[PATCH] i2c: aspeed: Add multi-master use case support

Jae Hyun Yoo jae.hyun.yoo at linux.intel.com
Tue Feb 12 05:09:53 AEDT 2019

> Hmmm, the #ifdeffery quite increases with this patch. Maybe it is easier
> to select I2C_SLAVE in Kconfig? I'll let you decide.
> My code checkers found this:
> drivers/i2c/busses/i2c-aspeed.c:694:10: warning: Variable 'ret' is assigned a value that is never used. [unreadVariable]

Hi Wolfram,

Yes, cppcheck pointed it out correctly. The assignment on the variable
'ret' is not needed at there. Actually, the code should not be wrapped
using I2C_SLAVE because a bus can also be in multi-master environment
even when slave is not enabled. So the warning can be removed by below

diff --git a/drivers/i2c/busses/i2c-aspeed.c 
index 9253ebccb008..882c4ab1d18a 100644
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -655,7 +655,6 @@ static int aspeed_i2c_master_xfer(struct i2c_adapter 
         struct aspeed_i2c_bus *bus = i2c_get_adapdata(adap);
         unsigned long time_left, flags;
-       int ret;

         spin_lock_irqsave(&bus->lock, flags);
         bus->cmd_err = 0;
@@ -664,6 +663,8 @@ static int aspeed_i2c_master_xfer(struct i2c_adapter 
         if (!bus->multi_master &&
             (readl(bus->base + ASPEED_I2C_CMD_REG) &
              ASPEED_I2CD_BUS_BUSY_STS)) {
+               int ret;
                 spin_unlock_irqrestore(&bus->lock, flags);
                 ret = aspeed_i2c_recover_bus(bus);
                 if (ret)
@@ -691,7 +692,7 @@ static int aspeed_i2c_master_xfer(struct i2c_adapter 
                 if (bus->multi_master &&
                     (readl(bus->base + ASPEED_I2C_CMD_REG) &
-                       ret = aspeed_i2c_recover_bus(bus);
+                       aspeed_i2c_recover_bus(bus);

                 return -ETIMEDOUT;

The reason of adding changes at line 658 and 667 is to remove below
cppcheck warning when the change at 694 is applied.

[drivers/i2c/busses/i2c-aspeed.c:670]: (style) The scope of the variable 
'ret' can be reduced.

Can you please apply above changes on top of this patch? Or I can submit
v2 with it.


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