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Merge branch 'i2c-embedded/for-3.3' of git://git.pengutronix.de/git/wsa/linux-2.6

Browse Source 
i2c bugfix from Wolfram Sang:
  "This patch fixes a wrong assumption in the mxs-i2c-driver about a
   command queue being done.  Without it, we have seen races when the
   bus was under load."

* 'i2c-embedded/for-3.3' of git://git.pengutronix.de/git/wsa/linux-2.6:
  i2c: mxs: only flag completion when queue is completely done
This commit is contained in:
Linus Torvalds 2012-03-01 18:24:52 -08:00
commit a223c52280
1 changed files with 10 additions and 3 deletions
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13
drivers/i2c/busses/i2c-mxs.c
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@ -72,6 +72,7 @@
#define MXS_I2C_QUEUESTAT (0x70)
#define MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY 0x00002000
#define MXS_I2C_QUEUESTAT_WRITE_QUEUE_CNT_MASK 0x0000001F
#define MXS_I2C_QUEUECMD (0x80)
@ -219,14 +220,14 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
int ret;
int flags;
init_completion(&i2c->cmd_complete);
dev_dbg(i2c->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
msg->addr, msg->len, msg->flags, stop);
if (msg->len == 0)
return -EINVAL;
init_completion(&i2c->cmd_complete);
flags = stop ? MXS_I2C_CTRL0_POST_SEND_STOP : 0;
if (msg->flags & I2C_M_RD)
@ -286,6 +287,7 @@ static irqreturn_t mxs_i2c_isr(int this_irq, void *dev_id)
{
struct mxs_i2c_dev *i2c = dev_id;
u32 stat = readl(i2c->regs + MXS_I2C_CTRL1) & MXS_I2C_IRQ_MASK;
bool is_last_cmd;
if (!stat)
return IRQ_NONE;
@ -300,9 +302,14 @@ static irqreturn_t mxs_i2c_isr(int this_irq, void *dev_id)
else
i2c->cmd_err = 0;
complete(&i2c->cmd_complete);
is_last_cmd = (readl(i2c->regs + MXS_I2C_QUEUESTAT) &
MXS_I2C_QUEUESTAT_WRITE_QUEUE_CNT_MASK) == 0;
if (is_last_cmd || i2c->cmd_err)
complete(&i2c->cmd_complete);
writel(stat, i2c->regs + MXS_I2C_CTRL1_CLR);
return IRQ_HANDLED;
}