Message-ID: <9f60698a-bb4f-4559-b347-44c8bb078a0f@linaro.org>
Date: Thu, 26 Jun 2025 17:29:27 +0200
From: neil.armstrong@...aro.org
To: Muhammed Efe Cetin <muhammed.efecetin.67@...il.com>
Cc: daniel.lezcano@...aro.org, devicetree@...r.kernel.org,
 efectn@...tonmail.com, heiko@...ech.de, krzysztof.kozlowski+dt@...aro.org,
 lee@...nel.org, linux-arm-kernel@...ts.infradead.org,
 linux-kernel@...r.kernel.org, linux-rockchip@...ts.infradead.org,
 rafael@...nel.org, robh+dt@...nel.org
Subject: Re: [PATCH 4/5] thermal: khadas_mcu_fan: add support for Khadas Edge
 2

On 26/06/2025 17:16, Muhammed Efe Cetin wrote:
> On 6/26/25 17:46, neil.armstrong@...aro.org wrote:
>> On 26/06/2025 16:36, muhammed.efecetin.67@...il.com wrote:
>>> On 6/26/25 17:11, neil.armstrong@...aro.org wrote:
>>>> On 26/06/2025 16:04, muhammed.efecetin.67@...il.com wrote:
>>>>> From: Muhammed Efe Cetin <efectn@...tonmail.com>
>>>>>
>>>>> Fan control on the Khadas Edge 2 is controlled with the 0x8A register,
>>>>> using percentage values from 0 to 100, whereas there are only 3 constant steps in previous Khadas boards.
>>>>> Therefore, i added a new cooling-levels property, similar to the one used in the pwm-fan driver.
>>>>> The original behavior can still be used when the cooling-levels property is not specified,
>>>>> ensuring that the new functionality does not break old boards.
>>>>
>>>> Thanks for the explanation, but would would you like to change that ? The MCU can accept
>>>> any value between 0 and 99, so why change the levels from DT ?
>>>>
>>>> Neil
>>>
>>> Thanks for the review. Therefore, you say just add values between 0-100 to cooling-device instead of remapping them using cooling-levels property?
>>>
>>> What would be the best practise of detecting whether the board is Khadas Edge 2? Adding new bool property, reading model propety from devicetree etc.
>>
>> The register DEVICE_NO should be set at 0x12 for Edge V, 0x11 for Edge 1. I don't have the number for Edge 2, perhaps you can read it ?
>>
>> Neil
> 
> The DEVICE_NO register is not available for Khadas Edge 2. Here are the registers [0].
> 
> [0] https://dl.khadas.com/products/edge2/tools/mcu/edge2-mcu-register-description-en-v1.0-230520.pdf

OK so it's basically completely different.

In this case introduce a separate compatible since we can't detect it dynamically,
and just add the registers with EDGE2 prefix.
But keep the khadas-mcu-fan-ctrl, it will work if you pass the device type detected
via the new compatible.

