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Message-ID: <f564b1b4-d8d1-4809-9cc0-b01aa53570a0@gmail.com>
Date: Sat, 30 Dec 2023 17:32:04 +0100
From: Maximilian Luz <luzmaximilian@...il.com>
To: Ivor Wanders <ivor@...nders.net>, Jean Delvare <jdelvare@...e.com>,
Guenter Roeck <linux@...ck-us.net>, Jonathan Corbet <corbet@....net>,
Hans de Goede <hdegoede@...hat.com>, Mark Gross <markgross@...nel.org>
Cc: linux-hwmon@...r.kernel.org, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org
Subject: Re: [PATCH v2 1/2] hwmon: add fan speed monitoring driver for Surface
devices
On 12/28/23 01:34, Ivor Wanders wrote:
> Adds a driver that provides read only access to the fan speed for Microsoft
> Surface Pro devices. The fan speed is always regulated by the EC and cannot
> be influenced directly.
>
> Signed-off-by: Ivor Wanders <ivor@...nders.net>
> Link: https://github.com/linux-surface/kernel/pull/144
> ---
> Changes in v2:
> - Removed all sysfs attributes except fan1_input. Simplified code
> and updated documentation accordingly.
> ---
> Documentation/hwmon/index.rst | 1 +
> Documentation/hwmon/surface_fan.rst | 25 +++++++
> MAINTAINERS | 8 +++
> drivers/hwmon/Kconfig | 13 ++++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/surface_fan.c | 105 ++++++++++++++++++++++++++++
> 6 files changed, 153 insertions(+)
> create mode 100644 Documentation/hwmon/surface_fan.rst
> create mode 100644 drivers/hwmon/surface_fan.c
>
[...]
> diff --git a/drivers/hwmon/surface_fan.c b/drivers/hwmon/surface_fan.c
> new file mode 100644
> index 000000000..0160a585c
> --- /dev/null
> +++ b/drivers/hwmon/surface_fan.c
> @@ -0,0 +1,105 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Surface Fan driver for Surface System Aggregator Module. It provides access
> + * to the fan's rpm through the hwmon system.
> + *
> + * Copyright (C) 2023 Ivor Wanders <ivor@...nders.net>
> + */
> +
> +#include <linux/hwmon.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
As far as I can see, linux/platform_device.h is not needed.
Regards,
Max
> +#include <linux/surface_aggregator/device.h>
> +#include <linux/types.h>
> +
> +// SSAM
> +SSAM_DEFINE_SYNC_REQUEST_CL_R(__ssam_fan_rpm_get, __le16, {
> + .target_category = SSAM_SSH_TC_FAN,
> + .command_id = 0x01,
> +});
> +
> +// hwmon
> +umode_t surface_fan_hwmon_is_visible(const void *drvdata,
> + enum hwmon_sensor_types type, u32 attr,
> + int channel)
> +{
> + if (type != hwmon_fan)
> + return 0;
> +
> + if (attr != hwmon_fan_input)
> + return 0;
> +
> + return 0444;
> +}
> +
> +static int surface_fan_hwmon_read(struct device *dev,
> + enum hwmon_sensor_types type, u32 attr,
> + int channel, long *val)
> +{
> + struct ssam_device *sdev = dev_get_drvdata(dev);
> + __le16 value;
> +
> + if (type != hwmon_fan)
> + return -EOPNOTSUPP;
> +
> + if (attr != hwmon_fan_input)
> + return -EOPNOTSUPP;
> +
> + if (__ssam_fan_rpm_get(sdev, &value))
> + return -EIO;
> +
> + *val = le16_to_cpu(value);
> +
> + return 0;
> +}
> +
> +static const struct hwmon_channel_info *const surface_fan_info[] = {
> + HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
> + NULL
> +};
> +
> +static const struct hwmon_ops surface_fan_hwmon_ops = {
> + .is_visible = surface_fan_hwmon_is_visible,
> + .read = surface_fan_hwmon_read,
> +};
> +
> +static const struct hwmon_chip_info surface_fan_chip_info = {
> + .ops = &surface_fan_hwmon_ops,
> + .info = surface_fan_info,
> +};
> +
> +static int surface_fan_probe(struct ssam_device *sdev)
> +{
> + struct device *hdev;
> +
> + hdev = devm_hwmon_device_register_with_info(&sdev->dev, "fan", sdev,
> + &surface_fan_chip_info,
> + NULL);
> + if (IS_ERR(hdev))
> + return PTR_ERR(hdev);
> +
> + ssam_device_set_drvdata(sdev, sdev);
> +
> + return 0;
> +}
> +
> +static const struct ssam_device_id ssam_fan_match[] = {
> + { SSAM_SDEV(FAN, SAM, 0x01, 0x01) },
> + {},
> +};
> +MODULE_DEVICE_TABLE(ssam, ssam_fan_match);
> +
> +static struct ssam_device_driver surface_fan = {
> + .probe = surface_fan_probe,
> + .match_table = ssam_fan_match,
> + .driver = {
> + .name = "surface_fan",
> + .probe_type = PROBE_PREFER_ASYNCHRONOUS,
> + },
> +};
> +module_ssam_device_driver(surface_fan);
> +
> +MODULE_AUTHOR("Ivor Wanders <ivor@...nders.net>");
> +MODULE_DESCRIPTION("Fan Driver for Surface System Aggregator Module");
> +MODULE_LICENSE("GPL");
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