Input: add driver for SiS 9200 family I2C touchscreen controllers

This is a driver for SiS 9200 family touchscreen controllers using I2C bus.

Signed-off-by: Mika Penttilä <mika.penttila@nextfour.com>
Acked-by: Tammy Tseng <tammy_tseng@sis.com>
Acked-by: Yuger Yu <yuger_yu@sis.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

5 files changed, 460 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/input/touchscreen/sis_i2c.txt b/Documentation/devicetree/bindings/input/touchscreen/sis_i2c.txt
new file mode 100644
index 000000000000..d87ad14f1efe
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/sis_i2c.txt
@@ -0,0 +1,33 @@
+* SiS I2C Multiple Touch Controller
+
+Required properties:
+- compatible: must be "sis,9200-ts"
+- reg: i2c slave address
+- interrupt-parent: the phandle for the interrupt controller
+  (see interrupt binding [0])
+- interrupts: touch controller interrupt (see interrupt
+  binding [0])
+
+Optional properties:
+- pinctrl-names: should be "default" (see pinctrl binding [1]).
+- pinctrl-0: a phandle pointing to the pin settings for the
+  device (see pinctrl binding [1]).
+- attn-gpios: the gpio pin used as attention line
+- reset-gpios: the gpio pin used to reset the controller
+- wakeup-source: touchscreen can be used as a wakeup source
+
+[0]: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
+[1]: Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
+
+Example:
+
+        sis9255@5c  {
+                compatible = "sis,9200-ts";
+                reg = <0x5c>;
+                pinctrl-names = "default";
+                pinctrl-0 = <&pinctrl_sis>;
+                interrupt-parent = <&gpio3>;
+                interrupts = <19 IRQ_TYPE_EDGE_FALLING>;
+                irq-gpios = <&gpio3 19 GPIO_ACTIVE_LOW>;
+                reset-gpios = <&gpio2 30 GPIO_ACTIVE_LOW>;
+        };
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index 80fdbe2ce088..99029cfed459 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -221,6 +221,7 @@ simtek
 sii     Seiko Instruments, Inc.
 silergy Silergy Corp.
 sirf    SiRF Technology, Inc.
+sis     Silicon Integrated Systems Corp.
 sitronix        Sitronix Technology Corporation
 skyworks        Skyworks Solutions, Inc.
 smsc    Standard Microsystems Corporation
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 6abcd1766092..8d893cefb0e3 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -1071,6 +1071,18 @@ config TOUCHSCREEN_SILEAD
           To compile this driver as a module, choose M here: the
           module will be called silead.
 
+config TOUCHSCREEN_SIS_I2C
+        tristate "SiS 9200 family I2C touchscreen"
+        depends on I2C
+        depends on GPIOLIB || COMPILE_TEST
+        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.
+
 config TOUCHSCREEN_ST1232
         tristate "Sitronix ST1232 touchscreen controllers"
         depends on I2C
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 3b598c901677..b4373d6be402 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_TOUCHSCREEN_PIXCIR)	+= pixcir_i2c_ts.o
 obj-$(CONFIG_TOUCHSCREEN_RM_TS)         += raydium_i2c_ts.o
 obj-$(CONFIG_TOUCHSCREEN_S3C2410)       += s3c2410_ts.o
 obj-$(CONFIG_TOUCHSCREEN_SILEAD)        += silead.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 000000000000..8d93f8c9a403
--- /dev/null
+++ b/drivers/input/touchscreen/sis_i2c.c
@@ -0,0 +1,413 @@
+/*
+ * Touch Screen driver for SiS 9200 family I2C Touch panels
+ *
+ * Copyright (C) 2015 SiS, Inc.
+ * Copyright (C) 2016 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/crc-itu-t.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/interrupt.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <asm/unaligned.h>
+
+#define SIS_I2C_NAME            "sis_i2c_ts"
+
+/*
+ * The I2C packet format:
+ * le16         byte count
+ * u8           Report ID
+ * <contact data - variable length>
+ * u8           Number of contacts
+ * le16         Scan Time (optional)
+ * le16         CRC
+ *
+ * One touch point information consists of 6+ bytes, the order is:
+ * u8           contact state
+ * u8           finger id
+ * le16         x axis
+ * le16         y axis
+ * u8           contact width (optional)
+ * u8           contact height (optional)
+ * u8           pressure (optional)
+ *
+ * Maximum amount of data transmitted in one shot is 64 bytes, if controller
+ * needs to report more contacts than fit in one packet it will send true
+ * number of contacts in first packet and 0 as number of contacts in second
+ * packet.
