From 2303248b291f537f0414a644a53483c71023136f Mon Sep 17 00:00:00 2001 From: Alexandru Ardelean Date: Tue, 25 Feb 2020 12:33:19 +0200 Subject: iio: imu: adis: add a note better explaining state_lock The 'state_lock' mutex was renamed from 'txrx_lock' in a previous patch and is intended to be used by ADIS drivers to protect the state of devices during consecutive R/W ops. The initial patch that introduced this change did not do a good [well, any] job at explaining this. This patch adds a comment to the 'state_lock' better explaining it's use. Signed-off-by: Alexandru Ardelean Signed-off-by: Jonathan Cameron --- include/linux/iio/imu/adis.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/linux/iio') diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h index 20339025c75f..dd8219138c2e 100644 --- a/include/linux/iio/imu/adis.h +++ b/include/linux/iio/imu/adis.h @@ -98,6 +98,17 @@ struct adis { const struct adis_data *data; struct adis_burst *burst; + /** + * The state_lock is meant to be used during operations that require + * a sequence of SPI R/W in order to protect the SPI transfer + * information (fields 'xfer', 'msg' & 'current_page') between + * potential concurrent accesses. + * This lock is used by all "adis_{functions}" that have to read/write + * registers. These functions also have unlocked variants + * (see "__adis_{functions}"), which don't hold this lock. + * This allows users of the ADIS library to group SPI R/W into + * the drivers, but they also must manage this lock themselves. + */ struct mutex state_lock; struct spi_message msg; struct spi_transfer *xfer; -- cgit v1.2.3