From: Mika Penttilä <mika.pentt...@nextfour.com>

Multitouch protocol B support.

v5:
  - rebased to 4.6.0-rc6

v4:
  - cleanups and fixes according to review feedback
  - irq and reset gpios are now optional,
    if not spesified it is expected the firmware / hw
    takes care of reset states and irq flow
  - irq and reset gpio polarities come from dts/firmware
  - report parsing and reporting are done at once
  - error handling improvements
  - misc cleanups
  - added comments
    
v3:
  - cleanup unused defines
  - added acked-bys from SiS

v2:
  - use gpio descriptor api
  - probe cleanups
  - error handling cleanups

Signed-off-by: Mika Penttilä <mika.pentt...@nextfour.com>
Acked-by: Tammy Tseng <tammy_ts...@sis.com>
Acked-by: Yuger Yu <yuger...@sis.com>
---
 drivers/input/touchscreen/Kconfig   |  12 +
 drivers/input/touchscreen/Makefile  |   1 +
 drivers/input/touchscreen/sis_i2c.c | 461 ++++++++++++++++++++++++++++++++++++
 3 files changed, 474 insertions(+)
 create mode 100644 drivers/input/touchscreen/sis_i2c.c

diff --git a/drivers/input/touchscreen/Kconfig 
b/drivers/input/touchscreen/Kconfig
index 8ecdc38..8f06ae7 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -1155,4 +1155,16 @@ config TOUCHSCREEN_ROHM_BU21023
          To compile this driver as a module, choose M here: the
          module will be called bu21023_ts.
 
