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Revert "i2c: rcar: remove spinlock"

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This reverts commit 150b8be3cd.

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>
This commit is contained in:
Sergei Shtylyov 2014-08-24 00:44:09 +04:00 committed by Wolfram Sang
parent 75b81f339c
commit 91bfe2989a
1 changed files with 22 additions and 0 deletions
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22
drivers/i2c/busses/i2c-rcar.c
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@ -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;