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 4BF04EB64D7 for ; Tue, 20 Jun 2023 13:41:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231974AbjFTNlP (ORCPT ); Tue, 20 Jun 2023 09:41:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229966AbjFTNlO (ORCPT ); Tue, 20 Jun 2023 09:41:14 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 49E42E7D; Tue, 20 Jun 2023 06:41:12 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5AA7B1063; Tue, 20 Jun 2023 06:41:56 -0700 (PDT) Received: from [10.1.197.1] (ewhatever.cambridge.arm.com [10.1.197.1]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2EBD63F71E; Tue, 20 Jun 2023 06:41:10 -0700 (PDT) Message-ID: Date: Tue, 20 Jun 2023 14:41:08 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH v6 09/13] Add nodes for dsb edge control Content-Language: en-US To: Tao Zhang , Greg Kroah-Hartman Cc: Mathieu Poirier , Alexander Shishkin , Konrad Dybcio , Mike Leach , Rob Herring , Krzysztof Kozlowski , Jinlong Mao , Leo Yan , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Tingwei Zhang , Yuanfang Zhang , Trilok Soni , Hao Zhang , linux-arm-msm@vger.kernel.org, andersson@kernel.org References: <1687246361-23607-1-git-send-email-quic_taozha@quicinc.com> <1687246361-23607-10-git-send-email-quic_taozha@quicinc.com> <2023062024-sincere-tripod-95dc@gregkh> <3aca4a55-0dc7-b34c-d2c0-111a96c33ec3@quicinc.com> From: Suzuki K Poulose In-Reply-To: <3aca4a55-0dc7-b34c-d2c0-111a96c33ec3@quicinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 20/06/2023 09:31, Tao Zhang wrote: > > On 6/20/2023 3:37 PM, Greg Kroah-Hartman wrote: >> On Tue, Jun 20, 2023 at 03:32:37PM +0800, Tao Zhang wrote: >>> Add the nodes to set value for DSB edge control and DSB edge >>> control mask. Each DSB subunit TPDM has maximum of n(n<16) EDCR >>> resgisters to configure edge control. DSB edge detection control >>> 00: Rising edge detection >>> 01: Falling edge detection >>> 10: Rising and falling edge detection (toggle detection) >>> And each DSB subunit TPDM has maximum of m(m<8) ECDMR registers to >>> configure mask. Eight 32 bit registers providing DSB interface >>> edge detection mask control. >>> >>> Signed-off-by: Tao Zhang >>> --- >>>   .../ABI/testing/sysfs-bus-coresight-devices-tpdm   |  32 +++++ >>>   drivers/hwtracing/coresight/coresight-tpdm.c       | 143 >>> ++++++++++++++++++++- >>>   drivers/hwtracing/coresight/coresight-tpdm.h       |  22 ++++ >>>   3 files changed, 196 insertions(+), 1 deletion(-) >>> >>> diff --git >>> a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm >>> b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm >>> index 2a82cd0..34189e4a 100644 >>> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm >>> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm >>> @@ -60,3 +60,35 @@ Description: >>>           Bit[3] : Set to 0 for low performance mode. >>>                    Set to 1 for high performance mode. >>>           Bit[4:8] : Select byte lane for high performance mode. >>> + >>> +What:        /sys/bus/coresight/devices//dsb_edge_ctrl >>> +Date:        March 2023 >>> +KernelVersion    6.5 >>> +Contact:    Jinlong Mao (QUIC) , Tao Zhang >>> (QUIC) >>> +Description: >>> +        Read/Write a set of the edge control registers of the DSB >>> +        in TPDM. >>> + >>> +        Expected format is the following: >>> +        >> sysfs is "one value", not 3.  Please never have to parse a sysfs file. > > Do you mean sysfs file can only accept "one value"? > > I see that more than one value are written to the sysfs file > "trigout_attach". > >> >>> +static ssize_t dsb_edge_ctrl_show(struct device *dev, >>> +                       struct device_attribute *attr, >>> +                       char *buf) >>> +{ >>> +    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent); >>> +    ssize_t size = 0; >>> +    unsigned long bytes; >>> +    int i; >>> + >>> +    spin_lock(&drvdata->spinlock); >>> +    for (i = 0; i < TPDM_DSB_MAX_EDCR; i++) { >>> +        bytes = sysfs_emit_at(buf, size, >>> +                  "Index:0x%x Val:0x%x\n", i, >> Again, no, one value, no "string" needed to parse anything. > > I also see other sysfs files can be read more than one value in other > drivers. > > Is this "one value" limitation the usage rule of Linux sysfs system? > > Or am I misunderstanding what you mean? Please fix the other sysfs tunables in the following patches. Kind regards Suzuki