On 2019-04-13 00:59, Peter Rosin wrote: > On 2019-04-03 23:05, Ray Jui wrote: >> Change the iProc I2C driver to use the 'BIT' macro from all '1 << XXX' >> bit operations to get rid of compiler warning and improve readability of >> the code > > All? I see lots more '1 << XXX_SHIFT' matches. I might be behind though? I verified that, and yes indeed, I was behind. That said, see below... > Anyway, if you are cleaning up, I'm just flagging that BIT(XXX_SHIFT) looks > a bit clunky to me. You might consider renaming all those single-bit > XXX_SHIFT macros to simple be > > #define XXX BIT(<xxx>) > > instead of > > #define XXX_SHIFT <xxx> > > but that triggers more churn, so is obviously more error prone. You might > not dare it? > > Cheers, > Peter > >> Signed-off-by: Ray Jui <ray.jui@xxxxxxxxxxxx> >> --- >> drivers/i2c/busses/i2c-bcm-iproc.c | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c >> index 562942d0c05c..a845b8decac8 100644 >> --- a/drivers/i2c/busses/i2c-bcm-iproc.c >> +++ b/drivers/i2c/busses/i2c-bcm-iproc.c >> @@ -717,7 +717,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, >> >> /* mark the last byte */ >> if (i == msg->len - 1) >> - val |= 1 << M_TX_WR_STATUS_SHIFT; >> + val |= BIT(M_TX_WR_STATUS_SHIFT); >> >> iproc_i2c_wr_reg(iproc_i2c, M_TX_OFFSET, val); >> } >> @@ -844,7 +844,7 @@ static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *iproc_i2c) >> >> iproc_i2c->bus_speed = bus_speed; >> val = iproc_i2c_rd_reg(iproc_i2c, TIM_CFG_OFFSET); >> - val &= ~(1 << TIM_CFG_MODE_400_SHIFT); >> + val &= ~BIT(TIM_CFG_MODE_400_SHIFT); >> val |= (bus_speed == 400000) << TIM_CFG_MODE_400_SHIFT; These two statements now no longer "match". One uses BIT and the other open codes the shift. I think that's bad. Losing the _SHIFT suffix and including BIT in the macro expansion, as suggested above, yields: val &= ~TIM_CFG_MODE_400; if (bus_speed == 400000) val |= TIM_CFG_MODE_400; which is perhaps one more line, but also more readable IMO. But all this is of course in deep nit-pick-territory... Cheers, Peter >> iproc_i2c_wr_reg(iproc_i2c, TIM_CFG_OFFSET, val); >> >> @@ -995,7 +995,7 @@ static int bcm_iproc_i2c_resume(struct device *dev) >> >> /* configure to the desired bus speed */ >> val = iproc_i2c_rd_reg(iproc_i2c, TIM_CFG_OFFSET); >> - val &= ~(1 << TIM_CFG_MODE_400_SHIFT); >> + val &= ~BIT(TIM_CFG_MODE_400_SHIFT); >> val |= (iproc_i2c->bus_speed == 400000) << TIM_CFG_MODE_400_SHIFT; >> iproc_i2c_wr_reg(iproc_i2c, TIM_CFG_OFFSET, val); >> >> >
