From patchwork Mon May 3 21:58:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 430915 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 EA8D7C433ED for ; Mon, 3 May 2021 21:59:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD18D613BB for ; Mon, 3 May 2021 21:59:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229721AbhECWAM (ORCPT ); Mon, 3 May 2021 18:00:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38112 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229781AbhECWAM (ORCPT ); Mon, 3 May 2021 18:00:12 -0400 Received: from mail-pf1-x431.google.com (mail-pf1-x431.google.com [IPv6:2607:f8b0:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5505AC06174A for ; Mon, 3 May 2021 14:59:18 -0700 (PDT) Received: by mail-pf1-x431.google.com with SMTP id i13so5394034pfu.2 for ; Mon, 03 May 2021 14:59:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=C70V1ep2OC0kZd3ksfbxSiRkqnQcxIJ5Zt5dguO6jEA=; b=ddABHDYPpcDSWspsVe5JjaRfWW2WGzybj41mDN4dyyhwjLnvgl8JpgEMRrm0zl8014 sghhgQqUZi2bnSITlK49Sqef/89J5Z0uzWa29w7OYowYEtVZghumEDiQhCbYWYhRuDeL 8Ga3xvrQTHc+QoTZKO6w2zXurJ7km4LRNn3M8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=C70V1ep2OC0kZd3ksfbxSiRkqnQcxIJ5Zt5dguO6jEA=; b=T4kytsMUKvLe9TvbmRU22RCAArB9Ve+jrHkFSu1MVrW603Eo/pEuOh7l+8xr58E7z5 sy6AOlmAqm0EqAYH4MNupwSXbZrQVBFY++v4BDmPDhKjlAET280IfK6BBephXdRVwg8J 7KI0tAS9Vz6dNLx70Z84V8K4zsWzdYyc4iq+JtCsBR2vBPm/NG8CZfI0TK70fez4aCOx lj8WTwYbi4FKAavBK7rVNnbyFGXUc5xgx5MizJjEDU5XUFzA18+cBHQLYk7dzD/YaTzu RDK7Vu8yX1iK0EdTFpazmw10o72Qe1Eqa04PJv9xhfoJMiguB07D2jaZUPODXpNmea31 TVpg== X-Gm-Message-State: AOAM530zGhan5SXwPtDnKAH56E0dBjNfyOELb2gElsfwSqbq7itAWC32 ciw9UUWdY2hWK6UmCD9RfRZiFw== X-Google-Smtp-Source: ABdhPJxCffXNMJSO10RrlyG4KuAU0sSx6Cz3Lg0v+K+XZhSsqwIjdP9TiZSAgQzu7azyCwAucvUELg== X-Received: by 2002:a17:90b:3684:: with SMTP id mj4mr958049pjb.50.1620079157449; Mon, 03 May 2021 14:59:17 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:201:a592:ac50:b17b:5c43]) by smtp.gmail.com with ESMTPSA id w1sm639186pgp.31.2021.05.03.14.59.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 May 2021 14:59:16 -0700 (PDT) From: Douglas Anderson To: Andrzej Hajda , Neil Armstrong , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Sam Ravnborg , Wolfram Sang Cc: Lyude Paul , Steev Klimaszewski , Stephen Boyd , Bjorn Andersson , linux-arm-msm@vger.kernel.org, Stanislav Lisovskiy , Linus W , robdclark@chromium.org, Maarten Lankhorst , Thierry Reding , linux-i2c@vger.kernel.org, dri-devel@lists.freedesktop.org, Douglas Anderson , linux-kernel@vger.kernel.org Subject: [PATCH v6 1/5] i2c: i2c-core-of: Fix corner case of finding adapter by node Date: Mon, 3 May 2021 14:58:40 -0700 Message-Id: <20210503145750.v6.1.Ib7e3a4af2f3e2cb3bd8e4adbac3bcfc966f27791@changeid> X-Mailer: git-send-email 2.31.1.527.g47e6f16901-goog In-Reply-To: <20210503215844.2996320-1-dianders@chromium.org> References: <20210503215844.2996320-1-dianders@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org The of_find_i2c_adapter_by_node() could end up failing to find an adapter in certain conditions. Specifically it's possible that of_dev_or_parent_node_match() could end up finding an I2C client in the list and cause bus_find_device() to stop early even though an I2C adapter was present later in the list. Let's move the i2c_verify_adapter() into the predicate function to prevent this. Now we'll properly skip over the I2C client and be able to find the I2C adapter. This issue has always been a potential problem if a single device tree node could represent both an I2C client and an adapter. I believe this is a sane thing to do if, for instance, an I2C-connected DP