From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [RFC PATCH 0/7] add at91sam9 LCDC DRM driver Date: Fri, 24 Aug 2018 10:22:33 +0200 Message-ID: <20180824102233.73852596@bbrezillon> References: <20180812184152.GA22343@ravnborg.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <20180812184152.GA22343@ravnborg.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Sam Ravnborg Cc: Mark Rutland , devicetree@vger.kernel.org, Alexandre Belloni , linux-pwm@vger.kernel.org, Nicolas Ferre , dri-devel@lists.freedesktop.org, Rob Herring , Lee Jones , linux-arm-kernel@lists.infradead.org List-Id: linux-pwm@vger.kernel.org SGkgU2FtLAoKT24gU3VuLCAxMiBBdWcgMjAxOCAyMDo0MTo1MiArMDIwMApTYW0gUmF2bmJvcmcg PHNhbUByYXZuYm9yZy5vcmc+IHdyb3RlOgoKPiBOZXcgRFJNIGJhc2VkIGRyaXZlciBmb3IgYXQ5 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Hi Sam, On Sun, 12 Aug 2018 20:41:52 +0200 Sam Ravnborg wrote: > New DRM based driver for at91sam9 SOC's that uses the > Atmel LCDC IP core. First of all, thanks for this contribution. > > This is first version of a patch set that adds > drivers for the Atmel LCDC IP core. > Posted for review as the basics works now. > > The LCDC IP core contains two devices: > - a PWM often used for backlight > - a LCD display controller > > Both devices are supported today by the atmel_lcdfb driver. > For this new set of drivers the compatible strings was > selected to avoid clash with the existing compatible > strings used for the atmel_lcdfb driver to allow them > to co-exist. Hm, I think Rob commented on that already, but we usually try to stay compatible with the exisiting/old bindings when introducing a new one. Don't know how feasible this is in this particular case though. > > This patchset implements three drivers. > - A MFD driver that include the generic parts. > - A PWM driver. > - A DRM display controller driver. > This is the same split as used for the Atmel hlcdc IP. > > The hlcdc and lcdc has only a few things in common and > trying to share the code for them was not a viable solution. > > The DRM implementation has a few shortcomings compared to the > existing fbdev based driver: > - STN displays are not supported > Binding support is missing but most of the > STN specific functionality is otherwise ported > from the fbdev driver. > I assume the info should come from the panel > but as I lack HW I have not looked too much > into what is required. > - gamma support is missing > The driver utilises drm_simple_kms_helper and > this helper lacks support for setting up gamma. > If this is useful please let me know and I > will extend drm_simple_kms_helper to support this > and update the driver. I guess you can skip that for now. > - modesetting is not checked (see TODO in file) > Is this required for such a simple setup? Well, that's always better if you can check that the requested display mode is supported before trying to apply it. > - support for extra modes as applicable (and lcd-wiring-mode) Peter already suggested something I think. > - support for AVR32 (is it relevant?) It is, AVR32 is no longer supported in mainline. > > The first patch renames .../drm/atmel-hlcdc to .../drm/atmel > to have a nice home for both drivers. Sounds good. Regards, Boris