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i2c-s3c2410: Fix I2C SDA to SCL setup time

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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>
This commit is contained in:
Ben Dooks 2007-05-01 23:26:35 +02:00 committed by Jean Delvare
parent e8c76eed2e
commit e00a8cdf32
1 changed files with 20 additions and 6 deletions
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24
drivers/i2c/busses/i2c-s3c2410.c
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@ -61,6 +61,8 @@ struct s3c24xx_i2c {
unsigned int msg_idx; unsigned int msg_idx;
unsigned int msg_ptr; unsigned int msg_ptr;
unsigned int tx_setup;
enum s3c24xx_i2c_state state; enum s3c24xx_i2c_state state;
void __iomem *regs; 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); dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
writeb(addr, i2c->regs + S3C2410_IICDS); writeb(addr, i2c->regs + S3C2410_IICDS);
// delay a bit and reset iiccon before setting start (per samsung) /* delay here to ensure the data byte has gotten onto the bus
udelay(1); * before the transaction is started */
ndelay(i2c->tx_setup);
dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon); dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
writel(iiccon, i2c->regs + S3C2410_IICCON); writel(iiccon, i2c->regs + S3C2410_IICCON);
@ -323,6 +328,14 @@ static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
byte = i2c->msg->buf[i2c->msg_ptr++]; byte = i2c->msg->buf[i2c->msg_ptr++];
writeb(byte, i2c->regs + S3C2410_IICDS); 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)) { } else if (!is_lastmsg(i2c)) {
/* we need to go to the next i2c message */ /* 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 = { static struct s3c24xx_i2c s3c24xx_i2c = {
.lock = __SPIN_LOCK_UNLOCKED(s3c24xx_i2c.lock), .lock = __SPIN_LOCK_UNLOCKED(s3c24xx_i2c.lock),
.wait = __WAIT_QUEUE_HEAD_INITIALIZER(s3c24xx_i2c.wait), .wait = __WAIT_QUEUE_HEAD_INITIALIZER(s3c24xx_i2c.wait),
.adap = { .tx_setup = 50,
.adap = {
.name = "s3c2410-i2c", .name = "s3c2410-i2c",
.owner = THIS_MODULE, .owner = THIS_MODULE,
.algo = &s3c24xx_i2c_algorithm, .algo = &s3c24xx_i2c_algorithm,