bridge chip is present. The bridge chip is an I2C client but it can also provide an I2C adapter (DDC tunneled over AUX channel). We don't want to have to create a sub-node just so a panel can link to it with the "ddc-i2c-bus" property. I believe that this problem got worse, however, with commit e814e688413a ("i2c: of: Try to find an I2C adapter matching the parent"). Starting at that commit it would be even easier to accidentally miss finding the adapter. Signed-off-by: Douglas Anderson Reviewed-by: Bjorn Andersson --- Later patches in this series won't work right without this one, but they won't crash. If we can't find the i2c bus we'll just fall back to the hardcoded panel modes which, at least today, all panels have. I'll also note that part of me wonders if we should actually fix this further to run two passes through everything: first look to see if we find an exact match and only look at the parent pointer if there is no match. I don't currently have a need for that and it's a slightly bigger change, but it seems conceivable that it could affect someone? (no changes since v1) drivers/i2c/i2c-core-of.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/i2c/i2c-core-of.c b/drivers/i2c/i2c-core-of.c index 3ed74aa4b44b..de0bf5fce3a2 100644 --- a/drivers/i2c/i2c-core-of.c +++ b/drivers/i2c/i2c-core-of.c @@ -124,6 +124,14 @@ static int of_dev_or_parent_node_match(struct device *dev, const void *data) return 0; } +static int of_i2c_adapter_match(struct device *dev, const void *data) +{ + if (!of_dev_or_parent_node_match(dev, data)) + return 0; + + return !!i2c_verify_adapter(dev); +} + /* must call put_device() when done with returned i2c_client device */ struct i2c_client *of_find_i2c_device_by_node(struct device_node *node) { @@ -146,18 +154,13 @@ EXPORT_SYMBOL(of_find_i2c_device_by_node); struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node) { struct device *dev; - struct i2c_adapter *adapter; dev = bus_find_device(&i2c_bus_type, NULL, node, - of_dev_or_parent_node_match); + of_i2c_adapter_match); if (!dev) return NULL; - adapter = i2c_verify_adapter(dev); - if (!adapter) - put_device(dev); - - return adapter; + return to_i2c_adapter(dev); } EXPORT_SYMBOL(of_find_i2c_adapter_by_node); From patchwork Mon May 3 21:58:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 430914 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 10CD0C433ED for ; Mon, 3 May 2021 21:59:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3825611EE for ; 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Mon, 03 May 2021 14:59:19 -0700 (PDT) From: Douglas Anderson To: Andrzej Hajda , Neil Armstrong , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Sam Ravnborg , Wolfram Sang Cc: Lyude Paul , Steev Klimaszewski , Stephen Boyd , Bjorn Andersson , linux-arm-msm@vger.kernel.org, Stanislav Lisovskiy , Linus W , robdclark@chromium.org, Maarten Lankhorst , Thierry Reding , linux-i2c@vger.kernel.org, dri-devel@lists.freedesktop.org, Douglas Anderson , Daniel Vetter , David Airlie , Maxime Ripard , Thomas Zimmermann , linux-kernel@vger.kernel.org Subject: [PATCH v6 2/5] drm/dp: Allow an early call to register DDC i2c bus Date: Mon, 3 May 2021 14:58:41 -0700 Message-Id: <20210503145750.v6.2.Iff8f2957d86af40f2bfcfb5a7163928481fccea4@changeid> X-Mailer: git-send-email 2.31.1.527.g47e6f16901-goog In-Reply-To: <20210503215844.2996320-1-dianders@chromium.org> References: <20210503215844.2996320-1-dianders@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org It can be helpful to fully register the AUX channel as an i2c bus even before the bridge is created. Let's optionally allow bridges to do