From patchwork Thu Sep 9 21:00:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 12483909 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=-19.1 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 82D32C41535 for ; Thu, 9 Sep 2021 21:01:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 66833611B0 for ; Thu, 9 Sep 2021 21:01:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346400AbhIIVCi (ORCPT ); Thu, 9 Sep 2021 17:02:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50018 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346178AbhIIVCe (ORCPT ); Thu, 9 Sep 2021 17:02:34 -0400 Received: from mail-pg1-x52b.google.com (mail-pg1-x52b.google.com [IPv6:2607:f8b0:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 62475C061574 for ; Thu, 9 Sep 2021 14:01:24 -0700 (PDT) Received: by mail-pg1-x52b.google.com with SMTP id n18so3090693pgm.12 for ; Thu, 09 Sep 2021 14:01:24 -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=wgdd7k2meN+TTX6Jg3GzgzE7H76ZLGquQVy1sMGiGZ4=; b=MGMmmuxNGOl5nA2L8i1UACBEDd+APufRbYL5wqzKPPpNcAV+1Zp4qsTrTzUuWBhYNZ RW6cG6JJAeckRKgjnRag/Gb6VdL6aoK0eVIAGWiXcKioTmZIswINTzMBt24Ov/kf5Q8w VxpkJRryXxXMQGR+R6bHJ/Q1IWToWdEMQPgwo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=wgdd7k2meN+TTX6Jg3GzgzE7H76ZLGquQVy1sMGiGZ4=; b=5b5IqjnoBlbqUtZVoRsiky9dGrmjD6gQclGLH1vbbly7jrlGYj101JmxS1OBuBpde+ H6h4XDU7Ln9jS3HvcVWIXvbgRo+1Ca12QeYIEih9zsT3xF+k00uAPbj9XzfhFk0WaCQi sZWVJimqsEctFD2tHGd/Vy9XSfYSPeFBgkV76NCJB0Xx4ruELIQxbsCpZZ/9h18yr/eE 2XKi/i0iG94m0BMV9DUhajyPksywTzf36+TUS7jjmOSpw0XDI2aLFvtApPgjuFayKGx1 CFa3TLhoqnaUR6VE5Pe4LCq/ixYLR7ebi/7yF8dFEL3MdKp5ZbCNK/eKQ9xX4/cFSTwj lc8A== X-Gm-Message-State: AOAM533UAvIhfGfHSDBsLtJmpHRbDgsvSzGwJb3vzajWldm8K13BCiYR VS7dB2U0O+42pN9IzBiWD8QzLQ== X-Google-Smtp-Source: ABdhPJxQgS0HpYosTZpAWKSO5dwrgqpNc6QSn0MBODteWKAZ7JkDBz3BTPwOp8wNUPQiYT4+HVYx1Q== X-Received: by 2002:a63:2d07:: with SMTP id t7mr4411763pgt.101.1631221283830; Thu, 09 Sep 2021 14:01:23 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:201:8da3:b0fb:4261:2c10]) by smtp.gmail.com with ESMTPSA id l143sm177069pfd.60.2021.09.09.14.01.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Sep 2021 14:01:23 -0700 (PDT) From: Douglas Anderson To: Thierry Reding , Rob Herring , Sam Ravnborg Cc: devicetree@vger.kernel.org, Maxime Ripard , Thomas Zimmermann , Linus W , Daniel Vetter , linux-arm-msm@vger.kernel.org, Steev Klimaszewski , Maarten Lankhorst , Bjorn Andersson , David Airlie , dri-devel@lists.freedesktop.org, Douglas Anderson , linux-kernel@vger.kernel.org Subject: [PATCH v4 03/15] drm/edid: Allow querying/working with the panel ID from the EDID Date: Thu, 9 Sep 2021 14:00:19 -0700 Message-Id: <20210909135838.v4.3.I4a672175ba1894294d91d3dbd51da11a8239cf4a@changeid> X-Mailer: git-send-email 2.33.0.309.g3052b89438-goog In-Reply-To: <20210909210032.465570-1-dianders@chromium.org> References: <20210909210032.465570-1-dianders@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org EDIDs have 32-bits worth of data which is intended to be used to uniquely identify the make/model of a panel. This has historically been used only internally in the EDID processing code to identify quirks with panels. We'd like to use this panel ID in panel drivers to identify which panel is hooked up and from that information figure out power sequence timings. Let's expose this information from the EDID code and also allow it to be accessed early, before a connector has been created. To make matching in the panel drivers code easier, we'll return the panel ID as a 32-bit value. We'll provide some functions for converting this value back and forth to something more human readable. Signed-off-by: Douglas Anderson Acked-by: Sam Ravnborg Reviewed-by: Jani Nikula --- Changes in v4: - Don't refer to "panel-simple" in commit message. - decode_edid_id() => drm_edid_decode_panel_id() - drm_do_get_edid_blk0() => drm_do_get_edid_base_block() - drm_get_panel_id() => drm_edid_get_panel_id() - encode_edid_id() => drm_edid_encode_panel_id() - split panel id extraction out to its own function. Changes in v3: - Decode hex product ID w/ same endianness as everyone else. drivers/gpu/drm/drm_edid.c | 67 ++++++++++++++++++++++++++++++++++++++ include/drm/drm_edid.h | 47 ++++++++++++++++++++++++++ 2 files changed, 114 insertions(+) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 520fe1391769..f84e0dd264f4 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -2087,6 +2087,73 @@ struct edid *drm_get_edid(struct drm_connector *connector, } EXPORT_SYMBOL(drm_get_edid); +static u32 edid_extract_panel_id(const struct edid *edid) +{ + /* + * In theory we could try to de-obfuscate this like edid_get_quirks() + * does, but it's easier to just deal with a 32-bit number since then + * it can be compared with "==". + * + * NOTE that