linux-kernel - [PATCH 1/3] clocksource: timer-ti-dm: Fix pwm dmtimer usage of fck reparenting

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Date:   Tue, 22 Jan 2019 09:57:15 -0800
From:   Tony Lindgren <tony@...mide.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-omap@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        "H . Nikolaus Schaller" <hns@...delico.com>,
        Keerthy <j-keerthy@...com>,
        Ladislav Michl <ladis@...ux-mips.org>,
        Pavel Machek <pavel@....cz>,
        Sebastian Reichel <sre@...nel.org>,
        Tero Kristo <t-kristo@...com>,
        Thierry Reding <thierry.reding@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Andy Shevchenko <andy.shevchenko@...il.com>
Subject: [PATCH 1/3] clocksource: timer-ti-dm: Fix pwm dmtimer usage of fck reparenting

Commit 84badc5ec5fc ("ARM: dts: omap4: Move l4 child devices to probe
them with ti-sysc") moved some omap4 timers to probe with ti-sysc
interconnect target module. Turns out this broke pwm-omap-dmtimer
where we now try to reparent the clock to itself with the following:

omap_dm_timer_of_set_source: failed to set parent

With ti-sysc, we can now configure the clock sources in the dts
with assigned-clocks and assigned-clock-parents. So we should be able
to remove omap_dm_timer_of_set_source with clean-up patches later on.
But for now, let's just fix it first by checking if parent and fck
are the same and bail out of so.

Fixes: 84badc5ec5fc ("ARM: dts: omap4: Move l4 child devices to probe
them with ti-sysc")
Cc: Bartosz Golaszewski <bgolaszewski@...libre.com>
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: H. Nikolaus Schaller <hns@...delico.com>
Cc: Keerthy <j-keerthy@...com>
Cc: Ladislav Michl <ladis@...ux-mips.org>
Cc: Pavel Machek <pavel@....cz>
Cc: Sebastian Reichel <sre@...nel.org>
Cc: Tero Kristo <t-kristo@...com>
Cc: Thierry Reding <thierry.reding@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Reported-by: H. Nikolaus Schaller <hns@...delico.com>
Signed-off-by: Tony Lindgren <tony@...mide.com>
---
 drivers/clocksource/timer-ti-dm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/clocksource/timer-ti-dm.c b/drivers/clocksource/timer-ti-dm.c
--- a/drivers/clocksource/timer-ti-dm.c
+++ b/drivers/clocksource/timer-ti-dm.c
@@ -154,6 +154,10 @@ static int omap_dm_timer_of_set_source(struct omap_dm_timer *timer)
 	if (IS_ERR(parent))
 		return -ENODEV;
 
+	/* Bail out if both clocks point to fck */
+	if (clk_is_match(parent, timer->fclk))
+		return 0;
+
 	ret = clk_set_parent(timer->fclk, parent);
 	if (ret < 0)
 		pr_err("%s: failed to set parent\n", __func__);
-- 
2.20.1