static int __init at91_rtc_probe()

in rtc-at91rm9200.c [470:557]

• 64 lines of code
• 12 McCabe index (conditional complexity)

static int __init at91_rtc_probe(struct platform_device *pdev)
{
	struct rtc_device *rtc;
	struct resource *regs;
	int ret = 0;

	at91_rtc_config = of_device_get_match_data(&pdev->dev);
	if (!at91_rtc_config)
		return -ENODEV;

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!regs) {
		dev_err(&pdev->dev, "no mmio resource defined\n");
		return -ENXIO;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return -ENXIO;

	at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
				     resource_size(regs));
	if (!at91_rtc_regs) {
		dev_err(&pdev->dev, "failed to map registers, aborting.\n");
		return -ENOMEM;
	}

	rtc = devm_rtc_allocate_device(&pdev->dev);
	if (IS_ERR(rtc))
		return PTR_ERR(rtc);
	platform_set_drvdata(pdev, rtc);

	sclk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(sclk))
		return PTR_ERR(sclk);

	ret = clk_prepare_enable(sclk);
	if (ret) {
		dev_err(&pdev->dev, "Could not enable slow clock\n");
		return ret;
	}

	at91_rtc_write(AT91_RTC_CR, 0);
	at91_rtc_write(AT91_RTC_MR, at91_rtc_read(AT91_RTC_MR) & ~AT91_RTC_HRMOD);

	/* Disable all interrupts */
	at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
					AT91_RTC_SECEV | AT91_RTC_TIMEV |
					AT91_RTC_CALEV);

	ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
			       IRQF_SHARED | IRQF_COND_SUSPEND,
			       "at91_rtc", pdev);
	if (ret) {
		dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
		goto err_clk;
	}

	/* cpu init code should really have flagged this device as
	 * being wake-capable; if it didn't, do that here.
	 */
	if (!device_can_wakeup(&pdev->dev))
		device_init_wakeup(&pdev->dev, 1);

	if (at91_rtc_config->has_correction)
		rtc->ops = &sama5d4_rtc_ops;
	else
		rtc->ops = &at91_rtc_ops;

	rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
	rtc->range_max = RTC_TIMESTAMP_END_2099;
	ret = devm_rtc_register_device(rtc);
	if (ret)
		goto err_clk;

	/* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
	 * completion.
	 */
	at91_rtc_write_ier(AT91_RTC_SECEV);

	dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
	return 0;

err_clk:
	clk_disable_unprepare(sclk);

	return ret;
}