int __init ostm_init(struct device_node *np)
 {
+       struct reset_control *rstc;
        struct timer_of *to;
        int ret;
 
@@ -166,6 +169,14 @@ static int __init ostm_init(struct device_node *np)
        if (!to)
                return -ENOMEM;
 
+       rstc = of_reset_control_get_optional_exclusive(np, NULL);
+       if (IS_ERR(rstc)) {
+               ret = PTR_ERR(rstc);
+               goto err_free;
+       }
+
+       reset_control_deassert(rstc);
+
        to->flags = TIMER_OF_BASE | TIMER_OF_CLOCK;
        if (system_clock) {
                /*
@@ -178,7 +189,7 @@ static int __init ostm_init(struct device_node *np)
 
        ret = timer_of_init(np, to);
        if (ret)
-               goto err_free;
+               goto err_reset;
 
        /*
         * First probed device will be used as system clocksource. Any
@@ -203,9 +214,35 @@ static int __init ostm_init(struct device_node *np)
 
 err_cleanup:
        timer_of_cleanup(to);
+err_reset:
+       reset_control_assert(rstc);
+       reset_control_put(rstc);
 err_free:
        kfree(to);
        return ret;
 }
 
 TIMER_OF_DECLARE(ostm, "renesas,ostm", ostm_init);
+
+#ifdef CONFIG_ARCH_R9A07G044
+static int __init ostm_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+
+       return ostm_init(dev->of_node);
+}
+
+static const struct of_device_id ostm_of_table[] = {
+       { .compatible = "renesas,ostm", },
+       { /* sentinel */ }
+};
+
+static struct platform_driver ostm_device_driver = {
+       .driver = {
+               .name = "renesas_ostm",
+               .of_match_table = of_match_ptr(ostm_of_table),
+               .suppress_bind_attrs = true,
+       },
+};
+builtin_platform_driver_probe(ostm_device_driver, ostm_probe);
+#endif