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authorTony Lindgren <tony@atomide.com>2008-03-23 20:28:20 +0100
committerJean Delvare <khali@hyperion.delvare>2008-03-23 20:28:20 +0100
commitf08ac4e79424c266aed8282939649104b37f53b4 (patch)
treecf41c7a0e3f388a91c39d77a0ce43bad5333b902 /drivers/i2c
parent70849251147c3499afb8d7500d0fba240da73456 (diff)
i2c-omap: Fix unhandled fault
If an I2C interrupt happens between disabling interface clock and functional clock, the interrupt handler will produce an external abort on non-linefetch error when trying to access driver registers while interface clock is disabled. This patch fixes the problem by saving and disabling i2c-omap interrupt before turning off the clocks. Also disable functional clock before the interface clock as suggested by Paul Walmsley. Patch also renames enable/disable_clocks functions to unidle/idle functions. Note that the driver is currently not taking advantage of the idle interrupts. To use the idle interrupts, driver would have to enable interface clock based on the idle interrupt and dev->idle flag. This patch has been tested in linux-omap tree with various omaps. Cc: Paul Walmsley <paul@pwsan.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-omap.c36
1 files changed, 28 insertions, 8 deletions
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index da6639707ea..7ba31770d77 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -128,6 +128,8 @@ struct omap_i2c_dev {
size_t buf_len;
struct i2c_adapter adapter;
unsigned rev1:1;
+ unsigned idle:1;
+ u16 iestate; /* Saved interrupt register */
};
static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev,
@@ -174,18 +176,30 @@ static void omap_i2c_put_clocks(struct omap_i2c_dev *dev)
}
}
-static void omap_i2c_enable_clocks(struct omap_i2c_dev *dev)
+static void omap_i2c_unidle(struct omap_i2c_dev *dev)
{
if (dev->iclk != NULL)
clk_enable(dev->iclk);
clk_enable(dev->fclk);
+ if (dev->iestate)
+ omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
+ dev->idle = 0;
}
-static void omap_i2c_disable_clocks(struct omap_i2c_dev *dev)
+static void omap_i2c_idle(struct omap_i2c_dev *dev)
{
+ u16 iv;
+
+ dev->idle = 1;
+ dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
+ omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0);
+ if (dev->rev1)
+ iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG); /* Read clears */
+ else
+ omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate);
+ clk_disable(dev->fclk);
if (dev->iclk != NULL)
clk_disable(dev->iclk);
- clk_disable(dev->fclk);
}
static int omap_i2c_init(struct omap_i2c_dev *dev)
@@ -360,7 +374,7 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
int i;
int r;
- omap_i2c_enable_clocks(dev);
+ omap_i2c_unidle(dev);
if ((r = omap_i2c_wait_for_bb(dev)) < 0)
goto out;
@@ -374,7 +388,7 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
if (r == 0)
r = num;
out:
- omap_i2c_disable_clocks(dev);
+ omap_i2c_idle(dev);
return r;
}
@@ -403,6 +417,9 @@ omap_i2c_rev1_isr(int this_irq, void *dev_id)
struct omap_i2c_dev *dev = dev_id;
u16 iv, w;
+ if (dev->idle)
+ return IRQ_NONE;
+
iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
switch (iv) {
case 0x00: /* None */
@@ -457,6 +474,9 @@ omap_i2c_isr(int this_irq, void *dev_id)
u16 stat, w;
int count = 0;
+ if (dev->idle)
+ return IRQ_NONE;
+
bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) {
dev_dbg(dev->dev, "IRQ (ISR = 0x%04x)\n", stat);
@@ -575,7 +595,7 @@ omap_i2c_probe(struct platform_device *pdev)
if ((r = omap_i2c_get_clocks(dev)) != 0)
goto err_free_mem;
- omap_i2c_enable_clocks(dev);
+ omap_i2c_unidle(dev);
if (cpu_is_omap15xx())
dev->rev1 = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) < 0x20;
@@ -610,7 +630,7 @@ omap_i2c_probe(struct platform_device *pdev)
goto err_free_irq;
}
- omap_i2c_disable_clocks(dev);
+ omap_i2c_idle(dev);
return 0;
@@ -618,7 +638,7 @@ err_free_irq:
free_irq(dev->irq, dev);
err_unuse_clocks:
omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
- omap_i2c_disable_clocks(dev);
+ omap_i2c_idle(dev);
omap_i2c_put_clocks(dev);
err_free_mem:
platform_set_drvdata(pdev, NULL);