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fc54b9bf15
(stable-branch of Openmoko) git-svn-id: svn://svn.openwrt.org/openwrt/trunk@13613 3c298f89-4303-0410-b956-a3cf2f4a3e73
116 lines
3.4 KiB
Diff
116 lines
3.4 KiB
Diff
From d3063c1ec65b37b45e808313133196185ea4901f Mon Sep 17 00:00:00 2001
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From: mokopatches <mokopatches@openmoko.org>
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Date: Fri, 4 Apr 2008 11:30:03 +0100
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Subject: [PATCH] fix-i2c-s3c2410-resume-race.patch
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fix-i2c-s3c2410-resume-race.patch
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There is a nasty race between i2c-s3c2410 resume and resume of I2C
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driver and the client drivers -- the watchdog device actually gets to
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use the dead I2C bus before it is reinitialized by the I2C driver
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resume! This patch makes sure any customers get turned away until
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the shopkeeper has woken up.
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Signed-off-by: Andy Green <andy@openmoko.com>
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---
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drivers/i2c/busses/i2c-s3c2410.c | 35 ++++++++++++++++++++++++++++++++++-
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1 files changed, 34 insertions(+), 1 deletions(-)
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diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
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index c44ada5..5ac8309 100644
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--- a/drivers/i2c/busses/i2c-s3c2410.c
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+++ b/drivers/i2c/busses/i2c-s3c2410.c
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@@ -71,6 +71,8 @@ struct s3c24xx_i2c {
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struct resource *irq;
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struct resource *ioarea;
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struct i2c_adapter adap;
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+
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+ int suspended;
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};
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/* default platform data to use if not supplied in the platform_device
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@@ -156,6 +158,14 @@ static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
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unsigned long tmp;
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tmp = readl(i2c->regs + S3C2410_IICCON);
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+
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+/* S3c2442 datasheet
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+ *
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+ * If the IICCON[5]=0, IICCON[4] does not operate correctly.
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+ * So, It is recommended that you should set IICCON[5]=1,
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+ * although you does not use the IIC interrupt.
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+ */
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+
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writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
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}
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@@ -282,7 +292,7 @@ static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
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case STATE_STOP:
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dev_err(i2c->dev, "%s: called in STATE_STOP\n", __FUNCTION__);
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- s3c24xx_i2c_disable_irq(i2c);
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+ s3c24xx_i2c_disable_irq(i2c);
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goto out_ack;
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case STATE_START:
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@@ -502,6 +512,14 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, struct i2c_msg *msgs, int
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unsigned long timeout;
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int ret;
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+ if (i2c->suspended) {
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+ dev_err(i2c->dev,
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+ "Hey I am still asleep (suspended: %d), retry later\n",
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+ i2c->suspended);
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+ ret = -EAGAIN;
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+ goto out;
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+ }
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+
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ret = s3c24xx_i2c_set_master(i2c);
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if (ret != 0) {
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dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
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@@ -886,6 +904,17 @@ static int s3c24xx_i2c_remove(struct platform_device *pdev)
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}
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#ifdef CONFIG_PM
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+
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+static int s3c24xx_i2c_suspend(struct platform_device *dev, pm_message_t state)
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+{
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+ struct s3c24xx_i2c *i2c = platform_get_drvdata(dev);
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+
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+ if (i2c != NULL)
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+ i2c->suspended++;
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+
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+ return 0;
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+}
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+
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static int s3c24xx_i2c_resume(struct platform_device *dev)
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{
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struct s3c24xx_i2c *i2c = platform_get_drvdata(dev);
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@@ -893,6 +922,8 @@ static int s3c24xx_i2c_resume(struct platform_device *dev)
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if (i2c != NULL)
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s3c24xx_i2c_init(i2c);
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+ i2c->suspended--;
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+
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return 0;
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}
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@@ -905,6 +936,7 @@ static int s3c24xx_i2c_resume(struct platform_device *dev)
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static struct platform_driver s3c2410_i2c_driver = {
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.probe = s3c24xx_i2c_probe,
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.remove = s3c24xx_i2c_remove,
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+ .suspend = s3c24xx_i2c_suspend,
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.resume = s3c24xx_i2c_resume,
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.driver = {
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.owner = THIS_MODULE,
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@@ -915,6 +947,7 @@ static struct platform_driver s3c2410_i2c_driver = {
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static struct platform_driver s3c2440_i2c_driver = {
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.probe = s3c24xx_i2c_probe,
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.remove = s3c24xx_i2c_remove,
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+ .suspend = s3c24xx_i2c_suspend,
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.resume = s3c24xx_i2c_resume,
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.driver = {
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.owner = THIS_MODULE,
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--
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1.5.6.5
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