static int __init mps2_clocksource_init()

in mps2-timer.c [183:247]

• 51 lines of code
• 6 McCabe index (conditional complexity)

static int __init mps2_clocksource_init(struct device_node *np)
{
	void __iomem *base;
	struct clk *clk = NULL;
	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 out;
		}

		ret = clk_prepare_enable(clk);
		if (ret) {
			pr_err("failed to enable clock for clocksource: %d\n", ret);
			goto out_clk_put;
		}

		rate = clk_get_rate(clk);
	}

	base = of_iomap(np, 0);
	if (!base) {
		ret = -EADDRNOTAVAIL;
		pr_err("failed to map register for clocksource: %d\n", ret);
		goto out_clk_disable;
	}

	/* Ensure timer is disabled */
	writel_relaxed(0, base + TIMER_CTRL);

	/* ... and set it up as free-running clocksource */
	writel_relaxed(0xffffffff, base + TIMER_VALUE);
	writel_relaxed(0xffffffff, base + TIMER_RELOAD);

	writel_relaxed(TIMER_CTRL_ENABLE, base + TIMER_CTRL);

	ret = clocksource_mmio_init(base + TIMER_VALUE, name,
				    rate, 200, 32,
				    clocksource_mmio_readl_down);
	if (ret) {
		pr_err("failed to init clocksource: %d\n", ret);
		goto out_iounmap;
	}

	sched_clock_base = base;
	sched_clock_register(mps2_sched_read, 32, rate);

	return 0;

out_iounmap:
	iounmap(base);
out_clk_disable:
	/* clk_{disable, unprepare, put}() can handle NULL as a parameter */
	clk_disable_unprepare(clk);
out_clk_put:
	clk_put(clk);
out:
	return ret;
}