+ */
+
+#define SIS_MAX_PACKET_SIZE             64
+
+#define SIS_PKT_LEN_OFFSET              0
+#define SIS_PKT_REPORT_OFFSET           2 /* Report ID/type */
+#define SIS_PKT_CONTACT_OFFSET          3 /* First contact */
+
+#define SIS_SCAN_TIME_LEN               2
+
+/* Supported report types */
+#define SIS_ALL_IN_ONE_PACKAGE          0x10
+#define SIS_PKT_IS_TOUCH(x)             (((x) & 0x0f) == 0x01)
+#define SIS_PKT_IS_HIDI2C(x)            (((x) & 0x0f) == 0x06)
+
+/* Contact properties within report */
+#define SIS_PKT_HAS_AREA(x)             ((x) & BIT(4))
+#define SIS_PKT_HAS_PRESSURE(x)         ((x) & BIT(5))
+#define SIS_PKT_HAS_SCANTIME(x)         ((x) & BIT(6))
+
+/* Contact size */
+#define SIS_BASE_LEN_PER_CONTACT        6
+#define SIS_AREA_LEN_PER_CONTACT        2
+#define SIS_PRESSURE_LEN_PER_CONTACT    1
+
+/* Offsets within contact data */
+#define SIS_CONTACT_STATUS_OFFSET       0
+#define SIS_CONTACT_ID_OFFSET           1 /* Contact ID */
+#define SIS_CONTACT_X_OFFSET            2
+#define SIS_CONTACT_Y_OFFSET            4
+#define SIS_CONTACT_WIDTH_OFFSET        6
+#define SIS_CONTACT_HEIGHT_OFFSET       7
+#define SIS_CONTACT_PRESSURE_OFFSET(id) (SIS_PKT_HAS_AREA(id) ? 8 : 6)
+
+/* Individual contact state */
+#define SIS_STATUS_UP                   0x0
+#define SIS_STATUS_DOWN                 0x3
+
+/* Touchscreen parameters */
+#define SIS_MAX_FINGERS                 10
+#define SIS_MAX_X                       4095
+#define SIS_MAX_Y                       4095
+#define SIS_MAX_PRESSURE                255
+
+/* Resolution diagonal */
+#define SIS_AREA_LENGTH_LONGER          5792
+/*((SIS_MAX_X^2) + (SIS_MAX_Y^2))^0.5*/
+#define SIS_AREA_LENGTH_SHORT           5792
+#define SIS_AREA_UNIT                   (5792 / 32)
+
+struct sis_ts_data {
+        struct i2c_client *client;
+        struct input_dev *input;
+
+        struct gpio_desc *attn_gpio;
+        struct gpio_desc *reset_gpio;
+
+        u8 packet[SIS_MAX_PACKET_SIZE];
+};
+
+static int sis_read_packet(struct i2c_client *client, u8 *buf,
+                           unsigned int *num_contacts,
+                           unsigned int *contact_size)
+{
+        int count_idx;
+        int ret;
+        u16 len;
+        u16 crc, pkg_crc;
+        u8 report_id;
+
+        ret = i2c_master_recv(client, buf, SIS_MAX_PACKET_SIZE);
+        if (ret <= 0)
+                return -EIO;
+
+        len = get_unaligned_le16(&buf[SIS_PKT_LEN_OFFSET]);
+        if (len > SIS_MAX_PACKET_SIZE) {
+                dev_err(&client->dev,
+                        "%s: invalid packet length (%d vs %d)\n",
+                        __func__, len, SIS_MAX_PACKET_SIZE);
+                return -E2BIG;
+        }
+
+        if (len < 10)
+                return -EINVAL;
+
+        report_id = buf[SIS_PKT_REPORT_OFFSET];
+        count_idx  = len - 1;
+        *contact_size = SIS_BASE_LEN_PER_CONTACT;
+
+        if (report_id != SIS_ALL_IN_ONE_PACKAGE) {
+                if (SIS_PKT_IS_TOUCH(report_id)) {
+                        /*
+                         * Calculate CRC ignoring packet length
+                         * in the beginning and CRC transmitted
+                         * at the end of the packet.
