linux-kernel - Re: [PATCH V5 4/5] clk: qcom: camcc-sm8550: Add support for qdss, sleep and xo clocks

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Date:   Sat, 1 Jul 2023 01:21:07 +0200
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Jagadeesh Kona <quic_jkona@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Andy Gross <agross@...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>
Cc:     Bjorn Andersson <andersson@...nel.org>,
        Vladimir Zapolskiy <vladimir.zapolskiy@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Taniya Das <quic_tdas@...cinc.com>,
        Satya Priya Kakitapalli <quic_skakitap@...cinc.com>,
        Imran Shaik <quic_imrashai@...cinc.com>,
        Ajit Pandey <quic_ajipan@...cinc.com>
Subject: Re: [PATCH V5 4/5] clk: qcom: camcc-sm8550: Add support for qdss,
 sleep and xo clocks

On 30.06.2023 09:14, Jagadeesh Kona wrote:
> 
> 
> On 6/26/2023 7:10 PM, Dmitry Baryshkov wrote:
>> On 26/06/2023 14:59, Jagadeesh Kona wrote:
>>>
>>>
>>> On 6/24/2023 5:49 PM, Konrad Dybcio wrote:
>>>> On 23.06.2023 18:46, Jagadeesh Kona wrote:
>>>>> Add support for camera qdss, sleep and xo clocks.
>>>>>
>>>>> Co-developed-by: Taniya Das <quic_tdas@...cinc.com>
>>>>> Signed-off-by: Taniya Das <quic_tdas@...cinc.com>
>>>>> Signed-off-by: Jagadeesh Kona <quic_jkona@...cinc.com>
>>>>> ---
>>>>> Changes since v4:
>>>>>   - No changes.
>>>>> Changes since v3:
>>>>>   - No changes.
>>>>> Changes since v2:
>>>>>   - No changes.
>>>>> Changes since v1:
>>>>>   - Newly added.
>>>>>
>>>>>   drivers/clk/qcom/camcc-sm8550.c | 180 ++++++++++++++++++++++++++++++++
>>>>>   1 file changed, 180 insertions(+)
>>>>>
>>>>> diff --git a/drivers/clk/qcom/camcc-sm8550.c b/drivers/clk/qcom/camcc-sm8550.c
>>>>> index 075bea32087c..7b4882444d58 100644
>>>>> --- a/drivers/clk/qcom/camcc-sm8550.c
>>>>> +++ b/drivers/clk/qcom/camcc-sm8550.c
>>>>> @@ -22,6 +22,8 @@
>>>>>   enum {
>>>>>       DT_IFACE,
>>>>>       DT_BI_TCXO,
>>>>> +    DT_BI_TCXO_AO,
>>>>> +    DT_SLEEP_CLK,
>>>>>   };
>>>>>   enum {
>>>>> @@ -43,6 +45,7 @@ enum {
>>>>>       P_CAM_CC_PLL10_OUT_EVEN,
>>>>>       P_CAM_CC_PLL11_OUT_EVEN,
>>>>>       P_CAM_CC_PLL12_OUT_EVEN,
>>>>> +    P_SLEEP_CLK,
>>>>>   };
>>>>>   static const struct pll_vco lucid_ole_vco[] = {
>>>>> @@ -881,6 +884,22 @@ static const struct clk_parent_data cam_cc_parent_data_11[] = {
>>>>>       { .hw = &cam_cc_pll7_out_even.clkr.hw },
>>>>>   };
>>>>> +static const struct parent_map cam_cc_parent_map_12[] = {
>>>>> +    { P_SLEEP_CLK, 0 },
>>>>> +};
>>>>> +
>>>>> +static const struct clk_parent_data cam_cc_parent_data_12[] = {
>>>>> +    { .index = DT_SLEEP_CLK },
>>>>> +};
>>>>> +
>>>>> +static const struct parent_map cam_cc_parent_map_13[] = {
>>>>> +    { P_BI_TCXO, 0 },
>>>>> +};
>>>>> +
>>>>> +static const struct clk_parent_data cam_cc_parent_data_13_ao[] = {
>>>>> +    { .index = DT_BI_TCXO_AO },
>>>>> +};
>>>>> +
>>>>>   static const struct freq_tbl ftbl_cam_cc_bps_clk_src[] = {
>>>>>       F(19200000, P_BI_TCXO, 1, 0, 0),
>>>>>       F(200000000, P_CAM_CC_PLL8_OUT_EVEN, 1, 0, 0),
>>>>> @@ -1565,6 +1584,29 @@ static struct clk_rcg2 cam_cc_mclk7_clk_src = {
>>>>>       },
>>>>>   };
>>>>> +static const struct freq_tbl ftbl_cam_cc_qdss_debug_clk_src[] = {
