From patchwork Wed Apr 26 09:32:29 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fei Shao X-Patchwork-Id: 13224319 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A0E2BC77B78 for ; Wed, 26 Apr 2023 09:33:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:To:From:Reply-To:Content-Type:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; 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Wed, 26 Apr 2023 02:33:37 -0700 (PDT) Received: from fshao-glinux.tpe.corp.google.com ([2401:fa00:1:10:dcf6:797f:140d:6d]) by smtp.gmail.com with ESMTPSA id g1-20020a056a00078100b005810c4286d6sm10730075pfu.0.2023.04.26.02.33.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Apr 2023 02:33:37 -0700 (PDT) From: Fei Shao To: Jeff LaBundy , Douglas Anderson , Benjamin Tissoires , Rob Herring Subject: [PATCH v2 1/2] dt-bindings: input: goodix: Add "goodix,no-reset-during-suspend" property Date: Wed, 26 Apr 2023 17:32:29 +0800 Message-ID: <20230426093231.1466984-2-fshao@chromium.org> X-Mailer: git-send-email 2.40.1.495.gc816e09b53d-goog In-Reply-To: <20230426093231.1466984-1-fshao@chromium.org> References: <20230426093231.1466984-1-fshao@chromium.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230426_023338_973189_AEB89DF5 X-CRM114-Status: GOOD ( 12.77 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Dmitry Torokhov , linux-kernel@vger.kernel.org, linux-mediatek , Krzysztof Kozlowski , linux-input@vger.kernel.org, Matthias Brugger Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org We observed that on Chromebook device Steelix, if Goodix GT7375P touchscreen is powered in suspend (because, for example, it connects to an always-on regulator) and with the reset GPIO asserted, it will introduce about 14mW power leakage. To address that, we add this property to skip reset during suspend. If it's set, the driver will stop asserting the reset GPIO during power-down. Refer to the comments in the driver for details. Signed-off-by: Fei Shao Reviewed-by: Douglas Anderson Reviewed-by: Matthias Brugger --- Changes in v2: - Use a more accurate property name and with "goodix," prefix. .../devicetree/bindings/input/goodix,gt7375p.yaml | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml b/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml index ce18d7dadae2..1edad1da1196 100644 --- a/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml +++ b/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml @@ -43,6 +43,15 @@ properties: itself as long as it allows the main board to make signals compatible with what the touchscreen is expecting for its IO rails. + goodix,no-reset-during-suspend: + description: + Set this to true to enforce the driver to not assert the reset GPIO + during suspend. + Due to potential touchscreen hardware flaw, back-powering could happen in + suspend if the power supply is on and with active-low reset GPIO asserted. + This property is used to avoid the back-powering issue. + type: boolean + required: - compatible - reg From patchwork Wed Apr 26 09:32:30 2023 Content-Type: text/plain; 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Wed, 26 Apr 2023 02:33:40 -0700 (PDT) Received: from fshao-glinux.tpe.corp.google.com ([2401:fa00:1:10:dcf6:797f:140d:6d]) by smtp.gmail.com with ESMTPSA id g1-20020a056a00078100b005810c4286d6sm10730075pfu.0.2023.04.26.02.33.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Apr 2023 02:33:40 -0700 (PDT) From: Fei Shao To: Jeff LaBundy , Douglas Anderson , Benjamin Tissoires , Rob Herring Subject: [PATCH v2 2/2] HID: i2c-hid: goodix: Add support for "goodix,no-reset-during-suspend" property Date: Wed, 26 Apr 2023 17:32:30 +0800 Message-ID: <20230426093231.1466984-3-fshao@chromium.org> X-Mailer: git-send-email 2.40.1.495.gc816e09b53d-goog In-Reply-To: <20230426093231.1466984-1-fshao@chromium.org> References: <20230426093231.1466984-1-fshao@chromium.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230426_023342_084037_8235F1F2 X-CRM114-Status: GOOD ( 23.54 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Dmitry Torokhov , Stephen Kitt , Jiri Kosina , linux-kernel@vger.kernel.org, Matthias Kaehlcke , linux-mediatek , linux-input@vger.kernel.org Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org In the beginning, commit 18eeef46d359 ("HID: i2c-hid: goodix: Tie the reset line to true state of the regulator") introduced a change to tie the reset line of the Goodix touchscreen to the state of the regulator to fix a power leakage issue in suspend. After some time, the change was deemed unnecessary and was reverted in commit 557e05fa9fdd ("HID: i2c-hid: goodix: Stop tying the reset line to the regulator") due to difficulties in managing regulator notifiers for designs like Evoker, which provides a second power rail to touchscreen. However, the revert caused a power regression on another Chromebook device Steelix in the field, which has a dedicated always-on regulator for touchscreen and was covered by the workaround in the first commit. To address both cases, this patch adds the support for the new "goodix,no-reset-during-suspend" property in the driver: - When set to true, the driver does not assert the reset GPIO during power-down. Instead, the GPIO will be asserted during power-up to ensure the touchscreen always has a clean start and consistent behavior after resuming. This is for designs with a dedicated always-on regulator. - When set to false or unset, the driver uses the original control flow and asserts GPIO and disable regulators normally. This is for the two-regulator and shared-regulator designs. Signed-off-by: Fei Shao Reviewed-by: Douglas Anderson --- Changes in v2: - Do not change the regulator_enable logic during power-up. drivers/hid/i2c-hid/i2c-hid-of-goodix.c | 26 +++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c index 0060e3dcd775..fc4532fcadcc 100644 --- a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c +++ b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c @@ -28,6 +28,7 @@ struct i2c_hid_of_goodix { struct regulator *vdd; struct regulator *vddio; struct gpio_desc *reset_gpio; + bool no_reset_during_suspend; const struct goodix_i2c_hid_timing_data *timings; }; @@ -37,6 +38,20 @@ static int goodix_i2c_hid_power_up(struct i2chid_ops *ops) container_of(ops, struct i2c_hid_of_goodix, ops); int ret; + if (ihid_goodix->no_reset_during_suspend) { + /* + * This is not mandatory, but we assert reset here (instead of + * during power-down) to ensure the device will have a clean + * state after powering up, just like the normal scenarios will + * have. + * + * Note that in this case we assume the regulators should be + * (marked as) always-on, so the regulator core knows what to + * do with them in the following regulator_enable() calls + * despite regulator_disable() was not called previously. + */ + gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1); + } ret = regulator_enable(ihid_goodix->vdd); if (ret) return ret; @@ -60,6 +75,14 @@ static void goodix_i2c_hid_power_down(struct i2chid_ops *ops) struct i2c_hid_of_goodix *ihid_goodix = container_of(ops, struct i2c_hid_of_goodix, ops); + /* + * Don't assert reset GPIO if it's set. + * Also, it's okay to skip the following regulator_disable() calls + * because the regulators should be always-on in this case. + */ + if (ihid_goodix->no_reset_during_suspend) + return; + gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1); regulator_disable(ihid_goodix->vddio); regulator_disable(ihid_goodix->vdd); @@ -91,6 +114,9 @@ static int i2c_hid_of_goodix_probe(struct i2c_client *client) if (IS_ERR(ihid_goodix->vddio)) return PTR_ERR(ihid_goodix->vddio); + ihid_goodix->no_reset_during_suspend = + of_property_read_bool(client->dev.of_node, "goodix,no-reset-during-suspend"); + ihid_goodix->timings = device_get_match_data(&client->dev); return i2c_hid_core_probe(client, &ihid_goodix->ops, 0x0001, 0);