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From: Kamlesh Gurudasani <kamlesh@ti.com>
To: "Kumar, Udit" <u-kumar1@ti.com>, CHANDRU DHAVAMANI <chandru@ti.com>,
        Nishanth Menon <nm@ti.com>
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        <vigneshr@ti.com>, <mturquette@baylibre.com>, <sboyd@kernel.org>,
        <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
        <linux-clk@vger.kernel.org>, <u-kumar1@ti.com>
Subject: Re: [PATCH v2] clk: keystone: sci-clk: Adding support for non
 contiguous clocks
In-Reply-To: <a4fdbcfe-e0e0-4280-8638-e39b6b46778e@ti.com>
References: <20240206104357.3803517-1-u-kumar1@ti.com>
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 <871q9pzoiq.fsf@kamlesh.i-did-not-set--mail-host-address--so-tickle-me>
 <c5b6bd1d-dbb4-4bfb-8b3e-9b0733e2ba5d@ti.com>
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 <a4fdbcfe-e0e0-4280-8638-e39b6b46778e@ti.com>
Date: Tue, 6 Feb 2024 21:24:01 +0530
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"Kumar, Udit" <u-kumar1@ti.com> writes:

>>>>> 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 ?
>>
>>
>> get_clock doesn't require any flags to be passed.
>
>
> May be firmware does not need it but=A0 I was referring to
>
> https://elixir.bootlin.com/linux/latest/source/drivers/clk/keystone/sci-c=
lk.c#L78
Just took a look,

I now understand the reason for confusion,

#define TI_SCI_MSG_SET_CLOCK_STATE	0x0100
#define TI_SCI_MSG_GET_CLOCK_STATE	0x0101

cops->get_clock =3D ti_sci_cmd_get_clock;  --> refers to
TI_SCI_MSG_SET_CLOCK_STATE
That's why we are passing the flag from linux for get_clock

Linux is using terminology of get/put.

As Chandru pointed, we don't have to pass flags, cause he is refering
to TI_SCI_MSG_GET_CLOCK_STATE

Below functions passes TI_SCI_MSG_GET_CLOCK_STATE to DM, which is what
we actually want.
cops->is_auto =3D ti_sci_cmd_clk_is_auto;
cops->is_on =3D ti_sci_cmd_clk_is_on;
cops->is_off =3D ti_sci_cmd_clk_is_off;

Which should be safe to call, Chandru can confirm.

Regards,
Kamlesh
>
>
>
>>
>>
>>>
>>>
>>>> Regards,
>>>> Kamlesh