Re: [PATCH 4/5] thermal: khadas_mcu_fan: add support for Khadas Edge 2

[neil.armstrong@linaro.org]

On 26/06/2025 16:36, muhammed.efecetin.67@gmail.com wrote:
> On 6/26/25 17:11, neil.armstrong@linaro.org wrote:
>> On 26/06/2025 16:04, muhammed.efecetin.67@gmail.com wrote:
>>> From: Muhammed Efe Cetin <efectn@protonmail.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

> 
> Best regards.
> 
>>
>>>
>>> Signed-off-by: Muhammed Efe Cetin <efectn@protonmail.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);
>>
>