Before calling __dw_i2c_set_bus_speed(), the I2C could already be set as ether enable or disable, we should restore the original setting instead of enable i2c anyway.
This patch fix a bug happened in init function: __dw_i2c_init(){ /* Disable i2c */ ... __dw_i2c_set_bus_speed(i2c_base, NULL, speed); writel(slaveaddr, &i2c_base->ic_sar); /* Enable i2c */ } In this case, enable i2c inside __dw_i2c_set_bus_speed() function will cause ic_sar write fail.
Signed-off-by: Jun Chen ptchentw@gmail.com ---
drivers/i2c/designware_i2c.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c index 9ccc241..d11d47d 100644 --- a/drivers/i2c/designware_i2c.c +++ b/drivers/i2c/designware_i2c.c @@ -82,6 +82,7 @@ static unsigned int __dw_i2c_set_bus_speed(struct i2c_regs *i2c_base, { unsigned int cntl; unsigned int hcnt, lcnt; + unsigned int ena; int i2c_spd;
if (speed >= I2C_MAX_SPEED) @@ -91,6 +92,9 @@ static unsigned int __dw_i2c_set_bus_speed(struct i2c_regs *i2c_base, else i2c_spd = IC_SPEED_MODE_STANDARD;
+ /* Get enable setting for restore later */ + ena = readl(&i2c_base->ic_enable) & IC_ENABLE_0B; + /* to set speed cltr must be disabled */ dw_i2c_enable(i2c_base, false);
@@ -146,8 +150,9 @@ static unsigned int __dw_i2c_set_bus_speed(struct i2c_regs *i2c_base, if (scl_sda_cfg) writel(scl_sda_cfg->sda_hold, &i2c_base->ic_sda_hold);
- /* Enable back i2c now speed set */ - dw_i2c_enable(i2c_base, true); + /* Restore back i2c now speed set */ + if (ena == IC_ENABLE_0B) + dw_i2c_enable(i2c_base, true);
return 0; }