linux-kernel - Re: [PATCH v2 02/10] clockevents/drivers: add MPS2 Timer driver

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Date:	Tue, 2 Feb 2016 14:04:29 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Vladimir Murzin <vladimir.murzin@....com>
cc:	arnd@...db.de, linux@....linux.org.uk, gregkh@...uxfoundation.org,
	daniel.lezcano@...aro.org, u.kleine-koenig@...gutronix.de,
	andy.shevchenko@...il.com, mark.rutland@....com,
	pawel.moll@....com, ijc+devicetree@...lion.org.uk,
	galak@...eaurora.org, jslaby@...e.cz, robh+dt@...nel.org,
	devicetree@...r.kernel.org, linux-serial@...r.kernel.org,
	linux-api@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 02/10] clockevents/drivers: add MPS2 Timer driver

On Tue, 2 Feb 2016, Vladimir Murzin wrote:
> +static int __init mps2_clockevent_init(struct device_node *np)
> +{
> +	void __iomem *base;
> +	struct clk *clk;
> +	struct clockevent_mps2 *ce;
> +	u32 rate;
> +	int irq, ret;
> +	const char *name = "mps2-clkevt";
> +
> +	ret = of_property_read_u32(np, "clock-frequency", &rate);
> +	if (ret) {
> +		clk = of_clk_get(np, 0);
> +		if (IS_ERR(clk)) {
> +			ret = PTR_ERR(clk);
> +			pr_err("failed to get clock for clockevent: %d\n", ret);
> +			goto err_clk_get;
> +		}
> +
> +		ret = clk_prepare_enable(clk);
> +		if (ret) {
> +			pr_err("failed to enable clock for clockevent: %d\n", ret);
> +			clk_put(clk);
> +			goto err_clk_enable;
> +		}
> +
> +		rate = clk_get_rate(clk);
> +	}

So in case that "clock-frequency" is available in DT, what enables and
configures the clock?

> +err_ia_alloc:
> +	kfree(ce);
> +err_ce_alloc:
> +err_get_irq:
> +	iounmap(base);
> +err_iomap:
> +	clk_disable_unprepare(clk);

clk is not initialized when "clock-frequency" is available in DT. The compiler
should have told you ....

> +err_clk_enable:
> +	clk_put(clk);

Put without get ....

> +static int __init mps2_clocksource_init(struct device_node *np)
> +{
> +	void __iomem *base;
> +	struct clk *clk;
> +	u32 rate;
> +	int ret;
> +	const char *name = "mps2-clksrc";
> +
> +	ret = of_property_read_u32(np, "clock-frequency", &rate);
> +	if (ret) {
> +		clk = of_clk_get(np, 0);
> +		if (IS_ERR(clk)) {
> +			ret = PTR_ERR(clk);
> +			pr_err("failed to get clock for clocksource: %d\n", ret);
> +			goto err_clk_get;
> +		}
> +
> +		ret = clk_prepare_enable(clk);
> +		if (ret) {
> +			pr_err("failed to enable clock for clocksource: %d\n", ret);
> +			clk_put(clk);
> +			goto err_clk_enable;
> +		}
> +
> +		rate = clk_get_rate(clk);
> +	}

Same problem as above.

> +err_clocksource_init:
> +	iounmap(base);
> +err_iomap:
> +	clk_disable_unprepare(clk);

Ditto.

> +err_clk_enable:
> +	clk_put(clk);

Ditto.

> +err_clk_get:
> +	return ret;
> +}
> +
> +static void __init mps2_timer_init(struct device_node *np)
> +{
> +	static int has_clocksource, has_clockevent;
> +	int ret;
> +
> +	if (!has_clocksource) {
> +		ret = mps2_clocksource_init(np);
> +		if (!ret) {
> +			has_clocksource = 1;
> +			return;
> +		}
> +	}
> +
> +	if (!has_clockevent) {
> +		ret = mps2_clockevent_init(np);
> +		if (!ret) {
> +			has_clockevent = 1;
> +			return;
> +		}
> +	}

You take randomly the first timer as clocksource and the second one as
clockevent. If clocksource init fails, you try to install it as clockevent.

Sorry, but I really cannot follow the logic here.

Thanks,

	tglx