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Commit a223c522 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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

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
parents cfa5555c 844990da

drivers/i2c/busses/i2c-mxs.c

+10 −3
Original line number Diff line number Diff line
@@ -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;



	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;

}