that. Specifically the case we're running into: - The panel driver wants to get its DDC bus at probe time. - The ti-sn65dsi86 MIPI-to-eDP bridge code, which provides the DDC bus, wants to get the panel at probe time. The next patches ("drm/bridge: ti-sn65dsi86: Promote the AUX channel to its own sub-dev") solves the chicken-and-egg problem by breaking the ti-sn65dsi86 driver into sub-devices, but in order for it to actually work we need the i2c bus to get registered at probe time and not in bridge attach time. Cc: Lyude Paul Cc: Thierry Reding Signed-off-by: Douglas Anderson --- Changes in v6: - ("drm/dp: Allow an early call to register DDC i2c bus") new for v6. drivers/gpu/drm/drm_dp_helper.c | 67 +++++++++++++++++++++++++++------ include/drm/drm_dp_helper.h | 2 + 2 files changed, 57 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index cb56d74e9d38..830294f0b341 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -1757,6 +1757,49 @@ void drm_dp_aux_init(struct drm_dp_aux *aux) } EXPORT_SYMBOL(drm_dp_aux_init); +/** + * drm_dp_aux_register_ddc() - register the DDC parts of the aux channel + * @aux: DisplayPort AUX channel + * + * This can be called after drm_dp_aux_init() to fully register the ddc bus + * as an i2c adapter with the rest of Linux. + * + * If you don't explicitly call this function it will be done implicitly as + * part of drm_dp_aux_register(). + * + * Returns 0 on success or a negative error code on failure. + */ +int drm_dp_aux_register_ddc(struct drm_dp_aux *aux) +{ + WARN_ON_ONCE(!aux->dev); + + aux->ddc.class = I2C_CLASS_DDC; + aux->ddc.owner = THIS_MODULE; + aux->ddc.dev.parent = aux->dev; + + strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev), + sizeof(aux->ddc.name)); + + return i2c_add_adapter(&aux->ddc); +} +EXPORT_SYMBOL(drm_dp_aux_register_ddc); + +/** + * drm_dp_aux_unregister_ddc() - unregister the DDC parts of the aux channel + * + * This is useful if you called drm_dp_aux_register_ddc(). If you let + * drm_dp_aux_register() implicitly register the DDC for you then you don't + * need to worry about calling this yourself. + * + * @aux: DisplayPort AUX channel + */ +void drm_dp_aux_unregister_ddc(struct drm_dp_aux *aux) +{ + i2c_del_adapter(&aux->ddc); + aux->ddc.dev.parent = NULL; +} +EXPORT_SYMBOL(drm_dp_aux_unregister_ddc); + /** * drm_dp_aux_register() - initialise and register aux channel * @aux: DisplayPort AUX channel @@ -1793,20 +1836,19 @@ int drm_dp_aux_register(struct drm_dp_aux *aux) if (!aux->ddc.algo) drm_dp_aux_init(aux); - aux->ddc.class = I2C_CLASS_DDC; - aux->ddc.owner = THIS_MODULE; - aux->ddc.dev.parent = aux->dev; - - strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev), - sizeof(aux->ddc.name)); + /* + * Implicitly register if drm_dp_aux_register_ddc() wasn't already + * called (as evidenced by a NULL parent pointer). + */ + if (!aux->ddc.dev.parent) { + ret = drm_dp_aux_register_ddc(aux); + if (ret) + return ret; + } ret = drm_dp_aux_register_devnode(aux); - if (ret) - return ret; - - ret = i2c_add_adapter(&aux->ddc); if (ret) { - drm_dp_aux_unregister_devnode(aux); + drm_dp_aux_unregister_ddc(aux); return ret; } @@ -1821,7 +1863,8 @@ EXPORT_SYMBOL(drm_dp_aux_register); void drm_dp_aux_unregister(struct drm_dp_aux *aux) { drm_dp_aux_unregister_devnode(aux); - i2c_del_adapter(&aux->ddc); + if (aux->ddc.dev.parent) + drm_dp_aux_unregister_ddc(aux); } EXPORT_SYMBOL(drm_dp_aux_unregister); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index e932b2c40095..d4d2d5e25bb7 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -2021,6 +2021,8 @@ bool drm_dp_lttpr_pre_emphasis_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_ void drm_dp_remote_aux_init(struct drm_dp_aux *aux); void drm_dp_aux_init(struct drm_dp_aux *aux); +int drm_dp_aux_register_ddc(struct drm_dp_aux *aux); +void drm_dp_aux_unregister_ddc(struct drm_dp_aux *aux); int drm_dp_aux_register(struct drm_dp_aux *aux); void drm_dp_aux_unregister(struct drm_dp_aux *aux); From patchwork Mon May 3 21:58:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 430641 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 0C47EC43603 for ; Mon, 3 May 2021 21:59:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D859F611EE for ; Mon, 3 May 2021 21:59:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229867AbhECWAS (ORCPT ); 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Mon, 03 May 2021 14:59:20 -0700 (PDT) From: Douglas Anderson To: Andrzej Hajda , Neil Armstrong , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Sam Ravnborg , Wolfram Sang Cc: Lyude Paul , Steev Klimaszewski , Stephen Boyd , Bjorn Andersson , linux-arm-msm@vger.kernel.org, Stanislav Lisovskiy , Linus W , robdclark@chromium.org, Maarten Lankhorst , Thierry Reding , linux-i2c@vger.kernel.org, dri-devel@lists.freedesktop.org, Douglas Anderson , Daniel Vetter , David Airlie , Robert Foss , linux-kernel@vger.kernel.org Subject: [PATCH v6 3/5] drm/bridge: ti-sn65dsi86: Promote the AUX channel to its own sub-dev Date: Mon, 3 May 2021 14:58:42 -0700 Message-Id: <20210503145750.v6.3.If89144992cb9d900f8c91a8d1817dbe00f543720@changeid> X-Mailer: git-send-email 2.31.1.527.g47e6f16901-goog In-Reply-To: <20210503215844.2996320-1-dianders@chromium.org> References: <20210503215844.2996320-1-dianders@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org We'd like to be able to expose the DDC-over-AUX channel bus to our panel. This gets into a chicken-and-egg problem because: - The panel wants to get its DDC bus at probe time. - The ti-sn65dsi86 MIPI-to-eDP bridge code, which provides the DDC bus, wants to get the panel at probe time. By using a sub device we can fully create the AUX channel bits so that the panel can get them. Then the panel can finish probing and the bridge can probe. To accomplish this, we use the new functions introduced in ("drm/dp: Allow an early call to register DDC i2c bus") to register the i2c bus early. NOTE: there's a little bit of a trick here. Though the AUX channel can run without the MIPI-to-eDP bits of the code, the MIPI-to-eDP bits can't run without the AUX channel. We could come up a complicated signaling scheme (have the MIPI-to-eDP bits return EPROBE_DEFER for a while or wait on some sort of completion), but it seems simple enough to just not even bother creating the bridge device until the AUX channel probes. That's what we'll do. Signed-off-by: Douglas Anderson --- Commit 6cba3fe43341 ("drm/dp: Add backpointer to drm_device in drm_dp_aux") made it very explicit that it's not OK to fully register the aux device until we have the bridge, but hopefully just getting the i2c bits early is OK? Changes in v6: - Use new drm_dp_aux_register_ddc() calls. drivers/gpu/drm/bridge/ti-sn65dsi86.c | 77 +++++++++++++++++++++++---- 1 file changed, 66 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index db027528febd..594aac57bdbc 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -116,6 +116,7 @@ * struct ti_sn65dsi86 - Platform data for ti-sn65dsi86 driver. * @bridge_aux: AUX-bus sub device for MIPI-to-eDP bridge functionality. * @gpio_aux: AUX-bus sub device for GPIO controller functionality. + * @aux_aux: AUX-bus sub device for eDP AUX channel functionality. * * @dev: Pointer to the top level (i2c) device. * @regmap: Regmap for accessing