linux-kernel - Re: [PATCH v2 2/3] platform: arm64: thinkpad-t14s-ec: new driver

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Message-ID: <4913e5eb-c7bc-4c77-ab2c-b0452e9b495e@oss.qualcomm.com>
Date: Fri, 5 Sep 2025 12:27:11 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Sebastian Reichel <sre@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
 <conor+dt@...nel.org>, Hans de Goede <hansg@...nel.org>,
        Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
        Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>,
        Mark Pearson <mpearson-lenovo@...ebb.ca>
Cc: "Derek J. Clark" <derekjohn.clark@...il.com>,
        Henrique de Moraes Holschuh <hmh@....eng.br>,
        Neil Armstrong <neil.armstrong@...aro.org>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v2 2/3] platform: arm64: thinkpad-t14s-ec: new driver

On 9/5/25 3:09 AM, Sebastian Reichel wrote:
> Introduce EC driver for the ThinkPad T14s Gen6 Snapdragon, which is in
> theory compatible with ThinkPad ACPI. On Linux the system is booted with
> device tree, which is not supported by the ThinkPad ACPI driver
> (drivers/platform/x86/lenovo/thinkpad_acpi.c). Also most of the hardware
> compatibility is handled via ACPI tables, which are obviously not used
> when booting via device tree. Thus adding DT compatibility to the
> existing driver is not worth it as there is almost no code sharing.
> 
> The driver currently exposes features, which are not available
> via other means:
> 
>  * Extra Keys
>  * System LEDs
>  * Keyboard Backlight Control
> 
> The driver has been developed by reading the ACPI DSDT. There
> are some more features around thermal control, which are not
> yet supported by the driver.
> 
> The speaker mute and mic mute LEDs need some additional changes
> in the ALSA UCM to be set automatically.
> 
> Tested-by: Neil Armstrong <neil.armstrong@...aro.org> # on Thinkpad T14S OLED
> Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@...aro.org>
> Signed-off-by: Sebastian Reichel <sre@...nel.org>
> ---

[...]

> +#define THINKPAD_T14S_EC_CMD_ECRD 0x02
> +#define THINKPAD_T14S_EC_CMD_ECWR 0x03
> +#define THINKPAD_T14S_EC_CMD_EVT 0xf0

T14S_EC_ is already a good prefix, imo

[...]

> +static enum led_brightness thinkpad_t14s_audio_led_get(struct thinkpad_t14s_ec *ec,
> +						       u8 led_bit)
> +{
> +	unsigned int val;
> +	int ret;
> +
> +	ret = regmap_read(ec->regmap, THINKPAD_T14S_EC_REG_AUD, &val);
> +	if (ret < 0)
> +		return ret;
> +
> +	return !!(val && led_bit) ? LED_ON : LED_OFF;

&& already returns a boolean

but I think you meant to use & here

> +}
> +
> +static enum led_brightness thinkpad_t14s_audio_led_set(struct thinkpad_t14s_ec *ec,
> +						       u8 led_bit,
> +						       enum led_brightness brightness)
> +{
> +	u8 val = brightness ? led_bit : 0;
> +
> +	return regmap_update_bits(ec->regmap, THINKPAD_T14S_EC_REG_AUD, led_bit, val);

regmap_assign_bits()

> +static int thinkpad_t14s_input_probe(struct thinkpad_t14s_ec *ec)
> +{
> +	int ret;
> +
> +	ec->inputdev = devm_input_allocate_device(ec->dev);
> +	if (!ec->inputdev)
> +		return -ENOMEM;
> +
> +	ec->inputdev->name = "ThinkPad Extra Buttons";
> +	ec->inputdev->phys = "thinkpad/input0";
> +	ec->inputdev->id.bustype = BUS_HOST;
> +	ec->inputdev->dev.parent = ec->dev;
> +
> +	ret = sparse_keymap_setup(ec->inputdev, thinkpad_t14s_keymap, NULL);
> +	if (ret)
> +		return ret;
> +
> +	ret = input_register_device(ec->inputdev);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;

You can return input_register_device() directly 

Konrad