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 939D8C433EF for ; Thu, 7 Jul 2022 06:04:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234709AbiGGGEV (ORCPT ); Thu, 7 Jul 2022 02:04:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45606 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232207AbiGGGET (ORCPT ); Thu, 7 Jul 2022 02:04:19 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E312D218A; Wed, 6 Jul 2022 23:04:16 -0700 (PDT) X-UUID: 2272104881814e489bbc405371cd0e69-20220707 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.8,REQID:575e4fd5-74e0-43ed-af4b-341731f417fe,OB:0,LO B:0,IP:0,URL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,RULE:Release_Ham,ACTI ON:release,TS:0 X-CID-META: VersionHash:0f94e32,CLOUDID:a703a563-0b3f-4b2c-b3a6-ed5c044366a0,C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,IP:nil,URL:0,File:nil ,QS:nil,BEC:nil,COL:0 X-UUID: 2272104881814e489bbc405371cd0e69-20220707 Received: from mtkmbs10n2.mediatek.inc [(172.21.101.183)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 59786837; Thu, 07 Jul 2022 14:04:11 +0800 Received: from mtkmbs11n1.mediatek.inc (172.21.101.186) by mtkmbs10n1.mediatek.inc (172.21.101.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.792.15; Thu, 7 Jul 2022 14:04:09 +0800 Received: from mtksdccf07 (172.21.84.99) by mtkmbs11n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.792.3 via Frontend Transport; Thu, 7 Jul 2022 14:04:09 +0800 Message-ID: <92ca3b870ad980a998d5b792924bede450ebbd73.camel@mediatek.com> Subject: Re: [PATCH v13 05/10] drm/mediatek: Add MT8195 Embedded DisplayPort driver From: CK Hu To: Bo-Chen Chen , , , , , , , , , , CC: , , , , , , , , , , , , Date: Thu, 7 Jul 2022 14:04:09 +0800 In-Reply-To: <20220701062808.18596-6-rex-bc.chen@mediatek.com> References: <20220701062808.18596-1-rex-bc.chen@mediatek.com> <20220701062808.18596-6-rex-bc.chen@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Bo-Chen: On Fri, 2022-07-01 at 14:28 +0800, Bo-Chen Chen wrote: > From: Markus Schneider-Pargmann > > This patch adds a embedded displayport driver for the MediaTek mt8195 > SoC. > > It supports the MT8195, the embedded DisplayPort units. It offers > DisplayPort 1.4 with up to 4 lanes. > > The driver creates a child device for the phy. The child device will > never exist without the parent being active. As they are sharing a > register range, the parent passes a regmap pointer to the child so > that > both can work with the same register range. The phy driver sets > device > data that is read by the parent to get the phy device that can be > used > to control the phy properties. > > This driver is based on an initial version by > Jitao shi > > Signed-off-by: Markus Schneider-Pargmann > Signed-off-by: Guillaume Ranquet > Signed-off-by: Bo-Chen Chen > --- [snip] > + > +static ssize_t mtk_dp_aux_transfer(struct drm_dp_aux *mtk_aux, > + struct drm_dp_aux_msg *msg) > +{ > + struct mtk_dp *mtk_dp; > + bool is_read; > + u8 request; > + size_t accessed_bytes = 0; > + int ret = 0; > + > + mtk_dp = container_of(mtk_aux, struct mtk_dp, aux); > + > + if (!mtk_dp->train_info.cable_plugged_in) { > + ret = -EAGAIN; > + goto err; > + } > + > + switch (msg->request) { > + case DP_AUX_I2C_MOT: > + case DP_AUX_I2C_WRITE: > + case DP_AUX_NATIVE_WRITE: > + case DP_AUX_I2C_WRITE_STATUS_UPDATE: > + case DP_AUX_I2C_WRITE_STATUS_UPDATE | DP_AUX_I2C_MOT: > + request = msg->request & > ~DP_AUX_I2C_WRITE_STATUS_UPDATE; > + is_read = false; > + break; > + case DP_AUX_I2C_READ: > + case DP_AUX_NATIVE_READ: > + case DP_AUX_I2C_READ | DP_AUX_I2C_MOT: > + request = msg->request; > + is_read = true; > + break; > + default: > + drm_err(mtk_aux->drm_dev, "invalid aux cmd = %d\n", > + msg->request); > + ret = -EINVAL; > + goto err; > + } > + > + if (msg->size == 0) { > + ret = mtk_dp_aux_do_transfer(mtk_dp, is_read, request, > + msg->address + > accessed_bytes, > + msg->buffer + > accessed_bytes, 0); > + } else { > + while (accessed_bytes < msg->size) { > + size_t to_access = > + min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES, > + msg->size - accessed_bytes); > + > + ret = mtk_dp_aux_do_transfer(mtk_dp, is_read, > request, > + msg->address + > accessed_bytes, > + msg->buffer + > accessed_bytes, > + to_access); > + > + if (ret) { > + drm_info(mtk_dp->drm_dev, > + "Failed to do AUX transfer: > %d\n", ret); > + break; > + } > + accessed_bytes += to_access; > + } > + } This if-else could be simplified as: do { size_t to_access = min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES, msg->size - accessed_bytes); ret = mtk_dp_aux_do_transfer(mtk_dp, is_read, request, msg->address + accessed_bytes, msg->buffer + accessed_bytes, to_access); if (ret) { drm_info(mtk_dp->drm_dev, "Failed to do AUX transfer: %d\n", ret); break; } accessed_bytes += to_access; } while (accessed_bytes < msg->size); Regards, CK > +err: > + if (ret) { > + msg->reply = DP_AUX_NATIVE_REPLY_NACK | > DP_AUX_I2C_REPLY_NACK; > + return ret; > + } > + > + msg->reply = DP_AUX_NATIVE_REPLY_ACK | DP_AUX_I2C_REPLY_ACK; > + return msg->size; > +} > +