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authorPaul Walmsley <paul@pwsan.com>2008-11-21 13:39:47 -0800
committerTony Lindgren <tony@atomide.com>2008-11-21 13:39:47 -0800
commit3831f154418e058616129942e8175dc4c7e4a1d8 (patch)
tree39373d541573f986cce29acd8b54f7e4584e11af
parentc1a473bde4c06e8e6996ce3a33121b7a9a86b4b9 (diff)
downloadop-kernel-dev-3831f154418e058616129942e8175dc4c7e4a1d8.zip
op-kernel-dev-3831f154418e058616129942e8175dc4c7e4a1d8.tar.gz
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: Paul 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: Tony Lindgren <tony@atomide.com>
-rw-r--r--drivers/i2c/busses/i2c-omap.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 4aeebad..40a1e4b 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -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:
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