+config TOUCHSCREEN_SIS_I2C
+       tristate "SiS 9200 family I2C touchscreen driver"
+       depends on I2C
+       depends on GPIOLIB
+       help
+         This enables support for SiS 9200 family over I2C based touchscreens.
+
+         If unsure, say N.
+
+         To compile this driver as a module, choose M here: the
+         module will be called sis_i2c.
+
 endif
diff --git a/drivers/input/touchscreen/Makefile 
b/drivers/input/touchscreen/Makefile
index f42975e..0839e99 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -63,6 +63,7 @@ obj-$(CONFIG_TOUCHSCREEN_PCAP)                += pcap_ts.o
 obj-$(CONFIG_TOUCHSCREEN_PENMOUNT)     += penmount.o
 obj-$(CONFIG_TOUCHSCREEN_PIXCIR)       += pixcir_i2c_ts.o
 obj-$(CONFIG_TOUCHSCREEN_S3C2410)      += s3c2410_ts.o
+obj-$(CONFIG_TOUCHSCREEN_SIS_I2C)       += sis_i2c.o
 obj-$(CONFIG_TOUCHSCREEN_ST1232)       += st1232.o
 obj-$(CONFIG_TOUCHSCREEN_STMPE)                += stmpe-ts.o
 obj-$(CONFIG_TOUCHSCREEN_SUN4I)                += sun4i-ts.o
diff --git a/drivers/input/touchscreen/sis_i2c.c 
b/drivers/input/touchscreen/sis_i2c.c
new file mode 100644
index 0000000..f1b66fa
--- /dev/null
+++ b/drivers/input/touchscreen/sis_i2c.c
@@ -0,0 +1,461 @@
+/* drivers/input/touchscreen/sis_i2c.c
+ *  - I2C Touch panel driver for SiS 9200 family
+ *
+ * Copyright (C) 2011 SiS, Inc.
+ * Copyright (C) 2015 Nextfour Group
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/linkage.h>
+#include <linux/slab.h>
+#include <linux/of_gpio.h>
+#include <linux/uaccess.h>
+#include <linux/irq.h>
+#include <asm/unaligned.h>
+#include <linux/crc-itu-t.h>
+
+#define SIS_I2C_NAME "sis_i2c_ts"
+#define MAX_FINGERS                                    10
+
+#define SIS_MAX_X                                      4095
+#define SIS_MAX_Y                                      4095
+
+#define PACKET_BUFFER_SIZE                             128
+
+#define SIS_CMD_NORMAL                                 0x0
+
+#define TOUCHDOWN                                       0x3
+#define TOUCHUP                                         0x0
+#define MAX_BYTE                                        64
+#define PRESSURE_MAX                                    255
+
+/* Resolution diagonal */
+#define AREA_LENGTH_LONGER                             5792
+/*((SIS_MAX_X^2) + (SIS_MAX_Y^2))^0.5*/
+#define AREA_LENGTH_SHORT                              5792
+#define AREA_UNIT                                      (5792/32)
+
+#define P_BYTECOUNT                                    0
+#define ALL_IN_ONE_PACKAGE                             0x10
+#define IS_TOUCH(x)                                    ((x) & 0x1)
+#define IS_HIDI2C(x)                                   (((x) & 0xF) == 0x06)
+#define IS_AREA(x)                                     (((x) >> 4) & 0x1)
+#define IS_PRESSURE(x)                                 (((x) >> 5) & 0x1)
+#define IS_SCANTIME(x)                                 (((x) >> 6) & 0x1)
+
+#define NORMAL_LEN_PER_POINT                           6
+#define AREA_LEN_PER_POINT                             2
+#define PRESSURE_LEN_PER_POINT                         1
+
+#define TOUCH_FORMAT                                   0x1
+#define HIDI2C_FORMAT                                  0x6
+#define P_REPORT_ID                                    2
+#define BYTE_BYTECOUNT                                 2
+#define BYTE_REPORTID                                  1
+#define BYTE_CRC_HIDI2C                                 0
+#define BYTE_CRC_I2C                                   2
+#define BYTE_SCANTIME                                  2
+
+struct _touchpoint {
+       u8 id;
+       u16 x, y;
+       u16 pressure;
+       u16 width;
+       u16 height;
+};
+
+struct sistp_driver_data {
+       int fingers;
+       struct _touchpoint pt[MAX_FINGERS];
+};
+
+struct sis_ts_data {
+       struct gpio_desc *irq_gpiod;
+       struct gpio_desc *reset_gpiod;
+       struct i2c_client *client;
+       struct input_dev *input_dev;
+struct sistp_driver_data tpinfo;
+};
+
+static int sis_cul_unit(u8 report_id)
+{
+       int ret = NORMAL_LEN_PER_POINT;
+
+       if (report_id != ALL_IN_ONE_PACKAGE) {
+
+               if (IS_AREA(report_id) /*&& IS_TOUCH(report_id)*/)
+                       ret += AREA_LEN_PER_POINT;
+
+               if (IS_PRESSURE(report_id))
