Re: [PATCH] drivers/nfc: remove obsolete setting of DEBUG

From: Paul Bolle
Date: Wed Apr 29 2015 - 04:27:40 EST


[Added Joe.]

On Tue, 2015-04-28 at 11:08 +0200, Valentin Rothberg wrote:
> The CPP identifier 'DEBUG' is not used in the source code of nfc at all,
> so we can safely remove setting it in both Makefiles.
>
> Signed-off-by: Valentin Rothberg <valentinrothberg@xxxxxxxxx>
> ---
> I detected this issue with ./scripts/checkkconfigsymbols.py since
> CONFIG_NFC_DEBUG is not defined in Kconfig.

The patch should be fine, as there is no NFC_DEBUG Kconfig symbol, but
I'm not sure whether the commit explanation is correct.

As it turns out I submitted a very similar patch two years ago (see
https://lkml.kernel.org/r/1365179481.1830.69.camel@xxxxxxxxxxxxxxx ).
And it was pointed out to me that the DEBUG macro is used by the
pr_debug() macro and friends. I already forgot the details but, in
short, DEBUG is a bit of a gotcha: you can't say whether or not it's
used by just grepping for it.

> ---
> drivers/nfc/Makefile | 2 --
> drivers/nfc/nxp-nci/Makefile | 2 --
> 2 files changed, 4 deletions(-)
>
> diff --git a/drivers/nfc/Makefile b/drivers/nfc/Makefile
> index a4292d790f9b..13b648baf175 100644
> --- a/drivers/nfc/Makefile
> +++ b/drivers/nfc/Makefile
> @@ -14,5 +14,3 @@ obj-$(CONFIG_NFC_TRF7970A) += trf7970a.o
> obj-$(CONFIG_NFC_ST21NFCA) += st21nfca/
> obj-$(CONFIG_NFC_ST21NFCB) += st21nfcb/
> obj-$(CONFIG_NFC_NXP_NCI) += nxp-nci/
> -
> -ccflags-$(CONFIG_NFC_DEBUG) := -DDEBUG
> diff --git a/drivers/nfc/nxp-nci/Makefile b/drivers/nfc/nxp-nci/Makefile
> index c008be30bb18..c9ec7869dbd2 100644
> --- a/drivers/nfc/nxp-nci/Makefile
> +++ b/drivers/nfc/nxp-nci/Makefile
> @@ -7,5 +7,3 @@ nxp-nci_i2c-objs = i2c.o
>
> obj-$(CONFIG_NFC_NXP_NCI) += nxp-nci.o
> obj-$(CONFIG_NFC_NXP_NCI_I2C) += nxp-nci_i2c.o
> -
> -ccflags-$(CONFIG_NFC_DEBUG) := -DDEBUG

Thanks,


Paul Bolle

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