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 43AFEC41513 for ; Fri, 11 Aug 2023 15:24:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236321AbjHKPYm (ORCPT ); Fri, 11 Aug 2023 11:24:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233991AbjHKPYl (ORCPT ); Fri, 11 Aug 2023 11:24:41 -0400 Received: from fllv0015.ext.ti.com (fllv0015.ext.ti.com [198.47.19.141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D6B9EDC; Fri, 11 Aug 2023 08:24:37 -0700 (PDT) Received: from lelv0265.itg.ti.com ([10.180.67.224]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 37BFOJY5024762; Fri, 11 Aug 2023 10:24:19 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1691767459; bh=TWTgIYHYo1gfxLfGJr3o5tMioqcbKX9+NAaHDSGtkAY=; h=Date:Subject:To:CC:References:From:In-Reply-To; b=ny79IsCyf9aXd+Xkc/HqviK/66Ot8EXYjdCfasdp+UcEU8y+WyLS71natAidAh+3j b+0v/KRmuqSJJsXRFaOj6ExcyErYL3Pfdy/eq3oU3qKwSN5hyPuiatoZxA2Ecl1Eob F1eKsj2X1JmJ4Z61i1Ijayvxw6A3Bl/iU1JtipjU= Received: from DLEE108.ent.ti.com (dlee108.ent.ti.com [157.170.170.38]) by lelv0265.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 37BFOJYF011768 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 11 Aug 2023 10:24:19 -0500 Received: from DLEE114.ent.ti.com (157.170.170.25) by DLEE108.ent.ti.com (157.170.170.38) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23; Fri, 11 Aug 2023 10:24:19 -0500 Received: from fllv0039.itg.ti.com (10.64.41.19) by DLEE114.ent.ti.com (157.170.170.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23 via Frontend Transport; Fri, 11 Aug 2023 10:24:19 -0500 Received: from [10.250.38.120] (ileaxei01-snat.itg.ti.com [10.180.69.5]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id 37BFOIKA127506; Fri, 11 Aug 2023 10:24:18 -0500 Message-ID: <4c40fbe4-3492-ec76-e452-3a3ecb0f2433@ti.com> Date: Fri, 11 Aug 2023 10:24:18 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v3 3/5] net: ti: icss-iep: Add IEP driver Content-Language: en-US To: Md Danish Anwar , MD Danish Anwar , Randy Dunlap , Roger Quadros , Simon Horman , Vignesh Raghavendra , Andrew Lunn , Richard Cochran , Conor Dooley , Krzysztof Kozlowski , Rob Herring , Paolo Abeni , Jakub Kicinski , Eric Dumazet , "David S. Miller" CC: , , , , , , References: <20230809114906.21866-1-danishanwar@ti.com> <20230809114906.21866-4-danishanwar@ti.com> From: Andrew Davis In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 8/10/23 6:50 AM, Md Danish Anwar wrote: > Hi Andrew, > > On 09/08/23 8:30 pm, Andrew Davis wrote: >> On 8/9/23 6:49 AM, MD Danish Anwar wrote: >>> From: Roger Quadros >>> >>> Add a driver for Industrial Ethernet Peripheral (IEP) block of PRUSS to >>> support timestamping of ethernet packets and thus support PTP and PPS >>> for PRU ethernet ports. >>> >>> Signed-off-by: Roger Quadros >>> Signed-off-by: Lokesh Vutla >>> Signed-off-by: Murali Karicheri >>> Signed-off-by: Vignesh Raghavendra >>> Signed-off-by: MD Danish Anwar >>> --- >>>   drivers/net/ethernet/ti/Kconfig          |  12 + >>>   drivers/net/ethernet/ti/Makefile         |   1 + >>>   drivers/net/ethernet/ti/icssg/icss_iep.c | 935 +++++++++++++++++++++++ >>>   drivers/net/ethernet/ti/icssg/icss_iep.h |  38 + >>>   4 files changed, 986 insertions(+) >>>   create mode 100644 drivers/net/ethernet/ti/icssg/icss_iep.c >>>   create mode 100644 drivers/net/ethernet/ti/icssg/icss_iep.h >>> >>> diff --git a/drivers/net/ethernet/ti/Kconfig b/drivers/net/ethernet/ti/Kconfig >>> index 63e510b6860f..88b5b1b47779 100644 >>> --- a/drivers/net/ethernet/ti/Kconfig >>> +++ b/drivers/net/ethernet/ti/Kconfig >>> @@ -186,6 +186,7 @@ config CPMAC >>>   config TI_ICSSG_PRUETH >>>       tristate "TI Gigabit PRU Ethernet driver" >>>       select PHYLIB >>> +    select TI_ICSS_IEP >> >> Why not save selecting this until you add its use in the ICSSG_PRUETH driver in >> the next patch. >> > > The next patch is only adding changes to icssg-prueth .c /.h files. This patch > is adding changes to Kconfig and the Makefile. To keep it that way selecting > this is added in this patch. No worries, I will move this to next patch. > >> [...] >> >>> + >>> +static u32 icss_iep_readl(struct icss_iep *iep, int reg) >>> +{ >>> +    return readl(iep->base + iep->plat_data->reg_offs[reg]); >>> +} >> >> Do these one line functions really add anything? Actually why >> not use the regmap you have here. > > These one line functions are not really adding anything but