+                         */
+                        crc = crc_itu_t(0, buf + 2, len - 2 - 2);
+                        pkg_crc = get_unaligned_le16(&buf[len - 2]);
+
+                        if (crc != pkg_crc) {
+                                dev_err(&client->dev,
+                                        "%s: CRC Error (%d vs %d)\n",
+                                        __func__, crc, pkg_crc);
+                                return -EINVAL;
+                        }
+
+                        count_idx -= 2;
+
+                } else if (!SIS_PKT_IS_HIDI2C(report_id)) {
+                        dev_err(&client->dev,
+                                "%s: invalid packet ID %#02x\n",
+                                __func__, report_id);
+                        return -EINVAL;
+                }
+
+                if (SIS_PKT_HAS_SCANTIME(report_id))
+                        count_idx -= SIS_SCAN_TIME_LEN;
+
+                if (SIS_PKT_HAS_AREA(report_id))
+                        *contact_size += SIS_AREA_LEN_PER_CONTACT;
+                if (SIS_PKT_HAS_PRESSURE(report_id))
+                        *contact_size += SIS_PRESSURE_LEN_PER_CONTACT;
+        }
+
+        *num_contacts = buf[count_idx];
+        return 0;
+}
+
+static int sis_ts_report_contact(struct sis_ts_data *ts, const u8 *data, u8 id)
+{
+        struct input_dev *input = ts->input;
+        int slot;
+        u8 status = data[SIS_CONTACT_STATUS_OFFSET];
+        u8 pressure;
+        u8 height, width;
+        u16 x, y;
+
+        if (status != SIS_STATUS_DOWN && status != SIS_STATUS_UP) {
+                dev_err(&ts->client->dev, "Unexpected touch status: %#02x\n",
+                        data[SIS_CONTACT_STATUS_OFFSET]);
+                return -EINVAL;
+        }
+
+        slot = input_mt_get_slot_by_key(input, data[SIS_CONTACT_ID_OFFSET]);
+        if (slot < 0)
+                return -ENOENT;
+
+        input_mt_slot(input, slot);
+        input_mt_report_slot_state(input, MT_TOOL_FINGER,
+                                   status == SIS_STATUS_DOWN);
+
+        if (status == SIS_STATUS_DOWN) {
+                pressure = height = width = 1;
+                if (id != SIS_ALL_IN_ONE_PACKAGE) {
+                        if (SIS_PKT_HAS_AREA(id)) {
+                                width = data[SIS_CONTACT_WIDTH_OFFSET];
+                                height = data[SIS_CONTACT_HEIGHT_OFFSET];
+                        }
+
+                        if (SIS_PKT_HAS_PRESSURE(id))
+                                pressure =
+                                        data[SIS_CONTACT_PRESSURE_OFFSET(id)];
+                }
+
+                x = get_unaligned_le16(&data[SIS_CONTACT_X_OFFSET]);
+                y = get_unaligned_le16(&data[SIS_CONTACT_Y_OFFSET]);
+
+                input_report_abs(input, ABS_MT_TOUCH_MAJOR,
+                                 width * SIS_AREA_UNIT);
+                input_report_abs(input, ABS_MT_TOUCH_MINOR,
+                                 height * SIS_AREA_UNIT);
+                input_report_abs(input, ABS_MT_PRESSURE, pressure);
+                input_report_abs(input, ABS_MT_POSITION_X, x);
+                input_report_abs(input, ABS_MT_POSITION_Y, y);
+        }
+
+        return 0;
+}
+
+static void sis_ts_handle_packet(struct sis_ts_data *ts)
+{
+        const u8 *contact;
+        unsigned int num_to_report = 0;
+        unsigned int num_contacts;
+        unsigned int num_reported;
+        unsigned int contact_size;
+        int error;
+        u8 report_id;
+
+        do {
+                error = sis_read_packet(ts->client, ts->packet,
+                                        &num_contacts, &contact_size);
+                if (error)
+                        break;
+
+                if (num_to_report == 0) {
+                        num_to_report = num_contacts;
+                } else if (num_contacts != 0) {
+                        dev_err(&ts->client->dev,
+                                "%s: nonzero (%d) point count in tail packet\n",
+                                __func__, num_contacts);
+                        break;
+                }
+
+                report_id = ts->packet[SIS_PKT_REPORT_OFFSET];
+                contact = &ts->packet[SIS_PKT_CONTACT_OFFSET];
+                num_reported = 0;
+
+                while (num_to_report > 0) {
+                        error = sis_ts_report_contact(ts, contact, report_id);
+                        if (error)
+                                break;
+
+                        contact += contact_size;
+                        num_to_report--;
+                        num_reported++;
+
+                        if (report_id != SIS_ALL_IN_ONE_PACKAGE &&
+                            num_reported >= 5) {
+                                /*
+                                 * The remainder of contacts is sent
+                                 * in the 2nd packet.
