예제 #1
0
static int mpc_write(struct mpc_i2c *i2c, int target,
		     const u8 * data, int length, int restart)
{
	int i;
	unsigned timeout = i2c->adap.timeout;
	u32 flags = restart ? CCR_RSTA : 0;

	/* Start with MEN */
	if (!restart)
		writeccr(i2c, CCR_MEN);
	/* Start as master */
	writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
	/* Write target byte */
	writeb((target << 1), i2c->base + MPC_I2C_DR);

	if (i2c_wait(i2c, timeout, 1) < 0)
		return -1;

	for (i = 0; i < length; i++) {
		/* Write data byte */
		writeb(data[i], i2c->base + MPC_I2C_DR);

		if (i2c_wait(i2c, timeout, 1) < 0)
			return -1;
	}

	return 0;
}
예제 #2
0
static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
{
	unsigned long orig_jiffies = jiffies;
	u32 x;
	int result = 0;

	if (i2c->irq == NO_IRQ)
	{
		while (!(readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
			schedule();
			if (time_after(jiffies, orig_jiffies + timeout)) {
				pr_debug("I2C: timeout\n");
				writeccr(i2c, 0);
				result = -EIO;
				break;
			}
		}
		x = readb(i2c->base + MPC_I2C_SR);
		writeb(0, i2c->base + MPC_I2C_SR);
	} else {
		/* Interrupt mode */
		result = wait_event_interruptible_timeout(i2c->queue,
			(i2c->interrupt & CSR_MIF), timeout * HZ);

		if (unlikely(result < 0)) {
			pr_debug("I2C: wait interrupted\n");
			writeccr(i2c, 0);
		} else if (unlikely(!(i2c->interrupt & CSR_MIF))) {
			pr_debug("I2C: wait timeout\n");
			writeccr(i2c, 0);
			result = -ETIMEDOUT;
		}

		x = i2c->interrupt;
		i2c->interrupt = 0;
	}

	if (result < 0)
		return result;

	if (!(x & CSR_MCF)) {
		pr_debug("I2C: unfinished\n");
		return -EIO;
	}

	if (x & CSR_MAL) {
		pr_debug("I2C: MAL\n");
		return -EIO;
	}

	if (writing && (x & CSR_RXAK)) {
		pr_debug("I2C: No RXAK\n");
		/* generate stop */
		writeccr(i2c, CCR_MEN);
		return -EIO;
	}
	return 0;
}
예제 #3
0
/* Sometimes 9th clock pulse isn't generated, and slave doesn't release
 * the bus, because it wants to send ACK.
 * Following sequence of enabling/disabling and sending start/stop generates
 * the pulse, so it's all OK.
 */
static void mpc_i2c_fixup(struct mpc_i2c *i2c)
{
	writeccr(i2c, 0);
	udelay(30);
	writeccr(i2c, CCR_MEN);
	udelay(30);
	writeccr(i2c, CCR_MSTA | CCR_MTX);
	udelay(30);
	writeccr(i2c, CCR_MSTA | CCR_MTX | CCR_MEN);
	udelay(30);
	writeccr(i2c, CCR_MEN);
	udelay(30);
}
예제 #4
0
static void mpc_i2c_start(struct mpc_i2c *i2c)
{
	/* Clear arbitration */
	writeb(0, i2c->base + MPC_I2C_SR);
	/* Start with MEN */
	writeccr(i2c, CCR_MEN);
}
예제 #5
0
static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
	struct i2c_msg *pmsg;
	int i;
	int ret = 0;
	unsigned long orig_jiffies = jiffies;
	struct mpc_i2c *i2c = i2c_get_adapdata(adap);

	mpc_i2c_start(i2c);

	/* Allow bus up to 1s to become not busy */
	while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
		if (signal_pending(current)) {
			pr_debug("I2C: Interrupted\n");
			writeccr(i2c, 0);
			return -EINTR;
		}
		if (time_after(jiffies, orig_jiffies + HZ)) {
			pr_debug("I2C: timeout\n");
			if (readb(i2c->base + MPC_I2C_SR) ==
			    (CSR_MCF | CSR_MBB | CSR_RXAK))
				mpc_i2c_fixup(i2c);
			return -EIO;
		}
		schedule();
	}

	for (i = 0; ret >= 0 && i < num; i++) {
		pmsg = &msgs[i];
		pr_debug("Doing %s %d bytes to 0x%02x - %d of %d messages\n",
			 pmsg->flags & I2C_M_RD ? "read" : "write",
			 pmsg->len, pmsg->addr, i + 1, num);
		if (pmsg->flags & I2C_M_RD)
			ret =
			    mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
		else
			ret =
			    mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
	}
	mpc_i2c_stop(i2c);
	return (ret < 0) ? ret : num;
}
예제 #6
0
static int mpc_read(struct mpc_i2c *i2c, int target,
		    u8 * data, int length, int restart)
{
	unsigned timeout = i2c->adap.timeout;
	int i, result;
	u32 flags = restart ? CCR_RSTA : 0;

	/* Start with MEN */
	if (!restart)
		writeccr(i2c, CCR_MEN);
	/* Switch to read - restart */
	writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
	/* Write target address byte - this time with the read flag set */
	writeb((target << 1) | 1, i2c->base + MPC_I2C_DR);

	result = i2c_wait(i2c, timeout, 1);
	if (result < 0)
		return result;

	if (length) {
		if (length == 1)
			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
		else
			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA);
		/* Dummy read */
		readb(i2c->base + MPC_I2C_DR);
	}

	for (i = 0; i < length; i++) {
		result = i2c_wait(i2c, timeout, 0);
		if (result < 0)
			return result;

		/* Generate txack on next to last byte */
		if (i == length - 2)
			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
		/* Generate stop on last byte */
		if (i == length - 1)
			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_TXAK);
		data[i] = readb(i2c->base + MPC_I2C_DR);
	}

	return length;
}
예제 #7
0
static void mpc_i2c_stop(struct mpc_i2c *i2c)
{
	writeccr(i2c, CCR_MEN);
}