From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Date: Mon, 02 Sep 2019 09:11:30 +0000 Subject: Re: [PATCH v3] backlight: gpio-backlight: Correct initial power state handling Message-Id: <20190902091130.GG32232@dell> List-Id: References: <20190731084018.5318-1-peter.ujfalusi@ti.com> In-Reply-To: <20190731084018.5318-1-peter.ujfalusi@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: Peter Ujfalusi Cc: daniel.thompson@linaro.org, jingoohan1@gmail.com, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, paul.kocialkowski@bootlin.com On Wed, 31 Jul 2019, Peter Ujfalusi wrote: > The default-on property - or the def_value via legacy pdata) should be > handled as: > if it is 1, the backlight must be enabled (kept enabled) > if it is 0, the backlight must be disabled (kept disabled) > > This only works for the case when default-on is set. If it is not set then > the brightness of the backlight is set to 0. Now if the backlight is > enabled by external driver (graphics) the backlight will stay disabled since > the brightness is configured as 0. The backlight will not turn on. > > In order to minimize screen flickering during device boot: > > The initial brightness should be set to 1. > > If booted in non DT mode or no phandle link to the backlight node: > follow the def_value/default-on to select UNBLANK or POWERDOWN > > If in DT boot we have phandle link then leave the GPIO in a state which the > bootloader left it and let the user of the backlight to configure it > further. > > Signed-off-by: Peter Ujfalusi > --- > Hi, > > sorry for the delay, but got distracted a bit with the resend of this... > Let's try again ;) > > Changes since v2 (https://lore.kernel.org/patchwork/patch/1002359/): > - Rebased on drm-next > > Changes since v1: > - Implement similiar initial power state handling as pwm backlight have > > Regards, > Peter > > drivers/video/backlight/gpio_backlight.c | 24 ++++++++++++++++++++---- > 1 file changed, 20 insertions(+), 4 deletions(-) Applied, thanks. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v3] backlight: gpio-backlight: Correct initial power state handling Date: Mon, 2 Sep 2019 10:11:30 +0100 Message-ID: <20190902091130.GG32232@dell> References: <20190731084018.5318-1-peter.ujfalusi@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from mail-wm1-x342.google.com (mail-wm1-x342.google.com [IPv6:2a00:1450:4864:20::342]) by gabe.freedesktop.org (Postfix) with ESMTPS id 08C9789C14 for ; Mon, 2 Sep 2019 09:11:34 +0000 (UTC) Received: by mail-wm1-x342.google.com with SMTP id k2so12237855wmj.4 for ; Mon, 02 Sep 2019 02:11:33 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20190731084018.5318-1-peter.ujfalusi@ti.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Peter Ujfalusi Cc: daniel.thompson@linaro.org, jingoohan1@gmail.com, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, paul.kocialkowski@bootlin.com List-Id: dri-devel@lists.freedesktop.org T24gV2VkLCAzMSBKdWwgMjAxOSwgUGV0ZXIgVWpmYWx1c2kgd3JvdGU6Cgo+IFRoZSBkZWZhdWx0 LW9uIHByb3BlcnR5IC0gb3IgdGhlIGRlZl92YWx1ZSB2aWEgbGVnYWN5IHBkYXRhKSBzaG91bGQg YmUKPiBoYW5kbGVkIGFzOgo+IGlmIGl0IGlzIDEsIHRoZSBiYWNrbGlnaHQgbXVzdCBiZSBlbmFi bGVkIChrZXB0IGVuYWJsZWQpCj4gaWYgaXQgaXMgMCwgdGhlIGJhY2tsaWdodCBtdXN0IGJlIGRp c2FibGVkIChrZXB0IGRpc2FibGVkKQo+IAo+IFRoaXMgb25seSB3b3JrcyBmb3IgdGhlIGNhc2Ug d2hlbiBkZWZhdWx0LW9uIGlzIHNldC4gSWYgaXQgaXMgbm90IHNldCB0aGVuCj4gdGhlIGJyaWdo dG5lc3Mgb2YgdGhlIGJhY2tsaWdodCBpcyBzZXQgdG8gMC4gTm93IGlmIHRoZSBiYWNrbGlnaHQg aXMKPiBlbmFibGVkIGJ5IGV4dGVybmFsIGRyaXZlciAoZ3JhcGhpY3MpIHRoZSBiYWNrbGlnaHQg d2lsbCBzdGF5IGRpc2FibGVkIHNpbmNlCj4gdGhlIGJyaWdodG5lc3MgaXMgY29uZmlndXJlZCBh cyAwLiBUaGUgYmFja2xpZ2h0IHdpbGwgbm90IHR1cm4gb24uCj4gCj4gSW4gb3JkZXIgdG8gbWlu aW1pemUgc2NyZWVuIGZsaWNrZXJpbmcgZHVyaW5nIGRldmljZSBib290Ogo+IAo+IFRoZSBpbml0 aWFsIGJyaWdodG5lc3Mgc2hvdWxkIGJlIHNldCB0byAxLgo+IAo+IElmIGJvb3RlZCBpbiBub24g