Re: [PATCH 1/2] platform/x86: uniwill-laptop: Introduce device descriptor system

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Tue, 16 Dec 2025, Werner Sembach wrote:

> 
> Am 16.12.25 um 14:40 schrieb Ilpo Järvinen:
> > On Thu, 4 Dec 2025, Werner Sembach wrote:
> > 
> > > From: Armin Wolf <W_Armin@gmx.de>
> > > 
> > > Future additions to the driver will depend on device-specific
> > > initialization steps. Extend the DMI-based feature detection system
> > > to include device descriptors. Each descriptor contains a bitmap of
> > > supported features and a set of callback for performing
> > > device-specific initialization.
> > > 
> > > Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> > > Co-developed-by: Werner Sembach <wse@tuxedocomputers.com>
> > > Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
> > > ---
> > >   drivers/platform/x86/uniwill/uniwill-acpi.c | 168 +++++++++++++++++---
> > >   1 file changed, 142 insertions(+), 26 deletions(-)
> > > 
> > > diff --git a/drivers/platform/x86/uniwill/uniwill-acpi.c
> > > b/drivers/platform/x86/uniwill/uniwill-acpi.c
> > > index bd7e63dd51810..01192c32608e5 100644
> > > --- a/drivers/platform/x86/uniwill/uniwill-acpi.c
> > > +++ b/drivers/platform/x86/uniwill/uniwill-acpi.c
> > > @@ -322,6 +322,7 @@ struct uniwill_data {
> > >   	struct device *dev;
> > >   	acpi_handle handle;
> > >   	struct regmap *regmap;
> > > +	unsigned int features;
> > >   	struct acpi_battery_hook hook;
> > >   	unsigned int last_charge_ctrl;
> > >   	struct mutex battery_lock;	/* Protects the list of currently
> > > registered batteries */
> > > @@ -341,12 +342,21 @@ struct uniwill_battery_entry {
> > >   	struct power_supply *battery;
> > >   };
> > >   +struct uniwill_device_descriptor {
> > > +	unsigned int features;
> > > +	/* Executed during driver probing */
> > > +	int (*probe)(struct uniwill_data *data);
> > > +};
> > > +
> > >   static bool force;
> > >   module_param_unsafe(force, bool, 0);
> > >   MODULE_PARM_DESC(force, "Force loading without checking for supported
> > > devices\n");
> > >   -/* Feature bitmask since the associated registers are not reliable */
> > > -static unsigned int supported_features;
> > > +/*
> > > + * Contains device specific data like the feature bitmap since
> > > + * the associated registers are not always reliable.
> > > + */
> > > +static struct uniwill_device_descriptor device_descriptor
> > > __ro_after_init;
> > >     static const char * const uniwill_temp_labels[] = {
> > >   	"CPU",
> > > @@ -411,6 +421,13 @@ static const struct key_entry uniwill_keymap[] = {
> > >   	{ KE_END }
> > >   };
> > >   +static inline bool uniwill_device_supports(struct uniwill_data *data,
> > > +					   unsigned int features_mask,
> > > +					   unsigned int features)
> > > +{
> > > +	return (data->features & features_mask) == features;
> > > +}
> > > +
> > >   static int uniwill_ec_reg_write(void *context, unsigned int reg,
> > > unsigned int val)
> > >   {
> > >   	union acpi_object params[2] = {
> > > @@ -799,24 +816,31 @@ static struct attribute *uniwill_attrs[] = {
> > >     static umode_t uniwill_attr_is_visible(struct kobject *kobj, struct
> > > attribute *attr, int n)
> > >   {
> > > +	struct device *dev = kobj_to_dev(kobj);
> > > +	struct uniwill_data *data = dev_get_drvdata(dev);
