umi: udfps: Disable HBM at fod_status changes

* This is a hack to ensure that no screen flash occurs when the finger is released. * Idea from Demon's Xiaomi sm8350-common. Change-Id: Ic29d0fabec1c97493370018223fb4559fb0ad622
chaptsand · Sep 2, 2022 · 867d70b · 867d70b
1 parent 04def82
commit 867d70b
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Showing 2 changed files with 27 additions and 6 deletions.
diff --git a/init/init.xiaomi.rc b/init/init.xiaomi.rc
@@ -92,6 +92,9 @@ on boot
 
     chmod 0666 /dev/input/event2
 
+    chown system system /sys/devices/platform/soc/ae00000.qcom,mdss_mdp/drm/card0/card0-DSI-1/disp_param
+    chmod 0660 /sys/devices/platform/soc/ae00000.qcom,mdss_mdp/drm/card0/card0-DSI-1/disp_param
+
 on property:sys.boot_completed=1
     # configure input boost settings
     write /sys/devices/system/cpu/cpu_boost/input_boost_freq "0:1344000"

diff --git a/udfps/UdfpsHandler.cpp b/udfps/UdfpsHandler.cpp
@@ -11,6 +11,7 @@
 #include <android-base/logging.h>
 #include <android-base/unique_fd.h>
 #include <fcntl.h>
+#include <fstream>
 #include <poll.h>
 #include <thread>
 #include <unistd.h>
@@ -27,11 +28,24 @@
 #define TOUCH_MAGIC 0x5400
 #define TOUCH_IOC_SETMODE TOUCH_MAGIC + 0
 
+#define DISPPARAM_PATH "/sys/devices/platform/soc/ae00000.qcom,mdss_mdp/drm/card0/card0-DSI-1/disp_param"
+#define DISPPARAM_FOD_HBM_OFF "0xE0000"
+
 static const char* kFodUiPaths[] = {
         "/sys/devices/platform/soc/soc:qcom,dsi-display-primary/fod_ui",
         "/sys/devices/platform/soc/soc:qcom,dsi-display/fod_ui",
 };
 
+namespace {
+
+template <typename T>
+static void set(const std::string& path, const T& value) {
+    std::ofstream file(path);
+    file << value;
+}
+
+} // anonymous namespace
+
 static bool readBool(int fd) {
     char c;
     int rc;
@@ -84,12 +98,16 @@ class XiaomiKonaUdfpsHander : public UdfpsHandler {
                     continue;
                 }
 
-                mDevice->extCmd(mDevice, COMMAND_NIT,
-                                readBool(fd) ? PARAM_NIT_FOD : PARAM_NIT_NONE);
-
-                int arg[2] = {TOUCH_FOD_ENABLE,
-                              readBool(fd) ? FOD_STATUS_ON : FOD_STATUS_OFF};
-                ioctl(touch_fd_.get(), TOUCH_IOC_SETMODE, &arg);
+                if (readBool(fd)) {
+                    mDevice->extCmd(mDevice, COMMAND_NIT, PARAM_NIT_FOD);
+                    int arg[2] = {TOUCH_FOD_ENABLE, FOD_STATUS_ON};
+                    ioctl(touch_fd_.get(), TOUCH_IOC_SETMODE, &arg);
+                } else {
+                    mDevice->extCmd(mDevice, COMMAND_NIT, PARAM_NIT_NONE);
+                    set(DISPPARAM_PATH, DISPPARAM_FOD_HBM_OFF);
+                    int arg[2] = {TOUCH_FOD_ENABLE, FOD_STATUS_OFF};
+                    ioctl(touch_fd_.get(), TOUCH_IOC_SETMODE, &arg);
+                }
             }
         }).detach();
     }