linux-kernel - [PATCH v2 06/11] iio: imu: adis: protect initial startup routine with state lock

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Message-ID: <20191122132421.5500-7-alexandru.ardelean@analog.com>
Date:   Fri, 22 Nov 2019 15:24:16 +0200
From:   Alexandru Ardelean <alexandru.ardelean@...log.com>
To:     <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:     <jic23@...nel.org>, <nuno.sa@...log.com>,
        <Michael.Hennerich@...log.com>,
        Alexandru Ardelean <alexandru.ardelean@...log.com>
Subject: [PATCH v2 06/11] iio: imu: adis: protect initial startup routine with state lock

The initial startup routine is called by some ADIS drivers during probe,
and before registering with IIO. Normally, userspace should not be able to
do any access to the device (as there shouldn't be any available).

This change extends the state lock to the entire initial-startup routine.
Behaviourally nothing should change, but this should make the library
function a bit more robust.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
---
 drivers/iio/imu/adis.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
index 615f174f0e6e..10b8922fd51b 100644
--- a/drivers/iio/imu/adis.c
+++ b/drivers/iio/imu/adis.c
@@ -331,7 +331,7 @@ static int adis_self_test(struct adis *adis)
 {
 	int ret;
 
-	ret = adis_write_reg_16(adis, adis->data->msc_ctrl_reg,
+	ret = __adis_write_reg_16(adis, adis->data->msc_ctrl_reg,
 			adis->data->self_test_mask);
 	if (ret) {
 		dev_err(&adis->spi->dev, "Failed to initiate self test: %d\n",
@@ -341,10 +341,10 @@ static int adis_self_test(struct adis *adis)
 
 	msleep(adis->data->startup_delay);
 
-	ret = adis_check_status(adis);
+	ret = __adis_check_status(adis);
 
 	if (adis->data->self_test_no_autoclear)
-		adis_write_reg_16(adis, adis->data->msc_ctrl_reg, 0x00);
+		__adis_write_reg_16(adis, adis->data->msc_ctrl_reg, 0x00);
 
 	return ret;
 }
@@ -362,19 +362,23 @@ int adis_initial_startup(struct adis *adis)
 {
 	int ret;
 
+	mutex_lock(&adis->state_lock);
+
 	ret = adis_self_test(adis);
 	if (ret) {
 		dev_err(&adis->spi->dev, "Self-test failed, trying reset.\n");
-		adis_reset(adis);
+		__adis_reset(adis);
 		msleep(adis->data->startup_delay);
 		ret = adis_self_test(adis);
 		if (ret) {
 			dev_err(&adis->spi->dev, "Second self-test failed, giving up.\n");
-			return ret;
+			goto out_unlock;
 		}
 	}
 
-	return 0;
+out_unlock:
+	mutex_unlock(&adis->state_lock);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(adis_initial_startup);
 
-- 
2.20.1