platform/x86: thinkpad_acpi: Register a privacy-screen device

Register a privacy-screen device on laptops with a privacy-screen,
this exports the PrivacyGuard features to user-space using a
standardized vendor-agnostic sysfs interface. Note the sysfs interface
is read-only.

Registering a privacy-screen device with the new privacy-screen class
code will also allow the GPU driver to get a handle to it and export
the privacy-screen setting as a property on the DRM connector object
for the LCD panel. This DRM connector property is a new standardized
interface which all user-space code should use to query and control
the privacy-screen.

Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Mark Pearson <markpearson@lenovo.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211005202322.700909-9-hdegoede@redhat.com

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index e21ea3d..2020820 100644 (file)
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -501,7 +501,9 @@ config THINKPAD_ACPI
        depends on ACPI_VIDEO || ACPI_VIDEO = n
        depends on BACKLIGHT_CLASS_DEVICE
        depends on I2C
+       depends on DRM
        select ACPI_PLATFORM_PROFILE
+       select DRM_PRIVACY_SCREEN
        select HWMON
        select NVRAM
        select NEW_LEDS

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index b8f2556..291cd18 100644 (file)
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -73,6 +73,7 @@
 #include <linux/uaccess.h>
 #include <acpi/battery.h>
 #include <acpi/video.h>
+#include <drm/drm_privacy_screen_driver.h>
 #include "dual_accel_detect.h"
 
 /* ThinkPad CMOS commands */
@@ -157,6 +158,7 @@ enum tpacpi_hkey_event_t {
        TP_HKEY_EV_VOL_UP               = 0x1015, /* Volume up or unmute */
        TP_HKEY_EV_VOL_DOWN             = 0x1016, /* Volume down or unmute */
        TP_HKEY_EV_VOL_MUTE             = 0x1017, /* Mixer output mute */
+       TP_HKEY_EV_PRIVACYGUARD_TOGGLE  = 0x130f, /* Toggle priv.guard on/off */
 
        /* Reasons for waking up from S3/S4 */
        TP_HKEY_EV_WKUP_S3_UNDOCK       = 0x2304, /* undock requested, S3 */
@@ -3889,6 +3891,12 @@ static bool hotkey_notify_extended_hotkey(const u32 hkey)
 {
        unsigned int scancode;
 
+       switch (hkey) {
+       case TP_HKEY_EV_PRIVACYGUARD_TOGGLE:
+               tpacpi_driver_event(hkey);
+               return true;
+       }
+
        /* Extended keycodes start at 0x300 and our offset into the map
         * TP_ACPI_HOTKEYSCAN_EXTENDED_START. The calculated scancode
         * will be positive, but might not be in the correct range.
@@ -9819,30 +9827,40 @@ static struct ibm_struct battery_driver_data = {
  * LCD Shadow subdriver, for the Lenovo PrivacyGuard feature
  */
 
+static struct drm_privacy_screen *lcdshadow_dev;
 static acpi_handle lcdshadow_get_handle;
 static acpi_handle lcdshadow_set_handle;
-static int lcdshadow_state;
 
-static int lcdshadow_on_off(bool state)
+static int lcdshadow_set_sw_state(struct drm_privacy_screen *priv,
+                                 enum drm_privacy_screen_status state)
 {
        int output;
 
+       if (WARN_ON(!mutex_is_locked(&priv->lock)))
+               return -EIO;
+
        if (!acpi_evalf(lcdshadow_set_handle, &output, NULL, "dd", (int)state))
                return -EIO;
 
-       lcdshadow_state = state;
+       priv->hw_state = priv->sw_state = state;
        return 0;
 }
 
-static int lcdshadow_set(bool on)
+static void lcdshadow_get_hw_state(struct drm_privacy_screen *priv)
 {
-       if (lcdshadow_state < 0)
-               return lcdshadow_state;
-       if (lcdshadow_state == on)
-               return 0;
-       return lcdshadow_on_off(on);
+       int output;
+
+       if (!acpi_evalf(lcdshadow_get_handle, &output, NULL, "dd", 0))
+               return;
+
+       priv->hw_state = priv->sw_state = output & 0x1;
 }
 
+static const struct drm_privacy_screen_ops lcdshadow_ops = {
+       .set_sw_state = lcdshadow_set_sw_state,
+       .get_hw_state = lcdshadow_get_hw_state,
+};
+
 static int tpacpi_lcdshadow_init(struct ibm_init_struct *iibm)
 {
        acpi_status status1, status2;
@@ -9850,36 +9868,44 @@ static int tpacpi_lcdshadow_init(struct ibm_init_struct *iibm)
 
        status1 = acpi_get_handle(hkey_handle, "GSSS", &lcdshadow_get_handle);
        status2 = acpi_get_handle(hkey_handle, "SSSS", &lcdshadow_set_handle);
-       if (ACPI_FAILURE(status1) || ACPI_FAILURE(status2)) {
-               lcdshadow_state = -ENODEV;
+       if (ACPI_FAILURE(status1) || ACPI_FAILURE(status2))
                return 0;
-       }
 
-       if (!acpi_evalf(lcdshadow_get_handle, &output, NULL, "dd", 0)) {
-               lcdshadow_state = -EIO;
+       if (!acpi_evalf(lcdshadow_get_handle, &output, NULL, "dd", 0))
                return -EIO;
-       }
-       if (!(output & 0x10000)) {
-               lcdshadow_state = -ENODEV;
+
+       if (!(output & 0x10000))
                return 0;
-       }
-       lcdshadow_state = output & 0x1;
+
+       lcdshadow_dev = drm_privacy_screen_register(&tpacpi_pdev->dev,
+                                                   &lcdshadow_ops);
+       if (IS_ERR(lcdshadow_dev))
+               return PTR_ERR(lcdshadow_dev);
 
        return 0;
 }
 
+static void lcdshadow_exit(void)
+{
+       drm_privacy_screen_unregister(lcdshadow_dev);
+}
+
 static void lcdshadow_resume(void)
 {
-       if (lcdshadow_state >= 0)
-               lcdshadow_on_off(lcdshadow_state);
+       if (!lcdshadow_dev)
+               return;
+
+       mutex_lock(&lcdshadow_dev->lock);
+       lcdshadow_set_sw_state(lcdshadow_dev, lcdshadow_dev->sw_state);
+       mutex_unlock(&lcdshadow_dev->lock);
 }
 
 static int lcdshadow_read(struct seq_file *m)
 {
-       if (lcdshadow_state < 0) {
+       if (!lcdshadow_dev) {
                seq_puts(m, "status:\t\tnot supported\n");
        } else {
-               seq_printf(m, "status:\t\t%d\n", lcdshadow_state);
+               seq_printf(m, "status:\t\t%d\n", lcdshadow_dev->hw_state);
                seq_puts(m, "commands:\t0, 1\n");
        }
 
@@ -9891,7 +9917,7 @@ static int lcdshadow_write(char *buf)
        char *cmd;
        int res, state = -EINVAL;
 
-       if (lcdshadow_state < 0)
+       if (!lcdshadow_dev)
                return -ENODEV;
 
        while ((cmd = strsep(&buf, ","))) {
@@ -9903,11 +9929,18 @@ static int lcdshadow_write(char *buf)
        if (state >= 2 || state < 0)
                return -EINVAL;
 
-       return lcdshadow_set(state);
+       mutex_lock(&lcdshadow_dev->lock);
+       res = lcdshadow_set_sw_state(lcdshadow_dev, state);
+       mutex_unlock(&lcdshadow_dev->lock);
+
+       drm_privacy_screen_call_notifier_chain(lcdshadow_dev);
+
+       return res;
 }
 
 static struct ibm_struct lcdshadow_driver_data = {
        .name = "lcdshadow",
+       .exit = lcdshadow_exit,
        .resume = lcdshadow_resume,
        .read = lcdshadow_read,
        .write = lcdshadow_write,
@@ -10717,6 +10750,20 @@ static void tpacpi_driver_event(const unsigned int hkey_event)
                if (!atomic_add_unless(&dytc_ignore_event, -1, 0))
                        dytc_profile_refresh();
        }
+
+       if (lcdshadow_dev && hkey_event == TP_HKEY_EV_PRIVACYGUARD_TOGGLE) {
+               enum drm_privacy_screen_status old_hw_state;
+               bool changed;
+
+               mutex_lock(&lcdshadow_dev->lock);
+               old_hw_state = lcdshadow_dev->hw_state;
+               lcdshadow_get_hw_state(lcdshadow_dev);
+               changed = lcdshadow_dev->hw_state != old_hw_state;
+               mutex_unlock(&lcdshadow_dev->lock);
+
+               if (changed)
+                       drm_privacy_screen_call_notifier_chain(lcdshadow_dev);
+       }
 }
 
 static void hotkey_driver_event(const unsigned int scancode)