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Commit 3831f154 authored by Paul Walmsley's avatar Paul Walmsley Committed by Tony Lindgren
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i2c-omap: fix I2C timeouts due to recursive omap_i2c_{un,}idle() 



omap_i2c_unidle() and omap_i2c_idle() are called recursively during
omap_i2c_probe().  This is evidently unexpected and will wipe
out the I2C interrupt enable register the second time that
omap_i2c_idle() is called consecutively.  Any I2C transactions
following a probe of a bus with at least one device on it will then
time out.

Fix by moving omap_i2c_idle() further up in omap_i2c_probe().  Ensure
the I2C controller is marked as idle before the probe starts.  Also
attempt to catch future reappearances of this bug early in development
by warning in omap_i2c_{un,}idle() when they are called recursively.

Problem reported by David Brownell <david-b@pacbell.net>.

Tested on 3430SDP and 2430SDP.

Signed-off-by: default avatarPaul Walmsley <paul@pwsan.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Richard Woodruff <r-woodruff2@ti.com>
Acked-by; Steve Sakoman <steve@sakoman.com>
Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
parent c1a473bd

drivers/i2c/busses/i2c-omap.c

+7 −2
Original line number Diff line number Diff line
@@ -191,6 +191,8 @@ static void omap_i2c_put_clocks(struct omap_i2c_dev *dev) 


static void omap_i2c_unidle(struct omap_i2c_dev *dev)

{

	WARN_ON(!dev->idle);



	if (dev->iclk != NULL)

		clk_enable(dev->iclk);

	clk_enable(dev->fclk);
@@ -203,6 +205,8 @@ static void omap_i2c_idle(struct omap_i2c_dev *dev) 
{

	u16 iv;



	WARN_ON(dev->idle);



	dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);

	omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0);

	if (dev->rev1) {
@@ -740,6 +744,7 @@ omap_i2c_probe(struct platform_device *pdev) 
		speed = 100;	/* Defualt speed */



	dev->speed = speed;

	dev->idle = 1;

	dev->dev = &pdev->dev;

	dev->irq = irq->start;

	dev->base = ioremap(mem->start, mem->end - mem->start + 1);
@@ -788,6 +793,8 @@ omap_i2c_probe(struct platform_device *pdev) 
	dev_info(dev->dev, "bus %d rev%d.%d at %d kHz\n",

		 pdev->id, r >> 4, r & 0xf, dev->speed);



	omap_i2c_idle(dev);



	adap = &dev->adapter;

	i2c_set_adapdata(adap, dev);

	adap->owner = THIS_MODULE;
@@ -804,8 +811,6 @@ omap_i2c_probe(struct platform_device *pdev) 
		goto err_free_irq;

	}



	omap_i2c_idle(dev);



	return 0;



err_free_irq: