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| author | Ben Dooks <ben-linux@fluff.org> | 2007-05-01 23:26:35 +0200 |
|---|---|---|
| committer | Jean Delvare <khali@hyperion.delvare> | 2007-05-01 23:26:35 +0200 |
| commit | e00a8cdf325346c531c841ee85c803792db60157 (patch) | |
| tree | cd77aa2a2f94e8577f73ec3e2e4073ad94c184b9 | |
| parent | e8c76eed2ecdb8e9ca5339761d2c076d32b7cbca (diff) | |
| download | linux-e00a8cdf325346c531c841ee85c803792db60157.tar.bz2 | |
i2c-s3c2410: Fix I2C SDA to SCL setup time
Fix the setup time for SDA to SCL due to the way
the S3C24XX I2C controller works.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
| -rw-r--r-- | drivers/i2c/busses/i2c-s3c2410.c | 26 |
1 files changed, 20 insertions, 6 deletions
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index 3eb5958f347d..e8395be0d92c 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -61,6 +61,8 @@ struct s3c24xx_i2c { unsigned int msg_idx; unsigned int msg_ptr; + unsigned int tx_setup; + enum s3c24xx_i2c_state state; void __iomem *regs; @@ -199,8 +201,11 @@ static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c, dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr); writeb(addr, i2c->regs + S3C2410_IICDS); - // delay a bit and reset iiccon before setting start (per samsung) - udelay(1); + /* delay here to ensure the data byte has gotten onto the bus + * before the transaction is started */ + + ndelay(i2c->tx_setup); + dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon); writel(iiccon, i2c->regs + S3C2410_IICCON); @@ -322,7 +327,15 @@ static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat) if (!is_msgend(i2c)) { byte = i2c->msg->buf[i2c->msg_ptr++]; writeb(byte, i2c->regs + S3C2410_IICDS); - + + /* delay after writing the byte to allow the + * data setup time on the bus, as writing the + * data to the register causes the first bit + * to appear on SDA, and SCL will change as + * soon as the interrupt is acknowledged */ + + ndelay(i2c->tx_setup); + } else if (!is_lastmsg(i2c)) { /* we need to go to the next i2c message */ @@ -570,9 +583,10 @@ static const struct i2c_algorithm s3c24xx_i2c_algorithm = { }; static struct s3c24xx_i2c s3c24xx_i2c = { - .lock = __SPIN_LOCK_UNLOCKED(s3c24xx_i2c.lock), - .wait = __WAIT_QUEUE_HEAD_INITIALIZER(s3c24xx_i2c.wait), - .adap = { + .lock = __SPIN_LOCK_UNLOCKED(s3c24xx_i2c.lock), + .wait = __WAIT_QUEUE_HEAD_INITIALIZER(s3c24xx_i2c.wait), + .tx_setup = 50, + .adap = { .name = "s3c2410-i2c", .owner = THIS_MODULE, .algo = &s3c24xx_i2c_algorithm, |