+                                 */
+                                break;
+                        }
+                }
+        } while (num_to_report > 0);
+
+        input_mt_sync_frame(ts->input);
+        input_sync(ts->input);
+}
+
+static irqreturn_t sis_ts_irq_handler(int irq, void *dev_id)
+{
+        struct sis_ts_data *ts = dev_id;
+
+        do {
+                sis_ts_handle_packet(ts);
+        } while (ts->attn_gpio && gpiod_get_value_cansleep(ts->attn_gpio));
+
+        return IRQ_HANDLED;
+}
+
+static void sis_ts_reset(struct sis_ts_data *ts)
+{
+        if (ts->reset_gpio) {
+                /* Get out of reset */
+                usleep_range(1000, 2000);
+                gpiod_set_value(ts->reset_gpio, 1);
+                usleep_range(1000, 2000);
+                gpiod_set_value(ts->reset_gpio, 0);
+                msleep(100);
+        }
+}
+
+static int sis_ts_probe(struct i2c_client *client,
+                        const struct i2c_device_id *id)
+{
+        struct sis_ts_data *ts;
+        struct input_dev *input;
+        int error;
+
+        ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
+        if (!ts)
+                return -ENOMEM;
+
+        ts->client = client;
+        i2c_set_clientdata(client, ts);
+
+        ts->attn_gpio = devm_gpiod_get_optional(&client->dev,
+                                                "attn", GPIOD_IN);
+        if (IS_ERR(ts->attn_gpio)) {
+                error = PTR_ERR(ts->attn_gpio);
+                if (error != -EPROBE_DEFER)
+                        dev_err(&client->dev,
+                                "Failed to get attention GPIO: %d\n", error);
+                return error;
+        }
+
+        ts->reset_gpio = devm_gpiod_get_optional(&client->dev,
+                                                 "reset", GPIOD_OUT_LOW);
+        if (IS_ERR(ts->reset_gpio)) {
+                error = PTR_ERR(ts->reset_gpio);
+                if (error != -EPROBE_DEFER)
+                        dev_err(&client->dev,
+                                "Failed to get reset GPIO: %d\n", error);
+                return error;
+        }
+
+        sis_ts_reset(ts);
+
+        ts->input = input = devm_input_allocate_device(&client->dev);
+        if (!input) {
+                dev_err(&client->dev, "Failed to allocate input device\n");
+                return -ENOMEM;
+        }
+
+        input->name = "SiS Touchscreen";
+        input->id.bustype = BUS_I2C;
+
+        input_set_abs_params(input, ABS_MT_POSITION_X, 0, SIS_MAX_X, 0, 0);
+        input_set_abs_params(input, ABS_MT_POSITION_Y, 0, SIS_MAX_Y, 0, 0);
+        input_set_abs_params(input, ABS_MT_PRESSURE, 0, SIS_MAX_PRESSURE, 0, 0);
+        input_set_abs_params(input, ABS_MT_TOUCH_MAJOR,
+                             0, SIS_AREA_LENGTH_LONGER, 0, 0);
+        input_set_abs_params(input, ABS_MT_TOUCH_MINOR,
+                             0, SIS_AREA_LENGTH_SHORT, 0, 0);
+
+        error = input_mt_init_slots(input, SIS_MAX_FINGERS, INPUT_MT_DIRECT);
+        if (error) {
+                dev_err(&client->dev,
+                        "Failed to initialize MT slots: %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, "Failed to request IRQ: %d\n", error);
+                return error;
+        }
+
+        error = input_register_device(ts->input);
+        if (error) {
+                dev_err(&client->dev,
+                        "Failed to register input device: %d\n", error);
+                return error;
+        }
+
+        return 0;
+}
+
+#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 const struct i2c_device_id sis_ts_id[] = {
+        { SIS_I2C_NAME, 0 },
+        { "9200-ts",    0 },
+        { /* sentinel */  }
+};
+MODULE_DEVICE_TABLE(i2c, sis_ts_id);
+
+static struct i2c_driver sis_ts_driver = {
+        .driver = {
+                .name   = SIS_I2C_NAME,
+                .of_match_table = of_match_ptr(sis_ts_dt_ids),
+        },
+        .probe          = sis_ts_probe,
+        .id_table       = sis_ts_id,
+};
+module_i2c_driver(sis_ts_driver);
+
+MODULE_DESCRIPTION("SiS 9200 Family Touchscreen Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Mika Penttilä <mika.penttila@nextfour.com>");