static int __init keystone_timer_init()

in timer-keystone.c [143:223]

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

static int __init keystone_timer_init(struct device_node *np)
{
	struct clock_event_device *event_dev = &timer.event_dev;
	unsigned long rate;
	struct clk *clk;
	int irq, error;

	irq  = irq_of_parse_and_map(np, 0);
	if (!irq) {
		pr_err("%s: failed to map interrupts\n", __func__);
		return -EINVAL;
	}

	timer.base = of_iomap(np, 0);
	if (!timer.base) {
		pr_err("%s: failed to map registers\n", __func__);
		return -ENXIO;
	}

	clk = of_clk_get(np, 0);
	if (IS_ERR(clk)) {
		pr_err("%s: failed to get clock\n", __func__);
		iounmap(timer.base);
		return PTR_ERR(clk);
	}

	error = clk_prepare_enable(clk);
	if (error) {
		pr_err("%s: failed to enable clock\n", __func__);
		goto err;
	}

	rate = clk_get_rate(clk);

	/* disable, use internal clock source */
	keystone_timer_writel(0, TCR);
	/* here we have to be sure the timer has been disabled */
	keystone_timer_barrier();

	/* reset timer as 64-bit, no pre-scaler, plus features are disabled */
	keystone_timer_writel(0, TGCR);

	/* unreset timer */
	keystone_timer_writel(TGCR_TIM_UNRESET_MASK, TGCR);

	/* init counter to zero */
	keystone_timer_writel(0, TIM12);
	keystone_timer_writel(0, TIM34);

	timer.hz_period = DIV_ROUND_UP(rate, HZ);

	/* enable timer interrupts */
	keystone_timer_writel(INTCTLSTAT_ENINT_MASK, INTCTLSTAT);

	error = request_irq(irq, keystone_timer_interrupt, IRQF_TIMER,
			    TIMER_NAME, event_dev);
	if (error) {
		pr_err("%s: failed to setup irq\n", __func__);
		goto err;
	}

	/* setup clockevent */
	event_dev->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
	event_dev->set_next_event = keystone_set_next_event;
	event_dev->set_state_shutdown = keystone_shutdown;
	event_dev->set_state_periodic = keystone_set_periodic;
	event_dev->set_state_oneshot = keystone_shutdown;
	event_dev->cpumask = cpu_possible_mask;
	event_dev->owner = THIS_MODULE;
	event_dev->name = TIMER_NAME;
	event_dev->irq = irq;

	clockevents_config_and_register(event_dev, rate, 1, ULONG_MAX);

	pr_info("keystone timer clock @%lu Hz\n", rate);
	return 0;
err:
	clk_put(clk);
	iounmap(timer.base);
	return error;
}