+                       ret += PRESSURE_LEN_PER_POINT;
+       }
+
+       return ret;
+}
+
+static int sis_readpacket(struct i2c_client *client, u8 cmd, u8 *buf)
+{
+       u8 tmpbuf[MAX_BYTE] = {0};
+       int ret = -1;
+       int touchnum = 0;
+       int p_count = 0;
+       int touch_format_id = 0;
+       int location = 0;
+       bool read_first = true;
+
+/*
+ * I2C touch report format
+ *
+ * The controller sends one or two
+ * 64 byte reports (depending on how many
+ * contacts down etc). We read first 64 bytes
+ * and then the second chunk if needed.
+ * The packets are individually CRC
+ * checksummed.
+ *
+ * buf[0] = Low 8 bits of byte count value
+ * buf[1] = High 8 bits of byte counte value
+ * buf[2] = Report ID
+ * buf[touch num * 6 + 2 ] = Touch information
+ * 1 touch point has 6 bytes, it could be none if no touch
+ * buf[touch num * 6 + 3] = Touch numbers
+ *
+ * One touch point information include 6 bytes, the order is
+ *
+ * 1. status = touch down or touch up
+ * 2. id = finger id
+ * 3. x axis low 8 bits
+ * 4. x axis high 8 bits
+ * 5. y axis low 8 bits
+ * 6. y axis high 8 bits
+ */
+       do {
+               if (location >= PACKET_BUFFER_SIZE) {
+                       dev_err(&client->dev, "sis_readpacket: buffer 
overflow\n");
+                       return -1;
+               }
+
+               ret = i2c_master_recv(client, tmpbuf, MAX_BYTE);
+
+               if (ret <= 0) {
+                       return touchnum;
+               } else if (tmpbuf[P_BYTECOUNT] > MAX_BYTE) {
+                       dev_err(&client->dev, "sis_readpacket: invalid 
bytecout\n");
+                       return -1;
+               }
+
+               if (tmpbuf[P_BYTECOUNT] < 10)
+                       return touchnum;
+
+               if (read_first)
+                       if (tmpbuf[P_BYTECOUNT] == 0)
+                               return 0;       /* touchnum is 0 */
+
+               touch_format_id = tmpbuf[P_REPORT_ID] & 0xf;
+
+               if ((touch_format_id != TOUCH_FORMAT)
+                       && (touch_format_id != HIDI2C_FORMAT)
+                       && (tmpbuf[P_REPORT_ID] != ALL_IN_ONE_PACKAGE)) {
+                       dev_err(&client->dev, "sis_readpacket: invalid 
reportid\n");
+                       return -1;
+               }
+
+               p_count = (int) tmpbuf[P_BYTECOUNT] - 1; /* start from 0 */
+               if (tmpbuf[P_REPORT_ID] != ALL_IN_ONE_PACKAGE) {
+                       if (IS_TOUCH(tmpbuf[P_REPORT_ID])) {
+                               p_count -= BYTE_CRC_I2C; /* delete 2 byte crc */
+                       } else if (IS_HIDI2C(tmpbuf[P_REPORT_ID])) {
+                               p_count -= BYTE_CRC_HIDI2C;
+                       } else {
+                               dev_err(&client->dev, "sis_readpacket: delete 
crc error\n");
+                               return -1;
+                       }
+                       if (IS_SCANTIME(tmpbuf[P_REPORT_ID]))
+                               p_count -= BYTE_SCANTIME;
+               }
+
+               if (read_first)
+                       touchnum = tmpbuf[p_count];
+               else {
+                       if (tmpbuf[p_count] != 0) {
+                               dev_err(&client->dev, "sis_readpacket: nonzero 
point count in tail packet\n");
+                               return -1;
+                       }
+               }
+
+               if ((touch_format_id != HIDI2C_FORMAT) &&
+                       (tmpbuf[P_BYTECOUNT] > 3)) {
+                       int crc_end = p_count +
+                               (IS_SCANTIME(tmpbuf[P_REPORT_ID]) * 2);
+                       u16 buf_crc =
+                               crc_itu_t(0, tmpbuf + 2, crc_end - 1);
+                       int l_package_crc =
+                               (IS_SCANTIME(tmpbuf[P_REPORT_ID]) * 2) +
+                               p_count + 1;
+                       u16 package_crc =
+                               get_unaligned_le16(&tmpbuf[l_package_crc]);
+                       if (buf_crc != package_crc) {
+                               dev_err(&client->dev, "sis_readpacket: CRC 
Error\n");
+                               return -1;
+                       }
+               }
+
+               memcpy(&buf[location], &tmpbuf[0], 64);
