--- /dev/null
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ * Author: Naveen Kumar G <naveen.gaddipati@stericsson.com> for ST-Ericsson
+ * License terms:GNU General Public License (GPL) version 2
+ */
+
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/workqueue.h>
+#include <linux/input.h>
+#include <linux/input/bu21013.h>
+#include <linux/slab.h>
+
+#define PEN_DOWN_INTR 0
+#define MAX_FINGERS 2
+#define RESET_DELAY 30
+#define PENUP_TIMEOUT (10)
+#define DELTA_MIN 16
+#define MASK_BITS 0x03
+#define SHIFT_8 8
+#define SHIFT_2 2
+#define LENGTH_OF_BUFFER 11
+#define I2C_RETRY_COUNT 5
+
+#define BU21013_SENSORS_BTN_0_7_REG 0x70
+#define BU21013_SENSORS_BTN_8_15_REG 0x71
+#define BU21013_SENSORS_BTN_16_23_REG 0x72
+#define BU21013_X1_POS_MSB_REG 0x73
+#define BU21013_X1_POS_LSB_REG 0x74
+#define BU21013_Y1_POS_MSB_REG 0x75
+#define BU21013_Y1_POS_LSB_REG 0x76
+#define BU21013_X2_POS_MSB_REG 0x77
+#define BU21013_X2_POS_LSB_REG 0x78
+#define BU21013_Y2_POS_MSB_REG 0x79
+#define BU21013_Y2_POS_LSB_REG 0x7A
+#define BU21013_INT_CLR_REG 0xE8
+#define BU21013_INT_MODE_REG 0xE9
+#define BU21013_GAIN_REG 0xEA
+#define BU21013_OFFSET_MODE_REG 0xEB
+#define BU21013_XY_EDGE_REG 0xEC
+#define BU21013_RESET_REG 0xED
+#define BU21013_CALIB_REG 0xEE
+#define BU21013_DONE_REG 0xEF
+#define BU21013_SENSOR_0_7_REG 0xF0
+#define BU21013_SENSOR_8_15_REG 0xF1
+#define BU21013_SENSOR_16_23_REG 0xF2
+#define BU21013_POS_MODE1_REG 0xF3
+#define BU21013_POS_MODE2_REG 0xF4
+#define BU21013_CLK_MODE_REG 0xF5
+#define BU21013_IDLE_REG 0xFA
+#define BU21013_FILTER_REG 0xFB
+#define BU21013_TH_ON_REG 0xFC
+#define BU21013_TH_OFF_REG 0xFD
+
+
+#define BU21013_RESET_ENABLE 0x01
+
+#define BU21013_SENSORS_EN_0_7 0x3F
+#define BU21013_SENSORS_EN_8_15 0xFC
+#define BU21013_SENSORS_EN_16_23 0x1F
+
+#define BU21013_POS_MODE1_0 0x02
+#define BU21013_POS_MODE1_1 0x04
+#define BU21013_POS_MODE1_2 0x08
+
+#define BU21013_POS_MODE2_ZERO 0x01
+#define BU21013_POS_MODE2_AVG1 0x02
+#define BU21013_POS_MODE2_AVG2 0x04
+#define BU21013_POS_MODE2_EN_XY 0x08
+#define BU21013_POS_MODE2_EN_RAW 0x10
+#define BU21013_POS_MODE2_MULTI 0x80
+
+#define BU21013_CLK_MODE_DIV 0x01
+#define BU21013_CLK_MODE_EXT 0x02
+#define BU21013_CLK_MODE_CALIB 0x80
+
+#define BU21013_IDLET_0 0x01
+#define BU21013_IDLET_1 0x02
+#define BU21013_IDLET_2 0x04
+#define BU21013_IDLET_3 0x08
+#define BU21013_IDLE_INTERMIT_EN 0x10
+
+#define BU21013_DELTA_0_6 0x7F
+#define BU21013_FILTER_EN 0x80
+
+#define BU21013_INT_MODE_LEVEL 0x00
+#define BU21013_INT_MODE_EDGE 0x01
