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Message-ID: <8cb43d05-3d0e-2ea1-fc52-ddfe38a4b60e@baylibre.com>
Date: Tue, 28 Apr 2020 14:58:37 +0200
From: Neil Armstrong <narmstrong@...libre.com>
To: Guenter Roeck <linux@...ck-us.net>, lee.jones@...aro.org,
jdelvare@...e.com, srinivas.kandagatla@...aro.org
Cc: nick@...das.com, art@...das.com, linux-amlogic@...ts.infradead.org,
linux-hwmon@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: Re: [RFC 3/8] hwmon: add support for the MCU controlled FAN on Khadas
boards
On 21/04/2020 11:24, Guenter Roeck wrote:
> On 4/21/20 1:00 AM, Neil Armstrong wrote:
>> The new Khadas VIM2 and VIM3 boards controls the cooling fan via the
>> on-board microcontroller.
>>
>> This implements the FAN control as HWMON devices as cell of the Khadas
>> MCU MFD driver.
>>
>> Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
>
> This should be a thermal driver, not a hwmon driver.
> I don't see a single standard hwmon attribute, making
> the driver quite pointless as hwmon device.
Sure,
Neil
>
> Guenter
>
>> ---
>> drivers/hwmon/Kconfig | 9 ++
>> drivers/hwmon/Makefile | 1 +
>> drivers/hwmon/khadas-mcu-fan.c | 230 +++++++++++++++++++++++++++++++++
>> 3 files changed, 240 insertions(+)
>> create mode 100644 drivers/hwmon/khadas-mcu-fan.c
>>
>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
>> index 4c62f900bf7e..7f63ff7bb732 100644
>> --- a/drivers/hwmon/Kconfig
>> +++ b/drivers/hwmon/Kconfig
>> @@ -1997,6 +1997,15 @@ config SENSORS_XGENE
>> If you say yes here you get support for the temperature
>> and power sensors for APM X-Gene SoC.
>>
>> +config SENSORS_KHADAS_MCU_FAN
>> + tristate "Khadas MCU controller FAN driver"
>> + depends on OF || COMPILE_TEST
>> + 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.
>> +
>> if ACPI
>>
>> comment "ACPI drivers"
>> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
>> index b0b9c8e57176..20db40f6d57f 100644
>> --- a/drivers/hwmon/Makefile
>> +++ b/drivers/hwmon/Makefile
>> @@ -185,6 +185,7 @@ obj-$(CONFIG_SENSORS_W83L786NG) += w83l786ng.o
>> obj-$(CONFIG_SENSORS_WM831X) += wm831x-hwmon.o
>> obj-$(CONFIG_SENSORS_WM8350) += wm8350-hwmon.o
>> obj-$(CONFIG_SENSORS_XGENE) += xgene-hwmon.o
>> +obj-$(CONFIG_SENSORS_KHADAS_MCU_FAN) += khadas-mcu-fan.o
>>
>> obj-$(CONFIG_SENSORS_OCC) += occ/
>> obj-$(CONFIG_PMBUS) += pmbus/
>> diff --git a/drivers/hwmon/khadas-mcu-fan.c b/drivers/hwmon/khadas-mcu-fan.c
>> new file mode 100644
>> index 000000000000..dd92b2bcb7e3
>> --- /dev/null
>> +++ b/drivers/hwmon/khadas-mcu-fan.c
>> @@ -0,0 +1,230 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Khadas MCU Controlled FAN driver
>> + *
>> + * Copyright (C) 2020 BayLibre SAS
>> + * Author(s): Neil Armstrong <narmstrong@...libre.com>
>> + */
>> +
>> +#include <linux/hwmon.h>
>> +#include <linux/hwmon-sysfs.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regulator/consumer.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 ssize_t level_store(struct device *dev, struct device_attribute *attr,
>> + const char *buf, size_t count)
>> +{
>> + struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
>> + unsigned long level;
>> + int ret;
>> +
>> + if (kstrtoul(buf, 10, &level) || level > MAX_LEVEL)
>> + return -EINVAL;
>> +
>> + ret = khadas_mcu_fan_set_level(ctx, level);
>> + if (ret < 0)
>> + return ret;
>> +
>> + return count;
>> +}
>> +
>> +static ssize_t level_show(struct device *dev, struct device_attribute *attr,
>> + char *buf)
>> +{
>> + struct khadas_mcu_fan_ctx *ctx = dev_get_drvdata(dev);
>> +
>> + return sprintf(buf, "%u\n", ctx->level);
>> +}
>> +
>> +static SENSOR_DEVICE_ATTR_RW(level1, level, 0);
>> +
>> +static struct attribute *khadas_mcu_fan_attrs[] = {
>> + &sensor_dev_attr_level1.dev_attr.attr,
>> + NULL,
>> +};
>> +
>> +static const struct attribute_group khadas_mcu_fan_group = {
>> + .attrs = khadas_mcu_fan_attrs,
>> +};
>> +
>> +static const struct attribute_group *khadas_mcu_fan_groups[] = {
>> + &khadas_mcu_fan_group,
>> + NULL,
>> +};
>> +
>> +/* thermal cooling device callbacks */
>> +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;
>> + struct device *hwmon;
>> + int ret;
>> +
>> + ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
>> + if (!ctx)
>> + return -ENOMEM;
>> + ctx->mcu = mcu;
>> + platform_set_drvdata(pdev, ctx);
>> +
>> + hwmon = devm_hwmon_device_register_with_groups(dev, "khadas-mcu-fan",
>> + ctx,
>> + khadas_mcu_fan_groups);
>> + if (IS_ERR(hwmon)) {
>> + dev_err(dev, "Failed to register hwmon device\n");
>> + return PTR_ERR(hwmon);
>> + }
>> +
>> + if (IS_ENABLED(CONFIG_THERMAL)) {
>> + 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@...libre.com>");
>> +MODULE_DESCRIPTION("Khadas MCU FAN driver");
>> +MODULE_LICENSE("GPL");
>>
>
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