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Commit 91bfe298 authored by Sergei Shtylyov's avatar Sergei Shtylyov Committed by Wolfram Sang
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Revert "i2c: rcar: remove spinlock" 



This reverts commit 150b8be3.

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: default avatarSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: stable@vger.kernel.org # 3.16+
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 75b81f33

drivers/i2c/busses/i2c-rcar.c

+22 −0
Original line number Diff line number Diff line
@@ -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 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr) 
		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;