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From: InKi Dae on 30 Mar 2010 23:00
Hi Hertley,

it's a good way.
this way is more clear and also Andrew's concern could be solved.

I'd like to apply it to local repository and then I will send the patch
in the near future.

and Andrew, If you think that Hertley's way is clear then I would make
the patch. maybe it would become second patch.

Thank you.

2010/3/31 H Hartley Sweeten <hartleys(a)visionengravers.com>:
> On Tuesday, March 30, 2010 4:03 PM, Andrew Morton wrote:
>> On Fri, 26 Mar 2010 12:24:24 +0900
>> InKi Dae <daeinki(a)gmail.com> wrote:
>>
>>> +static int s6e63m0_ldi_init(struct s6e63m0 *lcd)
>>> +{
>>> + � �int ret;
>>> +
>>> + � �ret = s6e63m0_panel_send_sequence(lcd, SEQ_PANEL_CONDITION_SET);
>>> + � �ret |= s6e63m0_panel_send_sequence(lcd, SEQ_DISPLAY_CONDITION_SET);
>>> + � �ret |= s6e63m0_panel_send_sequence(lcd, SEQ_GAMMA_SETTING);
>>> + � �ret |= s6e63m0_panel_send_sequence(lcd, SEQ_ETC_CONDITION_SET);
>>> + � �ret |= s6e63m0_panel_send_sequence(lcd, SEQ_ACL_ON);
>>> + � �ret |= s6e63m0_panel_send_sequence(lcd, SEQ_ELVSS_ON);
>>> +
>>> + � �return ret;
>>> +}
>>
>> Well. �If one call to s6e63m0_panel_send_sequence() returns -ENOMEM and
>> another call returns -EIO (for example), this function will return some
>> other, incorrect errno.
>>
>> Which is a rather minor problem, unless some caller is explicitly
>> looking for some particular error code, which doesn't happen often.
>
> Why not handle the calls with a loop?
>
> +static int s6e63m0_ldi_init(struct s6e63m0 *lcd)
> +{
> + � � � const unsigned short *init_seq[] = {
> + � � � � � � � SEQ_PANEL_CONDITION_SET,
> + � � � � � � � SEQ_DISPLAY_CONDITION_SET,
> + � � � � � � � SEQ_GAMMA_SETTING,
> + � � � � � � � SEQ_ETC_CONDITION_SET,
> + � � � � � � � SEQ_ACL_ON,
> + � � � � � � � SEQ_ELVSS_ON,
> + � � � };
> + � � � int i, ret;
> +
> + � � � for (i = 0; i < ARRAY_SIZE(init_seq); i++) {
> + � � � � � � � ret = s6e63m0_panel_send_sequence(lcd, init_seq[i]);
> + � � � � � � � if (ret)
> + � � � � � � � � � � � break;
> + � � � }
> + � � � return ret;
> +}
>
> Note that _s6e63m0_gamma_ctl has the same issue. �Actually, the whole
> driver has issues with returning errors properly.
>
> Regards,
> Hartley
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