Messages in this thread | | | Subject | Re: [PATCH v2 1/1] mux: consumer: Add dummy functions for !CONFIG_MULTIPLEXER case | From | "Kuppuswamy, Sathyanarayanan" <> | Date | Sun, 9 Jul 2017 00:42:58 -0700 |
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Hi,
On 7/8/2017 11:59 PM, Peter Rosin wrote: > On 2017-07-08 23:22, Andy Shevchenko wrote: >> On Sat, Jul 8, 2017 at 9:12 PM, >> <sathyanarayanan.kuppuswamy@linux.intel.com> wrote: >>> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> >>> >>> Add dummy functions to avoid compile time issues when CONFIG_MULTIPLEXER >>> is not enabled. >>> >> I don't think the error return code is okay to all of them. The return >> value should be choosen carefully (for some functions it's okay IMO to >> return 0). > BTW, is ENODEV correct for this situation? I have this nagging feeling > that ENODEV is over-used? I used ENODEV to signify that the MUX device is not available/enabled. > > And again, all these stubs should all be inlines, or things will break it > this file is included more than once. I will fix the inline problem in next version. > >>> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> >>> --- >>> include/linux/mux/consumer.h | 38 ++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 38 insertions(+) >>> >>> Changes since v1: >>> * Changed #ifdef to #if IS_ENABLED. >>> >>> diff --git a/include/linux/mux/consumer.h b/include/linux/mux/consumer.h >>> index 5577e1b..df78988 100644 >>> --- a/include/linux/mux/consumer.h >>> +++ b/include/linux/mux/consumer.h >>> @@ -16,6 +16,7 @@ >>> struct device; >>> struct mux_control; >>> >>> +#if IS_ENABLED(CONFIG_MULTIPLEXER) >>> unsigned int mux_control_states(struct mux_control *mux); >>> int __must_check mux_control_select(struct mux_control *mux, >>> unsigned int state); >>> @@ -29,4 +30,41 @@ void mux_control_put(struct mux_control *mux); >>> struct mux_control *devm_mux_control_get(struct device *dev, >>> const char *mux_name); >>> >>> +#else >>> +unsigned int mux_control_states(struct mux_control *mux) >>> +{ >>> + return -ENODEV; >> Peter, is here we are obliged to return error code in such case? > Since it will presumably be difficult to obtain a mux_control > w/o the mux-core being present, it doesn't matter much what > most of these stubs return. > > For this stub, 0 is perhaps best, since the kernel-doc for > mux_control_states mentions nothing about any error possibility. Agreed. Since it returns the total number of MUX states, 0 seems to more appropriate. I can fix it in next version. > >>> +} >>> + >>> +int __must_check mux_control_select(struct mux_control *mux, >>> + unsigned int state) >>> +{ >>> + return -ENODEV; >> return 0; ? > Maybe. But it doesn't matter much, but in this case the consumer must > handle errors. See above. > >>> +} >>> + >>> +int __must_check mux_control_try_select(struct mux_control *mux, >>> + unsigned int state) >>> +{ >>> + return -ENODEV; >>> +} >> return 0; ? > Maybe. But it doesn't matter much, but in this case the consumer must > handle errors. See above. > >>> + >>> +int mux_control_deselect(struct mux_control *mux) >>> +{ >>> + return -ENODEV; >>> +} >> return 0; ? > Probably. See above. > > Cheers, > peda > >>> + >>> +struct mux_control *mux_control_get(struct device *dev, const char *mux_name) >>> +{ >>> + return ERR_PTR(-ENODEV); >>> +} >>> + >>> +void mux_control_put(struct mux_control *mux) {} >>> + >>> +struct mux_control *devm_mux_control_get(struct device *dev, >>> + const char *mux_name) >>> +{ >>> + return ERR_PTR(-ENODEV); >>> +} >>> +#endif >>> + >>> #endif /* _LINUX_MUX_CONSUMER_H */ >>> -- >>> 2.7.4 >>> >> >>
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