i2c: designware: Enable fast mode plus

This patch enabled fast mode plus. The fast mode plus and fast speed
share the same HCNT and LCNT register. So, the fast mode plus will only
run when the HCNT and LCNT value is provided. Else, it will run at fast
speed as default.
Signed-off-by: Weifeng Voon <weifeng.voon@intel.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

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

@@ -347,8 +347,11 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 	dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT);
 	dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
 
-	/* Set SCL timing parameters for fast-mode */
-	if (dev->fs_hcnt && dev->fs_lcnt) {
+	/* Set SCL timing parameters for fast-mode or fast-mode plus */
+	if ((dev->clk_freq == 1000000) && dev->fp_hcnt && dev->fp_lcnt) {
+		hcnt = dev->fp_hcnt;
+		lcnt = dev->fp_lcnt;
+	} else if (dev->fs_hcnt && dev->fs_lcnt) {
 		hcnt = dev->fs_hcnt;
 		lcnt = dev->fs_lcnt;
 	} else {

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

@@ -196,10 +196,13 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 		dw_i2c_acpi_configure(pdev);
 
 	/*
-	 * Only standard mode at 100kHz and fast mode at 400kHz are supported.
+	 * Only standard mode at 100kHz, fast mode at 400kHz,
+	 * and fast mode plus at 1MHz are supported.
 	 */
-	if (dev->clk_freq != 100000 && dev->clk_freq != 400000) {
-		dev_err(&pdev->dev, "Only 100kHz and 400kHz supported");
+	if (dev->clk_freq != 100000 && dev->clk_freq != 400000
+	    && dev->clk_freq != 1000000) {
+		dev_err(&pdev->dev,
+			"Only 100kHz, 400kHz and 1MHz are supported");
 		return -EINVAL;
 	}