[PATCH v6 1/2] Input: Driver for SiS-9200 family I2C touchscreen controller

From: mika.penttila
Date: Tue Aug 02 2016 - 11:31:22 EST

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From: Mika PenttilÃ <mika.penttila@xxxxxxxxxxxx>

Multitouch protocol B support.

v6:
- rebased to 4.7
- simplify logic : send input reports while reading
i2c packets
- more cleanups

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 PenttilÃ <mika.penttila@xxxxxxxxxxxx>
Acked-by: Tammy Tseng <tammy_tseng@xxxxxxx>
Acked-by: Yuger Yu <yuger_yu@xxxxxxx>
---
drivers/input/touchscreen/Kconfig | 12 ++
drivers/input/touchscreen/Makefile | 2 +
drivers/input/touchscreen/sis_i2c.c | 409 ++++++++++++++++++++++++++++++++++++
3 files changed, 423 insertions(+)
create mode 100644 drivers/input/touchscreen/sis_i2c.c

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index ee02dc7..0633e8c 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -1181,4 +1181,16 @@ 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 3315882..cbb484f 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_TOUCHSCREEN_PENMOUNT) += penmount.o
obj-$(CONFIG_TOUCHSCREEN_PIXCIR) += pixcir_i2c_ts.o
obj-$(CONFIG_TOUCHSCREEN_RM_TS) += raydium_i2c_ts.o
obj-$(CONFIG_TOUCHSCREEN_S3C2410) += s3c2410_ts.o
+obj-$(CONFIG_TOUCHSCREEN_SIS_I2C) += sis_i2c.o
obj-$(CONFIG_TOUCHSCREEN_ST1232) += st1232.o
obj-$(CONFIG_TOUCHSCREEN_STMPE) += stmpe-ts.o
obj-$(CONFIG_TOUCHSCREEN_SUN4I) += sun4i-ts.o
@@ -97,3 +98,4 @@ obj-$(CONFIG_TOUCHSCREEN_TPS6507X) += tps6507x-ts.o
obj-$(CONFIG_TOUCHSCREEN_ZFORCE) += zforce_ts.o
obj-$(CONFIG_TOUCHSCREEN_COLIBRI_VF50) += colibri-vf50-ts.o
obj-$(CONFIG_TOUCHSCREEN_ROHM_BU21023) += rohm_bu21023.o
+
diff --git a/drivers/input/touchscreen/sis_i2c.c b/drivers/input/touchscreen/sis_i2c.c
new file mode 100644
index 0000000..51caad3
--- /dev/null
+++ b/drivers/input/touchscreen/sis_i2c.c
@@ -0,0 +1,409 @@
+/*
+ * 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;
+
+ 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)];
+ }
+
+ 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,
+ get_unaligned_le16(&data[SIS_CONTACT_X_OFFSET]));
+ input_report_abs(input, ABS_MT_POSITION_Y,
+ get_unaligned_le16(&data[SIS_CONTACT_Y_OFFSET]));
+ }
+
+ 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 PenttilÃ <mika.penttila@xxxxxxxxxxxx>");
--
1.9.1

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