Re: [PATCH 3/4] drm/tiny: Add driver for Solomon SSD1307 OLED displays

Javier Martinez Canillas
2022-02-01T14:36:11Z

On 2/1/22 15:05, Geert Uytterhoeven wrote:
> Hi Javier,
>
> On Tue, Feb 1, 2022 at 2:02 PM Javier Martinez Canillas
> <javierm@redhat.com> wrote:
>> On 2/1/22 10:33, Thomas Zimmermann wrote:
>>>> +{
>>>> + u8 col_end = col_start + cols - 1;
>>>> + int ret;
>>>> +
>>>> + if (col_start == ssd1307->col_start && col_end == ssd1307->col_end)
>>>> + return 0;
>>>> +
>>>> + ret = ssd1307_write_cmd(ssd1307->client, SSD1307_SET_COL_RANGE);
>>>> + if (ret < 0)
>>>> + return ret;
>>>> +
>>>> + ret = ssd1307_write_cmd(ssd1307->client, col_start);
>>>> + if (ret < 0)
>>>> + return ret;
>>>> +
>>>> + ret = ssd1307_write_cmd(ssd1307->client, col_end);
>>>> + if (ret < 0)
>>>> + return ret;
>>>
>>> Can you write these cmds in one step, such as setting up an array and
>>> sending it with ssd1307_write_array?
>>
>> I don't think so because the commands are different. But I'll check the
>> ssd1306 datasheet again to confirma that's the case.
>
> IIRC, I tried that while working on the optimizations for ssd1307fb,
> and it didn't work.
>

That's what I would had expected by reading the datasheet. Thanks a
lot for confirming my assumption.

Best regards,
--
Javier Martinez Canillas
Linux Engineering
Red Hat