i2c. @@ -148,6 +149,7 @@ struct ti_sn65dsi86 { struct auxiliary_device bridge_aux; struct auxiliary_device gpio_aux; + struct auxiliary_device aux_aux; struct device *dev; struct regmap *regmap; @@ -1331,11 +1333,6 @@ static int ti_sn_bridge_probe(struct auxiliary_device *adev, if (ret) return ret; - pdata->aux.name = "ti-sn65dsi86-aux"; - pdata->aux.dev = pdata->dev; - pdata->aux.transfer = ti_sn_aux_transfer; - drm_dp_aux_init(&pdata->aux); - pdata->bridge.funcs = &ti_sn_bridge_funcs; pdata->bridge.of_node = np; @@ -1430,6 +1427,50 @@ static int ti_sn65dsi86_add_aux_device(struct ti_sn65dsi86 *pdata, return ret; } +static void ti_sn65dsi86_unregister_dp_aux_ddc(void *data) +{ + drm_dp_aux_unregister_ddc(data); +} + +static int ti_sn_aux_probe(struct auxiliary_device *adev, + const struct auxiliary_device_id *id) +{ + struct ti_sn65dsi86 *pdata = dev_get_drvdata(adev->dev.parent); + int ret; + + pdata->aux.name = "ti-sn65dsi86-aux"; + pdata->aux.dev = pdata->dev; + pdata->aux.transfer = ti_sn_aux_transfer; + drm_dp_aux_init(&pdata->aux); + + ret = drm_dp_aux_register_ddc(&pdata->aux); + if (ret < 0) { + drm_err(pdata, "Failed to register AUX DDC channel: %d\n", ret); + return ret; + } + ret = devm_add_action_or_reset(&adev->dev, + ti_sn65dsi86_unregister_dp_aux_ddc, &pdata->aux); + if (ret) + return ret; + + /* + * The eDP to MIPI bridge parts don't work until the AUX channel is + * setup so we don't add it in the main driver probe, we add it now. + */ + return ti_sn65dsi86_add_aux_device(pdata, &pdata->bridge_aux, "bridge"); +} + +static const struct auxiliary_device_id ti_sn_aux_id_table[] = { + { .name = "ti_sn65dsi86.aux", }, + {}, +}; + +static struct auxiliary_driver ti_sn_aux_driver = { + .name = "aux", + .probe = ti_sn_aux_probe, + .id_table = ti_sn_aux_id_table, +}; + static int ti_sn65dsi86_probe(struct i2c_client *client, const struct i2c_device_id *id) { @@ -1488,10 +1529,11 @@ static int ti_sn65dsi86_probe(struct i2c_client *client, * motiviation here is to solve the chicken-and-egg problem of probe * ordering. The bridge wants the panel to be there when it probes. * The panel wants its HPD GPIO (provided by sn65dsi86 on some boards) - * when it probes. There will soon be other devices (DDC I2C bus, PWM) - * that have the same problem. Having sub-devices allows the some sub - * devices to finish probing even if others return -EPROBE_DEFER and - * gets us around the problems. + * when it probes. The panel and maybe backlight might want the DDC + * bus. Soon the PWM provided by the bridge chip will have the same + * problem. Having sub-devices allows the some sub devices to finish + * probing even if others return -EPROBE_DEFER and gets us around the + * problems. */ if (IS_ENABLED(CONFIG_OF_GPIO)) { @@ -1500,7 +1542,13 @@ static int ti_sn65dsi86_probe(struct i2c_client *client, return ret; } - return ti_sn65dsi86_add_aux_device(pdata, &pdata->bridge_aux, "bridge"); + /* + * NOTE: At the end of the AUX channel probe we'll add the aux device + * for the bridge. This is because the bridge can't be used until the + * AUX channel is there and this is a very simple solution to the + * dependency problem. + */ + return ti_sn65dsi86_add_aux_device(pdata, &pdata->aux_aux, "aux"); } static struct i2c_device_id ti_sn65dsi86_id[] = { @@ -1537,12 +1585,18 @@ static int __init ti_sn65dsi86_init(void) if (ret) goto err_main_was_registered; - ret = auxiliary_driver_register(&ti_sn_bridge_driver); + ret = auxiliary_driver_register(&ti_sn_aux_driver); if (ret) goto err_gpio_was_registered; + ret = auxiliary_driver_register(&ti_sn_bridge_driver); + if (ret) + goto err_aux_was_registered; + return 