> > > +
> > >   	if (attr == &dev_attr_fn_lock_toggle_enable.attr) {
> > > -		if (supported_features & UNIWILL_FEATURE_FN_LOCK_TOGGLE)
> > > +		if (uniwill_device_supports(data,
> > > UNIWILL_FEATURE_FN_LOCK_TOGGLE,
> > > +					    UNIWILL_FEATURE_FN_LOCK_TOGGLE))
> > >   			return attr->mode;
> > >   	}
> > >     	if (attr == &dev_attr_super_key_toggle_enable.attr) {
> > > -		if (supported_features & UNIWILL_FEATURE_SUPER_KEY_TOGGLE)
> > > +		if (uniwill_device_supports(data,
> > > UNIWILL_FEATURE_SUPER_KEY_TOGGLE,
> > > +					    UNIWILL_FEATURE_SUPER_KEY_TOGGLE))
> > >   			return attr->mode;
> > >   	}
> > >     	if (attr == &dev_attr_touchpad_toggle_enable.attr) {
> > > -		if (supported_features & UNIWILL_FEATURE_TOUCHPAD_TOGGLE)
> > > +		if (uniwill_device_supports(data,
> > > UNIWILL_FEATURE_TOUCHPAD_TOGGLE,
> > > +					    UNIWILL_FEATURE_TOUCHPAD_TOGGLE))
> > >   			return attr->mode;
> > >   	}
> > >     	if (attr == &dev_attr_rainbow_animation.attr ||
> > >   	    attr == &dev_attr_breathing_in_suspend.attr) {
> > > -		if (supported_features & UNIWILL_FEATURE_LIGHTBAR)
> > > +		if (uniwill_device_supports(data, UNIWILL_FEATURE_LIGHTBAR,
> > > +					    UNIWILL_FEATURE_LIGHTBAR))
> > >   			return attr->mode;
> > >   	}
> > >   @@ -944,7 +968,8 @@ static int uniwill_hwmon_init(struct uniwill_data
> > > *data)
> > >   {
> > >   	struct device *hdev;
> > >   -	if (!(supported_features & UNIWILL_FEATURE_HWMON))
> > > +	if (!uniwill_device_supports(data, UNIWILL_FEATURE_HWMON,
> > > +				     UNIWILL_FEATURE_HWMON))
> > >   		return 0;
> > >     	hdev = devm_hwmon_device_register_with_info(data->dev,
> > > "uniwill", data,
> > > @@ -1019,7 +1044,8 @@ static int uniwill_led_init(struct uniwill_data
> > > *data)
> > >   	unsigned int value;
> > >   	int ret;
> > >   -	if (!(supported_features & UNIWILL_FEATURE_LIGHTBAR))
> > > +	if (!uniwill_device_supports(data, UNIWILL_FEATURE_LIGHTBAR,
> > > +				     UNIWILL_FEATURE_LIGHTBAR))
> > >   		return 0;
> > >     	ret = devm_mutex_init(data->dev, &data->led_lock);
> > > @@ -1232,7 +1258,8 @@ static int uniwill_battery_init(struct uniwill_data
> > > *data)
> > >   {
> > >   	int ret;
> > >   -	if (!(supported_features & UNIWILL_FEATURE_BATTERY))
> > > +	if (!uniwill_device_supports(data, UNIWILL_FEATURE_BATTERY,
> > > +				     UNIWILL_FEATURE_BATTERY))
> > >   		return 0;
> > >     	ret = devm_mutex_init(data->dev, &data->battery_lock);
> > > @@ -1361,6 +1388,19 @@ static int uniwill_probe(struct platform_device
> > > *pdev)
> > >   	if (ret < 0)
> > >   		return ret;
> > >   +	data->features = device_descriptor.features;
> > > +
> > > +	/*
> > > +	 * Some devices might need to perform some device-specific
> > > initialization steps
> > > +	 * before the supported features are initialized. Because of this we
> > > have to call
> > > +	 * this callback just after the EC itself was initialized.
> > > +	 */
> > > +	if (device_descriptor.probe) {
> > > +		ret = device_descriptor.probe(data);
> > > +		if (ret < 0)
> > > +			return ret;
> > > +	}
> > > +
> > >   	ret = uniwill_battery_init(data);
> > >   	if (ret < 0)
> > >   		return ret;
> > > @@ -1385,7 +1425,8 @@ static void uniwill_shutdown(struct platform_device
> > > *pdev)
> > >     static int uniwill_suspend_keyboard(struct uniwill_data *data)
> > >   {
> > > -	if (!(supported_features & UNIWILL_FEATURE_SUPER_KEY_TOGGLE))
> > > +	if (!uniwill_device_supports(data, UNIWILL_FEATURE_SUPER_KEY_TOGGLE,
> > > +				     UNIWILL_FEATURE_SUPER_KEY_TOGGLE))
> > >   		return 0;
> > >     	/*
> > > @@ -1397,7 +1438,8 @@ static int uniwill_suspend_keyboard(struct
> > > uniwill_data *data)
> > >     static int uniwill_suspend_battery(struct uniwill_data *data)
> > >   {
> > > -	if (!(supported_features & UNIWILL_FEATURE_BATTERY))
> > > +	if (!uniwill_device_supports(data, UNIWILL_FEATURE_BATTERY,
> > > +				     UNIWILL_FEATURE_BATTERY))
> > >   		return 0;
> > >     	/*
> > > @@ -1432,7 +1474,8 @@ static int uniwill_resume_keyboard(struct
> > > uniwill_data *data)
> > >   	unsigned int value;
> > >   	int ret;
> > >   -	if (!(supported_features & UNIWILL_FEATURE_SUPER_KEY_TOGGLE))
> > > +	if (!uniwill_device_supports(data, UNIWILL_FEATURE_SUPER_KEY_TOGGLE,
> > > +				     UNIWILL_FEATURE_SUPER_KEY_TOGGLE))
> > >   		return 0;
> > >     	ret = regmap_read(data->regmap, EC_ADDR_SWITCH_STATUS,
> > > &value);
> > > @@ -1448,7 +1491,8 @@ static int uniwill_resume_keyboard(struct
> > > uniwill_data *data)
> > >     static int uniwill_resume_battery(struct uniwill_data *data)
> > >   {
> > > -	if (!(supported_features & UNIWILL_FEATURE_BATTERY))
> > > +	if (!uniwill_device_supports(data, UNIWILL_FEATURE_BATTERY,
> > > +				     UNIWILL_FEATURE_BATTERY))
> > >   		return 0;
> > >     	return regmap_update_bits(data->regmap, EC_ADDR_CHARGE_CTRL,
> > > CHARGE_CTRL_MASK,
> > > @@ -1496,6 +1540,25 @@ static struct platform_driver uniwill_driver = {
> > >   	.shutdown = uniwill_shutdown,
> > >   };
> > >   +static struct uniwill_device_descriptor lapac71h_descriptor __initdata
> > > = {
> > > +	.features = UNIWILL_FEATURE_FN_LOCK_TOGGLE |
> > > +		    UNIWILL_FEATURE_SUPER_KEY_TOGGLE |
> > > +		    UNIWILL_FEATURE_TOUCHPAD_TOGGLE |
> > > +		    UNIWILL_FEATURE_BATTERY |
> > > +		    UNIWILL_FEATURE_HWMON
> > > +};
> > > +
> > > +static struct uniwill_device_descriptor lapkc71f_descriptor __initdata =
> > > {
> > > +	.features = UNIWILL_FEATURE_FN_LOCK_TOGGLE |
> > > +		    UNIWILL_FEATURE_SUPER_KEY_TOGGLE |
> > > +		    UNIWILL_FEATURE_TOUCHPAD_TOGGLE |
> > > +		    UNIWILL_FEATURE_LIGHTBAR |
> > > +		    UNIWILL_FEATURE_BATTERY |
> > > +		    UNIWILL_FEATURE_HWMON
> > > +};
> > > +
> > > +static struct uniwill_device_descriptor empty_descriptor __initdata = {};
> > > +
> > >   static const struct dmi_system_id uniwill_dmi_table[] __initconst = {
> > >   	{
> > >   		.ident = "XMG FUSION 15",
> > > @@ -1503,6 +1566,7 @@ static const struct dmi_system_id
> > > uniwill_dmi_table[] __initconst = {
> > >   			DMI_MATCH(DMI_SYS_VENDOR, "SchenkerTechnologiesGmbH"),
> > >   			DMI_EXACT_MATCH(DMI_BOARD_NAME, "LAPQC71A"),
> > >   		},
> > > +		.driver_data = &empty_descriptor,
> > Hi,
> > 
> > Is there some advantage of having an "empty descriptor" over just NULL
> > checking its presence in the code?
> 
> One less "if"

That pays no respect to devs who have read those dummy driver_data 
lines. ;-)

> In the long run (with more features implemented and tested) there probably
> wont be any device using the empty descriptor, then it can be removed again.

Fair (so I'm fine with keeping empty_descriptor for now).

-- 
 i.