From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DCA6D6D24 for ; Mon, 14 Aug 2023 07:33:08 +0000 (UTC) Received: from fllv0015.ext.ti.com (fllv0015.ext.ti.com [198.47.19.141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7199010E3; Mon, 14 Aug 2023 00:33:06 -0700 (PDT) Received: from fllv0034.itg.ti.com ([10.64.40.246]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 37E7Wcq2125087; Mon, 14 Aug 2023 02:32:38 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1691998358; bh=bdFeH2qZcAR1f3pLZ/uXJO+MJdOLdWxGk+XknPyZBWU=; h=Date:Subject:To:CC:References:From:In-Reply-To; b=m2tiXeq61s36w4XXM4p2Qz8TUxiWU0KJVCHEd48Mr1hNxLuw1qRjhdLlQHvczValZ 9sWvZn/kIWuyIzXRXRGmG7/Jw4NEI3L57s04ztorsJzJqSn3pxIsWw9Gc47Re0AWGU 48cAx1kIJl81VSco1uk3NaNFozUFqbW5rcaTp8+s= Received: from DLEE102.ent.ti.com (dlee102.ent.ti.com [157.170.170.32]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 37E7Wccw025922 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 14 Aug 2023 02:32:38 -0500 Received: from DLEE107.ent.ti.com (157.170.170.37) by DLEE102.ent.ti.com (157.170.170.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.23; Mon, 14 Aug 2023 02:32:37 -0500 Received: from fllv0039.itg.ti.com (10.64.41.19) by DLEE107.ent.ti.com (157.170.170.37) 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; Mon, 14 Aug 2023 02:32:37 -0500 Received: from [172.24.227.217] (ileaxei01-snat2.itg.ti.com [10.180.69.6]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id 37E7WVTf028513; Mon, 14 Aug 2023 02:32:32 -0500 Message-ID: <1f6a36fb-dfbe-1536-47de-f2335aac5bfa@ti.com> Date: Mon, 14 Aug 2023 13:02:31 +0530 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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: Andrew Davis , 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> <4c40fbe4-3492-ec76-e452-3a3ecb0f2433@ti.com> From: Md Danish Anwar Organization: Texas Instruments In-Reply-To: <4c40fbe4-3492-ec76-e452-3a3ecb0f2433@ti.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-Spam-Status: No, score=-6.5 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On 11/08/23 8:54 pm, Andrew Davis wrote: > 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. > In total both icss_iep_readl() and writel() are used 4 time each. All related to gettime / settime. This is the only place where these helper APIs are used. I will drop these helper apis and used readl / writel directly. >>> >>> [...] >>> >>>> +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. > Sure Andrew. For now I will keep it as regmap_update_bits(). I will look into regmap_fields for my 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 >> -- Thanks and Regards, Danish.