Bug about changing I2C clock rate at runtime

[josonsyue]

There is a bug that causes the following error when in fact the clock rate has been set successfully.

Output of dmesg:

Fix:

diff --git a/kernel/kernel-5.10/drivers/i2c/busses/i2c-tegra.c b/kernel/kernel-5.10/drivers/i2c/busses/i2c-tegra.c
index 22672c53c..092b35ae7 100644
--- a/kernel/kernel-5.10/drivers/i2c/busses/i2c-tegra.c
+++ b/kernel/kernel-5.10/drivers/i2c/busses/i2c-tegra.c
@@ -1738,12 +1738,12 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 
        if (adap->bus_clk_rate != i2c_dev->bus_clk_rate) {
                i2c_dev->bus_clk_rate = adap->bus_clk_rate;
-                tegra_i2c_change_clock_rate(i2c_dev);
-                if (ret) {
-                        dev_err(i2c_dev->dev,
-                                        "failed changing clock rate: %d\n", ret);
-                        return ret;
-                }
+               ret = tegra_i2c_change_clock_rate(i2c_dev);
+               if (ret) {
+                       dev_err(i2c_dev->dev,
+                                       "failed changing clock rate: %d\n", ret);
+                       return ret;
+               }
        }

Edit:
Should puts i2c_dev->bus_clk_rate = adap->bus_clk_rate; before ret = tegra_i2c_change_clock_rate(i2c_dev);

And should we save the old clock rate so we can restore it if failed to change?

[ShaneCCC]

Thanks for the reporting.
Will check it.