[PATCH] drm/panel: db7430: Improve error reporting

[Noralf Trønnes]

Den 30.06.2021 21.46, skrev Noralf Trønnes:
> 
> 
> Den 30.06.2021 21.13, skrev Linus Walleij:
>> This creates a macro wrapping mipi_dbi_command() such that we get
>> some explicit error reporting if something goes wrong.
>>
>> Cc: Noralf Trønnes <noralf at tronnes.org>
>> Suggested-by: Douglas Anderson <dianders at chromium.org>
>> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
>> ---
>>  drivers/gpu/drm/panel/panel-samsung-db7430.c | 66 +++++++++++---------
>>  1 file changed, 36 insertions(+), 30 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/panel/panel-samsung-db7430.c b/drivers/gpu/drm/panel/panel-samsung-db7430.c
>> index fe58263bd9cd..c42d43ab6a4f 100644
>> --- a/drivers/gpu/drm/panel/panel-samsung-db7430.c
>> +++ b/drivers/gpu/drm/panel/panel-samsung-db7430.c
>> @@ -90,9 +90,17 @@ static inline struct db7430 *to_db7430(struct drm_panel *panel)
>>  	return container_of(panel, struct db7430, panel);
>>  }
>>  
>> +#define db7430_command(db, cmd, seq...) \
>> +({ \
>> +	struct mipi_dbi *dbi = &db->dbi;	\
>> +	int ret;				\
>> +	ret = mipi_dbi_command(dbi, cmd, seq);  \
>> +	if (ret)							\
>> +		dev_err(db->dev, "failure in writing command %#02x\n", cmd); \
>> +})
>> +
> 
> I did a grep and there's only one mipi_dbi_command() caller that checks
> the return code: mipi_dbi_poweron_reset_conditional().
> 
> Can you add the error reporting to mipi_dbi_command() instead? Instead
> of drivers adding their own similar macros.
> 
> In that case I think you need to add a plain 'ret' at the end of the
> macro for it to return the error code.
> 

I think the error reporting needs to ratelimited if added to
mipi_dbi_command() because worst case a blinking fbcon cursor will
trigger 10 errors a second for the framebuffer drivers.

Noralf.