Re: [PATCH v2 1/2] platform/x86: alienware-wmi-wmax: Expose GPIO debug methods

[Armin Wolf <W_Armin@gmx.de>]

Am 27.04.25 um 08:24 schrieb Kurt Borja via B4 Relay:

> From: Kurt Borja <kuurtb@gmail.com>
>
> Devices with the AWCC interface come with a USB RGB-lighting STM32 MCU,
> which has two GPIO pins with debug capabilities:
>
>   - Device Firmware Update mode (DFU)
>   - Negative Reset (NRST)
>
> The WMAX device has methods to toggle or read the state of these GPIO
> pins. Expose these methods through DebugFS, hidden behind an unsafe
> module parameter to avoid common users from toying with these without
> consideration.
>
> Suggested-by: Gabriel Marcano <gabemarcano@yahoo.com>
> Reviewed-by: Armin Wolf <W_Armin@gmx.de>
> Signed-off-by: Kurt Borja <kuurtb@gmail.com>
> ---
>   Documentation/ABI/testing/debugfs-alienware-wmi |  20 +++++
>   drivers/platform/x86/dell/alienware-wmi-wmax.c  | 108 +++++++++++++++++++++++-
>   2 files changed, 127 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/debugfs-alienware-wmi b/Documentation/ABI/testing/debugfs-alienware-wmi
> index 48cfd4d0b002efd7b68d9c1d3aa91a3a05f49db5..d20b8627ac5f1528396549a81481e26889bc410e 100644
> --- a/Documentation/ABI/testing/debugfs-alienware-wmi
> +++ b/Documentation/ABI/testing/debugfs-alienware-wmi
> @@ -42,3 +42,23 @@ Description:
>   		details.
>   
>   		RO
> +
> +What:		/sys/kernel/debug/alienware-wmi-<wmi_device_name>/gpio_ctl/total_gpios
> +Date:		May 2025
> +KernelVersion:	6.16
> +Contact:	Kurt Borja <kuurtb@gmail.com>
> +Description:
> +		Total number of GPIO pins reported by the device.
> +
> +		RO
> +
> +What:		/sys/kernel/debug/alienware-wmi-<wmi_device_name>/gpio_ctl/<pin_name>_pin
> +Date:		May 2025
> +KernelVersion:	6.16
> +Contact:	Kurt Borja <kuurtb@gmail.com>
> +Description:
> +		This file controls <pin_name> status.
> +
> +		See Documentation/wmi/devices/alienware-wmi.rst for details.
> +
> +		RW
> diff --git a/drivers/platform/x86/dell/alienware-wmi-wmax.c b/drivers/platform/x86/dell/alienware-wmi-wmax.c
> index faeddfe3b79e0aa51e7c8c6b23aa4ac5c7218706..8e682427580a629f48530d7c926db4587352c04c 100644
> --- a/drivers/platform/x86/dell/alienware-wmi-wmax.c
> +++ b/drivers/platform/x86/dell/alienware-wmi-wmax.c
> @@ -38,6 +38,9 @@
>   #define AWCC_METHOD_GET_FAN_SENSORS		0x13
>   #define AWCC_METHOD_THERMAL_INFORMATION		0x14
>   #define AWCC_METHOD_THERMAL_CONTROL		0x15
> +#define AWCC_METHOD_FWUP_GPIO_CONTROL		0x20
> +#define AWCC_METHOD_READ_TOTAL_GPIOS		0x21
> +#define AWCC_METHOD_READ_GPIO_STATUS		0x22
>   #define AWCC_METHOD_GAME_SHIFT_STATUS		0x25
>   
>   #define AWCC_FAILURE_CODE			0xFFFFFFFF
> @@ -217,6 +220,11 @@ enum AWCC_TEMP_SENSOR_TYPES {
>   	AWCC_TEMP_SENSOR_GPU			= 0x06,
>   };
>   
> +enum AWCC_GPIO_PINS {
> +	AWCC_GPIO_PIN_DFU			= 0x00,
> +	AWCC_GPIO_PIN_NRST			= 0x01,
> +};
> +
>   enum awcc_thermal_profile {
>   	AWCC_PROFILE_USTT_BALANCED,
>   	AWCC_PROFILE_USTT_BALANCED_PERFORMANCE,
> @@ -571,6 +579,38 @@ static int awcc_thermal_information(struct wmi_device *wdev, u8 operation, u8 ar
>   	return awcc_wmi_command(wdev, AWCC_METHOD_THERMAL_INFORMATION, &args, out);
>   }
>   
> +static int awcc_fwup_gpio_control(struct wmi_device *wdev, u8 pin, u8 status)
> +{
> +	struct wmax_u32_args args = {
> +		.operation = pin,
> +		.arg1 = status,
> +		.arg2 = 0,
> +		.arg3 = 0,
> +	};
> +	u32 out;
> +
> +	return awcc_wmi_command(wdev, AWCC_METHOD_FWUP_GPIO_CONTROL, &args, &out);
> +}
> +
> +static int awcc_read_total_gpios(struct wmi_device *wdev, u32 *count)
> +{
> +	struct wmax_u32_args args = {};
> +
> +	return awcc_wmi_command(wdev, AWCC_METHOD_READ_TOTAL_GPIOS, &args, count);
> +}
> +
> +static int awcc_read_gpio_status(struct wmi_device *wdev, u8 pin, u32 *status)
> +{
> +	struct wmax_u32_args args = {
> +		.operation = pin,
> +		.arg1 = 0,
> +		.arg2 = 0,
> +		.arg3 = 0,
> +	};
> +
> +	return awcc_wmi_command(wdev, AWCC_METHOD_READ_GPIO_STATUS, &args, status);
> +}
> +
>   static int awcc_game_shift_status(struct wmi_device *wdev, u8 operation,
>   				  u32 *out)
>   {
> @@ -1318,6 +1358,63 @@ static int awcc_debugfs_pprof_data_read(struct seq_file *seq, void *data)
>   	return 0;
>   }
>   
> +static int awcc_debugfs_total_gpios_read(struct seq_file *seq, void *data)
> +{
> +	struct device *dev = seq->private;
> +	struct wmi_device *wdev = to_wmi_device(dev);
> +	u32 count;
> +	int ret;
> +
> +	ret = awcc_read_total_gpios(wdev, &count);
> +	if (ret)
> +		return ret;
> +
> +	seq_printf(seq, "%u\n", count);
> +
> +	return 0;
> +}
> +
> +static int awcc_gpio_pin_show(struct seq_file *seq, void *data)
> +{
> +	unsigned long pin = debugfs_get_aux_num(seq->file);
> +	struct wmi_device *wdev = seq->private;
> +	u32 status;
> +	int ret;
> +
> +	ret = awcc_read_gpio_status(wdev, pin, &status);
> +	if (ret)
> +		return ret;
> +
> +	seq_printf(seq, "%u\n", status);
> +
> +	return 0;
> +}
> +
> +static ssize_t awcc_gpio_pin_write(struct file *file, const char __user *buf,
> +				   size_t count, loff_t *ppos)
> +{
> +	unsigned long pin = debugfs_get_aux_num(file);
> +	struct seq_file *seq = file->private_data;
> +	struct wmi_device *wdev = seq->private;
> +	bool status;
> +	int ret;
> +
> +	if (!ppos || *ppos)
> +		return -EINVAL;
> +
> +	ret = kstrtobool_from_user(buf, count, &status);
> +	if (ret)
> +		return ret;
> +
> +	ret = awcc_fwup_gpio_control(wdev, pin, status);
> +	if (ret)
> +		return ret;
> +
> +	return count;
> +}
> +
> +DEFINE_SHOW_STORE_ATTRIBUTE(awcc_gpio_pin);
> +
>   static void awcc_debugfs_remove(void *data)
>   {
>   	struct dentry *root = data;
> @@ -1327,7 +1424,7 @@ static void awcc_debugfs_remove(void *data)
>   
>   static void awcc_debugfs_init(struct wmi_device *wdev)
>   {
> -	struct dentry *root;
> +	struct dentry *root, *gpio_ctl;
>   	char name[64];
>   
>   	scnprintf(name, sizeof(name), "%s-%s", "alienware-wmi", dev_name(&wdev->dev));
> @@ -1344,6 +1441,15 @@ static void awcc_debugfs_init(struct wmi_device *wdev)
>   		debugfs_create_devm_seqfile(&wdev->dev, "pprof_data", root,
>   					    awcc_debugfs_pprof_data_read);
>   
> +	gpio_ctl = debugfs_create_dir("gpio_ctl", root);
> +
> +	debugfs_create_devm_seqfile(&wdev->dev, "total_gpios", gpio_ctl,
> +				    awcc_debugfs_total_gpios_read);
> +	debugfs_create_file_aux_num("dfu_pin", 0644, gpio_ctl, wdev,
> +				    AWCC_GPIO_PIN_DFU, &awcc_gpio_pin_fops);
> +	debugfs_create_file_aux_num("nrst_pin", 0644, gpio_ctl, wdev,
> +				    AWCC_GPIO_PIN_NRST, &awcc_gpio_pin_fops);

I just noticed: what happens if the total number of GPIOs is greater than/lower than 2?

Maybe you could instead name the debugfs files pinX with X being the pin number. Then you just
have to create the debugfs files inside a for loop.

What do you thing?

Thanks,
Armin Wolf

> +
>   	devm_add_action_or_reset(&wdev->dev, awcc_debugfs_remove, root);
>   }
>   
>