linux-kernel - Re: [PATCH v2 5/5] clk: amlogic: Change the active level of l

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Message-ID: <7e95df48-8f27-47ab-a5e8-5bc0777d41b9@amlogic.com>
Date: Thu, 30 Oct 2025 17:27:32 +0800
From: Chuan Liu <chuan.liu@...ogic.com>
To: Jerome Brunet <jbrunet@...libre.com>,
 Chuan Liu via B4 Relay <devnull+chuan.liu.amlogic.com@...nel.org>
Cc: Neil Armstrong <neil.armstrong@...aro.org>,
 Michael Turquette <mturquette@...libre.com>, Stephen Boyd
 <sboyd@...nel.org>, Kevin Hilman <khilman@...libre.com>,
 Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
 linux-amlogic@...ts.infradead.org, linux-clk@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 da@...re.computer
Subject: Re: [PATCH v2 5/5] clk: amlogic: Change the active level of l_detect

Hi Jerome,

On 10/30/2025 4:40 PM, Jerome Brunet wrote:
> [ EXTERNAL EMAIL ]
> 
> On Thu 30 Oct 2025 at 13:24, Chuan Liu via B4 Relay <devnull+chuan.liu.amlogic.com@...nel.org> wrote:
> 
>> From: Chuan Liu <chuan.liu@...ogic.com>
>>
>> l_detect controls the enable/disable of the PLL lock-detect module.
>>
>> The enable signal is normally active-high. This design ensures that
>> the module remains disabled during the power-on process, preventing
>> power fluctuations from affecting its operating state.
>>
>> For A1, the l_detect signal is active-low:
>> 0 -> Enable lock-detect module;
>> 1 -> Disable lock-detect module.
>>
>> Here, a flag CLK_MESON_PLL_L_DETECT_N is added to handle cases like
>> A1, where the signal is active-low.
> 
> Given that A1 is the only ship supporting l_detect, this change is not
> necessary.
> 
> Not now at least.
> 

The SoCs queued for upstreaming later will depend on this patch, so I
included it in this patchset.

If that’s not appropriate, would it be acceptable for me to include
it in the A4 submission instead?

>>
>> Signed-off-by: Chuan Liu <chuan.liu@...ogic.com>
>> ---
>>   drivers/clk/meson/a1-pll.c  |  1 +
>>   drivers/clk/meson/clk-pll.c | 16 ++++++++++++----
>>   drivers/clk/meson/clk-pll.h |  2 ++
>>   3 files changed, 15 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/clk/meson/a1-pll.c b/drivers/clk/meson/a1-pll.c
>> index 1f82e9c7c14e..bfe559c71402 100644
>> --- a/drivers/clk/meson/a1-pll.c
>> +++ b/drivers/clk/meson/a1-pll.c
>> @@ -137,6 +137,7 @@ static struct clk_regmap a1_hifi_pll = {
>>                .range = &a1_hifi_pll_range,
>>                .init_regs = a1_hifi_pll_init_regs,
>>                .init_count = ARRAY_SIZE(a1_hifi_pll_init_regs),
>> +             .flags = CLK_MESON_PLL_L_DETECT_N
>>        },
>>        .hw.init = &(struct clk_init_data){
>>                .name = "hifi_pll",
>> diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c
>> index c6eebde1f516..d729e933aa1c 100644
>> --- a/drivers/clk/meson/clk-pll.c
>> +++ b/drivers/clk/meson/clk-pll.c
>> @@ -384,8 +384,12 @@ static int meson_clk_pll_enable(struct clk_hw *hw)
>>                meson_parm_write(clk->map, &pll->rst, 1);
>>
>>        /* Disable the PLL lock-detect module */
>> -     if (MESON_PARM_APPLICABLE(&pll->l_detect))
>> -             meson_parm_write(clk->map, &pll->l_detect, 1);
>> +     if (MESON_PARM_APPLICABLE(&pll->l_detect)) {
>> +             if (pll->flags & CLK_MESON_PLL_L_DETECT_N)
>> +                     meson_parm_write(clk->map, &pll->l_detect, 1);
>> +             else
>> +                     meson_parm_write(clk->map, &pll->l_detect, 0);
>> +     }
>>
>>        /* Enable the pll */
>>        meson_parm_write(clk->map, &pll->en, 1);
>> @@ -413,8 +417,12 @@ static int meson_clk_pll_enable(struct clk_hw *hw)
>>        udelay(20);
>>
>>        /* Enable the lock-detect module */
>> -     if (MESON_PARM_APPLICABLE(&pll->l_detect))
>> -             meson_parm_write(clk->map, &pll->l_detect, 0);
>> +     if (MESON_PARM_APPLICABLE(&pll->l_detect)) {
>> +             if (pll->flags & CLK_MESON_PLL_L_DETECT_N)
>> +                     meson_parm_write(clk->map, &pll->l_detect, 0);
>> +             else
>> +                     meson_parm_write(clk->map, &pll->l_detect, 1);
>> +     }
>>
>>        if (meson_clk_pll_wait_lock(hw)) {
>>                /* disable PLL when PLL lock failed. */
>> diff --git a/drivers/clk/meson/clk-pll.h b/drivers/clk/meson/clk-pll.h
>> index 949157fb7bf5..83295a24721f 100644
>> --- a/drivers/clk/meson/clk-pll.h
>> +++ b/drivers/clk/meson/clk-pll.h
>> @@ -29,6 +29,8 @@ struct pll_mult_range {
>>
>>   #define CLK_MESON_PLL_ROUND_CLOSEST  BIT(0)
>>   #define CLK_MESON_PLL_NOINIT_ENABLED BIT(1)
>> +/* l_detect signal is active-low */
>> +#define CLK_MESON_PLL_L_DETECT_N     BIT(2)
>>
>>   struct meson_clk_pll_data {
>>        struct parm en;
> 
> --
> Jerome