Re: [PATCH 1/4] asus-wmi: Add panel overdrive functionality

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 7/17/21 10:13 AM, Luke D. Jones wrote:
> Some ASUS ROG laptops have the ability to drive the display panel
> a higher rate to eliminate or reduce ghosting.
> 
> Signed-off-by: Luke D. Jones <luke@ljones.dev>

Looks good, almost there some small remarks inline.


> ---
>  drivers/platform/x86/asus-wmi.c            | 91 ++++++++++++++++++++++
>  include/linux/platform_data/x86/asus-wmi.h |  1 +
>  2 files changed, 92 insertions(+)
> 
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index ebaeb7bb80f5..cd881443bc2f 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -216,6 +216,9 @@ struct asus_wmi {
>  	// The RSOC controls the maximum charging percentage.
>  	bool battery_rsoc_available;
>  
> +	bool panel_overdrive_available;
> +	bool panel_overdrive;
> +
>  	struct hotplug_slot hotplug_slot;
>  	struct mutex hotplug_lock;
>  	struct mutex wmi_lock;
> @@ -1221,6 +1224,86 @@ static int asus_wmi_rfkill_init(struct asus_wmi *asus)
>  	return result;
>  }
>  
> +/* Panel Overdrive ************************************************************/
> +static int panel_od_check_present(struct asus_wmi *asus)
> +{
> +	u32 result;
> +	int err;
> +
> +	asus->panel_overdrive_available = false;
> +
> +	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_PANEL_OD, &result);
> +	if (err) {
> +		if (err == -ENODEV)
> +			return 0;
> +		return err;
> +	}
> +
> +	if (result & ASUS_WMI_DSTS_PRESENCE_BIT) {
> +		asus->panel_overdrive_available = true;
> +		asus->panel_overdrive = result & ASUS_WMI_DSTS_STATUS_BIT;
> +	}
> +
> +	return 0;
> +}
> +
> +static int panel_od_write(struct asus_wmi *asus)
> +{
> +	int err;
> +	u8 value;
> +	u32 retval;

nitpick: Please use upside-down-christmastree style for variable-declarations,
what that means is put the longest line first, so in this case:

	u32 retval;
	u8 value;
	int err;

> +
> +	value = asus->panel_overdrive;
> +
> +	err = asus_wmi_set_devstate(ASUS_WMI_DEVID_PANEL_OD, value, &retval);
> +
> +	if (err) {
> +		pr_warn("Failed to set panel overdrive: %d\n", err);
> +		return err;
> +	}
> +
> +	if (retval > 1 || retval < 0) {
> +		pr_warn("Failed to set panel overdrive (retval): 0x%x\n", retval);
> +		return -EIO;
> +	}
> +
> +	sysfs_notify(&asus->platform_device->dev.kobj, NULL, "panel_od");
> +
> +	return 0;
> +}
> +
> +static ssize_t panel_od_show(struct device *dev,
> +				   struct device_attribute *attr, char *buf)
> +{
> +	struct asus_wmi *asus = dev_get_drvdata(dev);
> +	bool mode = asus->panel_overdrive;
> +
> +	return sysfs_emit(buf, "%d\n", mode);
> +}
> +
> +static ssize_t panel_od_store(struct device *dev,
> +				    struct device_attribute *attr,
> +				    const char *buf, size_t count)
> +{
> +	int result;
> +	bool overdrive;
> +	struct asus_wmi *asus = dev_get_drvdata(dev);

Nitpick again, please make this:

	struct asus_wmi *asus = dev_get_drvdata(dev);
	bool overdrive;
	int result;

> +
> +	result = kstrtobool(buf, &overdrive);
> +	if (result == -EINVAL)

Any return from kstrtobool() other then 0 is an error,
for v3 please just make this:

	if (result)
		return result;


> +		return result;
> +
> +	asus->panel_overdrive = overdrive;
> +	result = panel_od_write(asus);
> +
> +	if (result != 0)
> +		return result;
> +
> +	return count;
> +}
> +
> +static DEVICE_ATTR_RW(panel_od);
> +
>  /* Quirks *********************************************************************/
>  
>  static void asus_wmi_set_xusb2pr(struct asus_wmi *asus)
> @@ -2332,6 +2415,7 @@ static struct attribute *platform_attributes[] = {
>  	&dev_attr_als_enable.attr,
>  	&dev_attr_fan_boost_mode.attr,
>  	&dev_attr_throttle_thermal_policy.attr,
> +	&dev_attr_panel_od.attr,
>  	NULL
>  };
>  
> @@ -2357,6 +2441,8 @@ static umode_t asus_sysfs_is_visible(struct kobject *kobj,
>  		ok = asus->fan_boost_mode_available;
>  	else if (attr == &dev_attr_throttle_thermal_policy.attr)
>  		ok = asus->throttle_thermal_policy_available;
> +	else if (attr == &dev_attr_panel_od.attr)
> +		ok = asus->panel_overdrive_available;
>  
>  	if (devid != -1)
>  		ok = !(asus_wmi_get_devstate_simple(asus, devid) < 0);
> @@ -2622,6 +2708,10 @@ static int asus_wmi_add(struct platform_device *pdev)
>  	else
>  		throttle_thermal_policy_set_default(asus);
>  
> +	err = panel_od_check_present(asus);
> +	if (err)
> +		goto fail_panel_od;
> +
>  	err = asus_wmi_sysfs_init(asus->platform_device);
>  	if (err)
>  		goto fail_sysfs;
> @@ -2709,6 +2799,7 @@ static int asus_wmi_add(struct platform_device *pdev)
>  fail_throttle_thermal_policy:
>  fail_fan_boost_mode:
>  fail_platform:
> +fail_panel_od:
>  	kfree(asus);
>  	return err;
>  }
> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> index 2f274cf52805..428aea701c7b 100644
> --- a/include/linux/platform_data/x86/asus-wmi.h
> +++ b/include/linux/platform_data/x86/asus-wmi.h
> @@ -61,6 +61,7 @@
>  #define ASUS_WMI_DEVID_THROTTLE_THERMAL_POLICY 0x00120075
>  
>  /* Misc */
> +#define ASUS_WMI_DEVID_PANEL_OD		0x00050019
>  #define ASUS_WMI_DEVID_CAMERA		0x00060013
>  #define ASUS_WMI_DEVID_LID_FLIP		0x00060062
>  
> 

Regards,

Hans