lkml.org 
[lkml]   [2018]   [May]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v8 6/7] i2c: fsi: Add I2C master locking
Date
Since there are many ports per master, each with it's own adapter and
chardev, we need some locking to prevent transfers from changing the
master state while other transfers are in progress.

Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
---
drivers/i2c/busses/i2c-fsi.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c
index f24e4b9..5dad16a 100644
--- a/drivers/i2c/busses/i2c-fsi.c
+++ b/drivers/i2c/busses/i2c-fsi.c
@@ -21,6 +21,7 @@
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
+#include <linux/mutex.h>
#include <linux/of.h>

#define FSI_ENGID_I2C 0x7
@@ -142,6 +143,7 @@ struct fsi_i2c_master {
struct fsi_device *fsi;
u8 fifo_size;
struct list_head ports;
+ struct mutex lock;
};

struct fsi_i2c_port {
@@ -569,11 +571,14 @@ static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int i, rc;
unsigned long start_time;
struct fsi_i2c_port *port = adap->algo_data;
+ struct fsi_i2c_master *master = port->master;
struct i2c_msg *msg;

+ mutex_lock(&master->lock);
+
rc = fsi_i2c_set_port(port);
if (rc)
- return rc;
+ goto unlock;

for (i = 0; i < num; ++i) {
msg = msgs + i;
@@ -581,15 +586,17 @@ static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,

rc = fsi_i2c_start(port, msg, i == num - 1);
if (rc)
- return rc;
+ goto unlock;

rc = fsi_i2c_wait(port, msg,
adap->timeout - (jiffies - start_time));
if (rc)
- return rc;
+ goto unlock;
}

- return 0;
+unlock:
+ mutex_unlock(&master->lock);
+ return rc;
}

static u32 fsi_i2c_functionality(struct i2c_adapter *adap)
@@ -615,6 +622,7 @@ static int fsi_i2c_probe(struct device *dev)
if (!i2c)
return -ENOMEM;

+ mutex_init(&i2c->lock);
i2c->fsi = to_fsi_dev(dev);
INIT_LIST_HEAD(&i2c->ports);

--
1.8.3.1
\
 
 \ /
  Last update: 2018-05-30 23:08    [W:0.089 / U:2.716 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site