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Date:   Thu, 12 Oct 2023 14:26:38 +0200
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Subject: Re: [PATCH] platform/x86: support to store/show powermode for Inspur
Content-Language: en-US, nl
To:     Ai Chao <aichao@kylinos.cn>, ilpo.jarvinen@linux.intel.com,
        markgross@kernel.org
Cc:     linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org
References: <20231008092149.967239-1-aichao@kylinos.cn>
From:   Hans de Goede <hdegoede@redhat.com>
In-Reply-To: <20231008092149.967239-1-aichao@kylinos.cn>
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Precedence: bulk

Hi Ai,

On 10/8/23 11:21, Ai Chao wrote:
> Support to store/show powermode for Inspur.
> 
> Signed-off-by: Ai Chao <aichao@kylinos.cn>

Thank you for your patch.

Comments inline.

> ---
>  drivers/platform/x86/Kconfig      |  11 ++
>  drivers/platform/x86/Makefile     |   3 +
>  drivers/platform/x86/inspur-wmi.c | 180 ++++++++++++++++++++++++++++++
>  3 files changed, 194 insertions(+)
>  create mode 100644 drivers/platform/x86/inspur-wmi.c
> 
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 2a1070543391..9e565ee01a9f 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -988,6 +988,17 @@ config TOUCHSCREEN_DMI
>  	  the OS-image for the device. This option supplies the missing info.
>  	  Enable this for x86 tablets with Silead or Chipone touchscreens.
>  
> +config INSPUR_WMI
> +	tristate "Inspur WMI hotkeys driver"
> +	depends on ACPI_WMI
> +	depends on INPUT
> +	help
> +	This driver provides support for Inspur WMI hotkeys.
> +	It's support to store/show powermode.

The use of the work "hotkeys" here seems wrong since this
only supports the powermode WMI interface.


> +
> +	To compile this driver as a module, choose M here: the module
> +	will be called inspur-wmi.
> +
>  source "drivers/platform/x86/x86-android-tablets/Kconfig"
>  
>  config FW_ATTR_CLASS
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index b457de5abf7d..9285c252757e 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -98,6 +98,9 @@ obj-$(CONFIG_TOSHIBA_WMI)	+= toshiba-wmi.o
>  # before toshiba_acpi initializes
>  obj-$(CONFIG_ACPI_TOSHIBA)	+= toshiba_acpi.o
>  
> +# Inspur
> +obj-$(CONFIG_INSPUR_WMI)	+= inspur-wmi.o
> +
>  # Laptop drivers
>  obj-$(CONFIG_ACPI_CMPC)		+= classmate-laptop.o
>  obj-$(CONFIG_COMPAL_LAPTOP)	+= compal-laptop.o
> diff --git a/drivers/platform/x86/inspur-wmi.c b/drivers/platform/x86/inspur-wmi.c
> new file mode 100644
> index 000000000000..6c4d722e98dc
> --- /dev/null
> +++ b/drivers/platform/x86/inspur-wmi.c
> @@ -0,0 +1,180 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + *  Inspur WMI hotkeys
> + *
> + *  Copyright (C) 2018	      Ai Chao <aichao@kylinos.cn>
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/device.h>
> +#include <linux/input.h>
> +#include <linux/module.h>
> +#include <linux/wmi.h>
> +
> +#define WMI_INSPUR_POWERMODE_EVENT_GUID "854FA5AC-58C7-451D-AAB1-57D6F4E6DDD4"
> +#define WMI_INSPUR_POWERMODE_BIOS_GUID "596C31E3-332D-43C9-AEE9-585493284F5D"
> +
> +enum inspur_wmi_method_ids {
> +	INSPUR_WMI_GET_POWERMODE = 0x02,
> +	INSPUR_WMI_SET_POWERMODE = 0x03,
> +};
> +
> +struct inspur_wmi_priv {
> +	struct input_dev *idev;
> +};
> +
> +static int inspur_wmi_perform_query(char *guid,
> +		enum inspur_wmi_method_ids query_id,
> +		void *buffer, size_t insize, size_t outsize)
> +{
> +	union acpi_object *obj;
> +	int ret = 0;
> +	u32 wmi_outsize;
> +	struct acpi_buffer input = { insize, buffer};
> +	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
> +
> +	wmi_evaluate_method(guid, 0, query_id, &input, &output);
> +
> +	obj = output.pointer;
> +	if (!obj)
> +		return -EINVAL;
> +
> +	if (obj->type != ACPI_TYPE_BUFFER) {
> +		ret = -EINVAL;
> +		goto out_free;
> +	}
> +
> +	/* Ignore output data of zero size */
> +	if (!outsize)
> +		goto out_free;
> +
> +	wmi_outsize = min_t(size_t, outsize, obj->buffer.length);
> +	memcpy(buffer, obj->buffer.pointer, wmi_outsize);
> +
> +out_free:
> +	kfree(obj);
> +	return ret;
> +}
> +
> +static ssize_t powermode_store(struct device *dev,
> +		struct device_attribute *attr,
> +		const char *buf, size_t count)
> +{
> +	int ret, mode;
> +
> +	ret = kstrtoint(buf, 0, &mode);
> +	if (ret)
> +		return ret;

So this allows sending any value of
-2^31 to +2^31 to the WMI interface
I have a hard time believing that that entire
range is valid ?

