static int ak8975_probe()

in magnetometer/ak8975.c [878:1018]

• 102 lines of code
• 18 McCabe index (conditional complexity)

static int ak8975_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct ak8975_data *data;
	struct iio_dev *indio_dev;
	struct gpio_desc *eoc_gpiod;
	struct gpio_desc *reset_gpiod;
	const void *match;
	unsigned int i;
	int err;
	enum asahi_compass_chipset chipset;
	const char *name = NULL;

	/*
	 * Grab and set up the supplied GPIO.
	 * We may not have a GPIO based IRQ to scan, that is fine, we will
	 * poll if so.
	 */
	eoc_gpiod = devm_gpiod_get_optional(&client->dev, NULL, GPIOD_IN);
	if (IS_ERR(eoc_gpiod))
		return PTR_ERR(eoc_gpiod);
	if (eoc_gpiod)
		gpiod_set_consumer_name(eoc_gpiod, "ak_8975");

	/*
	 * According to AK09911 datasheet, if reset GPIO is provided then
	 * deassert reset on ak8975_power_on() and assert reset on
	 * ak8975_power_off().
	 */
	reset_gpiod = devm_gpiod_get_optional(&client->dev,
					      "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(reset_gpiod))
		return PTR_ERR(reset_gpiod);

	/* Register with IIO */
	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
	if (indio_dev == NULL)
		return -ENOMEM;

	data = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);

	data->client = client;
	data->eoc_gpiod = eoc_gpiod;
	data->reset_gpiod = reset_gpiod;
	data->eoc_irq = 0;

	err = iio_read_mount_matrix(&client->dev, &data->orientation);
	if (err)
		return err;

	/* id will be NULL when enumerated via ACPI */
	match = device_get_match_data(&client->dev);
	if (match) {
		chipset = (uintptr_t)match;
		name = dev_name(&client->dev);
	} else if (id) {
		chipset = (enum asahi_compass_chipset)(id->driver_data);
		name = id->name;
	} else
		return -ENOSYS;

	for (i = 0; i < ARRAY_SIZE(ak_def_array); i++)
		if (ak_def_array[i].type == chipset)
			break;

	if (i == ARRAY_SIZE(ak_def_array)) {
		dev_err(&client->dev, "AKM device type unsupported: %d\n",
			chipset);
		return -ENODEV;
	}

	data->def = &ak_def_array[i];

	/* Fetch the regulators */
	data->vdd = devm_regulator_get(&client->dev, "vdd");
	if (IS_ERR(data->vdd))
		return PTR_ERR(data->vdd);
	data->vid = devm_regulator_get(&client->dev, "vid");
	if (IS_ERR(data->vid))
		return PTR_ERR(data->vid);

	err = ak8975_power_on(data);
	if (err)
		return err;

	err = ak8975_who_i_am(client, data->def->type);
	if (err < 0) {
		dev_err(&client->dev, "Unexpected device\n");
		goto power_off;
	}
	dev_dbg(&client->dev, "Asahi compass chip %s\n", name);

	/* Perform some basic start-of-day setup of the device. */
	err = ak8975_setup(client);
	if (err < 0) {
		dev_err(&client->dev, "%s initialization fails\n", name);
		goto power_off;
	}

	mutex_init(&data->lock);
	indio_dev->channels = ak8975_channels;
	indio_dev->num_channels = ARRAY_SIZE(ak8975_channels);
	indio_dev->info = &ak8975_info;
	indio_dev->available_scan_masks = ak8975_scan_masks;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->name = name;

	err = iio_triggered_buffer_setup(indio_dev, NULL, ak8975_handle_trigger,
					 NULL);
	if (err) {
		dev_err(&client->dev, "triggered buffer setup failed\n");
		goto power_off;
	}

	err = iio_device_register(indio_dev);
	if (err) {
		dev_err(&client->dev, "device register failed\n");
		goto cleanup_buffer;
	}

	/* Enable runtime PM */
	pm_runtime_get_noresume(&client->dev);
	pm_runtime_set_active(&client->dev);
	pm_runtime_enable(&client->dev);
	/*
	 * The device comes online in 500us, so add two orders of magnitude
	 * of delay before autosuspending: 50 ms.
	 */
	pm_runtime_set_autosuspend_delay(&client->dev, 50);
	pm_runtime_use_autosuspend(&client->dev);
	pm_runtime_put(&client->dev);

	return 0;

cleanup_buffer:
	iio_triggered_buffer_cleanup(indio_dev);
power_off:
	ak8975_power_off(data);
	return err;
}