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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 03331C3279B for ; Wed, 4 Jul 2018 16:17:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B07AF2400C for ; Wed, 4 Jul 2018 16:17:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B07AF2400C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752755AbeGDQRn (ORCPT ); Wed, 4 Jul 2018 12:17:43 -0400 Received: from smtp.nue.novell.com ([195.135.221.5]:59808 "EHLO smtp.nue.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752165AbeGDQRl (ORCPT ); Wed, 4 Jul 2018 12:17:41 -0400 Received: from ziggy.stardust ([37.223.136.20]) by smtp.nue.novell.com with ESMTP (TLS encrypted); Wed, 04 Jul 2018 18:17:37 +0200 Subject: Re: [v3 03/10] mfd: mtk-mmsys: Add mmsys driver To: Lee Jones , Matthias Brugger Cc: matthias.bgg@kernel.org, ulrich.hecht+renesas@gmail.com, laurent.pinchart@ideasonboard.com, ck.hu@mediatek.com, p.zabel@pengutronix.de, airlied@linux.ie, robh+dt@kernel.org, mark.rutland@arm.com, mturquette@baylibre.com, sboyd@codeaurora.org, davem@davemloft.net, gregkh@linuxfoundation.org, mchehab@kernel.org, rdunlap@infradead.org, sean.wang@mediatek.com, linux-clk@vger.kernel.org, linux@armlinux.org.uk, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org References: <20180430101826.GC5147@dell> <5269ccfd-0274-3c12-7eeb-5de923197d92@gmail.com> <20180703071103.GE20176@dell> From: Matthias Brugger Openpgp: preference=signencrypt Autocrypt: addr=mbrugger@suse.com; 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Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180703071103.GE20176@dell> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/07/18 09:11, Lee Jones wrote: > On Mon, 25 Jun 2018, Matthias Brugger wrote: >> On 30/04/18 12:18, Lee Jones wrote: >>> On Fri, 27 Apr 2018, matthias.bgg@kernel.org wrote: >>> >>>> From: Matthias Brugger >>>> >>>> The MMSYS subsystem includes clocks and drm components. >>>> This patch adds a MFD device to probe both drivers from the same >>>> device tree compatible. >>>> >>>> Signed-off-by: Matthias Brugger >>>> --- >>>> drivers/mfd/Kconfig | 9 ++++++ >>>> drivers/mfd/Makefile | 2 ++ >>>> drivers/mfd/mtk-mmsys.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++ >>>> 3 files changed, 90 insertions(+) >>>> create mode 100644 drivers/mfd/mtk-mmsys.c >>>> >>>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig >>>> index b860eb5aa194..d23a3b9a2c58 100644 >>>> --- a/drivers/mfd/Kconfig >>>> +++ b/drivers/mfd/Kconfig >>>> @@ -378,6 +378,15 @@ config MFD_MC13XXX_I2C >>>> help >>>> Select this if your MC13xxx is connected via an I2C bus. >>>> >>>> +config MFD_MEDIATEK_MMSYS >>>> + tristate "Mediatek MMSYS interface" >>>> + select MFD_CORE >>>> + select REGMAP_MMIO >>>> + help >>>> + Select this if you have a MMSYS subsystem in your SoC. The >>>> + MMSYS subsystem has at least a clock driver part and some >>>> + DRM components. >>>> + >>>> config MFD_MXS_LRADC >>>> tristate "Freescale i.MX23/i.MX28 LRADC" >>>> depends on ARCH_MXS || COMPILE_TEST >>>> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile >>>> index d9d2cf0d32ef..b96118bd68d9 100644 >>>> --- a/drivers/mfd/Makefile >>>> +++ b/drivers/mfd/Makefile >>>> @@ -98,6 +98,8 @@ obj-$(CONFIG_MFD_MC13XXX) += mc13xxx-core.o >>>> obj-$(CONFIG_MFD_MC13XXX_SPI) += mc13xxx-spi.o >>>> obj-$(CONFIG_MFD_MC13XXX_I2C) += mc13xxx-i2c.o >>>> >>>> +obj-$(CONFIG_MFD_MEDIATEK_MMSYS) += mtk-mmsys.o >>>> + >>>> obj-$(CONFIG_MFD_CORE) += mfd-core.o >>>> >>>> obj-$(CONFIG_EZX_PCAP) += ezx-pcap.o >>>> diff --git a/drivers/mfd/mtk-mmsys.c b/drivers/mfd/mtk-mmsys.c >>>> new file mode 100644 >>>> index 000000000000..c802343fb1c6 >>>> --- /dev/null >>>> +++ b/drivers/mfd/mtk-mmsys.c >>>> @@ -0,0 +1,79 @@ >>>> +// SPDX-License-Identifier: GPL-2.0+ >>>> + >>>> +/* >>>> + * mtk-mmsys.c -- Mediatek MMSYS multi-function driver >>>> + * >>>> + * Copyright (c) 2018 Matthias Brugger >>>> + * >>>> + * Author: Matthias Brugger >>>> + */ >>>> + >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> + >>>> +enum { >>>> + MMSYS_MT2701 = 1, >>>> +}; >>>> + >>>> +static const struct mfd_cell mmsys_mt2701_devs[] = { >>>> + { .name = "clk-mt2701-mm", }, >>>> + { .name = "drm-mt2701-mm", }, >>>> +}; >>>> + >>>> +static int mmsys_probe(struct platform_device *pdev) >>>> +{ >>>> + const struct mfd_cell *mmsys_cells; >>>> + int nr_cells; >>>> + long id; >>>> + int ret; >>>> + >>>> + id = (long) of_device_get_match_data(&pdev->dev); >>>> + if (!id) { >>>> + dev_err(&pdev->dev, "of_device_get match_data() failed\n"); >>>> + return -EINVAL; >>>> + } >>>> + >>>> + switch (id) { >>>> + case MMSYS_MT2701: >>>> + mmsys_cells = mmsys_mt2701_devs; >>>> + nr_cells = ARRAY_SIZE(mmsys_mt2701_devs); >>>> + break; >>>> + default: >>>> + return -ENODEV; >>>> + } >>>> + >>>> + ret = devm_mfd_add_devices(&pdev->dev, 0, mmsys_cells, nr_cells, >>>> + NULL, 0, NULL); >>>> + if (ret) { >>>> + dev_err(&pdev->dev, "failed to add MFD devices %d\n", ret); >>>> + return ret; >>>> + } >>>> + >>>> + return 0; >>>> +}; >>> >>> This driver is pretty pointless. It doesn't actually do anything. >>> >>> I think you just want to use "simple-mfd" instead. >>> >> >> I think the problem is, that right now we have two drivers which use the same >> devicetree binding, which are clk and drm driver. With a simple-mfd we would >> need two compatibles, and this would break backwards compatibility. > > So what functionality does this driver provide you with that you do > not have currently? > I'm not sure if I get your question. Point is, that the MMSYS implementation for mt8173 is broken, as it assumes that we can probe two drivers with the mediatek,mt8173-mmsys compatible. Somehow it used to work, but from what I understand it was a bug. So older devicetrees use just on mt8173-mmsys compatible in ther DTB. I would like to keep backwards compatibility for the device tree, that's why I was searching for a solution where we can probe two drivers and came up with this mfd solution. So no new functionality, the clk driver provides the clock the drm components need. Regards, Matthias