>>>>> +    F(19200000, P_BI_TCXO, 1, 0, 0),
>>>>> +    F(75000000, P_CAM_CC_PLL0_OUT_EVEN, 8, 0, 0),
>>>>> +    F(150000000, P_CAM_CC_PLL0_OUT_EVEN, 4, 0, 0),
>>>>> +    F(300000000, P_CAM_CC_PLL0_OUT_MAIN, 4, 0, 0),
>>>>> +    { }
>>>>> +};
>>>>> +
>>>>> +static struct clk_rcg2 cam_cc_qdss_debug_clk_src = {
>>>>> +    .cmd_rcgr = 0x13f24,
>>>>> +    .mnd_width = 0,
>>>>> +    .hid_width = 5,
>>>>> +    .parent_map = cam_cc_parent_map_0,
>>>>> +    .freq_tbl = ftbl_cam_cc_qdss_debug_clk_src,
>>>>> +    .clkr.hw.init = &(const struct clk_init_data) {
>>>>> +        .name = "cam_cc_qdss_debug_clk_src",
>>>>> +        .parent_data = cam_cc_parent_data_0,
>>>>> +        .num_parents = ARRAY_SIZE(cam_cc_parent_data_0),
>>>>> +        .flags = CLK_SET_RATE_PARENT,
>>>>> +        .ops = &clk_rcg2_shared_ops,
>>>>> +    },
>>>>> +};
>>>>> +
>>>>>   static const struct freq_tbl ftbl_cam_cc_sfe_0_clk_src[] = {
>>>>>       F(466000000, P_CAM_CC_PLL6_OUT_EVEN, 1, 0, 0),
>>>>>       F(594000000, P_CAM_CC_PLL6_OUT_EVEN, 1, 0, 0),
>>>>> @@ -1611,6 +1653,26 @@ static struct clk_rcg2 cam_cc_sfe_1_clk_src = {
>>>>>       },
>>>>>   };
>>>>> +static const struct freq_tbl ftbl_cam_cc_sleep_clk_src[] = {
>>>>> +    F(32000, P_SLEEP_CLK, 1, 0, 0),
>>>>> +    { }
>>>>> +};
>>>>> +
>>>>> +static struct clk_rcg2 cam_cc_sleep_clk_src = {
>>>>> +    .cmd_rcgr = 0x141a0,
>>>>> +    .mnd_width = 0,
>>>>> +    .hid_width = 5,
>>>>> +    .parent_map = cam_cc_parent_map_12,
>>>>> +    .freq_tbl = ftbl_cam_cc_sleep_clk_src,
>>>>> +    .clkr.hw.init = &(const struct clk_init_data) {
>>>>> +        .name = "cam_cc_sleep_clk_src",
>>>>> +        .parent_data = cam_cc_parent_data_12,
>>>>> +        .num_parents = ARRAY_SIZE(cam_cc_parent_data_12),
>>>>> +        .flags = CLK_SET_RATE_PARENT,
>>>>> +        .ops = &clk_rcg2_shared_ops,
>>>>> +    },
>>>>> +};
>>>>> +
>>>>>   static const struct freq_tbl ftbl_cam_cc_slow_ahb_clk_src[] = {
>>>>>       F(19200000, P_BI_TCXO, 1, 0, 0),
>>>>>       F(80000000, P_CAM_CC_PLL0_OUT_EVEN, 7.5, 0, 0),
>>>>> @@ -1632,6 +1694,26 @@ static struct clk_rcg2 cam_cc_slow_ahb_clk_src = {
>>>>>       },
>>>>>   };
>>>>> +static const struct freq_tbl ftbl_cam_cc_xo_clk_src[] = {
>>>>> +    F(19200000, P_BI_TCXO, 1, 0, 0),
>>>> You're overloading P_BI_TCXO with a different parent clock (XO_A).
>>>>
>>>
>>> This RCG just requires active only voting, hence using XO_A as its parent.
>>>
>>> Both XO and XO_A are same clock in HW (BI_TCXO), hence we can reuse P_BI_TCXO in frequency table for XO_A parent as well.
>>
>> Please don't do such things, it complicates understanding the driver. The reviewer could have thought that here the driver was really referencing to the BI_TCXO rather than BI_TCXO_AO.
>>
> 
> The enum in parent list indicates the actual HW clock, and since XO and XO_A are the same HW clock, parent enum needs to be a single one. Only parent_data needs to be updated with AO as we have been doing for all targets.
I see your point, however to Linux, XO and XO_A are two separate clocks
within the CCF.

Konrad
> 
> Thanks,
> Jagadeesh
> 
>>>
>>> Thanks,
>>> Jagadeesh
>>>
>>>> The rest lgtm
>>>>
>>>> Konrad
>>
>> [skipped the rest]
>>