linux-kernel - Re: [PATCH v3 06/15] clk: tegra: Remove tegra_pmc_clk

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Message-ID: <c81ccd45-781e-0fce-4f20-65281b8c6119@nvidia.com>
Date:   Sat, 7 Dec 2019 11:35:18 -0800
From:   Sowjanya Komatineni <skomatineni@...dia.com>
To:     Dmitry Osipenko <digetx@...il.com>, <thierry.reding@...il.com>,
        <jonathanh@...dia.com>, <mperttunen@...dia.com>,
        <gregkh@...uxfoundation.org>, <sboyd@...nel.org>,
        <tglx@...utronix.de>, <robh+dt@...nel.org>, <mark.rutland@....com>
CC:     <allison@...utok.net>, <pdeschrijver@...dia.com>,
        <pgaikwad@...dia.com>, <mturquette@...libre.com>,
        <horms+renesas@...ge.net.au>, <Jisheng.Zhang@...aptics.com>,
        <krzk@...nel.org>, <arnd@...db.de>, <spujar@...dia.com>,
        <josephl@...dia.com>, <vidyas@...dia.com>,
        <daniel.lezcano@...aro.org>, <mmaddireddy@...dia.com>,
        <markz@...dia.com>, <devicetree@...r.kernel.org>,
        <linux-clk@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <lgirdwood@...il.com>,
        <broonie@...nel.org>, <perex@...ex.cz>, <tiwai@...e.com>,
        <alexios.zavras@...el.com>, <alsa-devel@...a-project.org>
Subject: Re: [PATCH v3 06/15] clk: tegra: Remove tegra_pmc_clk_init along with
 clk ids


On 12/7/19 7:04 AM, Dmitry Osipenko wrote:
> 07.12.2019 17:43, Dmitry Osipenko пишет:
>> 07.12.2019 17:33, Dmitry Osipenko пишет:
>>> 06.12.2019 05:48, Sowjanya Komatineni пишет:
>>>> Current Tegra clock driver registers PMC clocks clk_out_1, clk_out_2,
>>>> clk_out_3 and blink output in tegra_pmc_init() which does direct Tegra
>>>> PMC access during clk_ops and these PMC register read and write access
>>>> will not happen when PMC is in secure mode.
>>>>
>>>> Any direct PMC register access from non-secure world will not go
>>>> through and all the PMC clocks and blink control are done in Tegra PMC
>>>> driver with PMC as clock provider.
>>>>
>>>> This patch removes tegra_pmc_clk_init along with corresponding clk ids
>>>> from Tegra clock driver.
>>>>
>>>> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
>>>> ---
>>> [snip]
>>>
>>>> @@ -1230,9 +1222,6 @@ static struct tegra_clk_init_table init_table[] __initdata = {
>>>>   	{ TEGRA30_CLK_PLL_A, TEGRA30_CLK_CLK_MAX, 564480000, 1 },
>>>>   	{ TEGRA30_CLK_PLL_A_OUT0, TEGRA30_CLK_CLK_MAX, 11289600, 1 },
>>>>   	{ TEGRA30_CLK_EXTERN1, TEGRA30_CLK_PLL_A_OUT0, 0, 1 },
>>> Perhaps these clocks do not need to be always-enabled?
>>>
>>> [snip]
>>>
>> Also, EXTERN1 parent configuration should be moved to the audio
>> driver/device-tree as well.
> Ah, I missed that it's done in the patch #10.
Yes its done in Patch#10
>
>> Maybe it even makes sense to move the whole configuration, including
>> PLLA. I don't see why clk driver need to do something for the audio driver.

Current ASoC driver already takes care of PLLA rate and enables.

So PLLA init can be removed from clock driver too. I didn't went through 
complete audio driver to be confident to remove this.

But PLLA is needed for i2s clock also and currently I2S driver takes 
care of only I2S clock rate using PLLA as parent set by clock driver and 
clock driver enables PLLA earlier to have it ready by the time both I2S 
driver and ASoC driver .