From ecb010d441088c447785a1249e69003437f96c9c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Nuno=20S=C3=A1?= Date: Mon, 10 Feb 2020 15:26:03 +0200 Subject: [PATCH] iio: imu: adis: Refactor adis_initial_startup MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Alexandru Ardelean Signed-off-by: Jonathan Cameron --- drivers/iio/imu/adis.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c index f7845a90f376..0bd6e32cf577 100644 --- a/drivers/iio/imu/adis.c +++ b/drivers/iio/imu/adis.c @@ -7,6 +7,7 @@ */ #include +#include #include #include #include @@ -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);