static int m48t59_rtc_probe()

in rtc-m48t59.c [358:472]

• 89 lines of code
• 25 McCabe index (conditional complexity)

static int m48t59_rtc_probe(struct platform_device *pdev)
{
	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
	struct m48t59_private *m48t59 = NULL;
	struct resource *res;
	int ret = -ENOMEM;
	struct nvmem_config nvmem_cfg = {
		.name = "m48t59-",
		.word_size = 1,
		.stride = 1,
		.reg_read = m48t59_nvram_read,
		.reg_write = m48t59_nvram_write,
		.priv = pdev,
	};

	/* This chip could be memory-mapped or I/O-mapped */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		res = platform_get_resource(pdev, IORESOURCE_IO, 0);
		if (!res)
			return -EINVAL;
	}

	if (res->flags & IORESOURCE_IO) {
		/* If we are I/O-mapped, the platform should provide
		 * the operations accessing chip registers.
		 */
		if (!pdata || !pdata->write_byte || !pdata->read_byte)
			return -EINVAL;
	} else if (res->flags & IORESOURCE_MEM) {
		/* we are memory-mapped */
		if (!pdata) {
			pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata),
						GFP_KERNEL);
			if (!pdata)
				return -ENOMEM;
			/* Ensure we only kmalloc platform data once */
			pdev->dev.platform_data = pdata;
		}
		if (!pdata->type)
			pdata->type = M48T59RTC_TYPE_M48T59;

		/* Try to use the generic memory read/write ops */
		if (!pdata->write_byte)
			pdata->write_byte = m48t59_mem_writeb;
		if (!pdata->read_byte)
			pdata->read_byte = m48t59_mem_readb;
	}

	m48t59 = devm_kzalloc(&pdev->dev, sizeof(*m48t59), GFP_KERNEL);
	if (!m48t59)
		return -ENOMEM;

	m48t59->ioaddr = pdata->ioaddr;

	if (!m48t59->ioaddr) {
		/* ioaddr not mapped externally */
		m48t59->ioaddr = devm_ioremap(&pdev->dev, res->start,
						resource_size(res));
		if (!m48t59->ioaddr)
			return ret;
	}

	/* Try to get irq number. We also can work in
	 * the mode without IRQ.
	 */
	m48t59->irq = platform_get_irq_optional(pdev, 0);
	if (m48t59->irq <= 0)
		m48t59->irq = NO_IRQ;

	if (m48t59->irq != NO_IRQ) {
		ret = devm_request_irq(&pdev->dev, m48t59->irq,
				m48t59_rtc_interrupt, IRQF_SHARED,
				"rtc-m48t59", &pdev->dev);
		if (ret)
			return ret;
	}

	m48t59->rtc = devm_rtc_allocate_device(&pdev->dev);
	if (IS_ERR(m48t59->rtc))
		return PTR_ERR(m48t59->rtc);

	switch (pdata->type) {
	case M48T59RTC_TYPE_M48T59:
		pdata->offset = 0x1ff0;
		break;
	case M48T59RTC_TYPE_M48T02:
		clear_bit(RTC_FEATURE_ALARM, m48t59->rtc->features);
		pdata->offset = 0x7f0;
		break;
	case M48T59RTC_TYPE_M48T08:
		clear_bit(RTC_FEATURE_ALARM, m48t59->rtc->features);
		pdata->offset = 0x1ff0;
		break;
	default:
		dev_err(&pdev->dev, "Unknown RTC type\n");
		return -ENODEV;
	}

	spin_lock_init(&m48t59->lock);
	platform_set_drvdata(pdev, m48t59);

	m48t59->rtc->ops = &m48t59_rtc_ops;

	nvmem_cfg.size = pdata->offset;
	ret = devm_rtc_nvmem_register(m48t59->rtc, &nvmem_cfg);
	if (ret)
		return ret;

	ret = devm_rtc_register_device(m48t59->rtc);
	if (ret)
		return ret;

	return 0;
}