[PATCH] i2c: convert ds1374 to use a workqueue

A tasklet is not suitable for what the ds1374 driver does: neither sleeping
nor mutex operations are allowed in tasklets, and ds1374_set_tlet may do
both.

We can use a workqueue instead, where both sleeping and mutex operations
are allowed.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Randy Vinson <rvinson@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/i2c/chips/ds1374.c

@@ -27,6 +27,7 @@
 #include <linux/rtc.h>
 #include <linux/bcd.h>
 #include <linux/mutex.h>
+#include <linux/workqueue.h>
 
 #define DS1374_REG_TOD0		0x00
 #define DS1374_REG_TOD1		0x01
@@ -139,7 +140,7 @@ ulong ds1374_get_rtc_time(void)
 	return t1;
 }
 
-static void ds1374_set_tlet(ulong arg)
+static void ds1374_set_work(void *arg)
 {
 	ulong t1, t2;
 	int limit = 10;		/* arbitrary retry limit */
@@ -168,17 +169,18 @@ static void ds1374_set_tlet(ulong arg)
 
 static ulong new_time;
 
-static DECLARE_TASKLET_DISABLED(ds1374_tasklet, ds1374_set_tlet,
-				(ulong) & new_time);
+static struct workqueue_struct *ds1374_workqueue;
+
+static DECLARE_WORK(ds1374_work, ds1374_set_work, &new_time);
 
 int ds1374_set_rtc_time(ulong nowtime)
 {
 	new_time = nowtime;
 
 	if (in_interrupt())
-		tasklet_schedule(&ds1374_tasklet);
+		queue_work(ds1374_workqueue, &ds1374_work);
 	else
-		ds1374_set_tlet((ulong) & new_time);
+		ds1374_set_work(&new_time);
 
 	return 0;
 }
@@ -204,6 +206,8 @@ static int ds1374_probe(struct i2c_adapter *adap, int addr, int kind)
 	client->adapter = adap;
 	client->driver = &ds1374_driver;
 
+	ds1374_workqueue = create_singlethread_workqueue("ds1374");
+
 	if ((rc = i2c_attach_client(client)) != 0) {
 		kfree(client);
 		return rc;
@@ -227,7 +231,7 @@ static int ds1374_detach(struct i2c_client *client)
 
 	if ((rc = i2c_detach_client(client)) == 0) {
 		kfree(i2c_get_clientdata(client));
-		tasklet_kill(&ds1374_tasklet);
+		destroy_workqueue(ds1374_workqueue);
 	}
 	return rc;
 }