+
+#define BU21013_GAIN_0 0x01
+#define BU21013_GAIN_1 0x02
+#define BU21013_GAIN_2 0x04
+
+#define BU21013_OFFSET_MODE_DEFAULT 0x00
+#define BU21013_OFFSET_MODE_MOVE 0x01
+#define BU21013_OFFSET_MODE_DISABLE 0x02
+
+#define BU21013_TH_ON_0 0x01
+#define BU21013_TH_ON_1 0x02
+#define BU21013_TH_ON_2 0x04
+#define BU21013_TH_ON_3 0x08
+#define BU21013_TH_ON_4 0x10
+#define BU21013_TH_ON_5 0x20
+#define BU21013_TH_ON_6 0x40
+#define BU21013_TH_ON_7 0x80
+#define BU21013_TH_ON_MAX 0xFF
+
+#define BU21013_TH_OFF_0 0x01
+#define BU21013_TH_OFF_1 0x02
+#define BU21013_TH_OFF_2 0x04
+#define BU21013_TH_OFF_3 0x08
+#define BU21013_TH_OFF_4 0x10
+#define BU21013_TH_OFF_5 0x20
+#define BU21013_TH_OFF_6 0x40
+#define BU21013_TH_OFF_7 0x80
+#define BU21013_TH_OFF_MAX 0xFF
+
+#define BU21013_X_EDGE_0 0x01
+#define BU21013_X_EDGE_1 0x02
+#define BU21013_X_EDGE_2 0x04
+#define BU21013_X_EDGE_3 0x08
+#define BU21013_Y_EDGE_0 0x10
+#define BU21013_Y_EDGE_1 0x20
+#define BU21013_Y_EDGE_2 0x40
+#define BU21013_Y_EDGE_3 0x80
+
+#define BU21013_DONE 0x01
+#define BU21013_NUMBER_OF_X_SENSORS (6)
+#define BU21013_NUMBER_OF_Y_SENSORS (11)
+
+#define DRIVER_TP "bu21013_tp"
+
+/**
+ * struct bu21013_ts_data - touch panel data structure
+ * @client: pointer to the i2c client
+ * @wait: variable to wait_queue_head_t structure
+ * @touch_stopped: touch stop flag
+ * @chip: pointer to the touch panel controller
+ * @in_dev: pointer to the input device structure
+ * @intr_pin: interrupt pin value
+ *
+ * Touch panel device data structure
+ */
+struct bu21013_ts_data {
+ struct i2c_client *client;
+ wait_queue_head_t wait;
+ bool touch_stopped;
+ const struct bu21013_platform_device *chip;
+ struct input_dev *in_dev;
+ unsigned int intr_pin;
+};
+
+/**
+ * bu21013_read_block_data(): read the touch co-ordinates
+ * @data: bu21013_ts_data structure pointer
+ * @buf: byte pointer
+ *
+ * Read the touch co-ordinates using i2c read block into buffer
+ * and returns integer.
+ */
+static int bu21013_read_block_data(struct bu21013_ts_data *data, u8 *buf)
+{
+ int ret, i;
+
+ for (i = 0; i < I2C_RETRY_COUNT; i++) {
+ ret = i2c_smbus_read_i2c_block_data
+ (data->client, BU21013_SENSORS_BTN_0_7_REG,
+ LENGTH_OF_BUFFER, buf);
+ if (ret == LENGTH_OF_BUFFER)
+ return 0;
+ }
+ return -EINVAL;
+}
+
+/**
+ * bu21013_do_touch_report(): Get the touch co-ordinates
+ * @data: bu21013_ts_data structure pointer
+ *
+ * Get the touch co-ordinates from touch sensor registers and writes
+ * into device structure and returns integer.
+ */
+static int bu21013_do_touch_report(struct bu21013_ts_data *data)
+{
+ u8 buf[LENGTH_OF_BUFFER];
+ unsigned int pos_x[2], pos_y[2];
+ bool has_x_sensors, has_y_sensors;
+ int finger_down_count = 0;
+ int i;
+
+ if (data == NULL)
+ return -EINVAL;
+
+ if (bu21013_read_block_data(data, buf) < 0)
+ return -EINVAL;
+
+ has_x_sensors = hweight32(buf[0] & BU21013_SENSORS_EN_0_7);
+ has_y_sensors = hweight32(((buf[1] & BU21013_SENSORS_EN_8_15) |
+ ((buf[2] & BU21013_SENSORS_EN_16_23) << SHIFT_8)) >> SHIFT_2);
+ if (!has_x_sensors || !has_y_sensors)
+ return 0;
+
+ for (i = 0; i < MAX_FINGERS; i++) {
+ const u8 *p = &buf[4 * i + 3];
+ unsigned int x = p[0] << SHIFT_2 | (p[1] & MASK_BITS);
+ unsigned int y = p[2] << SHIFT_2 | (p[3] & MASK_BITS);
+ if (x == 0 || y == 0)
+ continue;
+ pos_x[finger_down_count] = x;
+ pos_y[finger_down_count] = y;
+ finger_down_count++;
+ }
+
+ if (finger_down_count) {
+ if (finger_down_count == 2 &&
+ (abs(pos_x[0] - pos_x[1]) < DELTA_MIN ||
+ abs(pos_y[0] - pos_y[1]) < DELTA_MIN)) {
+ return 0;
+ }
+
+ for (i = 0; i < finger_down_count; i++) {
+ if (data->chip->x_flip)
+ pos_x[i] = data->chip->touch_x_max - pos_x[i];
+ if (data->chip->y_flip)
+ pos_y[i] = data->chip->touch_y_max - pos_y[i];
+
+ input_report_abs(data->in_dev,
+ ABS_MT_POSITION_X, pos_x[i]);
+ input_report_abs(data->in_dev,
+ ABS_MT_POSITION_Y, pos_y[i]);
+ input_mt_sync(data->in_dev);
+ }
+ } else
+ input_mt_sync(data->in_dev);
+
+ input_sync(data->in_dev);
+
+ return 0;
+}
+/**
+ * bu21013_gpio_irq() - gpio thread function for touch interrupt
+ * @irq: irq value
+ * @device_data: void pointer
+ *
+ * This gpio thread function for touch interrupt
+ * and returns irqreturn_t.
+ */
+static irqreturn_t bu21013_gpio_irq(int irq, void *device_data)
+{
+ struct bu21013_ts_data *data = device_data;
+ struct i2c_client *i2c = data->client;
+ int retval;
+
+ do {
+ retval = bu21013_do_touch_report(data);
+ if (retval < 0) {
+ dev_err(&i2c->dev, "bu21013_do_touch_report failed\n");
+ return IRQ_NONE;
+ }
+
+ data->intr_pin = data->chip->irq_read_val();
+ if (data->intr_pin == PEN_DOWN_INTR)
+ wait_event_timeout(data->wait, data->touch_stopped,
+ msecs_to_jiffies(2));
+ } while (!data->intr_pin && !data->touch_stopped);
+
+ return IRQ_HANDLED;
+}
+
+/**
+ * bu21013_init_chip() - power on sequence for the bu21013 controller
+ * @data: device structure pointer
+ *
+ * This function is used to power on
+ * the bu21013 controller and returns integer.
+ */
+static int bu21013_init_chip(struct bu21013_ts_data *data)
+{
+ int retval;
+ struct i2c_client *i2c = data->client;
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_RESET_REG,
+ BU21013_RESET_ENABLE);
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_RESET reg write failed\n");
+ return retval;
+ }
+ msleep(RESET_DELAY);
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_SENSOR_0_7_REG,
+ BU21013_SENSORS_EN_0_7);
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_SENSOR_0_7 reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_SENSOR_8_15_REG,
+ BU21013_SENSORS_EN_8_15);
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_SENSOR_8_15 reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_SENSOR_16_23_REG,
+ BU21013_SENSORS_EN_16_23);
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_SENSOR_16_23 reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_POS_MODE1_REG,
+ (BU21013_POS_MODE1_0 | BU21013_POS_MODE1_1));
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_POS_MODE1 reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_POS_MODE2_REG,
+ (BU21013_POS_MODE2_ZERO | BU21013_POS_MODE2_AVG1 |
+ BU21013_POS_MODE2_AVG2 | BU21013_POS_MODE2_EN_RAW |
+ BU21013_POS_MODE2_MULTI));
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_POS_MODE2 reg write failed\n");
+ return retval;
+ }
+
+ if (data->chip->ext_clk)
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_CLK_MODE_REG,
+ (BU21013_CLK_MODE_EXT | BU21013_CLK_MODE_CALIB));
+ else
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_CLK_MODE_REG,
+ (BU21013_CLK_MODE_DIV | BU21013_CLK_MODE_CALIB));
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_CLK_MODE reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_IDLE_REG,
+ (BU21013_IDLET_0 | BU21013_IDLE_INTERMIT_EN));
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_IDLE reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_INT_MODE_REG,
+ BU21013_INT_MODE_LEVEL);
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_INT_MODE reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_FILTER_REG,
+ (BU21013_DELTA_0_6 |
+ BU21013_FILTER_EN));
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_FILTER reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_TH_ON_REG,
+ BU21013_TH_ON_5);
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_TH_ON reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_TH_OFF_REG,
+ BU21013_TH_OFF_4 || BU21013_TH_OFF_3);
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_TH_OFF reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_GAIN_REG,
+ (BU21013_GAIN_0 | BU21013_GAIN_1));
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_GAIN reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_OFFSET_MODE_REG,
+ BU21013_OFFSET_MODE_DEFAULT);
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_OFFSET_MODE reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_XY_EDGE_REG,
+ (BU21013_X_EDGE_0 | BU21013_X_EDGE_2 |
+ BU21013_Y_EDGE_1 | BU21013_Y_EDGE_3));
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_XY_EDGE reg write failed\n");
+ return retval;
+ }
+
+ retval = i2c_smbus_write_byte_data(i2c, BU21013_DONE_REG,
+ BU21013_DONE);
+ if (retval < 0) {
+ dev_err(&i2c->dev, "BU21013_REG_DONE reg write failed\n");
+ return retval;
+ }
+
+ return 0;
+}
+
+/**
+ * bu21013_free_irq() - frees IRQ registered for touchscreen
+ * @bu21013_data: device structure pointer
+ *
+ * This function signals interrupt thread to stop processing and
+ * frees interrupt.