+               /* Buf_Data [0~63] [64~128] */
+               location += MAX_BYTE;
+               read_first = false;
+       } while (tmpbuf[P_REPORT_ID] != ALL_IN_ONE_PACKAGE &&
+               tmpbuf[p_count] > 5);
+
+       return touchnum;
+}
+
+static irqreturn_t sis_ts_irq_handler(int irq, void *dev_id)
+{
+       struct sis_ts_data *ts = dev_id;
+       struct sistp_driver_data *tpinfo = &ts->tpinfo;
+
+       int ret = -1;
+       int point_unit;
+       u8 buf[PACKET_BUFFER_SIZE] = {0};
+       u8 i = 0, fingers = 0;
+       u8 px = 0, py = 0, pstatus = 0;
+       u8 p_area = 0;
+       u8 p_preasure = 0;
+       int slot;
+
+redo:
+       /* I2C or SMBUS block data read */
+       ret = sis_readpacket(ts->client, SIS_CMD_NORMAL, buf);
+
+       if (ret < 0)
+               goto recheck_irq;
+
+       else if (ret == 0) {
+               fingers = 0;
+               goto label_sync_input;
+       }
+
+       point_unit = sis_cul_unit(buf[P_REPORT_ID]);
+       fingers = ret;
+
+       tpinfo->fingers = fingers = (fingers > MAX_FINGERS ? 0 : fingers);
+
+       for (i = 0; i < fingers; i++) {
+               if ((buf[P_REPORT_ID] != ALL_IN_ONE_PACKAGE) && (i >= 5)) {
+                       pstatus = BYTE_BYTECOUNT + BYTE_REPORTID
+                               + ((i - 5) * point_unit);
+                       pstatus += 64;
+               } else {
+                       pstatus = BYTE_BYTECOUNT + BYTE_REPORTID
+                               + (i * point_unit);
+               }
+               /* X and Y coordinate locations */
+               px = pstatus + 2;
+               py = px + 2;
+
+               if ((buf[pstatus]) == TOUCHUP) {
+                       tpinfo->pt[i].width    = 0;
+                       tpinfo->pt[i].height   = 0;
+                       tpinfo->pt[i].pressure = 0;
+               } else if (buf[P_REPORT_ID] == ALL_IN_ONE_PACKAGE
+                       && (buf[pstatus]) == TOUCHDOWN) {
+                       tpinfo->pt[i].width    = 1;
+                       tpinfo->pt[i].height   = 1;
+                       tpinfo->pt[i].pressure = 1;
+               } else if ((buf[pstatus]) == TOUCHDOWN) {
+                       p_area = py + 2;
+                       p_preasure = py + 2 + (IS_AREA(buf[P_REPORT_ID]) * 2);
+
+                       if (IS_AREA(buf[P_REPORT_ID])) {
+                               tpinfo->pt[i].width = buf[p_area];
+                               tpinfo->pt[i].height = buf[p_area + 1];
+                       } else {
+                               tpinfo->pt[i].width = 1;
+                               tpinfo->pt[i].height = 1;
+                       }
+
+                       if (IS_PRESSURE(buf[P_REPORT_ID]))
+                               tpinfo->pt[i].pressure = (buf[p_preasure]);
+                       else
+                               tpinfo->pt[i].pressure = 1;
+               } else {
+                       dev_err(&ts->client->dev, "Touch status error\n");
+                       goto recheck_irq;
+               }
+               tpinfo->pt[i].id = (buf[pstatus + 1]);
+               tpinfo->pt[i].x = le16_to_cpu(get_unaligned_le16(&buf[px]));
+               tpinfo->pt[i].y = le16_to_cpu(get_unaligned_le16(&buf[py]));
+
+               slot = input_mt_get_slot_by_key(
+                       ts->input_dev, tpinfo->pt[i].id);
+
+               if (slot < 0)
+                       continue;
+
+               input_mt_slot(ts->input_dev, slot);
+               input_mt_report_slot_state(ts->input_dev,
+                                       MT_TOOL_FINGER, tpinfo->pt[i].pressure);
+
+               if (tpinfo->pt[i].pressure) {
+
+                       tpinfo->pt[i].width *= AREA_UNIT;
+                       input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR,
+                                       tpinfo->pt[i].width);
+                       tpinfo->pt[i].height *= AREA_UNIT;
+                       input_report_abs(ts->input_dev, ABS_MT_TOUCH_MINOR,
+                                       tpinfo->pt[i].height);
+                       input_report_abs(ts->input_dev, ABS_MT_PRESSURE,
+                                       tpinfo->pt[i].pressure);
+                       input_report_abs(ts->input_dev, ABS_MT_POSITION_X,
