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@xxxxxxxxxxx>.
Tested on 3430SDP and 2430SDP.
Signed-off-by: Paul Walmsley <paul@xxxxxxxxx>
Cc: David Brownell <david-b@xxxxxxxxxxx>
Cc: Richard Woodruff <r-woodruff2@xxxxxx>
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 1e6c3fd..a999606 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -202,6 +202,8 @@ 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);
@@ -214,6 +216,8 @@ 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)
@@ -748,6 +752,7 @@ 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);
@@ -797,6 +802,8 @@ 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;
@@ -813,8 +820,6 @@ omap_i2c_probe(struct platform_device *pdev)
goto err_free_irq;
}
- omap_i2c_idle(dev);
-
return 0;
err_free_irq:
--
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