[PATCH v2] Input: Add generic driver for Zeitec touchscreens

From: Bogdan George Stefan
Date: Thu May 28 2015 - 08:15:55 EST


This driver adds support for Zeitec touchscreens. It has
been tested with ZET6273 and ZET9172.

It supports ACPI and device tree enumeration. For ACPI you need ACPI
5.1+ in order to be able to use named GPIOs.

Screen resolution, the maximum number of fingers supported,
if the touchscreen has hardware keys are configurable
using ACPI/DT properties.

Signed-off-by: Bogdan George Stefan <bogdan.g.stefan@xxxxxxxxx>
---
Changes since v1:

Implemented most changes following Dmitry Torokhov's recommendations
from https://lkml.org/lkml/2015/5/15/319
The only things I kept are described below in the Notes section.
- fixed style issues
- reset is activated when gpio is set to high
- switched from i2c_transfer to i2c_master_recv/i2c_master_send
- removed redundant evbit initialization. However EV_ABS still needs
to be reported and it is set through input_set_capability
- replaced usleep_range with msleep where neede. Checking the patch
with -strict will report an issue on this. Hope this is not a problem
- fixed casts in zet_process_events
- removed client->irq = gpiod_to_irq(ts->irq); from probe
- moved firmware loading from probe to open
- used proper casts in zet_suspend
- dropped zet_ts_remove as it was doing unnecesary things
Notes:
- I've kept the flags IRQF_TRIGGER_FALLING | IRQF_ONESHOT when calling
devm_request_threaded_irq. No the irq handler is not called whn only IRQF_ONESHOT
is used. Looking at other drivers, I saw that they use the same aproach. I am not
sure how to setup things in ACPI/DT so that the driver could work only with IRQF_ONESHOT
- The number of thingers that can simultaneously touch the device and if it has
HW keys or not, cannot be read from the device. I've asked Zeitec on this.

drivers/input/touchscreen/Kconfig | 12 +
drivers/input/touchscreen/Makefile | 1 +
drivers/input/touchscreen/zeitec.c | 550 +++++++++++++++++++++++++++++++++++++
3 files changed, 563 insertions(+)
create mode 100644 drivers/input/touchscreen/zeitec.c

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 80f6386..2046633 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -27,6 +27,18 @@ config TOUCHSCREEN_88PM860X
To compile this driver as a module, choose M here: the
module will be called 88pm860x-ts.

