Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH RESEND V2 1/3] clocksource/drivers/sysctr: Add optional
 clock-frequency property
To:     Anson Huang <anson.huang@nxp.com>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "mark.rutland@arm.com" <mark.rutland@arm.com>,
        "shawnguo@kernel.org" <shawnguo@kernel.org>,
        "s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
        "kernel@pengutronix.de" <kernel@pengutronix.de>,
        "festevam@gmail.com" <festevam@gmail.com>,
        "l.stach@pengutronix.de" <l.stach@pengutronix.de>,
        Abel Vesa <abel.vesa@nxp.com>,
        "ccaione@baylibre.com" <ccaione@baylibre.com>,
        "angus@akkea.ca" <angus@akkea.ca>,
        "andrew.smirnov@gmail.com" <andrew.smirnov@gmail.com>,
        "agx@sigxcpu.org" <agx@sigxcpu.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>
Cc:     dl-linux-imx <linux-imx@nxp.com>,
        Arnd Bergmann <arnd.bergmann@linaro.org>
References: <20190623123850.22584-1-Anson.Huang@nxp.com>
 <55abafbd-c010-32b5-6d76-26040830d5b0@linaro.org>
 <DB3PR0402MB3916AB9F2260B0E46CCDDEC0F5E20@DB3PR0402MB3916.eurprd04.prod.outlook.com>
 <9c017ba9-ac6b-480b-d1f3-120289343101@linaro.org>
 <DB3PR0402MB3916ED4AB17B6DDD2248DD44F5FD0@DB3PR0402MB3916.eurprd04.prod.outlook.com>
 <8f8aa6e0-5f31-8047-14b5-0e1f65316453@linaro.org>
 <DB3PR0402MB39162DB95FA958AC1425BFFDF5FD0@DB3PR0402MB3916.eurprd04.prod.outlook.com>
From:   Daniel Lezcano <daniel.lezcano@linaro.org>
Openpgp: preference=signencrypt
Autocrypt: addr=daniel.lezcano@linaro.org; prefer-encrypt=mutual; keydata=
 mQINBFv/yykBEADDdW8RZu7iZILSf3zxq5y8YdaeyZjI/MaqgnvG/c3WjFaunoTMspeusiFE
 sXvtg3ehTOoyD0oFjKkHaia1Zpa1m/gnNdT/WvTveLfGA1gH+yGes2Sr53Ht8hWYZFYMZc8V
 2pbSKh8wepq4g8r5YI1XUy9YbcTdj5mVrTklyGWA49NOeJz2QbfytMT3DJmk40LqwK6CCSU0
 9Ed8n0a+vevmQoRZJEd3Y1qXn2XHys0F6OHCC+VLENqNNZXdZE9E+b3FFW0lk49oLTzLRNIq
 0wHeR1H54RffhLQAor2+4kSSu8mW5qB0n5Eb/zXJZZ/bRiXmT8kNg85UdYhvf03ZAsp3qxcr
 xMfMsC7m3+ADOtW90rNNLZnRvjhsYNrGIKH8Ub0UKXFXibHbafSuq7RqyRQzt01Ud8CAtq+w
 P9EftUysLtovGpLSpGDO5zQ++4ZGVygdYFr318aGDqCljKAKZ9hYgRimPBToDedho1S1uE6F
 6YiBFnI3ry9+/KUnEP6L8Sfezwy7fp2JUNkUr41QF76nz43tl7oersrLxHzj2dYfWUAZWXva
 wW4IKF5sOPFMMgxoOJovSWqwh1b7hqI+nDlD3mmVMd20VyE9W7AgTIsvDxWUnMPvww5iExlY