Do you know which values are valid and do you know
what the meaning of the valid values are ?

Typically these values have meanings like:

low-power / balanced / high-performance

and assuming that is the case then this really
should be using the drivers/acpi/platform_profile.c
userspace API instead of registering a custom
sysfs attribute for this.

Regards,

Hans


> +
> +	inspur_wmi_perform_query(WMI_INSPUR_POWERMODE_BIOS_GUID,
> +			INSPUR_WMI_SET_POWERMODE,
> +			&mode, sizeof(mode), sizeof(mode));
> +
> +	return count;
> +}
> +
> +
> +static ssize_t powermode_show(struct device *dev,
> +		struct device_attribute *attr,
> +		char *buf)
> +{
> +	int mode = 0;
> +	u8 ret;
> +	u8 *ret_code;
> +
> +	inspur_wmi_perform_query(WMI_INSPUR_POWERMODE_BIOS_GUID,
> +			INSPUR_WMI_GET_POWERMODE,
> +			&mode, sizeof(mode), sizeof(mode));
> +	/*
> +	 *Byte [0]: Return code, 0x0 No error, 0x01 Error
> +	 *Byte [1]: Power Mode
> +	 */
> +	ret_code = (u8 *)(&mode);
> +	ret = ret_code[1];
> +
> +	return sprintf(buf, "%u\n", ret);
> +}
> +
> +DEVICE_ATTR_RW(powermode);
> +
> +static struct attribute *inspur_wmi_attrs[] = {
> +	&dev_attr_powermode.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group inspur_wmi_group = {
> +	.attrs = inspur_wmi_attrs,
> +};
> +
> +const struct attribute_group *inspur_wmi_groups[] = {
> +	&inspur_wmi_group,
> +	NULL,
> +};
> +
> +static void inspur_wmi_notify(struct wmi_device *wdev,
> +		union acpi_object *obj)
> +{
> +	//to do
> +}
> +
> +static int inspur_wmi_input_setup(struct wmi_device *wdev)
> +{
> +	struct inspur_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
> +
> +	priv->idev = devm_input_allocate_device(&wdev->dev);
> +	if (!priv->idev)
> +		return -ENOMEM;
> +
> +	priv->idev->name = "Inspur WMI hotkeys";
> +	priv->idev->phys = "wmi/input0";
> +	priv->idev->id.bustype = BUS_HOST;
> +	priv->idev->dev.parent = &wdev->dev;
> +
> +	return input_register_device(priv->idev);
> +}
> +
> +static int inspur_wmi_probe(struct wmi_device *wdev, const void *context)
> +{
> +	struct inspur_wmi_priv *priv;
> +	int err;
> +
> +	priv = devm_kzalloc(&wdev->dev, sizeof(struct inspur_wmi_priv),
> +			GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	dev_set_drvdata(&wdev->dev, priv);
> +
> +	err = inspur_wmi_input_setup(wdev);
> +	return err;
> +}
> +
> +static void inspur_wmi_remove(struct wmi_device *wdev)
> +{
> +	struct inspur_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
> +
> +	input_unregister_device(priv->idev);
> +}
> +
> +static const struct wmi_device_id inspur_wmi_id_table[] = {
> +	{ .guid_string = WMI_INSPUR_POWERMODE_EVENT_GUID },
> +	{  }
> +};
> +
> +static struct wmi_driver inspur_wmi_driver = {
> +	.driver = {
> +		.name = "inspur-wmi",
> +		.dev_groups = inspur_wmi_groups,
> +	},
> +	.id_table = inspur_wmi_id_table,
> +	.probe = inspur_wmi_probe,
> +	.notify = inspur_wmi_notify,
> +	.remove = inspur_wmi_remove,
> +};
> +
> +module_wmi_driver(inspur_wmi_driver);
> +
> +MODULE_DEVICE_TABLE(wmi, inspur_wmi_id_table);
> +MODULE_AUTHOR("Ai Chao <aichao@kylinos.cn>");
> +MODULE_DESCRIPTION("Inspur WMI hotkeys");
> +MODULE_LICENSE("GPL");