From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: [PATCH 09/12] i2c-omap: fix I2C timeouts due to recursive omap_i2c_{un, }idle() Date: Fri, 28 Nov 2008 17:29:10 -0800 Message-ID: <20081129012910.13042.28578.stgit@localhost> References: <20081129012612.13042.12283.stgit@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mho-01-bos.mailhop.org ([63.208.196.178]:54276 "EHLO mho-01-bos.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753341AbYK2B3L (ORCPT ); Fri, 28 Nov 2008 20:29:11 -0500 In-Reply-To: <20081129012612.13042.12283.stgit@localhost> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: i2c-linux@vger.kernel.org, ben-linux@fluff.org Cc: David Brownell , Paul Walmsley , linux-omap@vger.kernel.org, Richard Woodruff From: Paul Walmsley 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 --- drivers/i2c/busses/i2c-omap.c | 9 +++++++-- 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: