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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7E4A2C433F5 for ; Mon, 31 Jan 2022 00:03:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244077AbiAaADo (ORCPT ); Sun, 30 Jan 2022 19:03:44 -0500 Received: from gloria.sntech.de ([185.11.138.130]:55888 "EHLO gloria.sntech.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235023AbiAaADn (ORCPT ); Sun, 30 Jan 2022 19:03:43 -0500 Received: from ip5b412258.dynamic.kabel-deutschland.de ([91.65.34.88] helo=diego.localnet) by gloria.sntech.de with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nEKAS-0003bh-DW; Mon, 31 Jan 2022 01:03:36 +0100 From: Heiko =?ISO-8859-1?Q?St=FCbner?= To: Jagan Teki , Thierry Reding , Sam Ravnborg , David Airlie , Daniel Vetter , Peter Geis Cc: Peter Geis , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] drm/panel: feiyang-fy07024di26a30d: make reset gpio optional Date: Mon, 31 Jan 2022 01:03:35 +0100 Message-ID: <4380260.tF47cCTlra@diego> In-Reply-To: <20220107051335.3812535-3-pgwipeout@gmail.com> References: <20220107051335.3812535-1-pgwipeout@gmail.com> <20220107051335.3812535-3-pgwipeout@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter, Am Freitag, 7. Januar 2022, 06:13:33 CET schrieb Peter Geis: > Some implementations do not use the reset signal, instead tying it to dvdd. > Make the reset gpio optional to permit this. > > Signed-off-by: Peter Geis > --- > drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c b/drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c > index 581661b506f8..1c88d752b14e 100644 > --- a/drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c > +++ b/drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c > @@ -65,7 +65,8 @@ static int feiyang_prepare(struct drm_panel *panel) > /* T3 (dvdd rise + avdd start + avdd rise) T3 >= 20ms */ > msleep(20); > > - gpiod_set_value(ctx->reset, 0); > + if (ctx->reset) > + gpiod_set_value(ctx->reset, 0); gpio_set_value does VALIDATE_DESC_VOID(desc); which checks for "desc" (ctx->reset in this case) to be valid and especially not null and simply returns when this is the case. So from what I see, we don't need all the added conditionals here and below and would just need the switch to devm_gpiod_get_optional alone. Heiko > > /* > * T5 + T6 (avdd rise + video & logic signal rise) > @@ -73,7 +74,8 @@ static int feiyang_prepare(struct drm_panel *panel) > */ > msleep(20); > > - gpiod_set_value(ctx->reset, 1); > + if (ctx->reset) > + gpiod_set_value(ctx->reset, 1); > > /* T12 (video & logic signal rise + backlight rise) T12 >= 200ms */ > msleep(200); > @@ -126,7 +128,8 @@ static int feiyang_unprepare(struct drm_panel *panel) > /* T13 (backlight fall + video & logic signal fall) T13 >= 200ms */ > msleep(200); > > - gpiod_set_value(ctx->reset, 0); > + if (ctx->reset) > + gpiod_set_value(ctx->reset, 0); > > regulator_disable(ctx->avdd); > > @@ -211,7 +214,7 @@ static int feiyang_dsi_probe(struct mipi_dsi_device *dsi) > return PTR_ERR(ctx->avdd); > } > > - ctx->reset = devm_gpiod_get(&dsi->dev, "reset", GPIOD_OUT_LOW); > + ctx->reset = devm_gpiod_get_optional(&dsi->dev, "reset", GPIOD_OUT_LOW); > if (IS_ERR(ctx->reset)) { > dev_err(&dsi->dev, "Couldn't get our reset GPIO\n"); > return PTR_ERR(ctx->reset); >