linux-kernel - Re: [PATCH v2] clk: keystone: sci-clk: Adding support for non contiguous clocks

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Message-ID: <c5b6bd1d-dbb4-4bfb-8b3e-9b0733e2ba5d@ti.com>
Date: Tue, 6 Feb 2024 19:45:47 +0530
From: "Kumar, Udit" <u-kumar1@...com>
To: Kamlesh Gurudasani <kamlesh@...com>, Nishanth Menon <nm@...com>,
        <chandru@...com>
CC: <kristo@...nel.org>, <ssantosh@...nel.org>, <rishabh@...com>,
        <vigneshr@...com>, <mturquette@...libre.com>, <sboyd@...nel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-clk@...r.kernel.org>, <u-kumar1@...com>
Subject: Re: [PATCH v2] clk: keystone: sci-clk: Adding support for non
 contiguous clocks


On 2/6/2024 7:24 PM, Kamlesh Gurudasani wrote:
> Nishanth Menon <nm@...com> writes:
>
>> On 16:13-20240206, Udit Kumar wrote:
>>> Most of clocks and their parents are defined in contiguous range,
>>> But in few cases, there is gap in clock numbers[0].
>>> Driver assumes clocks to be in contiguous range, and add their clock
>>> ids incrementally.
>>>
>>> New firmware started returning error while calling get_freq and is_on
>>> API for non-available clock ids.
>>>
>>> In this fix, driver checks and adds only valid clock ids.
>>>
>>> Fixes: 3c13933c6033 ("clk: keystone: sci-clk: add support for dynamically probing clocks")
>>>
>>> [0] https://software-dl.ti.com/tisci/esd/latest/5_soc_doc/j7200/clocks.html
>>> Section Clocks for NAVSS0_CPTS_0 Device,
>>> clock id 12-15 not present.
>>>
>>> Signed-off-by: Udit Kumar <u-kumar1@...com>
>>>   				while (num_parents--) {
>>> +					/* Check if this clock id is valid */
>>> +					ret = provider->ops->get_freq(provider->sci,
>>> +						sci_clk->dev_id, clk_id, &freq);
>> get_freq is a bit expensive as it has to walk the clock tree to find
>> the clock frequency (at least the first time?). just wondering if
>> there is lighter alternative here?
>>
> How about get_clock? Doesn't read the registers at least.

Said API needs, some flags to be passed,

Can those flag be set to zero, Chandru ?


> Regards,
> Kamlesh