i2c: designware: Do not calculate SCL timing parameters needlessly

Do SCL timing parameter calculation conditionally depending are custom
parameters provided since calculated values will get instantly overwritten
by provided parameters.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-designware-core.c

@@ -320,7 +320,11 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 	sda_falling_time = dev->sda_falling_time ?: 300; /* ns */
 	scl_falling_time = dev->scl_falling_time ?: 300; /* ns */
 
-	/* Standard-mode */
+	/* Set SCL timing parameters for standard-mode */
+	if (dev->ss_hcnt && dev->ss_lcnt) {
+		hcnt = dev->ss_hcnt;
+		lcnt = dev->ss_lcnt;
+	} else {
 		hcnt = i2c_dw_scl_hcnt(input_clock_khz,
 					4000,	/* tHD;STA = tHIGH = 4.0 us */
 					sda_falling_time,
@@ -330,17 +334,16 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 					4700,	/* tLOW = 4.7 us */
 					scl_falling_time,
 					0);	/* No offset */
-
-	/* Allow platforms to specify the ideal HCNT and LCNT values */
-	if (dev->ss_hcnt && dev->ss_lcnt) {
-		hcnt = dev->ss_hcnt;
-		lcnt = dev->ss_lcnt;
 	}
 	dw_writel(dev, hcnt, DW_IC_SS_SCL_HCNT);
 	dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT);
 	dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
 
-	/* Fast-mode */
+	/* Set SCL timing parameters for fast-mode */
+	if (dev->fs_hcnt && dev->fs_lcnt) {
+		hcnt = dev->fs_hcnt;
+		lcnt = dev->fs_lcnt;
+	} else {
 		hcnt = i2c_dw_scl_hcnt(input_clock_khz,
 					600,	/* tHD;STA = tHIGH = 0.6 us */
 					sda_falling_time,
@@ -350,10 +353,6 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 					1300,	/* tLOW = 1.3 us */
 					scl_falling_time,
 					0);	/* No offset */
-
-	if (dev->fs_hcnt && dev->fs_lcnt) {
-		hcnt = dev->fs_hcnt;
-		lcnt = dev->fs_lcnt;
 	}
 	dw_writel(dev, hcnt, DW_IC_FS_SCL_HCNT);
 	dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);