0; +err_aux_was_registered: + auxiliary_driver_unregister(&ti_sn_aux_driver); err_gpio_was_registered: ti_sn_gpio_unregister(); err_main_was_registered: @@ -1555,6 +1609,7 @@ module_init(ti_sn65dsi86_init); static void __exit ti_sn65dsi86_exit(void) { auxiliary_driver_unregister(&ti_sn_bridge_driver); + auxiliary_driver_unregister(&ti_sn_aux_driver); ti_sn_gpio_unregister(); i2c_del_driver(&ti_sn65dsi86_driver); } From patchwork Mon May 3 21:58:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 430640 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 7F76DC43600 for ; Mon, 3 May 2021 21:59:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D3DB611EE for ; Mon, 3 May 2021 21:59:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229928AbhECWAV (ORCPT ); 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Mon, 03 May 2021 14:59:23 -0700 (PDT) From: Douglas Anderson To: Andrzej Hajda , Neil Armstrong , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Sam Ravnborg , Wolfram Sang Cc: Lyude Paul , Steev Klimaszewski , Stephen Boyd , Bjorn Andersson , linux-arm-msm@vger.kernel.org, Stanislav Lisovskiy , Linus W , robdclark@chromium.org, Maarten Lankhorst , Thierry Reding , linux-i2c@vger.kernel.org, dri-devel@lists.freedesktop.org, Douglas Anderson , Daniel Vetter , David Airlie , Robert Foss , linux-kernel@vger.kernel.org Subject: [PATCH v6 4/5] drm/bridge: ti-sn65dsi86: Don't read EDID blob over DDC Date: Mon, 3 May 2021 14:58:43 -0700 Message-Id: <20210503145750.v6.4.I9330684c25f65bb318eff57f0616500f83eac3cc@changeid> X-Mailer: git-send-email 2.31.1.527.g47e6f16901-goog In-Reply-To: <20210503215844.2996320-1-dianders@chromium.org> References: <20210503215844.2996320-1-dianders@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org This is really just a revert of commit 58074b08c04a ("drm/bridge: ti-sn65dsi86: Read EDID blob over DDC"), resolving conflicts. The old code failed to read the EDID properly in a very important case: before the bridge's pre_enable() was called. The way things need to work: 1. Read the EDID. 2. Based on the EDID, decide on video settings and pixel clock. 3. Enable the bridge w/ the desired settings. The way things were working: 1. Try to read the EDID but fail; fall back to hardcoded values. 2. Based on hardcoded values, decide on video settings and pixel clock. 3. Enable the bridge w/ the desired settings. 4. Try again to read the EDID, it works now! 5. Realize that the hardcoded settings weren't quite right. 6. Disable / reenable the bridge w/ the right settings. The reasons for the failures were twofold: a) Since we never ran the bridge chip's pre-enable then we never set the bit to ignore HPD. This meant the bridge chip didn't even _try_ to go out on the bus and communicate with the panel. b) Even if we fixed things to ignore HPD, the EDID still wouldn't read if the panel wasn't on. Instead of reverting the code, we could fix it to set the HPD bit and also power on the panel. However, it also works nicely to just let the panel code read the EDID. Now that we've split the driver up we can expose the DDC AUX channel bus to the panel node. The panel can take charge of reading the EDID. NOTE: in order for things to work, anyone that needs to read the EDID will need to add something that looks like this to their panel in the dts: ddc-i2c-bus = <&sn65dsi86_bridge>; Presumably it's OK to land this without waiting for users to add the dts property since the EDID reading was a bit broken anyway, was "recently" added, and we know we must have the fallback mode to use (since the EDID reading was a bit broken). Suggested-by: Andrzej Hajda