Merge branch 'i2c-fixes' of git://git.fluff.org/bjdooks/linux

* 'i2c-fixes' of git://git.fluff.org/bjdooks/linux:
  i2c-mpc: Do not generate STOP after read.
  i2c: imx: disable clock when it's possible to save power.
  i2c: imx: only imx1 needs disable delay
  i2c: imx: check busy bit when START/STOP

drivers/i2c/busses/i2c-imx.c

@@ -120,19 +120,26 @@ struct imx_i2c_struct {
 	wait_queue_head_t	queue;
 	unsigned long		i2csr;
 	unsigned int 		disable_delay;
+	int			stopped;
+	unsigned int		ifdr; /* IMX_I2C_IFDR */
 };
 
 /** Functions for IMX I2C adapter driver ***************************************
 *******************************************************************************/
 
-static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx)
+static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy)
 {
 	unsigned long orig_jiffies = jiffies;
+	unsigned int temp;
 
 	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 
-	/* wait for bus not busy */
-	while (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_IBB) {
+	while (1) {
+		temp = readb(i2c_imx->base + IMX_I2C_I2SR);
+		if (for_busy && (temp & I2SR_IBB))
+			break;
+		if (!for_busy && !(temp & I2SR_IBB))
+			break;
 		if (signal_pending(current)) {
 			dev_dbg(&i2c_imx->adapter.dev,
 				"<%s> I2C Interrupted\n", __func__);
@@ -179,41 +186,62 @@ static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx)
 	return 0;
 }
 
-static void i2c_imx_start(struct imx_i2c_struct *i2c_imx)
+static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
 {
 	unsigned int temp = 0;
+	int result;
 
 	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 
+	clk_enable(i2c_imx->clk);
+	writeb(i2c_imx->ifdr, i2c_imx->base + IMX_I2C_IFDR);
 	/* Enable I2C controller */
+	writeb(0, i2c_imx->base + IMX_I2C_I2SR);
 	writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
+
+	/* Wait controller to be stable */
+	udelay(50);
+
 	/* Start I2C transaction */
 	temp = readb(i2c_imx->base + IMX_I2C_I2CR);
 	temp |= I2CR_MSTA;
 	writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+	result = i2c_imx_bus_busy(i2c_imx, 1);
+	if (result)
+		return result;
+	i2c_imx->stopped = 0;
+
 	temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
 	writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+	return result;
 }
 
 static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
 {
 	unsigned int temp = 0;
 
-	/* Stop I2C transaction */
-	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
-	temp = readb(i2c_imx->base + IMX_I2C_I2CR);
-	temp &= ~I2CR_MSTA;
-	writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
-	/* setup chip registers to defaults */
-	writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
-	writeb(0, i2c_imx->base + IMX_I2C_I2SR);
-	/*
-	 * This delay caused by an i.MXL hardware bug.
-	 * If no (or too short) delay, no "STOP" bit will be generated.
-	 */
-	udelay(i2c_imx->disable_delay);
+	if (!i2c_imx->stopped) {
+		/* Stop I2C transaction */
+		dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
+		temp = readb(i2c_imx->base + IMX_I2C_I2CR);
+		temp &= ~(I2CR_MSTA | I2CR_MTX);
+		writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+		i2c_imx->stopped = 1;
+	}
+	if (cpu_is_mx1()) {
+		/*
+		 * This delay caused by an i.MXL hardware bug.
+		 * If no (or too short) delay, no "STOP" bit will be generated.
+		 */
+		udelay(i2c_imx->disable_delay);
+	}
+
+	if (!i2c_imx->stopped)
+		i2c_imx_bus_busy(i2c_imx, 0);
+
 	/* Disable I2C controller */
 	writeb(0, i2c_imx->base + IMX_I2C_I2CR);
+	clk_disable(i2c_imx->clk);
 }
 
 static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
@@ -233,8 +261,8 @@ static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
 	else
 		for (i = 0; i2c_clk_div[i][0] < div; i++);
 
-	/* Write divider value to register */
-	writeb(i2c_clk_div[i][1], i2c_imx->base + IMX_I2C_IFDR);
+	/* Store divider value */
+	i2c_imx->ifdr = i2c_clk_div[i][1];
 
 	/*
 	 * There dummy delay is calculated.
@@ -341,11 +369,15 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
 		if (result)
 			return result;
 		if (i == (msgs->len - 1)) {
+			/* It must generate STOP before read I2DR to prevent
+			   controller from generating another clock cycle */
 			dev_dbg(&i2c_imx->adapter.dev,
 				"<%s> clear MSTA\n", __func__);
 			temp = readb(i2c_imx->base + IMX_I2C_I2CR);
-			temp &= ~I2CR_MSTA;
+			temp &= ~(I2CR_MSTA | I2CR_MTX);
 			writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+			i2c_imx_bus_busy(i2c_imx, 0);
+			i2c_imx->stopped = 1;
 		} else if (i == (msgs->len - 2)) {
 			dev_dbg(&i2c_imx->adapter.dev,
 				"<%s> set TXAK\n", __func__);
@@ -370,14 +402,11 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
 
 	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 
-	/* Check if i2c bus is not busy */
-	result = i2c_imx_bus_busy(i2c_imx);
+	/* Start I2C transfer */
+	result = i2c_imx_start(i2c_imx);
 	if (result)
 		goto fail0;
 
-	/* Start I2C transfer */
-	i2c_imx_start(i2c_imx);
-
 	/* read/write data */
 	for (i = 0; i < num; i++) {
 		if (i) {
@@ -386,6 +415,9 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
 			temp = readb(i2c_imx->base + IMX_I2C_I2CR);
 			temp |= I2CR_RSTA;
 			writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+			result =  i2c_imx_bus_busy(i2c_imx, 1);
+			if (result)
+				goto fail0;
 		}
 		dev_dbg(&i2c_imx->adapter.dev,
 			"<%s> transfer message: %d\n", __func__, i);
@@ -500,7 +532,6 @@ static int __init i2c_imx_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "can't get I2C clock\n");
 		goto fail3;
 	}
-	clk_enable(i2c_imx->clk);
 
 	/* Request IRQ */
 	ret = request_irq(i2c_imx->irq, i2c_imx_isr, 0, pdev->name, i2c_imx);
@@ -549,7 +580,6 @@ static int __init i2c_imx_probe(struct platform_device *pdev)
 fail5:
 	free_irq(i2c_imx->irq, i2c_imx);
 fail4:
-	clk_disable(i2c_imx->clk);
 	clk_put(i2c_imx->clk);
 fail3:
 	release_mem_region(i2c_imx->res->start, resource_size(res));
@@ -586,8 +616,6 @@ static int __exit i2c_imx_remove(struct platform_device *pdev)
 	if (pdata && pdata->exit)
 		pdata->exit(&pdev->dev);
 
-	/* Disable I2C clock */
-	clk_disable(i2c_imx->clk);
 	clk_put(i2c_imx->clk);
 
 	release_mem_region(i2c_imx->res->start, resource_size(i2c_imx->res));

drivers/i2c/busses/i2c-mpc.c

@@ -365,9 +365,6 @@ static int mpc_write(struct mpc_i2c *i2c, int target,
 	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 */
@@ -396,9 +393,6 @@ static int mpc_read(struct mpc_i2c *i2c, int target,
 	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 */
@@ -425,9 +419,9 @@ static int mpc_read(struct mpc_i2c *i2c, int target,
 		/* 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 */
+		/* Do not generate stop on last byte */
 		if (i == length - 1)
-			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_TXAK);
+			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX);
 		data[i] = readb(i2c->base + MPC_I2C_DR);
 	}