Messages in this thread | | | Date | Wed, 16 Oct 2019 23:02:47 -0700 | From | Guru Das Srinagesh <> | Subject | Re: [PATCH 1/1] pwm: Convert period and duty cycle to u64 |
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On Wed, Oct 16, 2019 at 12:15:39PM +0200, Thierry Reding wrote: > On Tue, Oct 15, 2019 at 07:11:39PM -0700, Guru Das Srinagesh wrote: > > Because period and duty cycle are defined as ints with units of > > nanoseconds, the maximum time duration that can be set is limited to > > ~2.147 seconds. Change their definitions to u64 so that higher durations > > may be set. > > > > Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org> > > --- > > drivers/pwm/core.c | 4 ++-- > > drivers/pwm/sysfs.c | 10 +++++----- > > include/linux/pwm.h | 16 ++++++++-------- > > 3 files changed, 15 insertions(+), 15 deletions(-) > > Actually, we can't do that without further preparatory work. The reason > is that consumers use the period and duty_cycle members in computations > of their own, which lead to errors such as this: > > armv7l-unknown-linux-gnueabihf-ld: drivers/video/backlight/pwm_bl.o: in function `pwm_backlight_probe': > pwm_bl.c:(.text+0x3b0): undefined reference to `__aeabi_uldivmod' > > So I think we need to audit all consumers carefully and make sure that > they use do_div() where necessary to avoid such errors. > > Thierry
Hi Thierry,
I would like to try doing the preparatory work by fixing the errors seen in consumers so that this u64 patch may be applied without issues.
Before sending the patch, I tried "make"-ing for arm, arm64 and i386 architectures to check for compilation/linking errors and encountered none. I see that the above error arises from using a cross-compiler for arm v7, which I haven't tried yet.
Could you please provide details of the compile tests that you run at your end? I could then try to reproduce the errors you see in the consumer drivers and fix them. Please do share any other ideas or suggestions you may have in this regard.
Thank you.
Guru Das.
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