1 files changed, 21 insertions, 2 deletions

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index bc8773333155..8193e8eea764 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -123,6 +123,7 @@ static int dw_i2c_probe(struct platform_device *pdev)
         struct i2c_adapter *adap;
         struct resource *mem;
         int irq, r;
+        u32 clk_freq;
 
         irq = platform_get_irq(pdev, 0);
         if (irq < 0) {
@@ -152,6 +153,9 @@ static int dw_i2c_probe(struct platform_device *pdev)
                 return PTR_ERR(dev->clk);
         clk_prepare_enable(dev->clk);
 
+        /* fast mode by default because of legacy reasons */
+        clk_freq = 400000;
+
         if (pdev->dev.of_node) {
                 u32 ht = 0;
                 u32 ic_clk = dev->get_clk_rate_khz(dev);
@@ -167,6 +171,17 @@ static int dw_i2c_probe(struct platform_device *pdev)
                 of_property_read_u32(pdev->dev.of_node,
                                      "i2c-scl-falling-time-ns",
                                      &dev->scl_falling_time);
+
+                of_property_read_u32(pdev->dev.of_node, "clock-frequency",
+                                     &clk_freq);
+
+                /* Only standard mode at 100kHz and fast mode at 400kHz
+                 * are supported.
+                 */
+                if (clk_freq != 100000 && clk_freq != 400000) {
+                        dev_err(&pdev->dev, "Only 100kHz and 400kHz supported");
+                        return -EINVAL;
+                }
         }
 
         dev->functionality =
@@ -176,8 +191,12 @@ static int dw_i2c_probe(struct platform_device *pdev)
                 I2C_FUNC_SMBUS_BYTE_DATA |
                 I2C_FUNC_SMBUS_WORD_DATA |
                 I2C_FUNC_SMBUS_I2C_BLOCK;
-        dev->master_cfg =  DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
-                DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST;
+        if (clk_freq == 100000)
+                dev->master_cfg =  DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
+                        DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_STD;
+        else
+                dev->master_cfg =  DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
+                        DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST;
 
         /* Try first if we can configure the device from ACPI */
         r = dw_i2c_acpi_configure(pdev);