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Date: Mon, 9 Dec 2019 16:54:31 -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 08/15] ASoC: tegra: Add audio mclk control through
clk_out_1 and extern1
On 12/9/19 3:12 PM, Dmitry Osipenko wrote:
> 10.12.2019 02:05, Sowjanya Komatineni пишет:
>> On 12/9/19 12:06 PM, Dmitry Osipenko wrote:
>>> 07.12.2019 22:20, Sowjanya Komatineni пишет:
>>>> On 12/7/19 6:58 AM, Dmitry Osipenko wrote:
>>>>> 06.12.2019 05:48, Sowjanya Komatineni пишет:
>>>>>> Current ASoC driver uses extern1 as cdev1 clock from Tegra30 onwards
>>>>>> through device tree.
>>>>>>
>>>>>> Actual audio mclk is clk_out_1 and to use PLLA for mclk rate control,
>>>>>> need to clk_out_1_mux parent to extern1 and extern1 parent to
>>>>>> PLLA_OUT0.
>>>>>>
>>>>>> Currently Tegra clock driver init sets the parents and enables both
>>>>>> clk_out_1 and extern1 clocks. But these clocks parent and enables
>>>>>> should
>>>>>> be controlled by ASoC driver.
>>>>>>
>>>>>> Clock parents can be specified in device tree using assigned-clocks
>>>>>> and assigned-clock-parents.
>>>>>>
>>>>>> To enable audio mclk, both clk_out_1 and extern1 clocks need to be
>>>>>> enabled.
>>>>>>
>>>>>> This patch configures parents for clk_out_1 and extern1 clocks if
>>>>>> device
>>>>>> tree does not specify clock parents inorder to support old device tree
>>>>>> and controls mclk using both clk_out_1 and extern1 clocks.
>>>>>>
>>>>>> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
>>>>>> ---
>>>>>> sound/soc/tegra/tegra_asoc_utils.c | 66
>>>>>> ++++++++++++++++++++++++++++++++++++++
>>>>>> sound/soc/tegra/tegra_asoc_utils.h | 1 +
>>>>>> 2 files changed, 67 insertions(+)
>>>>>>
>>>>>> diff --git a/sound/soc/tegra/tegra_asoc_utils.c
>>>>>> b/sound/soc/tegra/tegra_asoc_utils.c
>>>>>> index 536a578e9512..8e3a3740df7c 100644
>>>>>> --- a/sound/soc/tegra/tegra_asoc_utils.c
>>>>>> +++ b/sound/soc/tegra/tegra_asoc_utils.c
>>>>>> @@ -60,6 +60,7 @@ int tegra_asoc_utils_set_rate(struct
>>>>>> tegra_asoc_utils_data *data, int srate,
>>>>>> data->set_mclk = 0;
>>>>>> clk_disable_unprepare(data->clk_cdev1);
>>>>>> + clk_disable_unprepare(data->clk_extern1);
>>>>>> clk_disable_unprepare(data->clk_pll_a_out0);
>>>>>> clk_disable_unprepare(data->clk_pll_a);
>>>>>> @@ -89,6 +90,14 @@ int tegra_asoc_utils_set_rate(struct
>>>>>> tegra_asoc_utils_data *data, int srate,
>>>>>> return err;
>>>>>> }
>>>>>> + if (!IS_ERR_OR_NULL(data->clk_extern1)) {
>>>>>> + err = clk_prepare_enable(data->clk_extern1);
>>>>>> + if (err) {
>>>>>> + dev_err(data->dev, "Can't enable extern1: %d\n", err);
>>>>>> + return err;
>>>>>> + }
>>>>>> + }
>>>>>> +
>>>>>> err = clk_prepare_enable(data->clk_cdev1);
>>>>>> if (err) {
>>>>>> dev_err(data->dev, "Can't enable cdev1: %d\n", err);
>>>>>> @@ -109,6 +118,7 @@ int tegra_asoc_utils_set_ac97_rate(struct
>>>>>> tegra_asoc_utils_data *data)
>>>>>> int err;
>>>>>> clk_disable_unprepare(data->clk_cdev1);
>>>>>> + clk_disable_unprepare(data->clk_extern1);
>>>>>> clk_disable_unprepare(data->clk_pll_a_out0);
>>>>>> clk_disable_unprepare(data->clk_pll_a);
>>>>>> @@ -142,6 +152,14 @@ int tegra_asoc_utils_set_ac97_rate(struct
>>>>>> tegra_asoc_utils_data *data)
>>>>>> return err;
>>>>>> }
>>>>>> + if (!IS_ERR_OR_NULL(data->clk_extern1)) {
>>>>>> + err = clk_prepare_enable(data->clk_extern1);
>>>>>> + if (err) {
>>>>>> + dev_err(data->dev, "Can't enable extern1: %d\n", err);
>>>>>> + return err;
>>>>>> + }
>>>>>> + }
>>>>> Why this is needed given that clk_extern1 is either a child of MCLK or
>>>>> MCLK itself (on T20)? The child clocks are enabled when the parent is
>>>>> enabled.
>>>> For T30 and later, clk_extern1 is one of the source for clk_out_1_mux.
>>>> clk_extern1 is in CAR and it has its own gate and mux.
>>>>
>>>> As audio mclk related clocks (clk_out_1, clk_out_1_mux, and extern1) are
>>>> moved into ASoC driver from clock driver
>>>>
>>>> need to enable extern1 gate as well along with clk_out1 for T30 through
>>>> T210.
>>>>
>>>> Just FYI, extern1 enable here happens only when data->clk_extern1 is
>>>> available which is for T30 onwards.
>>> clk_out_1 is the parent of extern1, thus extern1 is enabled by the clk
>>> core whenever clk_out_1 is enabled because data->clk_cdev1=clk_out_1. An
>>> I missing something?
>>>
>>> [snip]
>> extern1 is the parent for clk_out_1. explained extern1 clock path to
>> clk_out in reply to your comment in other patch of this series.
> Right, I meant extern1 the parent of clk_out_1, sorry for the confusion.
> So when clk_out_1 (child) is enabled, extern1 (parent) is enabled as well.
>
> I'll take a closer look at the other email tomorrow.
yes, will remove explicitly enabling extern1 in next version.
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