Messages in this thread | | | Date | Tue, 3 May 2011 21:15:25 +0200 | From | Uwe Kleine-König <> | Subject | Re: [RFC][PATCH] mfd: mc13xxx-core: put mutex lock down to mc13xxx_reg_rmw function |
| |
Hello Axel,
On Wed, May 04, 2011 at 12:27:59AM +0800, Axel Lin wrote: > The mc13xxx_reg_rmw function is doing read/modify/write bitmask operations, > thus add the lock to protect it. > Then we can remove the lock/unlock from the caller. > > Signed-off-by: Axel Lin <axel.lin@gmail.com> > --- > Note I don't have the hardware handy for testing. > I appreciate if someone who has the device can test this patch. > Regards, > Axel > > drivers/mfd/mc13xxx-core.c | 8 ++++++-- > drivers/regulator/mc13892-regulator.c | 16 +++++++--------- > drivers/regulator/mc13xxx-regulator-core.c | 6 ------ > 3 files changed, 13 insertions(+), 17 deletions(-) > > diff --git a/drivers/mfd/mc13xxx-core.c b/drivers/mfd/mc13xxx-core.c > index 7e4d44b..5fb0fcc 100644 [snip] > diff --git a/drivers/regulator/mc13892-regulator.c b/drivers/regulator/mc13892-regulator.c > index 1b8f739..679b315 100644 > --- a/drivers/regulator/mc13892-regulator.c > +++ b/drivers/regulator/mc13892-regulator.c > @@ -449,7 +449,8 @@ static int mc13892_sw_regulator_set_voltage(struct regulator_dev *rdev, > ret = mc13xxx_reg_read(priv->mc13xxx, > mc13892_regulators[id].vsel_reg, &val); > if (ret) > - goto err; > + mc13xxx_unlock(priv->mc13xxx); > + return ret; > > hi = val & MC13892_SWITCHERS0_SWxHI; > if (value > 1375) > @@ -464,11 +465,10 @@ static int mc13892_sw_regulator_set_voltage(struct regulator_dev *rdev, > value = (value - 600000) / 25000; > > mask = mc13892_regulators[id].vsel_mask | MC13892_SWITCHERS0_SWxHI; > - ret = mc13xxx_reg_rmw(priv->mc13xxx, mc13892_regulators[id].vsel_reg, > - mask, value << mc13892_regulators[id].vsel_shift); > -err: > mc13xxx_unlock(priv->mc13xxx); > > + ret = mc13xxx_reg_rmw(priv->mc13xxx, mc13892_regulators[id].vsel_reg, > + mask, value << mc13892_regulators[id].vsel_shift); I havn't looked deeply, but I guess this can have unwanted side effects here. Before you had:
lock() do(something) do(something, else, that, needs, rmw) unlock()
and you introduced an unlock()/lock() between these two do()s.
I'm not convinced this change is good, though I agree that
lock() rmw(...) unlock()
looks ugly, but imho this can better be fixed by adding a wrapper for that sequence if you really want.
Best regards Uwe
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |