Re: [PATCH v2 3/6] thermal: add support for the MCU controlled FAN on Khadas boards

[Neil Armstrong]

On 15/05/2020 08:41, Amit Kucheria wrote:
> On Tue, May 12, 2020 at 6:56 PM Neil Armstrong <narmstrong@xxxxxxxxxxxx> wrote:
>>
>> The new Khadas VIM2 and VIM3 boards controls the cooling fan via the
>> on-board microcontroller.
>>
>> This implements the FAN control as thermal devices and as cell of the Khadas
>> MCU MFD driver.
>>
>> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
>> ---
>>  drivers/thermal/Kconfig          |  10 ++
>>  drivers/thermal/Makefile         |   1 +
>>  drivers/thermal/khadas_mcu_fan.c | 174 +++++++++++++++++++++++++++++++
>>  3 files changed, 185 insertions(+)
>>  create mode 100644 drivers/thermal/khadas_mcu_fan.c
>>
>> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
>> index 91af271e9bb0..72b3960cc5ac 100644
>> --- a/drivers/thermal/Kconfig
>> +++ b/drivers/thermal/Kconfig
>> @@ -490,4 +490,14 @@ config SPRD_THERMAL
>>         help
>>           Support for the Spreadtrum thermal sensor driver in the Linux thermal
>>           framework.
>> +
>> +config KHADAS_MCU_FAN_THERMAL
>> +       tristate "Khadas MCU controller FAN cooling support"
>> +       depends on OF || COMPILE_TEST
> 
> Could you add a depends on the some board/SoC Kconfig option here so
> this doesn't show up for non-Amlogic/non-Khadas boards?