 eIC0Wj9K4UqSYBOHcUPrVOKTcsBVPQA6SAMJlt82/v5l4J0pSQARAQABtCpEYW5pZWwgTGV6
 Y2FubyA8ZGFuaWVsLmxlemNhbm9AbGluYXJvLm9yZz6JAlcEEwEIAEECGwEFCwkIBwIGFQoJ
 CAsCBBYCAwECHgECF4ACGQEWIQQk1ibyU76eh+bOW/SP9LjScWdVJwUCXAkeagUJDRnjhwAK
 CRCP9LjScWdVJ+vYEACStDg7is2JdE7xz1PFu7jnrlOzoITfw05BurgJMqlvoiFYt9tEeUMl
 zdU2+r0cevsmepqSUVuUvXztN8HA/Ep2vccmWnCXzlE56X1AK7PRRdaQd1SK/eVsJVaKbQTr
 ii0wjbs6AU1uo0LdLINLjwwItnQ83/ttbf1LheyN8yknlch7jn6H6J2A/ORZECTfJbG4ecVr
 7AEm4A/G5nyPO4BG7dMKtjQ+crl/pSSuxV+JTDuoEWUO+YOClg6azjv8Onm0cQ46x9JRtahw
 YmXdIXD6NsJHmMG9bKmVI0I7o5Q4XL52X6QxkeMi8+VhvqXXIkIZeizZe5XLTYUvFHLdexzX
 Xze0LwLpmMObFLifjziJQsLP2lWwOfg6ZiH8z8eQJFB8bYTSMqmfTulB61YO0mhd676q17Y7
 Z7u3md3CLH7rh61wU1g7FcLm9p5tXXWWaAud9Aa2kne2O3sirO0+JhsKbItz3d9yXuWgv6w3
 heOIF0b91JyrY6tjz42hvyjxtHywRr4cdAEQa2S7HeQkw48BQOG6PqQ9d3FYU34pt3WFJ19V
 A5qqAiEjqc4N0uPkC79W32yLGdyg0EEe8v0Uhs3CxM9euGg37kr5fujMm+akMtR1ENITo+UI
 fgsxdwjBD5lNb/UGodU4QvPipB/xx4zz7pS5+2jGimfLeoe7mgGJxrkBDQRb/8z6AQgAvSkg
 5w7dVCSbpP6nXc+i8OBz59aq8kuL3YpxT9RXE/y45IFUVuSc2kuUj683rEEgyD7XCf4QKzOw
 +XgnJcKFQiACpYAowhF/XNkMPQFspPNM1ChnIL5KWJdTp0DhW+WBeCnyCQ2pzeCzQlS/qfs3
 dMLzzm9qCDrrDh/aEegMMZFO+reIgPZnInAcbHj3xUhz8p2dkExRMTnLry8XXkiMu9WpchHy
 XXWYxXbMnHkSRuT00lUfZAkYpMP7La2UudC/Uw9WqGuAQzTqhvE1kSQe0e11Uc+PqceLRHA2
 bq/wz0cGriUrcCrnkzRmzYLoGXQHqRuZazMZn2/pSIMZdDxLbwARAQABiQI2BBgBCAAgFiEE
 JNYm8lO+nofmzlv0j/S40nFnVScFAlv/zPoCGwwACgkQj/S40nFnVSf4OhAAhWJPjgUu6VfS
 mV53AUGIyqpOynPvSaMoGJzhNsDeNUDfV5dEZN8K4qjuz2CTNvGIyt4DE/IJbtasvi5dW4wW
 Fl85bF6xeLM0qpCaZtXAsU5gzp3uT7ut++nTPYW+CpfYIlIpyOIzVAmw7rZbfgsId2Lj7g1w
 QCjvGHw19mq85/wiEiZZNHeJQ3GuAr/uMoiaRBnf6wVcdpUTFMXlkE8/tYHPWbW0YKcKFwJ3
 uIsNxZUe6coNzYnL0d9GK2fkDoqKfKbFjNhW9TygfeL2Qhk949jMGQudFS3zlwvN9wwVaC0i
 KC/D303DiTnB0WFPT8CltMAZSbQ1WEWfwqxhY26di3k9pj+X3BfOmDL9GBlnRTSgwjqjqzpG
 VZsWouuTfXd9ZPPzvYdUBrlTKgojk1C8v4fhSqb+ard+bZcwNp8Tzl/EI9ygw6lYEATGCUYI
 Wco+fjehCgG1FWvWavMU+jLNs8/8uwj1u+BtRpWFj4ug/VaDDIuiApKPwl1Ge+zoC7TLMtyb
 c00W5/8EckjmNgLDIINEsOsidMH61ZOlwDKCxo2lbV+Ij078KHBIY76zuHlwonEQaHLCAdqm
 WiI95pYZNruAJEqZCpvXDdClmBVMZRDRePzSljCvoHxn7ArEt3F14mabn2RRq/hqB8IhC6ny
 xAEPQIZaxxginIFYEziOjR65AQ0EW//NCAEIALcJqSmQdkt04vIBD12dryF6WcVWYvVwhspt
 RlZbZ/NZ6nzarzEYPFcXaYOZCOCv+Xtm6hB8fh5XHd7Y8CWuZNDVp3ozuqwTkzQuux/aVdNb
