vibrator: add calibration data loading support

This patch adds the support of loading a calibration file and write it
back to the drv2624 kernel driver. The calibration file contains the
BEMF, GAIN and COMP numbers generated using the auto-calibration feature
of the drv2624 driver IC. The file also contains the per-device resonant
frequency number.

Test: calibrate the device and read back the values from kernel
Change-Id: Ieafe5b317c7544bd8d657168250fb41e2ee0d8fc
Signed-off-by: David Lin <dtwlin@google.com>

init.hardware.rc

@@ -346,6 +346,8 @@ on early-boot
     chown system system /sys/class/leds/vibrator/device/set_sequencer
     chown system system /sys/class/leds/vibrator/device/autocal_result
     chown system system /sys/class/leds/vibrator/device/ctrl_loop
+    chown system system /sys/class/leds/vibrator/device/ol_lra_period
+    chown system system /sys/class/leds/vibrator/device/autocal
 
     # Permission for LED driver
     chown system system /sys/class/leds/red/on_off_ms

sepolicy/file.te

@@ -40,6 +40,7 @@ type persist_file, file_type;
 type persist_data_file, file_type;
 type persist_display_file, file_type;
 type persist_sensors_file, file_type;
+type persist_haptics_file, file_type;
 
 type netmgr_data_file, file_type, data_file_type;
 

sepolicy/file_contexts

@@ -305,6 +305,7 @@
 /persist/data(/.*)?       u:object_r:persist_data_file:s0
 /persist/display(/.*)?    u:object_r:persist_display_file:s0
 /persist/sensors(/.*)?    u:object_r:persist_sensors_file:s0
+/persist/haptics(/.*)?    u:object_r:persist_haptics_file:s0
 
 /metadata                 u:object_r:rootfs:s0
 /metadata/.*              u:object_r:vold_data_file:s0

sepolicy/hal_vibrator_default.te

@@ -2,3 +2,7 @@ r_dir_file(hal_vibrator_default, sysfs_leds)
 allow hal_vibrator_default sysfs_leds:file w_file_perms;
 allow hal_vibrator_default sysfs_msm_subsys:file rw_file_perms;
 allow hal_vibrator_default sysfs_msm_subsys:dir search;
+
+# read-only permission to obtain the calibration data
+r_dir_file(hal_vibrator_default, persist_haptics_file)
+allow hal_vibrator_default persist_file:dir search;

vibrator/service.cpp

@@ -31,14 +31,91 @@ using namespace android;
 
 // Refer to Documentation/ABI/testing/sysfs-class-led-driver-drv2624
 // kernel documentation on the detail usages for ABIs below
-static const char *ACTIVATE_PATH = "/sys/class/leds/vibrator/activate";
-static const char *DURATION_PATH = "/sys/class/leds/vibrator/duration";
-static const char *STATE_PATH = "/sys/class/leds/vibrator/state";
-static const char *RTP_INPUT_PATH = "/sys/class/leds/vibrator/device/rtp_input";
-static const char *MODE_PATH = "/sys/class/leds/vibrator/device/mode";
-static const char *SEQUENCER_PATH = "/sys/class/leds/vibrator/device/set_sequencer";
-static const char *SCALE_PATH = "/sys/class/leds/vibrator/device/scale";
-static const char *CTRL_LOOP_PATH = "/sys/class/leds/vibrator/device/ctrl_loop";
+static constexpr char ACTIVATE_PATH[] = "/sys/class/leds/vibrator/activate";
+static constexpr char DURATION_PATH[] = "/sys/class/leds/vibrator/duration";
+static constexpr char STATE_PATH[] = "/sys/class/leds/vibrator/state";
+static constexpr char RTP_INPUT_PATH[] = "/sys/class/leds/vibrator/device/rtp_input";
+static constexpr char MODE_PATH[] = "/sys/class/leds/vibrator/device/mode";
+static constexpr char SEQUENCER_PATH[] = "/sys/class/leds/vibrator/device/set_sequencer";
+static constexpr char SCALE_PATH[] = "/sys/class/leds/vibrator/device/scale";
+static constexpr char CTRL_LOOP_PATH[] = "/sys/class/leds/vibrator/device/ctrl_loop";
+
+// File path to the calibration file
+static constexpr char CALIBRATION_FILEPATH[] = "/persist/haptics/drv2624.cal";
+
+// Kernel ABIs for updating the calibration data
+static constexpr char AUTOCAL_CONFIG[] = "autocal";
+static constexpr char LRA_PERIOD_CONFIG[] = "lra_period";
+static constexpr char AUTOCAL_FILEPATH[] = "/sys/class/leds/vibrator/device/autocal";
+static constexpr char OL_LRA_PERIOD_FILEPATH[] = "/sys/class/leds/vibrator/device/ol_lra_period";
+
+static std::string trim(const std::string& str,
+        const std::string& whitespace = " \t") {
+    const auto str_begin = str.find_first_not_of(whitespace);
+    if (str_begin == std::string::npos) {
+        return "";
+    }
+
+    const auto str_end = str.find_last_not_of(whitespace);
+    const auto str_range = str_end - str_begin + 1;
+
+    return str.substr(str_begin, str_range);
+}
+
+static bool loadCalibrationData() {
+    std::map<std::string, std::string> config_data;
+
+    std::ofstream autocal{AUTOCAL_FILEPATH};
+    if (!autocal) {
+        int error = errno;
+        ALOGE("Failed to open %s (%d): %s", AUTOCAL_FILEPATH, error,
+                strerror(error));
+        return false;
+    }
+
+    std::ofstream ol_lra_period{OL_LRA_PERIOD_FILEPATH};
+    if (!ol_lra_period) {
+        int error = errno;
+        ALOGE("Failed to open %s (%d): %s", OL_LRA_PERIOD_FILEPATH, error,
+                strerror(error));
+        return false;
+    }
+
+    std::ifstream cal_data{CALIBRATION_FILEPATH};
+    if (!cal_data) {
+        int error = errno;
+        ALOGE("Failed to open %s (%d): %s", CALIBRATION_FILEPATH, error,
+                strerror(error));
+        return false;
+    }
+
+    std::string line;
+
+    while (std::getline(cal_data, line)) {
+        if (line.empty() || line[0] == '#') {
+            continue;
+        }
+        std::istringstream is_line(line);
+        std::string key;
+        if (std::getline(is_line, key, ':')) {
+            std::string value;
+
+            if (std::getline(is_line, value)) {
+                config_data[trim(key)] = trim(value);
+            }
+        }
+    }
+
+    if(config_data.find(AUTOCAL_CONFIG) != config_data.end()) {
+        autocal << config_data[AUTOCAL_CONFIG] << std::endl;
+    }
+
+    if(config_data.find(LRA_PERIOD_CONFIG) != config_data.end()) {
+        ol_lra_period << config_data[LRA_PERIOD_CONFIG] << std::endl;
+    }
+
+    return true;
+}
 
 status_t registerVibratorService() {
     // ostreams below are required
@@ -101,6 +178,10 @@ status_t registerVibratorService() {
         ALOGW("Failed to open %s (%d): %s", CTRL_LOOP_PATH, error, strerror(error));
     }
 
+    if (!loadCalibrationData()) {
+        ALOGW("Failed load calibration data");
+    }
+
     sp<IVibrator> vibrator = new Vibrator(std::move(activate), std::move(duration),
             std::move(state), std::move(rtpinput), std::move(mode),
             std::move(sequencer), std::move(scale), std::move(ctrlloop));