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[83.233.6.197]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-54c1e65d6d5sm1158583e87.181.2025.04.07.02.20.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Apr 2025 02:20:21 -0700 (PDT) Date: Mon, 7 Apr 2025 11:20:19 +0200 From: Marcus Folkesson To: Thomas Zimmermann Cc: David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Rob Herring , Krzysztof Kozlowski , Conor Dooley , dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/3] drm/st7571-i2c: add support for Sitronix ST7571 LCD controller Message-ID: References: <20250404-st7571-v2-0-4c78aab9cd5a@gmail.com> <20250404-st7571-v2-2-4c78aab9cd5a@gmail.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="j0p2bLMOkZcckCIM" Content-Disposition: inline In-Reply-To: --j0p2bLMOkZcckCIM Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Thomas, Thank you for your review and feedback! On Mon, Apr 07, 2025 at 10:30:28AM +0200, Thomas Zimmermann wrote: > Hi >=20 > Am 04.04.25 um 15:50 schrieb Marcus Folkesson: > > Sitronix ST7571 is a 4bit gray scale dot matrix LCD controller. > > The controller has a SPI, I2C and 8bit parallel interface, this > > driver is for the I2C interface only. > >=20 > > Signed-off-by: Marcus Folkesson >=20 > Reviewed-by: Thomas Zimmermann >=20 > I have a few points below, but it's all minor details. The driver looks g= ood > overall. >=20 > > --- > > drivers/gpu/drm/tiny/Kconfig | 11 + > > drivers/gpu/drm/tiny/Makefile | 1 + > > drivers/gpu/drm/tiny/st7571-i2c.c | 720 +++++++++++++++++++++++++++++= +++++++++ > > 3 files changed, 732 insertions(+) > >=20 [...] >=20 > > + select REGMAP_I2C > > + help > > + DRM driver for Sitronix ST7571 panels controlled over I2C. > > + > > + if M is selected the module will be called st7571-i2c. >=20 > Is there a reason why it is called _i2c? There's another interface, I > assume? Yes exactly, the ST7571 has a SPI and 8bit parallel interface as well. All common parts has been written so that it could easily be put into a common file later on. It should pretty much just be to create a new driver with another regmap interface to support other interfaces then. I only have the I2C interface to test with for now, so I leave it to the future. [...] > > +static const struct drm_connector_helper_funcs st7571_connector_helper= _funcs =3D { > > + .get_modes =3D st7571_connector_get_modes, > > +}; > > + > > +static const uint32_t st7571_primary_plane_formats[] =3D { > > + DRM_FORMAT_C1, > > + DRM_FORMAT_C2, > > +}; >=20 > I assume that you only get fbcon output for now. Some ancient X11window > managers might also work. Today's GUIs usually need something like XRGB to > work. We do have DRM helpers to convert from XRGB to Cn, but they current= ly > don't support formats with multiple pixels per byte. It's on my TODO list > and you driver could add XRGB support at some point. Yes I do. Oh, sounds good. I will keep myself updated. [...] > > + ret =3D st7571_lcd_init(st7571); > > + if (ret) > > + return ret; > > + >=20 >=20 > > + ret =3D st7571_mode_config_init(st7571); > > + if (ret) { > > + dev_err(&client->dev, "Failed to initialize mode config\n"); > > + return ret; > > + } > > + > > + ret =3D st7571_plane_init(st7571); > > + if (ret) { > > + dev_err(dev->dev, "Failed to initialize primary plane\n"); > > + return ret; > > + } > > + > > + ret =3D st7571_crtc_init(st7571); > > + if (ret < 0) { > > + dev_err(dev->dev, "Failed to initialize CRTC\n"); > > + return ret; > > + } > > + > > + ret =3D st7571_encoder_init(st7571); > > + if (ret < 0) { > > + dev_err(dev->dev, "Failed to initialize encoder\n"); > > + return ret; > > + } > > + > > + ret =3D st7571_connector_init(st7571); > > + if (ret < 0) { > > + dev_err(dev->dev, "Failed to initialize connector\n"); > > + return ret; > > + } > > + > > + drm_mode_config_reset(dev); >=20 > No need for all these individual _init functions. For such simple drivers, > it might be easier to put all pipeline setup here. Or put everything > including (drm_mode_config_reset()) into st7571_mode_config_init(). Just = an > advise; your choice. Yeah I know. It's partly to make it easier for me separate things in my head since I'm new to this subsystem, and partly as I plan to move these functions to a common file later when I add support for the other interfaces. When I started to dig into the code of other drivers, clear lines as this would have helped me, so I think I would like to keep it as it is if it doesn't hurt too many eyes. [...] >=20 > > + > > + ret =3D drm_dev_register(dev, 0); > > + if (ret) { > > + dev_err(dev->dev, "Failed to register DRM device\n"); > > + return ret; > > + } > > + > > + drm_client_setup(dev, NULL); > > + return 0; > > +} > > + > > +static void st7571_remove(struct i2c_client *client) > > +{ > > + struct st7571_device *st7571 =3D i2c_get_clientdata(client); > > + > > + drm_dev_unplug(&st7571->dev); >=20 > > + drm_atomic_helper_shutdown(&st7571->dev); >=20 > This would disable the mode-setting pipeline. But as the device has been > unplugged already, it won't really do anything. You can leave it out. >=20 > Best regards > Thomas Best regards, Marcus Folkesson --j0p2bLMOkZcckCIM Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEBVGi6LZstU1kwSxliIBOb1ldUjIFAmfzmM4ACgkQiIBOb1ld UjIbHxAAvJQI4p/Up9M6BNDaJqi2s//V0VbRWeRBBZ4T6TTA5YsGUkD6xcBQDrQE 92WT4pAv1VvU0qRf338GzLEdBm9iSiWXqsrhT/swa2MPpOcbxZGDO4oIp/wOswqy PYhAQACqp42hvTCxnx2kS8fqVsN0UHsPEBxvx5alO1RfJUb1RcehQhM0oQSgXWoU y/mT8gxAKXkZ482Jm6MZqbk8dYBKOD5fodWdrdh3ZyuW3DPHD5b6wUzAFRKLCtO5 1SDwf1b1yfYaBZhHFjv4VfZlpXsxsO8TNvgsiiuDk2pw+RshRC5pFZScfVeQNIgj yAEBoAsMbEyEIXDOhlkciuv6BDy3uZ/UxfvAi+L/vCOI41S9mLIuxAZj7H2vrWHg DGNRH21Ik6u1bvHwoUmfNz0hbziPHJ5ANebfzLJrzKmN0Gm5tRvFkqK53L9ISykk V5ET0gYBLT74hzlFs/zwg/TCSW7GAj3JhSPKdRUznKs2MJpN5/h+RLR5ZJ7UqhOB 4D7ydZjSmhTdnGfzyk+lVupbTw8C02qzGDhchVW2dwq+X/xakqfG3/pAfsX6sAhN /9tM5eBrZ9pMUSZWbKbXa7lQyC2zShroCEDzYn85AZXlv9LH9W7Rzz8JaPmicIXE vhYPu5AJnsrW8mX85FpkzXrtV45FRkPph16F6+2vlwssGL+87j0= =HKTr -----END PGP SIGNATURE----- --j0p2bLMOkZcckCIM--