Signed-off-by: Douglas Anderson Reviewed-by: Bjorn Andersson --- (no changes since v1) drivers/gpu/drm/bridge/ti-sn65dsi86.c | 22 ---------------------- 1 file changed, 22 deletions(-) diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index 594aac57bdbc..9f0f785f380d 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -125,7 +125,6 @@ * @connector: Our connector. * @host_node: Remote DSI node. * @dsi: Our MIPI DSI source. - * @edid: Detected EDID of eDP panel. * @refclk: Our reference clock. * @panel: Our panel. * @enable_gpio: The GPIO we toggle to enable the bridge. @@ -156,7 +155,6 @@ struct ti_sn65dsi86 { struct drm_dp_aux aux; struct drm_bridge bridge; struct drm_connector connector; - struct edid *edid; struct device_node *host_node; struct mipi_dsi_device *dsi; struct clk *refclk; @@ -405,24 +403,6 @@ connector_to_ti_sn65dsi86(struct drm_connector *connector) static int ti_sn_bridge_connector_get_modes(struct drm_connector *connector) { struct ti_sn65dsi86 *pdata = connector_to_ti_sn65dsi86(connector); - struct edid *edid = pdata->edid; - int num, ret; - - if (!edid) { - pm_runtime_get_sync(pdata->dev); - edid = pdata->edid = drm_get_edid(connector, &pdata->aux.ddc); - pm_runtime_put_autosuspend(pdata->dev); - } - - if (edid && drm_edid_is_valid(edid)) { - ret = drm_connector_update_edid_property(connector, edid); - if (!ret) { - num = drm_add_edid_modes(connector, edid); - if (num) - return num; - } - } - return drm_panel_get_modes(pdata->panel, connector); } @@ -1353,8 +1333,6 @@ static void ti_sn_bridge_remove(struct auxiliary_device *adev) mipi_dsi_device_unregister(pdata->dsi); } - kfree(pdata->edid); - drm_bridge_remove(&pdata->bridge); of_node_put(pdata->host_node); From patchwork Mon May 3 21:58:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 430913 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 8C2D6C43460 for ; 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Mon, 03 May 2021 14:59:25 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:201:a592:ac50:b17b:5c43]) by smtp.gmail.com with ESMTPSA id w1sm639186pgp.31.2021.05.03.14.59.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 May 2021 14:59:25 -0700 (PDT) From: Douglas Anderson To: Andrzej Hajda , Neil Armstrong , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Sam Ravnborg , Wolfram Sang Cc: Lyude Paul , Steev Klimaszewski , Stephen Boyd , Bjorn Andersson , linux-arm-msm@vger.kernel.org, Stanislav Lisovskiy , Linus W , robdclark@chromium.org, Maarten Lankhorst , Thierry Reding , linux-i2c@vger.kernel.org, dri-devel@lists.freedesktop.org, Douglas Anderson , Andy Gross , Rob Herring , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 5/5] arm64: dts: qcom: Link the panel to the bridge's DDC bus Date: Mon, 3 May 2021 14:58:44 -0700 Message-Id: <20210503145750.v6.5.Ibdb7735fb1844561b902252215a69526a14f9abd@changeid> X-Mailer: git-send-email 2.31.1.527.g47e6f16901-goog In-Reply-To: <20210503215844.2996320-1-dianders@chromium.org> References: <20210503215844.2996320-1-dianders@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Adding this link allows the panel code to do things like read the EDID. Signed-off-by: Douglas Anderson Reviewed-by: Bjorn Andersson --- (no changes since v1) arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi index 24d293ef56d7..96e530594509 100644 --- a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi +++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi @@ -265,6 +265,7 @@ panel: panel { power-supply = <&pp3300_dx_edp>; backlight = <&backlight>; hpd-gpios = <&sn65dsi86_bridge 2 GPIO_ACTIVE_HIGH>; + ddc-i2c-bus = <&sn65dsi86_bridge>; ports { port {