+ */
+static void bu21013_free_irq(struct bu21013_ts_data *bu21013_data)
+{
+ bu21013_data->touch_stopped = true;
+ wake_up(&bu21013_data->wait);
+ free_irq(bu21013_data->chip->irq, bu21013_data);
+}
+
+/**
+ * bu21013_probe() - initializes the i2c-client touchscreen driver
+ * @client: i2c client structure pointer
+ * @id: i2c device id pointer
+ *
+ * This function used to initializes the i2c-client touchscreen
+ * driver and returns integer.
+ */
+static int __devinit bu21013_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct bu21013_ts_data *bu21013_data;
+ struct input_dev *in_dev;
+ const struct bu21013_platform_device *pdata =
+ client->dev.platform_data;
+ int error;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_BYTE_DATA)) {
+ dev_err(&client->dev, "i2c smbus byte data not supported\n");
+ return -EIO;
+ }
+
+ if (!pdata) {
+ dev_err(&client->dev, "platform data not defined\n");
+ return -EINVAL;
+ }
+
+ bu21013_data = kzalloc(sizeof(struct bu21013_ts_data), GFP_KERNEL);
+ in_dev = input_allocate_device();
+ if (!bu21013_data || !in_dev) {
+ dev_err(&client->dev, "device memory alloc failed\n");
+ error = -ENOMEM;
+ goto err_free_mem;
+ }
+
+ bu21013_data->in_dev = in_dev;
+ bu21013_data->chip = pdata;
+ bu21013_data->client = client;
+ bu21013_data->touch_stopped = false;
+ init_waitqueue_head(&bu21013_data->wait);
+
+ /* configure the gpio pins */
+ if (pdata->cs_en) {
+ error = pdata->cs_en(pdata->cs_pin);
+ if (error < 0) {
+ dev_err(&client->dev, "chip init failed\n");
+ goto err_free_mem;
+ }
+ }
+
+ /* configure the touch panel controller */
+ error = bu21013_init_chip(bu21013_data);
+ if (error) {
+ dev_err(&client->dev, "error in bu21013 config\n");
+ goto err_cs_disable;
+ }
+
+ /* register the device to input subsystem */
+ in_dev->name = DRIVER_TP;
+ in_dev->id.bustype = BUS_I2C;
+ in_dev->dev.parent = &client->dev;
+
+ __set_bit(EV_SYN, in_dev->evbit);
+ __set_bit(EV_KEY, in_dev->evbit);
+ __set_bit(EV_ABS, in_dev->evbit);
+
+ input_set_abs_params(in_dev, ABS_MT_POSITION_X, 0,
+ pdata->x_max_res, 0, 0);
+ input_set_abs_params(in_dev, ABS_MT_POSITION_Y, 0,
+ pdata->y_max_res, 0, 0);
+ input_set_drvdata(in_dev, bu21013_data);
+
+ error = request_threaded_irq(pdata->irq, NULL, bu21013_gpio_irq,
+ IRQF_TRIGGER_FALLING | IRQF_SHARED,
+ DRIVER_TP, bu21013_data);
+ if (error) {
+ dev_err(&client->dev, "request irq %d failed\n", pdata->irq);
+ goto err_cs_disable;
+ }
+
+ error = input_register_device(in_dev);
+ if (error) {
+ dev_err(&client->dev, "failed to register input device\n");
+ goto err_free_irq;
+ }
+
+ device_init_wakeup(&client->dev, pdata->wakeup);
+ i2c_set_clientdata(client, bu21013_data);
+
+ return 0;
+
+err_free_irq:
+ bu21013_free_irq(bu21013_data);
+err_cs_disable:
+ pdata->cs_dis(pdata->cs_pin);
+err_free_mem:
+ input_free_device(bu21013_data->in_dev);
+ kfree(bu21013_data);
+
+ return error;
+}
+/**
+ * bu21013_remove() - removes the i2c-client touchscreen driver
+ * @client: i2c client structure pointer
+ *
+ * This function uses to remove the i2c-client
+ * touchscreen driver and returns integer.
