linux-kernel - Re: [PATCH 2/4] clk: qcom: apss-ipq5424: Add ipq5424 apss clock controller

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Message-ID: <7031f2da-36bb-4655-a4df-fa85c99e6eb4@quicinc.com>
Date: Tue, 4 Feb 2025 11:58:42 +0530
From: Sricharan Ramabadhran <quic_srichara@...cinc.com>
To: Konrad Dybcio <konrad.dybcio@....qualcomm.com>, <andersson@...nel.org>,
        <mturquette@...libre.com>, <sboyd@...nel.org>, <robh@...nel.org>,
        <krzk+dt@...nel.org>, <conor+dt@...nel.org>, <konradybcio@...nel.org>,
        <rafael@...nel.org>, <viresh.kumar@...aro.org>, <ilia.lin@...nel.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-clk@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 2/4] clk: qcom: apss-ipq5424: Add ipq5424 apss clock
 controller



On 2/1/2025 8:55 PM, Konrad Dybcio wrote:
> On 30.01.2025 11:03 AM, Sricharan Ramabadhran wrote:
>>
>>
>> On 1/28/2025 5:29 PM, Konrad Dybcio wrote:
>>> On 27.01.2025 10:31 AM, Sricharan R wrote:
>>>> From: Sricharan Ramabadhran <quic_srichara@...cinc.com>
>>>>
>>>> CPU on Qualcomm ipq5424 is clocked by huayra PLL with RCG support.
>>>> Add support for the APSS PLL, RCG and clock enable for ipq5424.
>>>> The PLL, RCG register space are clubbed. Hence adding new APSS driver
>>>> for both PLL and RCG/CBC control. Also the L3 cache has a separate pll
>>>> and needs to be scaled along with the CPU.
>>>>
>>>> Co-developed-by: Md Sadre Alam <quic_mdalam@...cinc.com>
>>>> Signed-off-by: Md Sadre Alam <quic_mdalam@...cinc.com>
>>>> Signed-off-by: Sricharan Ramabadhran <quic_srichara@...cinc.com>
>>>> ---
> 
> [...]
> 
>>>> +    clk_alpha_pll_configure(&ipq5424_l3_pll, regmap, &l3_pll_config);
>>>> +
>>>> +    clk_alpha_pll_configure(&ipq5424_apss_pll, regmap, &apss_pll_config);
>>>> +
>>>> +    ret = qcom_cc_really_probe(dev, &apss_ipq5424_desc, regmap);
>>>> +    if (ret)
>>>> +        return ret;
>>>> +
>>>> +    dev_dbg(&pdev->dev, "Registered APSS & L3 clock provider\n");
>>>> +
>>>> +    apss_ipq5424_cfg->dev = dev;
>>>> +    apss_ipq5424_cfg->hw = &apss_silver_clk_src.clkr.hw;
>>>> +    apss_ipq5424_cfg->cpu_clk_notifier.notifier_call = cpu_clk_notifier_fn;
>>>> +
>>>> +    apss_ipq5424_cfg->l3_clk = clk_hw_get_clk(&l3_core_clk.clkr.hw, "l3_clk");
>>>> +    if (IS_ERR(apss_ipq5424_cfg->l3_clk)) {
>>>> +        dev_err(&pdev->dev, "Failed to get L3 clk, %ld\n",
>>>> +            PTR_ERR(apss_ipq5424_cfg->l3_clk));
>>>> +        return PTR_ERR(apss_ipq5424_cfg->l3_clk);
>>>> +    }
>>>
>>> Now that you'll use OPP, you can drop all this getting.. maybe even the
>>> apss_ipq5424_cfg struct could be let go
>>
>> ok, is the suggestion here to use devm_pm_opp_set_config ?
> 
> Since what you tried to do here is binding CPU and L3 frequencies together,
> yeah, we can just scale two clocks from OPP.
> 
> On some newer platforms using the epss-l3 driver, or on msm8996 with a more
> complex setup, we expose the L3 voter as an interconnect, but here it would
> seem that we directly control the clock that feeds it.

ok, will update and check.

Regards,
Sricharan