they are acting as > a wrapper around readl /writel and providing some sort of encapsulation as > directly calling readl will result in a little complicated code. > > /* WIth One line function */ > ts_lo = icss_iep_readl(iep, ICSS_IEP_COUNT_REG0); > > /* Without one line function */ > ts_lo = readl(iep->base, iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG0]); > > Previously regmap was used in this driver. But in older commit [1] in > 5.10-ti-linux-kernel (Before I picked the driver for upstream) it got changed > to readl / writel stating that regmap_read / write is too slow. IEP is time > sensitive and needs faster read and write, probably because of this they > changed it. > Sounds like you only need direct register access for time sensitive gettime/settime functions, if that is the only place writel()/readl() is needed just drop the helper and use directly in that one spot. >> >> [...] >> >>> +static void icss_iep_enable(struct icss_iep *iep) >>> +{ >>> +    regmap_update_bits(iep->map, ICSS_IEP_GLOBAL_CFG_REG, >>> +               IEP_GLOBAL_CFG_CNT_ENABLE, >>> +               IEP_GLOBAL_CFG_CNT_ENABLE); >> >> Have you looked into regmap_fields? >> > > No I hadn't. But now I looked into regmap_fields, seems to be another way to > update the bits, instead of passing mask and value, regmap_filed_read / write > only takes the value. But for that we will need to create a regmap field. If > you want me to switch to regmap_fields instead of regmap_update_bits I can make > the changes. But I am fine with regmap_update_bits(). > I'm suggesting regmap fields as I have used it several times and it resulted in greatly improved readability. Yes you will need a regmap field table, but that is the best part, it lets you put all your bit definitions in one spot that can match 1:1 with the datasheet, much easier to check for correctness than if the bit usages are all spread out in the driver. I won't insist on you converting this driver to use it today, but I do recommend you at least give it a shot for your own learning. Andrew >> [...] >> >>> + >>> +    if (!!(iep->latch_enable & BIT(index)) == !!on) >>> +        goto exit; >>> + >> >> There has to be a better way to write this logic.. >> >> [...] >> >>> + >>> +static const struct of_device_id icss_iep_of_match[]; >>> + >> >> Why the forward declaration? > > I will remove this, I don't see any reason for this. > >> >>> +static int icss_iep_probe(struct platform_device *pdev) >>> +{ >>> +    struct device *dev = &pdev->dev; >>> +    struct icss_iep *iep; >>> +    struct clk *iep_clk; >>> + >>> +    iep = devm_kzalloc(dev, sizeof(*iep), GFP_KERNEL); >>> +    if (!iep) >>> +        return -ENOMEM; >>> + >>> +    iep->dev = dev; >>> +    iep->base = devm_platform_ioremap_resource(pdev, 0); >>> +    if (IS_ERR(iep->base)) >>> +        return -ENODEV; >>> + >>> +    iep_clk = devm_clk_get(dev, NULL); >>> +    if (IS_ERR(iep_clk)) >>> +        return PTR_ERR(iep_clk); >>> + >>> +    iep->refclk_freq = clk_get_rate(iep_clk); >>> + >>> +    iep->def_inc = NSEC_PER_SEC / iep->refclk_freq;    /* ns per clock tick */ >>> +    if (iep->def_inc > IEP_MAX_DEF_INC) { >>> +        dev_err(dev, "Failed to set def_inc %d.  IEP_clock is too slow to be >>> supported\n", >>> +            iep->def_inc); >>> +        return -EINVAL; >>> +    } >>> + >>> +    iep->plat_data = of_device_get_match_data(dev); >> >> Directly using of_*() functions is often wrong, try just device_get_match_data(). >> > > Sure. I will change to device_get_match_data(). > >> [...] >> >>> +static struct platform_driver icss_iep_driver = { >>> +    .driver = { >>> +        .name = "icss-iep", >>> +        .of_match_table = of_match_ptr(icss_iep_of_match), >> >> This driver cannot work without OF, using of_match_ptr() is not needed. >> > > Sure, I will drop of_match_ptr(). > >> Andrew > > > For reading and updating registers, we can have > 1. icss_iep_readl / writel and regmap_update_bits() OR > 2. regmap_read / write and regmap_update_bits() OR > 3. icss_iep_readl / writel and regmap_fields OR > 4. regmap_read / write and regmap_fields > > > Currently we are using 1. Please let me know if you are fine with this and I > can continue using 1. If not, please let me know your recommendation out of this 4. > > [1] > https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/commit/?h=linux-5.10.y&id=f4f45bf71cad5be232536d63a0557d13a7eed162 >