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Thu, 19 Feb 2026 10:11:00 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id hzTOCbThlmkEWwAAD6G6ig (envelope-from ); Thu, 19 Feb 2026 10:11:00 +0000 Message-ID: <34dd132a-ebec-4116-865b-72e46b7cf520@suse.de> Date: Thu, 19 Feb 2026 11:10:59 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH] drm/sitronix: add ST7789V panel driver To: Archit Anant , Javier Martinez Canillas Cc: wens@kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, airlied@gmail.com, simona@ffwll.ch, nathan@kernel.org, geert+renesas@glider.be, marcus.folkesson@gmail.com, david@lechnology.com, noralf@tronnes.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20260214070123.41374-1-architanant5@gmail.com> <87ikbx6sf1.fsf@ocarina.mail-host-address-is-not-set> Content-Language: en-US From: Thomas Zimmermann Autocrypt: addr=tzimmermann@suse.de; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; RCVD_TLS_ALL(0.00)[]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; MIME_TRACE(0.00)[0:+]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCPT_COUNT_TWELVE(0.00)[14]; TAGGED_RCPT(0.00)[renesas]; MID_RHS_MATCH_FROM(0.00)[]; TO_DN_SOME(0.00)[]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[kernel.org,linux.intel.com,gmail.com,ffwll.ch,glider.be,lechnology.com,tronnes.org,lists.freedesktop.org,vger.kernel.org]; FREEMAIL_TO(0.00)[gmail.com,redhat.com]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:url,suse.de:mid,imap1.dmz-prg2.suse.org:helo] X-Spam-Flag: NO X-Spam-Score: -2.80 X-Spam-Level: Hi Am 16.02.26 um 16:38 schrieb Archit Anant: > On Mon, Feb 16, 2026 at 1:17 PM Javier Martinez Canillas > wrote: > > Hi Javier, > >> Archit Anant writes: >> >> Hello Archit, >> >>> Hi ChenYu, >>> >>> Thank you for the detailed review and the pointers toward the documentation. >>> I will ensure the headers are sorted alphabetically and the driver name >>> conflict is resolved in the next iteration. >>> >>>> The reset logic in mipi_dbi is inverted when compared to panel-st7789v. >>>> mipi_dbi needs to be taught the "proper" reset polarity. >>> Noted. I will look into the mipi_dbi core to see how to handle the reset >>> polarity correctly. >>> >>>> Instead this functionality could be merged into the existing panel-st7789v >>>> driver. You mentioned above that that driver only supports the 9-bit SPI >>>> transfer mode. However porting that driver over to mipi_dbi would fix this, >>>> and remove some redundant code. And tinydrm support could be added on top >>>> of that. >>>> >>>> I actually mentioned I was going to work on this on IRC. But I only ported >>>> the driver over to use mipi_dbi, and haven't gotten around to adding >>>> tinydrm support. I can send out the conversion patches if that helps >>>> you. >>> That would be fantastic and would save a lot of redundant effort. If you >>> send out the patches to convert the existing panel-st7789v driver to >>> mipi_dbi, I would be happy to build the 'tiny' (simple display pipe) >>> support on top of your series. >>> >> I think we want to get rid of the simple display pipeline and instead just >> use regulator atomic helpers, even for the tiny DRM drivers. >> >> Please take a look to previous commits such as 2037174993c8 ("drm/bochs: >> Use regular atomic helpers") or 622113b9f11f ("drm/ssd130x: Replace simple >> display helpers with the atomic helpers"). >> >> -- >> Best regards, >> >> Javier Martinez Canillas >> Core Platforms >> Red Hat >> > Thank you for pointing this out. I based this implementation on the > existing st7735r driver, which currently uses the simple pipe. > > I will study the bochs and ssd130x commits to understand the migration to > regular atomic helpers. > > If the goal is to move tiny DRM drivers away from the simple pipe, updating > the Sitronix drivers to this new pattern sounds much better. > I will incorporate this into my plan for the next iteration > (building on top of ChenYu's work). The thing is that this driver builds upon mipi_dbi_dev, which uses simple_display_pipeline internally. So it might be legitimate to use it here. Otherwise all the MIPI support from drm_mipi_dbi.c would have to be duplicated. Best regards Thomas > -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)