 Fe4VNeKGN2FK1aNlguAXJNCDNRCpWgRHuU3rWwGUMgentJogARvxfex2/RV/5mzYG/N1DJKt
 F7g1zEcQD3JtK6WOwZXd+NDyke3tdG7vsNRFjMDkV4046bOOh1BKbWYu8nL3UtWBxhWKx3Pu
 1VOBUVwL2MJKW6umk+WqUNgYc2bjelgcTSdz4A6ZhJxstUO4IUfjvYRjoqle+dQcx1u+mmCn
 8EdKJlbAoR4NUFZy7WUAEQEAAYkDbAQYAQgAIBYhBCTWJvJTvp6H5s5b9I/0uNJxZ1UnBQJb
 /80IAhsCAUAJEI/0uNJxZ1UnwHQgBBkBCAAdFiEEGn3N4YVz0WNVyHskqDIjiipP6E8FAlv/
 zQgACgkQqDIjiipP6E+FuggAl6lkO7BhTkrRbFhrcjCm0bEoYWnCkQtX9YFvElQeA7MhxznO
 BY/r1q2Uf6Ifr3YGEkLnME/tQQzUwznydM94CtRJ8KDSa1CxOseEsKq6B38xJtjgYSxNdgQb
 EIfCzUHIGfk94AFKPdV6pqqSU5VpPUagF+JxiAkoEPOdFiQCULFNRLMsOtG7yp8uSyJRp6Tz
 cQ+0+1QyX1krcHBUlNlvfdmL9DM+umPtbS9F6oRph15mvKVYiPObI1z8ymHoc68ReWjhUuHc
 IDQs4w9rJVAyLypQ0p+ySDcTc+AmPP6PGUayIHYX63Q0KhJFgpr1wH0pHKpC78DPtX1a7HGM
 7MqzQ4NbD/4oLKKwByrIp12wLpSe3gDQPxLpfGgsJs6BBuAGVdkrdfIx2e6ENnwDoF0Veeji
 BGrVmjVgLUWV9nUP92zpyByzd8HkRSPNZNlisU4gnz1tKhQl+j6G/l2lDYsqKeRG55TXbu9M
 LqJYccPJ85B0PXcy63fL9U5DTysmxKQ5RgaxcxIZCM528ULFQs3dfEx5euWTWnnh7pN30RLg
 a+0AjSGd886Bh0kT1Dznrite0dzYlTHlacbITZG84yRk/gS7DkYQdjL8zgFr/pxH5CbYJDk0
 tYUhisTESeesbvWSPO5uNqqy1dAFw+dqRcF5gXIh3NKX0gqiAA87NM7nL5ym/CNpJ7z7nRC8
 qePOXubgouxumi5RQs1+crBmCDa/AyJHKdG2mqCt9fx5EPbDpw6Zzx7hgURh4ikHoS7/tLjK
 iqWjuat8/HWc01yEd8rtkGuUcMqbCi1XhcAmkaOnX8FYscMRoyyMrWClRZEQRokqZIj79+PR
 adkDXtr4MeL8BaB7Ij2oyRVjXUwhFQNKi5Z5Rve0a3zvGkkqw8Mz20BOksjSWjAF6g9byukl
 CUVjC03PdMSufNLK06x5hPc/c4tFR4J9cLrV+XxdCX7r0zGos9SzTPGNuIk1LK++S3EJhLFj
 4eoWtNhMWc1uiTf9ENza0ntqH9XBWEQ6IA1gubCniGG+Xg==
Message-ID: <f29a9a4b-8922-c8b5-f197-d33853f6341e@linaro.org>
Date:   Thu, 27 Jun 2019 12:27:37 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.7.0
MIME-Version: 1.0
In-Reply-To: <DB3PR0402MB39162DB95FA958AC1425BFFDF5FD0@DB3PR0402MB3916.eurprd04.prod.outlook.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


Hi Anson,

On 27/06/2019 10:11, Anson Huang wrote:
> Hi, Daniel
> 
>> On 27/06/2019 02:43, Anson Huang wrote:
>>> Hi, Daniel
>>>
>>>> On 26/06/2019 03:42, Anson Huang wrote:
>>>>> Hi, Daniel
>>>>>
>>>>>> On 23/06/2019 14:38, Anson.Huang@nxp.com wrote:
>>>>>>> From: Anson Huang <Anson.Huang@nxp.com>
>>>>>>>
>>>>>>> Systems which use platform driver model for clock driver require
>>>>>>> the clock frequency to be supplied via device tree when system
>>>>>>> counter driver is enabled.
>>>>>>>
>>>>>>> This is necessary as in the platform driver model the of_clk
>>>>>>> operations do not work correctly because system counter driver is
>>>>>>> initialized in early phase of system boot up, and clock driver
>>>>>>> using platform driver model is NOT ready at that time, it will
>>>>>>> cause system counter driver initialization failed.
>>>>>>>
>>>>>>> Add the optinal clock-frequency to the device tree bindings of the
>>>>>>> NXP system counter, so the frequency can be handed in and the
>>>>>>> of_clk operations can be skipped.
>>>>>>
>>>>>> Isn't it possible to create a fixed-clock and refer to it? So no
>>>>>> need to create a specific action before calling timer_of_init() ?
>>>>>>
>>>>>
>>>>> As the clock must be ready before the TIMER_OF_DECLARE, so adding a
>>>>> CLK_OF_DECLARE_DRIVER in clock driver to ONLY register a fixed-clock?
>>>>> The system counter's frequency are different on different platforms,
>>>>> so adding fixed clock in system counter driver is NOT a good idea,
>>>>> ONLY the DT node or the clock driver can create this fixed clock
>>>>> according to
>>>> platforms, can you advise where to create this fixed clock is better?
>>>>
>>>> Can you point me to a DT with the "nxp,sysctr-timer" ?
>>>
>>> The DT node of system counter is new added in 3/3 of this patch
>>> series, also can be found from below link:
>>> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatc
>>>
>> hwork.kernel.org%2Fpatch%2F11011703%2F&amp;data=02%7C01%7Canson.
>> huang%
>>>
>> 40nxp.com%7C8b9519ecceb346712be808d6fad675e4%7C686ea1d3bc2b4c6f
>> a92cd99
>>>
>> c5c301635%7C0%7C0%7C636972196338405582&amp;sdata=sOQQzDFxoCqe
>> VuHFuYPHh
>>> F8Bdj2Zu9WS7Go%2FV9lrWa8%3D&amp;reserved=0
>>
>> Sorry, I was unclear. I meant a patch with the timer defined using a clock as
>> defined currently in the binding (no clock-frequency).
> 
> OK, for i.MX8MM, we use clocks, check below patch series:
> 
> https://patchwork.kernel.org/patch/11008519/
> 
> code piece as below:
> 
> +			system_counter: timer@306a0000 {
> +				compatible = "nxp,sysctr-timer";
> +				reg = <0x306a0000 0x30000>;
> +				interrupts = <GIC_SPI 47 IRQ_TYPE_LEVEL_HIGH>,
> +					     <GIC_SPI 48 IRQ_TYPE_LEVEL_HIGH>;
> +				clocks = <&clk IMX8MM_CLK_SYS_CTR>;
> +				clock-names = "per";
> +			};

Thanks,

The fixed-clock can help to keep the code and the DT definition for the
timer untouched as the 'clocks' above will refer to it. But that means
we describe a fake clock. So it is up to you to decide if you want to
stick the clock-frequency or use a fixed-clock.


-- 
 <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog