'\" t
.\"     Title: spi_bus_lock
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: May 2018
.\"    Manual: Serial Peripheral Interface (SPI)
.\"    Source: Kernel Hackers Manual 3.16.56
.\"  Language: English
.\"
.TH "SPI_BUS_LOCK" "9" "May 2018" "Kernel Hackers Manual 3\&.16\&" "Serial Peripheral Interface (S"
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.SH "NAME"
spi_bus_lock \- obtain a lock for exclusive SPI bus usage
.SH "SYNOPSIS"
.HP \w'int\ spi_bus_lock('u
.BI "int spi_bus_lock(struct\ spi_master\ *\ " "master" ");"
.SH "ARGUMENTS"
.PP
\fImaster\fR
.RS 4
SPI bus master that should be locked for exclusive bus access
.RE
.SH "CONTEXT"
.PP
can sleep
.SH "DESCRIPTION"
.PP
This call may only be used from a context that may sleep\&. The sleep is non\-interruptible, and has no timeout\&.
.PP
This call should be used by drivers that require exclusive access to the SPI bus\&. The SPI bus must be released by a spi_bus_unlock call when the exclusive access is over\&. Data transfer must be done by spi_sync_locked and spi_async_locked calls when the SPI bus lock is held\&.
.PP
It returns zero on success, else a negative error code\&.
.SH "COPYRIGHT"
.br