From: Paul Walmsley Date: Fri, 10 Oct 2008 16:58:30 +0000 (-0600) Subject: i2c-omap: fix I2C timeouts due to recursive omap_i2c_{un,}idle() X-Git-Tag: v2.6.27-omap1~44 X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?p=linux-2.6-omap-h63xx.git;a=commitdiff_plain;h=663715fc55ea5d292171c6934a2b91d8f4874171 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 . Tested on 3430SDP and 2430SDP. Signed-off-by: Paul Walmsley Cc: David Brownell Cc: Richard Woodruff Acked-by; Steve Sakoman Signed-off-by: Tony Lindgren --- diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index 1e6c3fd9879..a9996063483 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: