Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) client-ip=23.128.96.32;
Message-ID: <a701ba6e-ae4e-4c4d-9d93-c54e56c3348e@linaro.org>
Date:   Fri, 24 Nov 2023 12:35:44 +0100
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [LINUX PATCH v2 1/3] clocksource: timer-cadence-ttc: Do not probe
 TTC device configured as PWM
Content-Language: en-US
To:     "Sayyed, Mubin" <mubin.sayyed@amd.com>
Cc:     "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-pwm@vger.kernel.org" <linux-pwm@vger.kernel.org>,
        "git (AMD-Xilinx)" <git@amd.com>,
        "mubin10@gmail.com" <mubin10@gmail.com>,
        "krzysztof.kozlowski+dt@linaro.org" 
        <krzysztof.kozlowski+dt@linaro.org>,
        "u.kleine-koenig@pengutronix.de" <u.kleine-koenig@pengutronix.de>,
        "thierry.reding@gmail.com" <thierry.reding@gmail.com>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "conor+dt@kernel.org" <conor+dt@kernel.org>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
        "Simek, Michal" <michal.simek@amd.com>
References: <20231114124748.581850-1-mubin.sayyed@amd.com>
 <20231114124748.581850-2-mubin.sayyed@amd.com>
 <d37db10b-f9fa-49b0-8b1e-36e20acbcfd6@linaro.org>
 <DM4PR12MB593888B73B65D25E42490EF29DB1A@DM4PR12MB5938.namprd12.prod.outlook.com>
 <e0f28ec5-b980-490b-a857-5218fe521381@linaro.org>
 <DM4PR12MB5938CB10059DF7E39A2A0E239DB8A@DM4PR12MB5938.namprd12.prod.outlook.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Autocrypt: addr=krzysztof.kozlowski@linaro.org; keydata=
 xsFNBFVDQq4BEAC6KeLOfFsAvFMBsrCrJ2bCalhPv5+KQF2PS2+iwZI8BpRZoV+Bd5kWvN79
 cFgcqTTuNHjAvxtUG8pQgGTHAObYs6xeYJtjUH0ZX6ndJ33FJYf5V3yXqqjcZ30FgHzJCFUu
 JMp7PSyMPzpUXfU12yfcRYVEMQrmplNZssmYhiTeVicuOOypWugZKVLGNm0IweVCaZ/DJDIH
 gNbpvVwjcKYrx85m9cBVEBUGaQP6AT7qlVCkrf50v8bofSIyVa2xmubbAwwFA1oxoOusjPIE
 J3iadrwpFvsZjF5uHAKS+7wHLoW9hVzOnLbX6ajk5Hf8Pb1m+VH/E8bPBNNYKkfTtypTDUCj
 NYcd27tjnXfG+SDs/EXNUAIRefCyvaRG7oRYF3Ec+2RgQDRnmmjCjoQNbFrJvJkFHlPeHaeS
 BosGY+XWKydnmsfY7SSnjAzLUGAFhLd/XDVpb1Een2XucPpKvt9ORF+48gy12FA5GduRLhQU
 vK4tU7ojoem/G23PcowM1CwPurC8sAVsQb9KmwTGh7rVz3ks3w/zfGBy3+WmLg++C2Wct6nM
 Pd8/6CBVjEWqD06/RjI2AnjIq5fSEH/BIfXXfC68nMp9BZoy3So4ZsbOlBmtAPvMYX6U8VwD
 TNeBxJu5Ex0Izf1NV9CzC3nNaFUYOY8KfN01X5SExAoVTr09ewARAQABzTRLcnp5c3p0b2Yg
 S296bG93c2tpIDxrcnp5c3p0b2Yua296bG93c2tpQGxpbmFyby5vcmc+wsGUBBMBCgA+FiEE
 m9B+DgxR+NWWd7dUG5NDfTtBYpsFAmI+BxMCGwMFCRRfreEFCwkIBwIGFQoJCAsCBBYCAwEC
 HgECF4AACgkQG5NDfTtBYptgbhAAjAGunRoOTduBeC7V6GGOQMYIT5n3OuDSzG1oZyM4kyvO
 XeodvvYv49/ng473E8ZFhXfrre+c1olbr1A8pnz9vKVQs9JGVa6wwr/6ddH7/yvcaCQnHRPK
 mnXyP2BViBlyDWQ71UC3N12YCoHE2cVmfrn4JeyK/gHCvcW3hUW4i5rMd5M5WZAeiJj3rvYh
 v8WMKDJOtZFXxwaYGbvFJNDdvdTHc2x2fGaWwmXMJn2xs1ZyFAeHQvrp49mS6PBQZzcx0XL5
 cU9ZjhzOZDn6Apv45/C/lUJvPc3lo/pr5cmlOvPq1AsP6/xRXsEFX/SdvdxJ8w9KtGaxdJuf
 rpzLQ8Ht+H0lY2On1duYhmro8WglOypHy+TusYrDEry2qDNlc/bApQKtd9uqyDZ+rx8bGxyY
 qBP6bvsQx5YACI4p8R0J43tSqWwJTP/R5oPRQW2O1Ye1DEcdeyzZfifrQz58aoZrVQq+innR
 aDwu8qDB5UgmMQ7cjDSeAQABdghq7pqrA4P8lkA7qTG+aw8Z21OoAyZdUNm8NWJoQy8m4nUP
 gmeeQPRc0vjp5JkYPgTqwf08cluqO6vQuYL2YmwVBIbO7cE7LNGkPDA3RYMu+zPY9UUi/ln5
 dcKuEStFZ5eqVyqVoZ9eu3RTCGIXAHe1NcfcMT9HT0DPp3+ieTxFx6RjY3kYTGLOwU0EVUNc
 NAEQAM2StBhJERQvgPcbCzjokShn0cRA4q2SvCOvOXD+0KapXMRFE+/PZeDyfv4dEKuCqeh0
 hihSHlaxTzg3TcqUu54w2xYskG8Fq5tg3gm4kh1Gvh1LijIXX99ABA8eHxOGmLPRIBkXHqJY
 oHtCvPc6sYKNM9xbp6I4yF56xVLmHGJ61KaWKf5KKWYgA9kfHufbja7qR0c6H79LIsiYqf92
 H1HNq1WlQpu/fh4/XAAaV1axHFt/dY/2kU05tLMj8GjeQDz1fHas7augL4argt4e+jum3Nwt
 yupodQBxncKAUbzwKcDrPqUFmfRbJ7ARw8491xQHZDsP82JRj4cOJX32sBg8nO2N5OsFJOcd
 5IE9v6qfllkZDAh1Rb1h6DFYq9dcdPAHl4zOj9EHq99/CpyccOh7SrtWDNFFknCmLpowhct9
 5ZnlavBrDbOV0W47gO33WkXMFI4il4y1+Bv89979rVYn8aBohEgET41SpyQz7fMkcaZU+ok/
 +HYjC/qfDxT7tjKXqBQEscVODaFicsUkjheOD4BfWEcVUqa+XdUEciwG/SgNyxBZepj41oVq
 FPSVE+Ni2tNrW/e16b8mgXNngHSnbsr6pAIXZH3qFW+4TKPMGZ2rZ6zITrMip+12jgw4mGjy
 5y06JZvA02rZT2k9aa7i9dUUFggaanI09jNGbRA/ABEBAAHCwXwEGAEKACYCGwwWIQSb0H4O
 DFH41ZZ3t1Qbk0N9O0FimwUCYDzvagUJFF+UtgAKCRAbk0N9O0Fim9JzD/0auoGtUu4mgnna
 oEEpQEOjgT7l9TVuO3Qa/SeH+E0m55y5Fjpp6ZToc481za3xAcxK/BtIX5Wn1mQ6+szfrJQ6
 59y2io437BeuWIRjQniSxHz1kgtFECiV30yHRgOoQlzUea7FgsnuWdstgfWi6LxstswEzxLZ
 Sj1EqpXYZE4uLjh6dW292sO+j4LEqPYr53hyV4I2LPmptPE9Rb9yCTAbSUlzgjiyyjuXhcwM
 qf3lzsm02y7Ooq+ERVKiJzlvLd9tSe4jRx6Z6LMXhB21fa5DGs/tHAcUF35hSJrvMJzPT/+u
 /oVmYDFZkbLlqs2XpWaVCo2jv8+iHxZZ9FL7F6AHFzqEFdqGnJQqmEApiRqH6b4jRBOgJ+cY
 qc+rJggwMQcJL9F+oDm3wX47nr6jIsEB5ZftdybIzpMZ5V9v45lUwmdnMrSzZVgC4jRGXzsU
 EViBQt2CopXtHtYfPAO5nAkIvKSNp3jmGxZw4aTc5xoAZBLo0OV+Ezo71pg3AYvq0a3/oGRG
 KQ06ztUMRrj8eVtpImjsWCd0bDWRaaR4vqhCHvAG9iWXZu4qh3ipie2Y0oSJygcZT7H3UZxq
 fyYKiqEmRuqsvv6dcbblD8ZLkz1EVZL6djImH5zc5x8qpVxlA0A0i23v5QvN00m6G9NFF0Le
 D2GYIS41Kv4Isx2dEFh+/Q==
In-Reply-To: <DM4PR12MB5938CB10059DF7E39A2A0E239DB8A@DM4PR12MB5938.namprd12.prod.outlook.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 24/11/2023 12:03, Sayyed, Mubin wrote:
> Hi Krzysztof,
> 
>> -----Original Message-----
>> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>> Sent: Wednesday, November 15, 2023 5:41 PM
>> To: Sayyed, Mubin <mubin.sayyed@amd.com>
>> Cc: linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
>> devicetree@vger.kernel.org; linux-pwm@vger.kernel.org; git (AMD-Xilinx)
>> <git@amd.com>; mubin10@gmail.com; krzysztof.kozlowski+dt@linaro.org;
>> u.kleine-koenig@pengutronix.de; thierry.reding@gmail.com;
>> robh+dt@kernel.org; conor+dt@kernel.org; tglx@linutronix.de;
>> daniel.lezcano@linaro.org; Simek, Michal <michal.simek@amd.com>
>> Subject: Re: [LINUX PATCH v2 1/3] clocksource: timer-cadence-ttc: Do not probe
>> TTC device configured as PWM
>>
>> On 15/11/2023 06:55, Sayyed, Mubin wrote:
>>>>> +	/*
>>>>> +	 * If pwm-cells property is present in TTC node,
>>>>> +	 * it would be treated as PWM device.
>>>>> +	 */
>>>>> +	if (of_property_read_bool(timer, "#pwm-cells"))
>>>>> +		return -ENODEV;
>>>>
>>>> You will introduce dmesg errors, so regressions.
>>>>
>>> [Mubin]: I will change it to "return 0" to avoid dmesg errors.
>>
>> No, because solution is wrong.
>>
>>>
>>>> This does not look right. What you want is to bind one device driver
>>>> and choose different functionality based on properties.
>>> [Mubin]:  I am doing it based on earlier discussion related to AXI Timer PWM
>> driver.  It was suggested to use #pwm-cells property for identifying role of
>> device(PWM/clocksource) https://lore.kernel.org/linux-
>> devicetree/20210513021631.GA878860@robh.at.kernel.org/.
>>
>> You are mixing bindings with driver. I said here about driver and yes - you must
>> use pwm-cells to differentiate that. It's obvious.
>>
>> So again, one driver binding.
> [Mubin]: I will explore whether mfd framework can be used to handle this.

You do not need MFD for this, because you do not have a really MFD. This
is just one device, so I expect here one driver. Why do you need
multiple drivers (which also would solve that problem but why?)?

Best regards,
Krzysztof