Suggested i2c_bcm2708 clock handling

gistfile1.txt

diff --git a/drivers/i2c/busses/i2c-bcm2708.c b/drivers/i2c/busses/i2c-bcm2708.c
index 63414a3..6bfb77f 100644
--- a/drivers/i2c/busses/i2c-bcm2708.c
+++ b/drivers/i2c/busses/i2c-bcm2708.c
@@ -67,6 +67,8 @@
 #define BSC_S_TA  	0x00000001
 
 #define I2C_TIMEOUT_MS	150
+#define SCL_TIMEOUT_MS	35
+#define BSC_CLKT_MIN	64
 
 #define DRV_NAME	"bcm2708_i2c"
 
@@ -149,17 +151,23 @@ static inline void bcm2708_bsc_setup(struct bcm2708_i2c *bi)
 {
 	unsigned long bus_hz;
 	u32 cdiv;
+	u32 clkt;
 	u32 c = BSC_C_I2CEN | BSC_C_INTD | BSC_C_ST | BSC_C_CLEAR_1;
 
 	bus_hz = clk_get_rate(bi->clk);
 	cdiv = bus_hz / baudrate;
-
+	
+	clkt = (baudrate/1000) * SCL_TIMEOUT_MS;
+	if(clkt > 65535) clkt = 65535;
+	if(clkt < BSC_CLKT_MIN) clkt = BSC_CLKT_MIN;
+	
 	if (bi->msg->flags & I2C_M_RD)
 		c |= BSC_C_INTR | BSC_C_READ;
 	else
 		c |= BSC_C_INTT;
 
 	bcm2708_wr(bi, BSC_DIV, cdiv);
+	bcm2708_wr(bi, BSC_CLKT, clkt);
 	bcm2708_wr(bi, BSC_A, bi->msg->addr);
 	bcm2708_wr(bi, BSC_DLEN, bi->msg->len);
 	bcm2708_wr(bi, BSC_C, c);
@@ -260,6 +268,8 @@ static int __devinit bcm2708_i2c_probe(struct platform_device *pdev)
 	struct clk *clk;
 	struct bcm2708_i2c *bi;
 	struct i2c_adapter *adap;
+	u32 div;
+	unsigned long bus_hz;
 
 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!regs) {
@@ -328,13 +338,32 @@ static int __devinit bcm2708_i2c_probe(struct platform_device *pdev)
 	}
 
 	bcm2708_bsc_reset(bi);
-
+	/* Check resulting BSC_DIV value.
+	 * Values less than 2 or greater than 65535 will cause undesired operation;
+	 * additionally the BSC controller will only use even divisors.
+	 */
+	bus_hz = clk_get_rate(clk);
+	div = (bus_hz/baudrate) & ~0x1;
+	if(div < 2) {
+		div = 2;
+		dev_warn(&pdev->dev, "BSC%d requested baudrate %dkHz is too high, setting to %dkHz\n",
+				pdev->id, baudrate/1000, ((unsigned int)bus_hz/div)/1000); 
+	}
+	if(div > 65535)
+	{
+		div = 65535;
+		dev_warn(&pdev->dev, "BSC%d requested baudrate %dkHz is too low, setting to %dkHz\n",
+				pdev->id, baudrate/1000, ((unsigned int)bus_hz/div)/1000);
+	}
+	baudrate = bus_hz/div;
+	
 	err = i2c_add_numbered_adapter(adap);
 	if (err < 0) {
 		dev_err(&pdev->dev, "could not add I2C adapter: %d\n", err);
 		goto out_free_irq;
 	}
-
+	
+	
 	dev_info(&pdev->dev, "BSC%d Controller at 0x%08lx (irq %d) (baudrate %dk)\n",
 		pdev->id, (unsigned long)regs->start, irq, baudrate/1000);