linux-kernel - Re: [PATCH 06/10] clk: qcom: add the SM8650 Global Clock Controller driver

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Date:   Thu, 26 Oct 2023 13:51:21 +0200
From:   Neil Armstrong <neil.armstrong@...aro.org>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Taniya Das <quic_tdas@...cinc.com>
Cc:     linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 06/10] clk: qcom: add the SM8650 Global Clock Controller
 driver

On 25/10/2023 10:41, Konrad Dybcio wrote:
> 
> 
> On 10/25/23 09:32, Neil Armstrong wrote:
>> Add Global Clock Controller (GCC) support for SM8650 platform.
>>
>> Signed-off-by: Neil Armstrong <neil.armstrong@...aro.org>
>> ---
> Just a couple remarks
> 
> 1. looks like there's no usage of shared ops (corresponding
>     to enable_safe_parent or something along these lines
>     downstream)

Indeed, it was missing, I'll give a test before posting a v2.

> 
> 2. none of the GDSCs have interesting flags.. I have this
>     little cheat sheet that you may find handy:
> 
> qcom,retain-regs -> RETAIN_FF_ENABLE
> qcom,support-hw-trigger + set_mode in driver -> HW_CONTROL
> qcom,no-status-check-on-disable -> VOTABLE
> qcom,reset-aon-logic -> AON_RESET
> domain-addr  = clamp_io_ctrl

Thx, I updated the GDSCs.

> 
> 3. gcc_cpuss_ubwcp_clk_src uses the XO_A clock as parent, but
>     it's not there in the ftbl.. Could you confirm whether this
>     clock should even be accessed from HLOS?

Downstream this clock is only used by gem_noc, since we don't use such
clock upstream I think it's safer to remove it until we have the usage.

> 
> [...]
> 
>> +static int gcc_sm8650_probe(struct platform_device *pdev)
>> +{
>> +    struct regmap *regmap;
>> +    int ret;
>> +
>> +    regmap = qcom_cc_map(pdev, &gcc_sm8650_desc);
>> +    if (IS_ERR(regmap))
>> +        return PTR_ERR(regmap);
>> +
>> +    ret = qcom_cc_register_rcg_dfs(regmap, gcc_dfs_clocks,
>> +                       ARRAY_SIZE(gcc_dfs_clocks));
>> +    if (ret)
>> +        return ret;
>> +
>> +    /*
>> +     * Keep the critical clock always-On
>> +     * gcc_camera_ahb_clk, gcc_camera_xo_clk, gcc_disp_ahb_clk,
>> +     * gcc_disp_xo_clk, gcc_gpu_cfg_ahb_clk, gcc_video_ahb_clk,
>> +     * gcc_video_xo_clk
>> +     */
> Could you make these comments inline, i.e.
> 
> regmap_update_bits(regmap, 0x26004, BIT(0), BIT(0)); /* gcc_camera_ahb_clk */
> 
> ?

Done

> 
> Konrad

Thanks,
Neil