+                                       tpinfo->pt[i].x);
+                       input_report_abs(ts->input_dev, ABS_MT_POSITION_Y,
+                                       tpinfo->pt[i].y);
+               }
+       }
+
+label_sync_input:
+       input_mt_sync_frame(ts->input_dev);
+       input_sync(ts->input_dev);
+
+recheck_irq:
+       if (ts->irq_gpiod) {
+               /*
+                * If provided and interrupt gpio and
+                * irq is still asserted,
+                * read data until interrupt is deasserted.
+                */
+               ret = gpiod_get_value_cansleep(ts->irq_gpiod);
+               if (ret == 1)
+                       goto redo;
+       }
+
+       return IRQ_HANDLED;
+}
+
+static void sis_ts_reset(struct i2c_client *client, struct sis_ts_data *ts)
+{
+
+       ts->irq_gpiod   = devm_gpiod_get_optional(&client->dev,
+                                               "irq", GPIOD_IN);
+       ts->reset_gpiod = devm_gpiod_get_optional(&client->dev,
+                                               "reset", GPIOD_OUT_LOW);
+
+       if (ts->reset_gpiod) {
+               /* Get out of reset */
+               msleep(1);
+               gpiod_set_value(ts->reset_gpiod, 1);
+               msleep(1);
+               gpiod_set_value(ts->reset_gpiod, 0);
+               msleep(100);
+       }
+}
+
+static int sis_ts_probe(
+       struct i2c_client *client, const struct i2c_device_id *id)
+{
+       int error = 0;
+       struct sis_ts_data *ts = NULL;
+
+       ts = devm_kzalloc(&client->dev, sizeof(struct sis_ts_data), GFP_KERNEL);
+       if (!ts)
+               return -ENOMEM;
+
+       sis_ts_reset(client, ts);
+
+       ts->client = client;
+       i2c_set_clientdata(client, ts);
+
+       ts->input_dev = devm_input_allocate_device(&client->dev);
+       if (!ts->input_dev) {
+               dev_err(&client->dev, "sis_ts_probe: Failed to allocate input 
device\n");
+               return -ENOMEM;
+       }
+
+       ts->input_dev->name = "sis_touch";
+       ts->input_dev->id.bustype = BUS_I2C;
+
+       input_set_abs_params(ts->input_dev, ABS_MT_PRESSURE,
+                       0, PRESSURE_MAX, 0, 0);
+       input_set_abs_params(ts->input_dev, ABS_MT_TOUCH_MAJOR,
+                       0, AREA_LENGTH_LONGER, 0, 0);
+       input_set_abs_params(ts->input_dev, ABS_MT_TOUCH_MINOR,
+                       0, AREA_LENGTH_SHORT, 0, 0);
+       input_set_abs_params(ts->input_dev, ABS_MT_POSITION_X,
+                       0, SIS_MAX_X, 0, 0);
+       input_set_abs_params(ts->input_dev, ABS_MT_POSITION_Y,
+                       0, SIS_MAX_Y, 0, 0);
+
+       error = input_mt_init_slots(ts->input_dev, MAX_FINGERS,
+                       INPUT_MT_DROP_UNUSED | INPUT_MT_DIRECT);
+
+       if (error) {
+               dev_err(&client->dev,
+                       "failed to initialize MT slots: %d\n", error);
+               return error;
+       }
+
+       error = input_register_device(ts->input_dev);
+       if (error) {
+               dev_err(&client->dev,
+                       "unable to register input device: %d\n", error);
+               return error;
+       }
+
+       error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+                                       sis_ts_irq_handler,
+                                       IRQF_ONESHOT,
+                                       client->name, ts);
+
+       if (error) {
+               dev_err(&client->dev, "request irq failed\n");
+               return error;
+       }
+
+       return 0;
+}
+
+static const struct i2c_device_id sis_ts_id[] = {
+       { SIS_I2C_NAME, 0 },
+       { }
+};
+
+MODULE_DEVICE_TABLE(i2c, sis_ts_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id sis_ts_dt_ids[] = {
+       { .compatible = "sis,9200_ts" },
+       { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sis_ts_dt_ids);
+#endif
+
+static struct i2c_driver sis_ts_driver = {
+       .probe          = sis_ts_probe,
+       .id_table       = sis_ts_id,
+       .driver = {
+               .name   = SIS_I2C_NAME,
+               .of_match_table = of_match_ptr(sis_ts_dt_ids),
+       },
+};
+
+module_i2c_driver(sis_ts_driver);
+MODULE_DESCRIPTION("SiS 9200 Family Touchscreen Driver");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

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