Re: [PATCH v2] pwm: fix pwm-rz-mtu3.c build errors

[Thierry Reding <thierry.reding@gmail.com>]

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On Tue, Jul 18, 2023 at 02:05:42PM +0200, Geert Uytterhoeven wrote:
> Hi Randy,
> 
> On Tue, Jul 18, 2023 at 8:44 AM Randy Dunlap <rd.dunlab@gmail.com> wrote:
> > From: Randy Dunlap <rd.dunlab@gmail.com>
> >
> > When (MFD) RZ_MTU3=m and PWM_RZ_MTU3=y, there are numerous build errors:
> >
> > ld: vmlinux.o: in function `rz_mtu3_pwm_config':
> > drivers/pwm/pwm-rz-mtu3.c:374: undefined reference to `rz_mtu3_disable'
> > ld: drivers/pwm/pwm-rz-mtu3.c:377: undefined reference to `rz_mtu3_8bit_ch_write'
> > ld: vmlinux.o: in function `rz_mtu3_pwm_write_tgr_registers':
> > drivers/pwm/pwm-rz-mtu3.c:110: undefined reference to `rz_mtu3_16bit_ch_write'
> > ld: vmlinux.o: in function `rz_mtu3_pwm_config':
> > drivers/pwm/pwm-rz-mtu3.c:382: undefined reference to `rz_mtu3_8bit_ch_write'
> > ld: vmlinux.o: in function `rz_mtu3_pwm_write_tgr_registers':
> > drivers/pwm/pwm-rz-mtu3.c:110: undefined reference to `rz_mtu3_16bit_ch_write'
> > ld: drivers/pwm/pwm-rz-mtu3.c:111: undefined reference to `rz_mtu3_16bit_ch_write'
> > ld: vmlinux.o: in function `rz_mtu3_pwm_config':
> > drivers/pwm/pwm-rz-mtu3.c:397: undefined reference to `rz_mtu3_enable'
> > ld: vmlinux.o: in function `rz_mtu3_pwm_disable':
> > drivers/pwm/pwm-rz-mtu3.c:259: undefined reference to `rz_mtu3_8bit_ch_write'
> > ld: drivers/pwm/pwm-rz-mtu3.c:264: undefined reference to `rz_mtu3_disable'
> > ld: vmlinux.o: in function `rz_mtu3_pwm_enable':
> > drivers/pwm/pwm-rz-mtu3.c:230: undefined reference to `rz_mtu3_8bit_ch_write'
> > ld: drivers/pwm/pwm-rz-mtu3.c:234: undefined reference to `rz_mtu3_8bit_ch_write'
> > ld: drivers/pwm/pwm-rz-mtu3.c:238: undefined reference to `rz_mtu3_enable'
> > ld: vmlinux.o: in function `rz_mtu3_pwm_is_ch_enabled':
> > drivers/pwm/pwm-rz-mtu3.c:155: undefined reference to `rz_mtu3_is_enabled'
> > ld: drivers/pwm/pwm-rz-mtu3.c:162: undefined reference to `rz_mtu3_8bit_ch_read'
> > ld: vmlinux.o: in function `rz_mtu3_pwm_read_tgr_registers':
> > drivers/pwm/pwm-rz-mtu3.c:102: undefined reference to `rz_mtu3_16bit_ch_read'
> > ld: drivers/pwm/pwm-rz-mtu3.c:102: undefined reference to `rz_mtu3_16bit_ch_read'
> > ld: drivers/pwm/pwm-rz-mtu3.c:103: undefined reference to `rz_mtu3_16bit_ch_read'
> > ld: vmlinux.o: in function `rz_mtu3_pwm_get_state':
> > drivers/pwm/pwm-rz-mtu3.c:296: undefined reference to `rz_mtu3_8bit_ch_read'
> >
> > Modify the dependencies of PWM_RZ_MTU3 so that COMPILE_TEST is
> > still allowed but PWM_RZ_MTU3 depends on RZ_MTU3 if it is being built
> > but also allow the latter not to be built.
> >
> > Fixes: 254d3a727421 ("pwm: Add Renesas RZ/G2L MTU3a PWM driver")
> > Signed-off-by: Randy Dunlap <rd.dunlab@gmail.com
> 
> Thanks for your patch!
> 
> > --- a/drivers/pwm/Kconfig
> > +++ b/drivers/pwm/Kconfig
> > @@ -505,7 +505,8 @@ config PWM_ROCKCHIP
> >
> >  config PWM_RZ_MTU3
> >         tristate "Renesas RZ/G2L MTU3a PWM Timer support"
> > -       depends on RZ_MTU3 || COMPILE_TEST
> > +       depends on COMPILE_TEST
> 
> This makes the driver always depend on COMPILE_TEST,
> which is definitely not what we want.

Honestly, do we really need all of this complexity? I have specific
configurations to test all of the PWM drivers to make sure they build.
There's probably edge cases that don't get tested, but sooner or later I
expect some build bot will encounter those and then we can rectify
things. But in many cases that I've seen COMPILE_TEST just happens to do
more harm than good.

Thierry

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