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iio: imu: adis: Refactor adis_initial_startup

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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: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Nuno Sá 2020-02-10 15:26:03 +02:00 committed by Jonathan Cameron
parent fdcf6bbb4e
commit ecb010d441
1 changed files with 22 additions and 7 deletions
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29
drivers/iio/imu/adis.c
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@ -7,6 +7,7 @@
*/ */
#include <linux/delay.h> #include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/mutex.h> #include <linux/mutex.h>
#include <linux/device.h> #include <linux/device.h>
#include <linux/kernel.h> #include <linux/kernel.h>
@ -368,6 +369,10 @@ static int adis_self_test(struct adis *adis)
* __adis_initial_startup() - Device initial setup * __adis_initial_startup() - Device initial setup
* @adis: The adis device * @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. * Returns 0 if the device is operational, a negative error code otherwise.
* *
* This function should be called early on in the device initialization sequence * 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) int __adis_initial_startup(struct adis *adis)
{ {
const struct adis_timeout *timeouts = adis->data->timeouts;
struct gpio_desc *gpio;
int ret; int ret;
ret = adis_self_test(adis); /* check if the device has rst pin low */
if (ret) { gpio = devm_gpiod_get_optional(&adis->spi->dev, "reset", GPIOD_ASIS);
dev_err(&adis->spi->dev, "Self-test failed, trying reset.\n"); if (IS_ERR(gpio))
__adis_reset(adis); return PTR_ERR(gpio);
ret = adis_self_test(adis);
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) 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); EXPORT_SYMBOL_GPL(__adis_initial_startup);