linux-kernel - Re: [PATCH 2/3] ARM: at91/tc/clocksource: improve driver robustness

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Message-ID: <524C15E6.7070500@atmel.com>
Date:	Wed, 2 Oct 2013 14:47:34 +0200
From:	Nicolas Ferre <nicolas.ferre@...el.com>
To:	Boris BREZILLON <b.brezillon@...rkiz.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>
CC:	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/3] ARM: at91/tc/clocksource: improve driver robustness

On 02/10/2013 14:35, Boris BREZILLON :
> Check function return values to avoid false positive driver init.
>
> Signed-off-by: Boris BREZILLON <b.brezillon@...rkiz.com>

Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>

> ---
>   drivers/clocksource/tcb_clksrc.c |   33 ++++++++++++++++++++++++++++-----
>   1 file changed, 28 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
> index 0481562..10a5d9e 100644
> --- a/drivers/clocksource/tcb_clksrc.c
> +++ b/drivers/clocksource/tcb_clksrc.c
> @@ -184,11 +184,18 @@ static struct irqaction tc_irqaction = {
>   	.handler	= ch2_irq,
>   };
>
> -static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
> +static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
>   {
> +	int ret;
>   	struct clk *t2_clk = tc->clk[2];
>   	int irq = tc->irq[2];
>
> +	/* try to enable t2 clk to avoid future errors in mode change */
> +	ret = clk_prepare_enable(t2_clk);
> +	if (ret)
> +		return ret;
> +	clk_disable_unprepare(t2_clk);
> +
>   	clkevt.regs = tc->regs;
>   	clkevt.clk = t2_clk;
>   	tc_irqaction.dev_id = &clkevt;
> @@ -197,16 +204,21 @@ static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
>
>   	clkevt.clkevt.cpumask = cpumask_of(0);
>
> +	ret = setup_irq(irq, &tc_irqaction);
> +	if (ret)
> +		return ret;
> +
>   	clockevents_config_and_register(&clkevt.clkevt, 32768, 1, 0xffff);
>
> -	setup_irq(irq, &tc_irqaction);
> +	return ret;
>   }
>
>   #else /* !CONFIG_GENERIC_CLOCKEVENTS */
>
> -static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
> +static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
>   {
>   	/* NOTHING */
> +	return 0;
>   }
>
>   #endif
> @@ -328,13 +340,24 @@ static int __init tcb_clksrc_init(void)
>   	}
>
>   	/* and away we go! */
> -	clocksource_register_hz(&clksrc, divided_rate);
> +	ret = clocksource_register_hz(&clksrc, divided_rate);
> +	if (ret)
> +		goto err_disable_t1;
>
>   	/* channel 2:  periodic and oneshot timer support */
> -	setup_clkevents(tc, clk32k_divisor_idx);
> +	ret = setup_clkevents(tc, clk32k_divisor_idx);
> +	if (ret)
> +		goto err_unregister_clksrc;
>
>   	return 0;
>
> +err_unregister_clksrc:
> +	clocksource_unregister(&clksrc);
> +
> +err_disable_t1:
> +	if (!tc->tcb_config || tc->tcb_config->counter_width != 32)
> +		clk_disable_unprepare(tc->clk[1]);
> +
>   err_disable_t0:
>   	clk_disable_unprepare(t0_clk);
>
>


-- 
Nicolas Ferre
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