RFQgbW9kZSBvciBubyBwaGFuZGxlIGxpbmsgdG8gdGhlIGJhY2tsaWdodCBub2RlOgo+IGZvbGxv dyB0aGUgZGVmX3ZhbHVlL2RlZmF1bHQtb24gdG8gc2VsZWN0IFVOQkxBTksgb3IgUE9XRVJET1dO Cj4gCj4gSWYgaW4gRFQgYm9vdCB3ZSBoYXZlIHBoYW5kbGUgbGluayB0aGVuIGxlYXZlIHRoZSBH UElPIGluIGEgc3RhdGUgd2hpY2ggdGhlCj4gYm9vdGxvYWRlciBsZWZ0IGl0IGFuZCBsZXQgdGhl IHVzZXIgb2YgdGhlIGJhY2tsaWdodCB0byBjb25maWd1cmUgaXQKPiBmdXJ0aGVyLgo+IAo+IFNp Z25lZC1vZmYtYnk6IFBldGVyIFVqZmFsdXNpIDxwZXRlci51amZhbHVzaUB0aS5jb20+Cj4gLS0t Cj4gSGksCj4gCj4gc29ycnkgZm9yIHRoZSBkZWxheSwgYnV0IGdvdCBkaXN0cmFjdGVkIGEgYml0 IHdpdGggdGhlIHJlc2VuZCBvZiB0aGlzLi4uCj4gTGV0J3MgdHJ5IGFnYWluIDspCj4gCj4gQ2hh bmdlcyBzaW5jZSB2MiAoaHR0cHM6Ly9sb3JlLmtlcm5lbC5vcmcvcGF0Y2h3b3JrL3BhdGNoLzEw MDIzNTkvKToKPiAtIFJlYmFzZWQgb24gZHJtLW5leHQKPiAKPiBDaGFuZ2VzIHNpbmNlIHYxOgo+ IC0gSW1wbGVtZW50IHNpbWlsaWFyIGluaXRpYWwgcG93ZXIgc3RhdGUgaGFuZGxpbmcgYXMgcHdt IGJhY2tsaWdodCBoYXZlCj4gCj4gUmVnYXJkcywKPiBQZXRlcgo+IAo+ICBkcml2ZXJzL3ZpZGVv L2JhY2tsaWdodC9ncGlvX2JhY2tsaWdodC5jIHwgMjQgKysrKysrKysrKysrKysrKysrKystLS0t Cj4gIDEgZmlsZSBjaGFuZ2VkLCAyMCBpbnNlcnRpb25zKCspLCA0IGRlbGV0aW9ucygtKQoKQXBw bGllZCwgdGhhbmtzLgoKLS0gCkxlZSBKb25lcyBb5p2O55C85pavXQpMaW5hcm8gU2VydmljZXMg VGVjaG5pY2FsIExlYWQKTGluYXJvLm9yZyDilIIgT3BlbiBzb3VyY2Ugc29mdHdhcmUgZm9yIEFS TSBTb0NzCkZvbGxvdyBMaW5hcm86IEZhY2Vib29rIHwgVHdpdHRlciB8IEJsb2cKX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVsIG1haWxpbmcg bGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlzdHMuZnJlZWRl c2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20DC2C3A59B for ; 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Mon, 02 Sep 2019 02:11:32 -0700 (PDT) Received: from dell ([95.147.198.93]) by smtp.gmail.com with ESMTPSA id s15sm6398842wmh.12.2019.09.02.02.11.31 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 02 Sep 2019 02:11:32 -0700 (PDT) Date: Mon, 2 Sep 2019 10:11:30 +0100 From: Lee Jones To: Peter Ujfalusi Cc: jingoohan1@gmail.com, daniel.thompson@linaro.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, paul.kocialkowski@bootlin.com Subject: Re: [PATCH v3] backlight: gpio-backlight: Correct initial power state handling Message-ID: <20190902091130.GG32232@dell> References: <20190731084018.5318-1-peter.ujfalusi@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190731084018.5318-1-peter.ujfalusi@ti.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 31 Jul 2019, Peter Ujfalusi wrote: > The default-on property - or the def_value via legacy pdata) should be > handled as: > if it is 1, the backlight must be enabled (kept enabled) > if it is 0, the backlight must be disabled (kept disabled) > > This only works for the case when default-on is set. If it is not set then > the brightness of the backlight is set to 0. Now if the backlight is > enabled by external driver (graphics) the backlight will stay disabled since > the brightness is configured as 0. The backlight will not turn on. > > In order to minimize screen flickering during device boot: > > The initial brightness should be set to 1. > > If booted in non DT mode or no phandle link to the backlight node: > follow the def_value/default-on to select UNBLANK or POWERDOWN > > If in DT boot we have phandle link then leave the GPIO in a state which the > bootloader left it and let the user of the backlight to configure it > further. > > Signed-off-by: Peter Ujfalusi > --- > Hi, > > sorry for the delay, but got distracted a bit with the resend of this... > Let's try again ;) > > Changes since v2 (https://lore.kernel.org/patchwork/patch/1002359/): > - Rebased on drm-next > > Changes since v1: > - Implement similiar initial power state handling as pwm backlight have > > Regards, > Peter > > drivers/video/backlight/gpio_backlight.c | 24 ++++++++++++++++++++---- > 1 file changed, 20 insertions(+), 4 deletions(-) Applied, thanks. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog