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Message-Id: <D9LI3QJTLK0T.2D8JGFI6XRJD4@gmail.com>
Date: Fri, 02 May 2025 04:36:47 -0300
From: "Kurt Borja" <kuurtb@...il.com>
To: "Armin Wolf" <W_Armin@....de>, "Hans de Goede" <hdegoede@...hat.com>,
Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: "Gabriel Marcano" <gabemarcano@...oo.com>,
<platform-driver-x86@...r.kernel.org>, <Dell.Client.Kernel@...l.com>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/2] platform/x86: alienware-wmi-wmax: Expose GPIO
debug methods
On Thu May 1, 2025 at 10:37 PM -03, Armin Wolf wrote:
> Am 27.04.25 um 08:24 schrieb Kurt Borja via B4 Relay:
>
>> From: Kurt Borja <kuurtb@...il.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@...oo.com>
>> Reviewed-by: Armin Wolf <W_Armin@....de>
>> Signed-off-by: Kurt Borja <kuurtb@...il.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@...il.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@...il.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?
Hi Armin,
I was a bit reluctant when I first made the patch because I wanted to
keep things simple.
I haven't seen any laptop with a GPIO count \neq 2, however some
ACPI implementations of this method don't handle invalid values very
well, so I'll take this approach just in case.
Thanks for your comments!
--
~ Kurt
>
> Thanks,
> Armin Wolf
>
>> +
>> devm_add_action_or_reset(&wdev->dev, awcc_debugfs_remove, root);
>> }
>>
>>
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