Commit ecb010d4 authored by Nuno Sá's avatar Nuno Sá Committed by Jonathan Cameron
Browse files

iio: imu: adis: Refactor adis_initial_startup 



All the ADIS devices perform, at the beginning, a self test to make sure
the device is in a sane state. Previously, the logic was that the self-test
was performed in adis_initial_startup() and if that failed a reset was done
and then a self-test was attempted again.

This change unifies the reset mechanism under the adis_initial_startup()
call. A HW reset will be done if  GPIO is configured, or a SW reset
otherwise. This should make sure that the chip is in a sane state for
self-test. Once the reset is done, the self-test operation will be
performed. If anything goes wrong with self-test, the driver should just
bail/error-out (i.e. no second attempt). The chip would likely not be a in
a sane state state if the self-test fails after a reset.

Signed-off-by: default avatarNuno Sá <nuno.sa@analog.com>
Signed-off-by: default avatarAlexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent fdcf6bbb

drivers/iio/imu/adis.c

+22 −7
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
 */



#include <linux/delay.h>

#include <linux/gpio/consumer.h>

#include <linux/mutex.h>

#include <linux/device.h>

#include <linux/kernel.h>
@@ -368,6 +369,10 @@ static int adis_self_test(struct adis *adis) 
 * __adis_initial_startup() - Device initial setup

 * @adis: The adis device

 *

 * The function performs a HW reset via a reset pin that should be specified

 * via GPIOLIB. If no pin is configured a SW reset will be performed.

 * The RST pin for the ADIS devices should be configured as ACTIVE_LOW.

 *

 * Returns 0 if the device is operational, a negative error code otherwise.

 *

 * This function should be called early on in the device initialization sequence
@@ -375,18 +380,28 @@ static int adis_self_test(struct adis *adis) 
 */

int __adis_initial_startup(struct adis *adis)

{

	const struct adis_timeout *timeouts = adis->data->timeouts;

	struct gpio_desc *gpio;

	int ret;



	ret = adis_self_test(adis);

	if (ret) {

		dev_err(&adis->spi->dev, "Self-test failed, trying reset.\n");

		__adis_reset(adis);

		ret = adis_self_test(adis);

	/* check if the device has rst pin low */

	gpio = devm_gpiod_get_optional(&adis->spi->dev, "reset", GPIOD_ASIS);

	if (IS_ERR(gpio))

		return PTR_ERR(gpio);



	if (gpio) {

		gpiod_set_value_cansleep(gpio, 1);

		msleep(10);

		/* bring device out of reset */

		gpiod_set_value_cansleep(gpio, 0);

		msleep(timeouts->reset_ms);

	} else {

		ret = __adis_reset(adis);

		if (ret)

			dev_err(&adis->spi->dev, "Second self-test failed, giving up.\n");

			return ret;

	}



	return ret;

	return adis_self_test(adis);

}

EXPORT_SYMBOL_GPL(__adis_initial_startup);

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