+ */
+static int __devexit bu21013_remove(struct i2c_client *client)
+{
+ struct bu21013_ts_data *bu21013_data = i2c_get_clientdata(client);
+
+ bu21013_free_irq(bu21013_data);
+
+ bu21013_data->chip->cs_dis(bu21013_data->chip->cs_pin);
+
+ input_unregister_device(bu21013_data->in_dev);
+ kfree(bu21013_data);
+
+ device_init_wakeup(&client->dev, false);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+/**
+ * bu21013_suspend() - suspend the touch screen controller
+ * @dev: pointer to device structure
+ *
+ * This function is used to suspend the
+ * touch panel controller and returns integer
+ */
+static int bu21013_suspend(struct device *dev)
+{
+ struct bu21013_ts_data *bu21013_data = dev_get_drvdata(dev);
+ struct i2c_client *client = bu21013_data->client;
+
+ bu21013_data->touch_stopped = true;
+ if (device_may_wakeup(&client->dev))
+ enable_irq_wake(bu21013_data->chip->irq);
+ else
+ disable_irq(bu21013_data->chip->irq);
+
+ return 0;
+}
+
+/**
+ * bu21013_resume() - resume the touch screen controller
+ * @dev: pointer to device structure
+ *
+ * This function is used to resume the touch panel
+ * controller and returns integer.
+ */
+static int bu21013_resume(struct device *dev)
+{
+ struct bu21013_ts_data *bu21013_data = dev_get_drvdata(dev);
+ struct i2c_client *client = bu21013_data->client;
+ int retval;
+
+ retval = bu21013_init_chip(bu21013_data);
+ if (retval < 0) {
+ dev_err(&client->dev, "bu21013 controller config failed\n");
+ return retval;
+ }
+
+ bu21013_data->touch_stopped = false;
+
+ if (device_may_wakeup(&client->dev))
+ disable_irq_wake(bu21013_data->chip->irq);
+ else
+ enable_irq(bu21013_data->chip->irq);
+
+ return 0;
+}
+
+static const struct dev_pm_ops bu21013_dev_pm_ops = {
+ .suspend = bu21013_suspend,
+ .resume = bu21013_resume,
+};
+#endif
+
+static const struct i2c_device_id bu21013_id[] = {
+ { DRIVER_TP, 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, bu21013_id);
+
+static struct i2c_driver bu21013_driver = {
+ .driver = {
+ .name = DRIVER_TP,
+ .owner = THIS_MODULE,
+#ifdef CONFIG_PM
+ .pm = &bu21013_dev_pm_ops,
+#endif
+ },
+ .probe = bu21013_probe,
+ .remove = __devexit_p(bu21013_remove),
+ .id_table = bu21013_id,
+};
+
+/**
+ * bu21013_init() - initializes the bu21013 touchscreen driver
+ *
+ * This function used to initializes the bu21013
+ * touchscreen driver and returns integer.
+ */
+static int __init bu21013_init(void)
+{
+ return i2c_add_driver(&bu21013_driver);
+}
+
+/**
+ * bu21013_exit() - de-initializes the bu21013 touchscreen driver
+ *
+ * This function uses to de-initializes the bu21013
+ * touchscreen driver and returns none.
+ */
+static void __exit bu21013_exit(void)
+{
+ i2c_del_driver(&bu21013_driver);
+}
+
+module_init(bu21013_init);
+module_exit(bu21013_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Naveen Kumar G <naveen.gaddipati@stericsson.com>");
+MODULE_DESCRIPTION("bu21013 touch screen controller driver");
git.openpandora.org / pandora-kernel.git / commitdiff