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Message-ID: <37d7db98-cae8-4d97-8e39-88602756dd62@roeck-us.net>
Date: Tue, 21 Apr 2020 02:24:30 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Neil Armstrong <narmstrong@...libre.com>, 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 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.
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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