we deal with endianness differently for the top half + * of this ID than for the bottom half. The bottom half (the product + * id) gets decoded as little endian by the EDID_PRODUCT_ID because + * that's how everyone seems to interpret it. The top half (the mfg_id) + * gets stored as big endian because that makes + * drm_edid_encode_panel_id() and drm_edid_decode_panel_id() easier + * to write (it's easier to extract the ASCII). It doesn't really + * matter, though, as long as the number here is unique. + */ + return (u32)edid->mfg_id[0] << 24 | + (u32)edid->mfg_id[1] << 16 | + (u32)EDID_PRODUCT_ID(edid); +} + +/** + * drm_edid_get_panel_id - Get a panel's ID through DDC + * @adapter: I2C adapter to use for DDC + * + * This function reads the first block of the EDID of a panel and (assuming + * that the EDID is valid) extracts the ID out of it. The ID is a 32-bit value + * (16 bits of manufacturer ID and 16 bits of per-manufacturer ID) that's + * supposed to be different for each different modem of panel. + * + * This function is intended to be used during early probing on devices where + * more than one panel might be present. Because of its intended use it must + * assume that the EDID of the panel is correct, at least as far as the ID + * is concerned (in other words, we don't process any overrides here). + * + * NOTE: it's expected that this function and drm_do_get_edid() will both + * be read the EDID, but there is no caching between them. Since we're only + * reading the first block, hopefully this extra overhead won't be too big. + * + * Return: A 32-bit ID that should be different for each make/model of panel. + * See the functions drm_edid_encode_panel_id() and + * drm_edid_decode_panel_id() for some details on the structure of this + * ID. + */ + +u32 drm_edid_get_panel_id(struct i2c_adapter *adapter) +{ + struct edid *edid; + u32 panel_id; + + edid = drm_do_get_edid_base_block(drm_do_probe_ddc_edid, adapter, + NULL, NULL); + + /* + * There are no manufacturer IDs of 0, so if there is a problem reading + * the EDID then we'll just return 0. + */ + if (IS_ERR_OR_NULL(edid)) + return 0; + + panel_id = edid_extract_panel_id(edid); + kfree(edid); + + return panel_id; +} +EXPORT_SYMBOL(drm_edid_get_panel_id); + /** * drm_get_edid_switcheroo - get EDID data for a vga_switcheroo output * @connector: connector we're probing diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h index deccfd39e6db..4d17cd04fff7 100644 --- a/include/drm/drm_edid.h +++ b/include/drm/drm_edid.h @@ -508,6 +508,52 @@ static inline u8 drm_eld_get_conn_type(const uint8_t *eld) return eld[DRM_ELD_SAD_COUNT_CONN_TYPE] & DRM_ELD_CONN_TYPE_MASK; } +/** + * drm_edid_encode_panel_id - Encode an ID for matching against drm_edid_get_panel_id() + * @vend_chr_0: First character of the vendor string. + * @vend_chr_2: Second character of the vendor string. + * @vend_chr_3: Third character of the vendor string. + * @product_id: The 16-bit product ID. + * + * This is a macro so that it can be calculated at compile time and used + * as an initializer. + * + * For instance: + * drm_edid_encode_panel_id('B', 'O', 'E', 0x2d08) => 0x09e52d08 + * + * Return: a 32-bit ID per panel. + */ +#define drm_edid_encode_panel_id(vend_chr_0, vend_chr_1, vend_chr_2, product_id) \ + ((((u32)(vend_chr_0) - '@') & 0x1f) << 26 | \ + (((u32)(vend_chr_1) - '@') & 0x1f) << 21 | \ + (((u32)(vend_chr_2) - '@') & 0x1f) << 16 | \ + ((product_id) & 0xffff)) + +/** + * drm_edid_decode_panel_id - Decode a panel ID from drm_edid_encode_panel_id() + * @panel_id: The panel ID to decode. + * @vend: A 4-byte buffer to store the 3-letter vendor string plus a '\0' + * termination + * @product_id: The product ID will be returned here. + * + * For instance, after: + * drm_edid_decode_panel_id(0x09e52d08, vend, &product_id) + * These will be true: + * vend[0] = 'B' + * vend[1] = 'O' + * vend[2] = 'E' + * vend[3] = '\0' + * product_id = 0x2d08 + */ +static inline void drm_edid_decode_panel_id(u32 panel_id, char vend[4], u16 *product_id) +{ + *product_id = (u16)(panel_id & 0xffff); + vend[0] = '@' + ((panel_id >> 26) & 0x1f); + vend[1] = '@' + ((panel_id >> 21) & 0x1f); + vend[2] = '@' + ((panel_id >> 16) & 0x1f); + vend[3] = '\0'; +} + bool drm_probe_ddc(struct i2c_adapter *adapter); struct edid *drm_do_get_edid(struct drm_connector *connector, int (*get_edid_block)(void *data, u8 *buf, unsigned int block, @@ -515,6 +561,7 @@ struct edid *drm_do_get_edid(struct drm_connector *connector, void *data); struct edid *drm_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter); +u32 drm_edid_get_panel_id(struct i2c_adapter *adapter); struct edid *drm_get_edid_switcheroo(struct drm_connector *connector, struct i2c_adapter *adapter); struct edid *drm_edid_duplicate(const struct edid *edid);