Neil

> 
>>
>>>
>>> Best regards.
>>>
>>>>
>>>>>
>>>>> Signed-off-by: Muhammed Efe Cetin <efectn@...tonmail.com>
>>>>> ---
>>>>>     drivers/thermal/khadas_mcu_fan.c | 76 ++++++++++++++++++++++++++++++--
>>>>>     1 file changed, 72 insertions(+), 4 deletions(-)
>>>>>
>>>>> diff --git a/drivers/thermal/khadas_mcu_fan.c b/drivers/thermal/khadas_mcu_fan.c
>>>>> index d35e5313b..504e7d254 100644
>>>>> --- a/drivers/thermal/khadas_mcu_fan.c
>>>>> +++ b/drivers/thermal/khadas_mcu_fan.c
>>>>> @@ -15,10 +15,16 @@
>>>>>     #include <linux/thermal.h>
>>>>>       #define MAX_LEVEL 3
>>>>> +#define MAX_SPEED 0x64
>>>>>       struct khadas_mcu_fan_ctx {
>>>>>         struct khadas_mcu *mcu;
>>>>>         unsigned int level;
>>>>> +
>>>>> +    unsigned int fan_max_level;
>>>>> +    unsigned int fan_register;
>>>>> +    unsigned int *fan_cooling_levels;
>>>>> +
>>>>>         struct thermal_cooling_device *cdev;
>>>>>     };
>>>>>     @@ -26,9 +32,21 @@ static int khadas_mcu_fan_set_level(struct khadas_mcu_fan_ctx *ctx,
>>>>>                         unsigned int level)
>>>>>     {
>>>>>         int ret;
>>>>> +    unsigned int write_level = level;
>>>>> +
>>>>> +    if (level > ctx->fan_max_level)
>>>>> +        return -EINVAL;
>>>>> +
>>>>> +    if (ctx->fan_cooling_levels != NULL) {
>>>>> +        write_level = ctx->fan_cooling_levels[level];
>>>>> +
>>>>> +        if (write_level > MAX_SPEED)
>>>>> +            return -EINVAL;
>>>>> +    }
>>>>> +
>>>>> +    ret = regmap_write(ctx->mcu->regmap, ctx->fan_register,
>>>>> +               write_level);
>>>>>     -    ret = regmap_write(ctx->mcu->regmap, KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG,
>>>>> -               level);
>>>>>         if (ret)
>>>>>             return ret;
>>>>>     @@ -40,7 +58,9 @@ static int khadas_mcu_fan_set_level(struct khadas_mcu_fan_ctx *ctx,
>>>>>     static int khadas_mcu_fan_get_max_state(struct thermal_cooling_device *cdev,
>>>>>                         unsigned long *state)
>>>>>     {
>>>>> -    *state = MAX_LEVEL;
>>>>> +    struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
>>>>> +
>>>>> +    *state = ctx->fan_max_level;
>>>>>           return 0;
>>>>>     }
>>>>> @@ -61,7 +81,7 @@ khadas_mcu_fan_set_cur_state(struct thermal_cooling_device *cdev,
>>>>>     {
>>>>>         struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
>>>>>     -    if (state > MAX_LEVEL)
>>>>> +    if (state > ctx->fan_max_level)
>>>>>             return -EINVAL;
>>>>>           if (state == ctx->level)
>>>>> @@ -76,6 +96,47 @@ static const struct thermal_cooling_device_ops khadas_mcu_fan_cooling_ops = {
>>>>>         .set_cur_state = khadas_mcu_fan_set_cur_state,
>>>>>     };
>>>>>     +static int khadas_mcu_fan_get_cooling_data_edge2(struct khadas_mcu_fan_ctx *ctx, struct device *dev)
>>>>> +{
>>>>> +    struct device_node *np = ctx->mcu->dev->of_node;
>>>>> +    int num, i, ret;
>>>>> +
>>>>> +    if (!of_property_present(np, "cooling-levels"))
>>>>> +        return 0;
>>>>> +
>>>>> +    ret = of_property_count_u32_elems(np, "cooling-levels");
>>>>> +    if (ret <= 0) {
>>>>> +        dev_err(dev, "Wrong data!\n");
>>>>> +        return ret ? : -EINVAL;
>>>>> +    }
>>>>> +
>>>>> +    num = ret;
>>>>> +    ctx->fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
>>>>> +                           GFP_KERNEL);
>>>>> +    if (!ctx->fan_cooling_levels)
>>>>> +        return -ENOMEM;
>>>>> +
>>>>> +    ret = of_property_read_u32_array(np, "cooling-levels",
>>>>> +                     ctx->fan_cooling_levels, num);
>>>>> +    if (ret) {
>>>>> +        dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
>>>>> +        return ret;
>>>>> +    }
>>>>> +
>>>>> +    for (i = 0; i < num; i++) {
>>>>> +        if (ctx->fan_cooling_levels[i] > MAX_SPEED) {
>>>>> +            dev_err(dev, "MCU fan state[%d]:%d > %d\n", i,
>>>>> +                ctx->fan_cooling_levels[i], MAX_SPEED);
>>>>> +            return -EINVAL;
>>>>> +        }
>>>>> +    }
>>>>> +
>>>>> +    ctx->fan_max_level = num - 1;
>>>>> +    ctx->fan_register = KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG_V2;
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>>     static int khadas_mcu_fan_probe(struct platform_device *pdev)
>>>>>     {
>>>>>         struct khadas_mcu *mcu = dev_get_drvdata(pdev->dev.parent);
>>>>> @@ -90,6 +151,13 @@ static int khadas_mcu_fan_probe(struct platform_device *pdev)
>>>>>         ctx->mcu = mcu;
>>>>>         platform_set_drvdata(pdev, ctx);
>>>>>     +    ctx->fan_max_level = MAX_LEVEL;
>>>>> +    ctx->fan_register = KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG;
>>>>> +
>>>>> +    ret = khadas_mcu_fan_get_cooling_data_edge2(ctx, dev);
>>>>> +    if (ret)
>>>>> +        return ret;
>>>>> +
>>>>>         cdev = devm_thermal_of_cooling_device_register(dev->parent,
>>>>>                 dev->parent->of_node, "khadas-mcu-fan", ctx,
>>>>>                 &khadas_mcu_fan_cooling_ops);
>>>>
>>>
>>
> 

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