I think the header file could avoid redefinition errors.
 at compile time by adding macro definitions.

Signed-off-by: Li zeming <zeming@nfschina.com>
---
 drivers/accessibility/speakup/speakup_acnt.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/accessibility/speakup/speakup_acnt.h b/drivers/accessibility/speakup/speakup_acnt.h
index cffa938ae580..cea05d770f6d 100644
--- a/drivers/accessibility/speakup/speakup_acnt.h
+++ b/drivers/accessibility/speakup/speakup_acnt.h
@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /* speakup_acntpc.h - header file for speakups Accent-PC driver. */
+#ifndef _SPEAKUP_ACNT_H
+#define _SPEAKUP_ACNT_H
 
 #define SYNTH_IO_EXTENT	0x02
 
@@ -17,3 +19,4 @@
 #define SYNTH_FULL	'F' /* synth is full. */
 #define SYNTH_ALMOST_EMPTY 'M' /* synth has less than 2 seconds of text left */
 #define SYNTH_SPEAKING	's' /* synth is speaking and has a fare way to go */
+#endif
-- 
2.18.2

Hello,

Li zeming, le mar. 05 juil. 2022 18:19:55 +0800, a ecrit:
> I think the header file could avoid redefinition errors.
>  at compile time by adding macro definitions.

Redefining a macro to the same value is not a problem, but better have it
indeed.

> Signed-off-by: Li zeming <zeming@nfschina.com>

Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

Could you also patch speakup_dtlk.h the same way? Thanks.

Samuel

> ---
>  drivers/accessibility/speakup/speakup_acnt.h | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/accessibility/speakup/speakup_acnt.h b/drivers/accessibility/speakup/speakup_acnt.h
> index cffa938ae580..cea05d770f6d 100644
> --- a/drivers/accessibility/speakup/speakup_acnt.h
> +++ b/drivers/accessibility/speakup/speakup_acnt.h
> @@ -1,5 +1,7 @@
>  /* SPDX-License-Identifier: GPL-2.0 */
>  /* speakup_acntpc.h - header file for speakups Accent-PC driver. */
> +#ifndef _SPEAKUP_ACNT_H
> +#define _SPEAKUP_ACNT_H
>  
>  #define SYNTH_IO_EXTENT	0x02
>  
> @@ -17,3 +19,4 @@
>  #define SYNTH_FULL	'F' /* synth is full. */
>  #define SYNTH_ALMOST_EMPTY 'M' /* synth has less than 2 seconds of text left */
>  #define SYNTH_SPEAKING	's' /* synth is speaking and has a fare way to go */
> +#endif
> -- 
> 2.18.2
>

Thank you very much for your approval. 
I continue to add macros to speakup_dtlk.h and any header files I could add.