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Message-ID: <92b39c01-1283-0b7c-6ba9-3edd2d4de002@linaro.org>
Date: Tue, 29 Nov 2022 14:21:32 +0100
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: neil.armstrong@...aro.org, Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konrad.dybcio@...ainline.org>,
Andy Gross <agross@...nel.org>
Cc: linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
linux-arm-msm@...r.kernel.org, linux-i2c@...r.kernel.org
Subject: Re: [PATCH v2 3/6] soc: qcom: geni-se: add desc struct to specify
clocks from device match data
On 29.11.2022 09:24, Neil Armstrong wrote:
> On 18/11/2022 10:06, Konrad Dybcio wrote:
>>
>>
>> On 18/11/2022 09:45, Neil Armstrong wrote:
>>> The I2C Master Hub is a stripped down version of the GENI Serial Engine
>>> QUP Wrapper Controller but only supporting I2C serial engines without
>>> DMA support.
>>>
>>> Prepare support for the I2C Master Hub variant by moving the required
>>> clocks list to a new desc struct then passing it through the compatible
>>> match data.
>>>
>>> Signed-off-by: Neil Armstrong <neil.armstrong@...aro.org>
>>> Reviewed-by: Konrad Dybcio <konrad.dybcio@...aro.org>
>>> ---
>>> drivers/soc/qcom/qcom-geni-se.c | 59 +++++++++++++++++++++++++++++++----------
>>> 1 file changed, 45 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
>>> index a0ceeede450f..ced2a2932eda 100644
>>> --- a/drivers/soc/qcom/qcom-geni-se.c
>>> +++ b/drivers/soc/qcom/qcom-geni-se.c
>>> @@ -81,19 +81,31 @@
>>> */
>>> #define MAX_CLK_PERF_LEVEL 32
>>> -#define NUM_AHB_CLKS 2
>>> +#define MAX_CLKS 2
>>> /**
>>> * struct geni_wrapper - Data structure to represent the QUP Wrapper Core
>>> * @dev: Device pointer of the QUP wrapper core
>>> * @base: Base address of this instance of QUP wrapper core
>>> - * @ahb_clks: Handle to the primary & secondary AHB clocks
>>> + * @clks: Handle to the primary & optional secondary AHB clocks
>>> + * @num_clks: Count of clocks
>>> * @to_core: Core ICC path
>>> */
>>> struct geni_wrapper {
>>> struct device *dev;
>>> void __iomem *base;
>>> - struct clk_bulk_data ahb_clks[NUM_AHB_CLKS];
>>> + struct clk_bulk_data clks[MAX_CLKS];
>>> + unsigned int num_clks;
>>> +};
>>> +
>>> +/**
>>> + * struct geni_se_desc - Data structure to represent the QUP Wrapper resources
>>> + * @clks: Name of the primary & optional secondary AHB clocks
>>> + * @num_clks: Count of clock names
>>> + */
>>> +struct geni_se_desc {
>>> + unsigned int num_clks;
>>> + const char * const *clks;
>>> };
>>> static const char * const icc_path_names[] = {"qup-core", "qup-config",
>>> @@ -496,8 +508,7 @@ static void geni_se_clks_off(struct geni_se *se)
>>> struct geni_wrapper *wrapper = se->wrapper;
>>> clk_disable_unprepare(se->clk);
>>> - clk_bulk_disable_unprepare(ARRAY_SIZE(wrapper->ahb_clks),
>>> - wrapper->ahb_clks);
>>> + clk_bulk_disable_unprepare(wrapper->num_clks, wrapper->clks);
>>> }
>>> /**
>>> @@ -528,15 +539,13 @@ static int geni_se_clks_on(struct geni_se *se)
>>> int ret;
>>> struct geni_wrapper *wrapper = se->wrapper;
>>> - ret = clk_bulk_prepare_enable(ARRAY_SIZE(wrapper->ahb_clks),
>>> - wrapper->ahb_clks);
>>> + ret = clk_bulk_prepare_enable(wrapper->num_clks, wrapper->clks);
>>> if (ret)
>>> return ret;
>>> ret = clk_prepare_enable(se->clk);
>>> if (ret)
>>> - clk_bulk_disable_unprepare(ARRAY_SIZE(wrapper->ahb_clks),
>>> - wrapper->ahb_clks);
>>> + clk_bulk_disable_unprepare(wrapper->num_clks, wrapper->clks);
>>> return ret;
>>> }
>>> @@ -887,11 +896,23 @@ static int geni_se_probe(struct platform_device *pdev)
>>> return PTR_ERR(wrapper->base);
>>> if (!has_acpi_companion(&pdev->dev)) {
>>> - wrapper->ahb_clks[0].id = "m-ahb";
>>> - wrapper->ahb_clks[1].id = "s-ahb";
>>> - ret = devm_clk_bulk_get(dev, NUM_AHB_CLKS, wrapper->ahb_clks);
>>> + const struct geni_se_desc *desc;
>>> + int i;
>>> +
>>> + desc = device_get_match_data(&pdev->dev);
>>> + if (!desc)
>>> + return -EINVAL;
>>> +
>>> + wrapper->num_clks = min_t(unsigned int, desc->num_clks, MAX_CLKS);
>>> + if (wrapper->num_clks < desc->num_clks)
>> This will never execute (except if somebody adding a third desc would make a mistake or not update MAX_CLKS), as wrapper->num_clks will only be < desc->num_clks if desc->num_clks > MAX_CLKS.
>
> You're right, I did read too fast.
>
>>
>> I was thinking about getting the number of actual clocks passed to the device in the DT, but I can't find a helper function for that, so it would probably require some kind of manual looping.. I guess we can drop this. Or leave it to save somebody pulling their hair out in an unlikely event. I guess I'm fine with both.
>
> This would be:
>
> of_count_phandle_with_args(dev->of_node, "clocks", "#clock-cells")
>
> but ultimately if the number of clocks is lower than requested, it will fail
> in the call to devm_clk_bulk_get().
>
> Would we warn if the DT clocks count is higher ? or simply fail if lower ?
Just "fail if lower" sounds good.
Konrad
>
> Neil
>
>>
>>
>>> + dev_warn(dev, "too much clocks described in DT\n")
>> If you leave it, s/too much/Too many/
>>
>>
>> Konrad
>>> +
>>> + for (i = 0; i < wrapper->num_clks; ++i)
>>> + wrapper->clks[i].id = desc->clks[i];
>>> +
>>> + ret = devm_clk_bulk_get(dev, wrapper->num_clks, wrapper->clks);
>>> if (ret) {
>>> - dev_err(dev, "Err getting AHB clks %d\n", ret);
>>> + dev_err(dev, "Err getting clks %d\n", ret);
>>> return ret;
>>> }
>>> }
>>> @@ -901,8 +922,18 @@ static int geni_se_probe(struct platform_device *pdev)
>>> return devm_of_platform_populate(dev);
>>> }
>>> +static const char * const qup_clks[] = {
>>> + "m-ahb",
>>> + "s-ahb",
>>> +};
>>> +
>>> +static const struct geni_se_desc qup_desc = {
>>> + .clks = qup_clks,
>>> + .num_clks = ARRAY_SIZE(qup_clks),
>>> +};
>>> +
>>> static const struct of_device_id geni_se_dt_match[] = {
>>> - { .compatible = "qcom,geni-se-qup", },
>>> + { .compatible = "qcom,geni-se-qup", .data = &qup_desc },
>>> {}
>>> };
>>> MODULE_DEVICE_TABLE(of, geni_se_dt_match);
>>>
>
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