linux-kernel - [PATCH V2 40/63] clocksource/drivers/timer-atmel-pit: Convert init function to return error

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Date:	Thu, 16 Jun 2016 23:26:59 +0200
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	daniel.lezcano@...aro.org, tglx@...utronix.de
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH V2 40/63] clocksource/drivers/timer-atmel-pit: Convert init function to return error

The init functions do not return any error. They behave as the following:

  - panic, thus leading to a kernel crash while another timer may work and
       make the system boot up correctly

  or

  - print an error and let the caller unaware if the state of the system

Change that by converting the init functions to return an error conforming
to the CLOCKSOURCE_OF_RET prototype.

Proper error handling (rollback, errno value) will be changed later case
by case, thus this change just return back an error or success in the init
function.

Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
---
 drivers/clocksource/timer-atmel-pit.c | 43 +++++++++++++++++++++++------------
 1 file changed, 29 insertions(+), 14 deletions(-)

diff --git a/drivers/clocksource/timer-atmel-pit.c b/drivers/clocksource/timer-atmel-pit.c
index d911c5d..ffaca7c 100644
--- a/drivers/clocksource/timer-atmel-pit.c
+++ b/drivers/clocksource/timer-atmel-pit.c
@@ -177,7 +177,7 @@ static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id)
 /*
  * Set up both clocksource and clockevent support.
  */
-static void __init at91sam926x_pit_common_init(struct pit_data *data)
+static int __init at91sam926x_pit_common_init(struct pit_data *data)
 {
 	unsigned long	pit_rate;
 	unsigned	bits;
@@ -204,14 +204,21 @@ static void __init at91sam926x_pit_common_init(struct pit_data *data)
 	data->clksrc.rating = 175;
 	data->clksrc.read = read_pit_clk;
 	data->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
-	clocksource_register_hz(&data->clksrc, pit_rate);
+	
+	ret = clocksource_register_hz(&data->clksrc, pit_rate);
+	if (ret) {
+		pr_err("Failed to register clocksource");
+		return ret;
+	}
 
 	/* Set up irq handler */
 	ret = request_irq(data->irq, at91sam926x_pit_interrupt,
 			  IRQF_SHARED | IRQF_TIMER | IRQF_IRQPOLL,
 			  "at91_tick", data);
-	if (ret)
-		panic(pr_fmt("Unable to setup IRQ\n"));
+	if (ret) {
+		pr_err("Unable to setup IRQ\n");
+		return ret;
+	}
 
 	/* Set up and register clockevents */
 	data->clkevt.name = "pit";
@@ -226,34 +233,42 @@ static void __init at91sam926x_pit_common_init(struct pit_data *data)
 	data->clkevt.resume = at91sam926x_pit_resume;
 	data->clkevt.suspend = at91sam926x_pit_suspend;
 	clockevents_register_device(&data->clkevt);
+
+	return 0;
 }
 
-static void __init at91sam926x_pit_dt_init(struct device_node *node)
+static int __init at91sam926x_pit_dt_init(struct device_node *node)
 {
 	struct pit_data *data;
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
-		panic(pr_fmt("Unable to allocate memory\n"));
+		return -ENOMEM;
 
 	data->base = of_iomap(node, 0);
-	if (!data->base)
-		panic(pr_fmt("Could not map PIT address\n"));
+	if (!data->base) {
+		pr_err("Could not map PIT address\n");
+		return -ENXIO;
+	}
 
 	data->mck = of_clk_get(node, 0);
 	if (IS_ERR(data->mck))
 		/* Fallback on clkdev for !CCF-based boards */
 		data->mck = clk_get(NULL, "mck");
 
-	if (IS_ERR(data->mck))
-		panic(pr_fmt("Unable to get mck clk\n"));
+	if (IS_ERR(data->mck)) {
+		pr_err("Unable to get mck clk\n");
+		return PTR_ERR(data->mck);
+	}
 
 	/* Get the interrupts property */
 	data->irq = irq_of_parse_and_map(node, 0);
-	if (!data->irq)
-		panic(pr_fmt("Unable to get IRQ from DT\n"));
+	if (!data->irq) {
+		pr_err("Unable to get IRQ from DT\n");
+		return -EINVAL;
+	}
 
-	at91sam926x_pit_common_init(data);
+	return at91sam926x_pit_common_init(data);
 }
-CLOCKSOURCE_OF_DECLARE(at91sam926x_pit, "atmel,at91sam9260-pit",
+CLOCKSOURCE_OF_DECLARE_RET(at91sam926x_pit, "atmel,at91sam9260-pit",
 		       at91sam926x_pit_dt_init);
-- 
1.9.1