Ok

> 
> Looks OK otherwise.
> 
>> +       select MFD_CORE
>> +       select REGMAP
>> +       help
>> +         If you say yes here you get support for the FAN controlled
>> +         by the Microcontroller found on the Khadas VIM boards.
>> +
>>  endif
>> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
>> index 8c8ed7b79915..460428c2122c 100644
>> --- a/drivers/thermal/Makefile
>> +++ b/drivers/thermal/Makefile
>> @@ -60,3 +60,4 @@ obj-$(CONFIG_ZX2967_THERMAL)  += zx2967_thermal.o
>>  obj-$(CONFIG_UNIPHIER_THERMAL) += uniphier_thermal.o
>>  obj-$(CONFIG_AMLOGIC_THERMAL)     += amlogic_thermal.o
>>  obj-$(CONFIG_SPRD_THERMAL)     += sprd_thermal.o
>> +obj-$(CONFIG_KHADAS_MCU_FAN_THERMAL)   += khadas_mcu_fan.o
>> diff --git a/drivers/thermal/khadas_mcu_fan.c b/drivers/thermal/khadas_mcu_fan.c
>> new file mode 100644
>> index 000000000000..044d4aba8be2
>> --- /dev/null
>> +++ b/drivers/thermal/khadas_mcu_fan.c
>> @@ -0,0 +1,174 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Khadas MCU Controlled FAN driver
>> + *
>> + * Copyright (C) 2020 BayLibre SAS
>> + * Author(s): Neil Armstrong <narmstrong@xxxxxxxxxxxx>
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/mfd/khadas-mcu.h>
>> +#include <linux/regmap.h>
>> +#include <linux/sysfs.h>
>> +#include <linux/thermal.h>
>> +
>> +#define MAX_LEVEL 3
>> +
>> +struct khadas_mcu_fan_ctx {
>> +       struct khadas_mcu *mcu;
>> +       unsigned int level;
>> +       struct thermal_cooling_device *cdev;
>> +};
>> +
>> +static int khadas_mcu_fan_set_level(struct khadas_mcu_fan_ctx *ctx,
>> +                                   unsigned int level)
>> +{
>> +       int ret;
>> +
>> +       ret = regmap_write(ctx->mcu->map, KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG,
>> +                          level);
>> +       if (ret)
>> +               return ret;
>> +
>> +       ctx->level = level;
>> +
>> +       return 0;
>> +}
>> +
>> +static int khadas_mcu_fan_get_max_state(struct thermal_cooling_device *cdev,
>> +                                       unsigned long *state)
>> +{
>> +       struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
>> +
>> +       if (!ctx)
>> +               return -EINVAL;
>> +
>> +       *state = MAX_LEVEL;
>> +
>> +       return 0;
>> +}
>> +
>> +static int khadas_mcu_fan_get_cur_state(struct thermal_cooling_device *cdev,
>> +                                       unsigned long *state)
>> +{
>> +       struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
>> +
>> +       if (!ctx)
>> +               return -EINVAL;
>> +
>> +       *state = ctx->level;
>> +
>> +       return 0;
>> +}
>> +
>> +static int
>> +khadas_mcu_fan_set_cur_state(struct thermal_cooling_device *cdev,
>> +                            unsigned long state)
>> +{
>> +       struct khadas_mcu_fan_ctx *ctx = cdev->devdata;
>> +
>> +       if (!ctx || (state > MAX_LEVEL))
>> +               return -EINVAL;
>> +
>> +       if (state == ctx->level)
>> +               return 0;
>> +
>> +       return khadas_mcu_fan_set_level(ctx, state);
>> +}
>> +
>> +static const struct thermal_cooling_device_ops khadas_mcu_fan_cooling_ops = {
>> +       .get_max_state = khadas_mcu_fan_get_max_state,
>> +       .get_cur_state = khadas_mcu_fan_get_cur_state,
>> +       .set_cur_state = khadas_mcu_fan_set_cur_state,
>> +};
>> +
>> +static int khadas_mcu_fan_probe(struct platform_device *pdev)
>> +{
>> +       struct khadas_mcu *mcu = dev_get_drvdata(pdev->dev.parent);
>> +       struct thermal_cooling_device *cdev;
>> +       struct device *dev = &pdev->dev;
>> +       struct khadas_mcu_fan_ctx *ctx;
>> +       int ret;
>> +
>> +       ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
>> +       if (!ctx)
>> +               return -ENOMEM;
>> +       ctx->mcu = mcu;
>> +       platform_set_drvdata(pdev, ctx);
>> +
>> +       cdev = devm_thermal_of_cooling_device_register(dev->parent,
>> +                       dev->parent->of_node, "khadas-mcu-fan", ctx,
>> +                       &khadas_mcu_fan_cooling_ops);
>> +       if (IS_ERR(cdev)) {
>> +               ret = PTR_ERR(cdev);
>> +               dev_err(dev,
>> +                               "Failed to register khadas-mcu-fan as cooling device: %d\n",
>> +                               ret);
>> +               return ret;
>> +       }
>> +       ctx->cdev = cdev;
>> +       thermal_cdev_update(cdev);
>> +
>> +       return 0;
>> +}
>> +
>> +static int khadas_mcu_fan_disable(struct device *dev)
>> +{
>> +       struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
>> +       unsigned int level_save = ctx->level;
>> +       int ret;
>> +
>> +       ret = khadas_mcu_fan_set_level(ctx, 0);
>> +       if (ret)
>> +               return ret;
>> +
>> +       ctx->level = level_save;
>> +
>> +       return 0;
>> +}
>> +
>> +static void khadas_mcu_fan_shutdown(struct platform_device *pdev)
>> +{
>> +       khadas_mcu_fan_disable(&pdev->dev);
>> +}
>> +
>> +#ifdef CONFIG_PM_SLEEP
>> +static int khadas_mcu_fan_suspend(struct device *dev)
>> +{
>> +       return khadas_mcu_fan_disable(dev);
>> +}
>> +
>> +static int khadas_mcu_fan_resume(struct device *dev)
>> +{
>> +       struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
>> +
>> +       return khadas_mcu_fan_set_level(ctx, ctx->level);
>> +}
>> +#endif
>> +
>> +static SIMPLE_DEV_PM_OPS(khadas_mcu_fan_pm, khadas_mcu_fan_suspend,
>> +                        khadas_mcu_fan_resume);
>> +
>> +static const struct platform_device_id khadas_mcu_fan_id_table[] = {
>> +       { .name = "khadas-mcu-fan-ctrl", },
>> +       {},
>> +};
>> +MODULE_DEVICE_TABLE(platform, khadas_mcu_fan_id_table);
>> +
>> +static struct platform_driver khadas_mcu_fan_driver = {
>> +       .probe          = khadas_mcu_fan_probe,
>> +       .shutdown       = khadas_mcu_fan_shutdown,
>> +       .driver = {
>> +               .name           = "khadas-mcu-fan-ctrl",
>> +               .pm             = &khadas_mcu_fan_pm,
>> +       },
>> +       .id_table       = khadas_mcu_fan_id_table,
>> +};
>> +
>> +module_platform_driver(khadas_mcu_fan_driver);
>> +
>> +MODULE_AUTHOR("Neil Armstrong <narmstrong@xxxxxxxxxxxx>");
>> +MODULE_DESCRIPTION("Khadas MCU FAN driver");
>> +MODULE_LICENSE("GPL");
>> --
>> 2.22.0
>>