static int m41t80_probe()

in rtc-m41t80.c [879:992]

• 96 lines of code
• 22 McCabe index (conditional complexity)

static int m41t80_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct i2c_adapter *adapter = client->adapter;
	int rc = 0;
	struct rtc_time tm;
	struct m41t80_data *m41t80_data = NULL;
	bool wakeup_source = false;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK |
				     I2C_FUNC_SMBUS_BYTE_DATA)) {
		dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
		return -ENODEV;
	}

	m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data),
				   GFP_KERNEL);
	if (!m41t80_data)
		return -ENOMEM;

	m41t80_data->client = client;
	if (client->dev.of_node)
		m41t80_data->features = (unsigned long)
			of_device_get_match_data(&client->dev);
	else
		m41t80_data->features = id->driver_data;
	i2c_set_clientdata(client, m41t80_data);

	m41t80_data->rtc =  devm_rtc_allocate_device(&client->dev);
	if (IS_ERR(m41t80_data->rtc))
		return PTR_ERR(m41t80_data->rtc);

#ifdef CONFIG_OF
	wakeup_source = of_property_read_bool(client->dev.of_node,
					      "wakeup-source");
#endif
	if (client->irq > 0) {
		rc = devm_request_threaded_irq(&client->dev, client->irq,
					       NULL, m41t80_handle_irq,
					       IRQF_TRIGGER_LOW | IRQF_ONESHOT,
					       "m41t80", client);
		if (rc) {
			dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
			client->irq = 0;
			wakeup_source = false;
		}
	}
	if (client->irq > 0 || wakeup_source)
		device_init_wakeup(&client->dev, true);
	else
		clear_bit(RTC_FEATURE_ALARM, m41t80_data->rtc->features);

	m41t80_data->rtc->ops = &m41t80_rtc_ops;
	m41t80_data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
	m41t80_data->rtc->range_max = RTC_TIMESTAMP_END_2099;

	if (client->irq <= 0) {
		/* We cannot support UIE mode if we do not have an IRQ line */
		m41t80_data->rtc->uie_unsupported = 1;
	}

	/* Make sure HT (Halt Update) bit is cleared */
	rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);

	if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
		if (m41t80_data->features & M41T80_FEATURE_HT) {
			m41t80_rtc_read_time(&client->dev, &tm);
			dev_info(&client->dev, "HT bit was set!\n");
			dev_info(&client->dev, "Power Down at %ptR\n", &tm);
		}
		rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
					       rc & ~M41T80_ALHOUR_HT);
	}

	if (rc < 0) {
		dev_err(&client->dev, "Can't clear HT bit\n");
		return rc;
	}

	/* Make sure ST (stop) bit is cleared */
	rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);

	if (rc >= 0 && rc & M41T80_SEC_ST)
		rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
					       rc & ~M41T80_SEC_ST);
	if (rc < 0) {
		dev_err(&client->dev, "Can't clear ST bit\n");
		return rc;
	}

#ifdef CONFIG_RTC_DRV_M41T80_WDT
	if (m41t80_data->features & M41T80_FEATURE_HT) {
		save_client = client;
		rc = misc_register(&wdt_dev);
		if (rc)
			return rc;
		rc = register_reboot_notifier(&wdt_notifier);
		if (rc) {
			misc_deregister(&wdt_dev);
			return rc;
		}
	}
#endif
#ifdef CONFIG_COMMON_CLK
	if (m41t80_data->features & M41T80_FEATURE_SQ)
		m41t80_sqw_register_clk(m41t80_data);
#endif

	rc = devm_rtc_register_device(m41t80_data->rtc);
	if (rc)
		return rc;

	return 0;
}