| Message ID | 4A8B164E.6030704@ruggedcom.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Kumar Gala |
| Headers | show |
Timur Tabi wrote: > Michael Barkowski wrote: > >> diff --git a/arch/powerpc/sysdev/qe_lib/gpio.c b/arch/powerpc/sysdev/qe_lib/gpio.c >> index 3485288..e7bf136 100644 >> --- a/arch/powerpc/sysdev/qe_lib/gpio.c >> +++ b/arch/powerpc/sysdev/qe_lib/gpio.c >> @@ -107,12 +107,11 @@ static int qe_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) >> >> spin_lock_irqsave(&qe_gc->lock, flags); >> >> + qe_gpio_set(gc, gpio, val); > > qe_gpio_set already calls spin_lock_irqsave(), so you'll have nested spinlocks, which will lock up on SMP. > > Let me guess, you didn't test this on a dual-core system? That is correct. See v2 and please test, YMMV, etc
diff --git a/arch/powerpc/sysdev/qe_lib/gpio.c b/arch/powerpc/sysdev/qe_lib/gpio.c index 3485288..e7bf136 100644 --- a/arch/powerpc/sysdev/qe_lib/gpio.c +++ b/arch/powerpc/sysdev/qe_lib/gpio.c @@ -107,12 +107,11 @@ static int qe_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) spin_lock_irqsave(&qe_gc->lock, flags); + qe_gpio_set(gc, gpio, val); __par_io_config_pin(mm_gc->regs, gpio, QE_PIO_DIR_OUT, 0, 0, 0); spin_unlock_irqrestore(&qe_gc->lock, flags); - qe_gpio_set(gc, gpio, val); - return 0; }
This avoids having a short glitch if the desired initial value is not the same as what was previously in the data register. Signed-off-by: Michael Barkowski <michaelbarkowski@ruggedcom.com> --- I can't think of a reason not to do this. The data register has no effect except when the pin is configured as an output, right? Please enlighten me if this is not correct. The behaviour I see gels with my thinking, but there may be a case I haven't thought of. arch/powerpc/sysdev/qe_lib/gpio.c | 3 +-- 1 files changed, 1 insertions(+), 2 deletions(-)