linux-kernel - [PATCH] clocksource: kona: Print warning rather than panic

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Date:	Thu, 5 Dec 2013 14:13:41 -0800
From:	Tim Kryger <tim.kryger@...aro.org>
To:	Christian Daudt <bcm@...thebug.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>
CC:	Tim Kryger <tim.kryger@...aro.org>,
	Broadcom Kernel Feedback List 
	<bcm-kernel-feedback-list@...adcom.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linaro Patches List <patches@...aro.org>
Subject: [PATCH] clocksource: kona: Print warning rather than panic

Since there may be other clocksources available, this driver should not
trigger a panic simply because it can not determine the frequency of an
external clock.  This change refactors the driver to allow a warning to
be printed in this case instead.

Signed-off-by: Tim Kryger <tim.kryger@...aro.org>
Reviewed-by: Markus Mayer <markus.mayer@...aro.org>
Reviewed-by: Matt Porter <matt.porter@...aro.org>
---

This patch depends on:  https://lkml.org/lkml/2013/12/5/513

 drivers/clocksource/bcm_kona_timer.c | 54 +++++++++++++++++++-----------------
 1 file changed, 28 insertions(+), 26 deletions(-)

diff --git a/drivers/clocksource/bcm_kona_timer.c b/drivers/clocksource/bcm_kona_timer.c
index 8a4ab36..75d26fe 100644
--- a/drivers/clocksource/bcm_kona_timer.c
+++ b/drivers/clocksource/bcm_kona_timer.c
@@ -105,31 +105,6 @@ static const struct of_device_id bcm_timer_ids[] __initconst = {
 	{},
 };
 
-static void __init kona_timers_init(struct device_node *node)
-{
-	u32 freq;
-	struct clk *external_clk;
-
-	external_clk = of_clk_get_by_name(node, NULL);
-
-	if (!IS_ERR(external_clk)) {
-		arch_timer_rate = clk_get_rate(external_clk);
-		clk_prepare_enable(external_clk);
-	} else if (!of_property_read_u32(node, "clock-frequency", &freq)) {
-		arch_timer_rate = freq;
-	} else {
-		panic("unable to determine clock-frequency");
-	}
-
-	/* Setup IRQ numbers */
-	timers.tmr_irq = irq_of_parse_and_map(node, 0);
-
-	/* Setup IO addresses */
-	timers.tmr_regs = of_iomap(node, 0);
-
-	kona_timer_disable_and_clear(timers.tmr_regs);
-}
-
 static int kona_timer_set_next_event(unsigned long clc,
 				  struct clock_event_device *unused)
 {
@@ -204,7 +179,34 @@ static struct irqaction kona_timer_irq = {
 
 static void __init kona_timer_init(struct device_node *node)
 {
-	kona_timers_init(node);
+	u32 freq;
+	struct clk *external_clk;
+
+	if (!of_device_is_available(node)) {
+		pr_info("Kona Timer v1 marked as disabled in device tree\n");
+		return;
+	}
+
+	external_clk = of_clk_get_by_name(node, NULL);
+
+	if (!IS_ERR(external_clk)) {
+		arch_timer_rate = clk_get_rate(external_clk);
+		clk_prepare_enable(external_clk);
+	} else if (!of_property_read_u32(node, "clock-frequency", &freq)) {
+		arch_timer_rate = freq;
+	} else {
+		pr_err("Kona Timer v1 unable to determine clock-frequency");
+		return;
+	}
+
+	/* Setup IRQ numbers */
+	timers.tmr_irq = irq_of_parse_and_map(node, 0);
+
+	/* Setup IO addresses */
+	timers.tmr_regs = of_iomap(node, 0);
+
+	kona_timer_disable_and_clear(timers.tmr_regs);
+
 	kona_timer_clockevents_init();
 	setup_irq(timers.tmr_irq, &kona_timer_irq);
 	kona_timer_set_next_event((arch_timer_rate / HZ), NULL);
-- 
1.8.0.1

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