i2c: sh_mobile: add helper to check frequency calculations

Because we will add a second formula soon, put the sanity checks for the
computed results into a separate function.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-sh_mobile.c

@@ -246,32 +246,10 @@ static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf)
 	return (((count_khz * (tHIGH + tf)) + 5000) / 10000);
 }
 
-static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
+static int sh_mobile_i2c_check_timing(struct sh_mobile_i2c_data *pd)
 {
-	unsigned long i2c_clk_khz;
-	u32 tHIGH, tLOW, tf;
-	uint16_t max_val;
+	u16 max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff;
 
-	i2c_clk_khz = clk_get_rate(pd->clk) / 1000 / pd->clks_per_count;
-
-	if (pd->bus_speed == STANDARD_MODE) {
-		tLOW	= 47;	/* tLOW = 4.7 us */
-		tHIGH	= 40;	/* tHD;STA = tHIGH = 4.0 us */
-		tf	= 3;	/* tf = 0.3 us */
-	} else if (pd->bus_speed == FAST_MODE) {
-		tLOW	= 13;	/* tLOW = 1.3 us */
-		tHIGH	= 6;	/* tHD;STA = tHIGH = 0.6 us */
-		tf	= 3;	/* tf = 0.3 us */
-	} else {
-		dev_err(pd->dev, "unrecognized bus speed %lu Hz\n",
-			pd->bus_speed);
-		return -EINVAL;
-	}
-
-	pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf);
-	pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf);
-
-	max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff;
 	if (pd->iccl > max_val || pd->icch > max_val) {
 		dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n",
 			pd->iccl, pd->icch);
@@ -294,6 +272,33 @@ static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
 	return 0;
 }
 
+static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
+{
+	unsigned long i2c_clk_khz;
+	u32 tHIGH, tLOW, tf;
+
+	i2c_clk_khz = clk_get_rate(pd->clk) / 1000 / pd->clks_per_count;
+
+	if (pd->bus_speed == STANDARD_MODE) {
+		tLOW	= 47;	/* tLOW = 4.7 us */
+		tHIGH	= 40;	/* tHD;STA = tHIGH = 4.0 us */
+		tf	= 3;	/* tf = 0.3 us */
+	} else if (pd->bus_speed == FAST_MODE) {
+		tLOW	= 13;	/* tLOW = 1.3 us */
+		tHIGH	= 6;	/* tHD;STA = tHIGH = 0.6 us */
+		tf	= 3;	/* tf = 0.3 us */
+	} else {
+		dev_err(pd->dev, "unrecognized bus speed %lu Hz\n",
+			pd->bus_speed);
+		return -EINVAL;
+	}
+
+	pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf);
+	pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf);
+
+	return sh_mobile_i2c_check_timing(pd);
+}
+
 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
 			    enum sh_mobile_i2c_op op, unsigned char data)
 {