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authorSergei Shtylyov <sergei.shtylyov@cogentembedded.com>2014-08-24 00:44:09 +0400
committerWolfram Sang <wsa@the-dreams.de>2014-09-04 19:59:42 +0200
commit91bfe2989af02e709ca01ccf518c4fbda3efc70f (patch)
treea4ebc7cde4b09aaea773dba793062cee10fefe80 /drivers
parent75b81f339c6af43f6f4a1b3eabe0603321dade65 (diff)
downloadlinux-91bfe2989af02e709ca01ccf518c4fbda3efc70f.tar.bz2
Revert "i2c: rcar: remove spinlock"
This reverts commit 150b8be3cda54412ad7b54f5392b513b25c0aaa7. The I2C core's per-adapter locks can't protect from IRQs, so the driver still needs a spinlock to protect the register accesses. Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> Cc: stable@vger.kernel.org # 3.16+ Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/i2c/busses/i2c-rcar.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index dc32f5fa75d0..1cc146cfc1f3 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -34,6 +34,7 @@
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
+#include <linux/spinlock.h>
/* register offsets */
#define ICSCR 0x00 /* slave ctrl */
@@ -95,6 +96,7 @@ struct rcar_i2c_priv {
struct i2c_msg *msg;
struct clk *clk;
+ spinlock_t lock;
wait_queue_head_t wait;
int pos;
@@ -365,6 +367,9 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
struct rcar_i2c_priv *priv = ptr;
u32 msr;
+ /*-------------- spin lock -----------------*/
+ spin_lock(&priv->lock);
+
msr = rcar_i2c_read(priv, ICMSR);
/* Only handle interrupts that are currently enabled */
@@ -403,6 +408,9 @@ out:
wake_up(&priv->wait);
}
+ spin_unlock(&priv->lock);
+ /*-------------- spin unlock -----------------*/
+
return IRQ_HANDLED;
}
@@ -412,14 +420,21 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
{
struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
struct device *dev = rcar_i2c_priv_to_dev(priv);
+ unsigned long flags;
int i, ret, timeout;
pm_runtime_get_sync(dev);
+ /*-------------- spin lock -----------------*/
+ spin_lock_irqsave(&priv->lock, flags);
+
rcar_i2c_init(priv);
/* start clock */
rcar_i2c_write(priv, ICCCR, priv->icccr);
+ spin_unlock_irqrestore(&priv->lock, flags);
+ /*-------------- spin unlock -----------------*/
+
ret = rcar_i2c_bus_barrier(priv);
if (ret < 0)
goto out;
@@ -431,6 +446,9 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
break;
}
+ /*-------------- spin lock -----------------*/
+ spin_lock_irqsave(&priv->lock, flags);
+
/* init each data */
priv->msg = &msgs[i];
priv->pos = 0;
@@ -440,6 +458,9 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
ret = rcar_i2c_prepare_msg(priv);
+ spin_unlock_irqrestore(&priv->lock, flags);
+ /*-------------- spin unlock -----------------*/
+
if (ret < 0)
break;
@@ -543,6 +564,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
irq = platform_get_irq(pdev, 0);
init_waitqueue_head(&priv->wait);
+ spin_lock_init(&priv->lock);
adap = &priv->adap;
adap->nr = pdev->id;