+config TOUCHSCREEN_ZEITEC
+ tristate "Generic ZEITEC touchscreen"
+ depends on I2C
+ help
+ Say Y here if you have the Zeitec touchscreen connected to
+ your system.
+
+ If unsure, say N.
+
+ To compile this driver as a module, choose M here: the
+ module will be called zeitec.
+
config TOUCHSCREEN_ADS7846
tristate "ADS7846/TSC2046/AD7873 and AD(S)7843 based touchscreens"
depends on SPI_MASTER
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 44deea7..7593fea 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -84,3 +84,4 @@ obj-$(CONFIG_TOUCHSCREEN_W90X900) += w90p910_ts.o
obj-$(CONFIG_TOUCHSCREEN_SX8654) += sx8654.o
obj-$(CONFIG_TOUCHSCREEN_TPS6507X) += tps6507x-ts.o
obj-$(CONFIG_TOUCHSCREEN_ZFORCE) += zforce_ts.o
+obj-$(CONFIG_TOUCHSCREEN_ZEITEC) += zeitec.o
diff --git a/drivers/input/touchscreen/zeitec.c b/drivers/input/touchscreen/zeitec.c
new file mode 100644
index 0000000..bffa6f9
--- /dev/null
+++ b/drivers/input/touchscreen/zeitec.c
@@ -0,0 +1,550 @@
+/*
+ * Driver for Zeitec touchscreens.
+ *
+ * Copyright (c) 2015 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/kernel.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <asm/unaligned.h>
+#include <linux/acpi.h>
+#include <linux/gpio.h>
+#include <linux/firmware.h>
+#include <linux/types.h>
+#include "../../gpio/gpiolib.h"
+
+#define FLASH_SIZE_ZET6273 0xA000
+#define ZET_TOTAL_PKT_SIZE 70
+#define ZET_MODEL_PKT_SIZE 17
+
+#define ZET_ROM_TYPE_UNKNOWN 0x00
+#define ZET_ROM_TYPE_SRAM 0x02
+#define ZET_ROM_TYPE_OTP 0x06
+#define ZET_ROM_TYPE_FLASH 0x0F
+
+#define ZET_FLASH_PAGE_LEN 128
+
+#define ZET_CMD_GET_CODEOPTION 0x27
+#define ZET_CMD_GET_INFORMATION 0xB2
+#define ZET_CMD_WRITE_PASSWORD 0x20
+#define ZET_CMD_WRITE_PROGRAM 0x22
+#define ZET_CMD_READ_CODE_OPTION 0x27
+#define ZET_CMD_RESET_MCU 0x29
+#define ZET_CMD_WRITE_SFR 0x2B
+#define ZET_CMD_READ_SFR 0x2C
+#define ZET_CMD_ENTER_SLEEP 0xB1
+
+#define ZET_PASSWORD 0x9DC5
+
+#define ZET_TS_WAKEUP_LOW_PERIOD 10
+#define ZET_TS_WAKEUP_HIGH_PERIOD 20
+
+#define ZET_FINGER_REPROT_DATA_HEADER 0x3C
+#define ZET_PAGE_HEADER_COMMAND_LEN 3
+#define FINGER_PACK_SIZE 4
+#define FINGER_HEADER_SHIFT 3
+#define ZET_FINGER_OFFSET (FINGER_PACK_SIZE + \
+ FINGER_HEADER_SHIFT)
+
+#define ZET_MODEL_6273 0x6270
+#define ZET_MODEL_9172 0x9172
+
+#define ZET_RESOLUTION_X "touchscreen-size-x"
+#define ZET_RESOLUTION_Y "touchscreen-size-y"
+#define ZET_MAX_FINGERS "max-fingers"
+#define ZET_HAS_KEYS "has-keys"
+
+struct zet_ts_data {
+ struct i2c_client *client;
+ struct input_dev *input_dev;
+ u16 resolution_x;
+ u16 resolution_y;
+ u8 finger_num;
+ u16 finger_packet_size;
+ struct gpio_desc *reset;
+ struct gpio_desc *irq;
+ u8 device_model;
+ u8 rom_type;
+ u16 model_type;
+ u8 has_keys;
+ char fw_name[32];
+};
+
+struct zet_finger_coordinate {
+ u32 report_x;
+ u32 report_y;
+ u32 report_z;
+ u8 valid;
+};
+
+static void zet_ts_reset(struct zet_ts_data *ts)
+{
+ gpiod_set_value_cansleep(ts->reset, 1);
+ msleep(ZET_TS_WAKEUP_LOW_PERIOD);
+ gpiod_set_value_cansleep(ts->reset, 0);
+ msleep(ZET_TS_WAKEUP_HIGH_PERIOD);
+}
+
+static int zet_get_model_type(struct zet_ts_data *ts)
+{
+ u8 ts_in_data[ZET_MODEL_PKT_SIZE];
+ int ret;
+
+ ret = i2c_smbus_read_i2c_block_data(ts->client,
+ ZET_CMD_GET_CODEOPTION,
+ ZET_MODEL_PKT_SIZE, ts_in_data);
+ if (ret < 0) {
+ dev_err(&ts->client->dev, "I2C read error= %d\n", ret);
+ return ret;
+ }
+
+ ts->model_type = le16_to_cpup((__le16 *)&ts_in_data[6]);
+
+ switch (ts->model_type) {
+ case ZET_MODEL_6273:
+ case ZET_MODEL_9172:
+ ts->rom_type = ZET_ROM_TYPE_SRAM;
+ snprintf(ts->fw_name, sizeof(ts->fw_name),
+ "zet%x.bin", ts->model_type);
+ break;
+ default:
+ ts->rom_type = ZET_ROM_TYPE_UNKNOWN;
+ }
+
+ return 0;
+}
+
+static int zet_ts_get_information(struct zet_ts_data *ts)
+{
+ int error;
+
+ error = device_property_read_u16(&ts->client->dev,
+ ZET_RESOLUTION_X,
+ &ts->resolution_x);
+ if (error < 0) {
+ dev_err(&ts->client->dev, "Failed to read %s property\n",
+ ZET_RESOLUTION_X);
+ return error;
+ }
+
+ error = device_property_read_u16(&ts->client->dev,
+ ZET_RESOLUTION_Y,
+ &ts->resolution_y);
+ if (error < 0) {
+ dev_err(&ts->client->dev, "Failed to read %s property\n",
+ ZET_RESOLUTION_Y);
+ return error;
+ }
+
+ error = device_property_read_u8(&ts->client->dev,
+ ZET_MAX_FINGERS,
+ &ts->finger_num);
+ if (error < 0) {
+ dev_err(&ts->client->dev, "Failed to read %s property\n",
+ ZET_MAX_FINGERS);
+ return error;
+ }
+
+ error = device_property_read_u8(&ts->client->dev,
+ ZET_HAS_KEYS,
+ &ts->has_keys);
+ if (error < 0) {
+ dev_err(&ts->client->dev, "Failed to read %s property\n",
+ ZET_HAS_KEYS);
+ return error;
+ }
+
+ ts->finger_packet_size = 3 + 4 * ts->finger_num;
+ if (ts->has_keys)
+ ts->finger_packet_size += 1;
+
+ return 0;
+}
+
+static int zet_gpio_probe(struct zet_ts_data *ts)
+{
+ struct device *dev;
+ struct gpio_desc *gpiod;
+ int err;
+
+ dev = &ts->client->dev;
+
+ gpiod = devm_gpiod_get(dev, "int", GPIOD_IN);
+ if (IS_ERR(gpiod)) {
+ err = PTR_ERR(gpiod);
+ dev_err(dev, "get int failed: %d\n", err);
+ return err;
+ }
+
+ ts->irq = gpiod;
+
+ gpiod = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+ if (IS_ERR(gpiod)) {
+ err = PTR_ERR(gpiod);
+ dev_err(dev, "get reset failed: %d\n", err);
+ return err;
+ }
+
+ ts->reset = gpiod;
+
+ return 0;
+}
+
+static bool zet_ts_check_skip_page(const u8 *data)
+{
+ int j;
+
+ for (j = 0 ; j < ZET_FLASH_PAGE_LEN ; j++) {
+ if (data[j] != 0xFF)
+ return false;
+ }
+
+ return true;
+}
+
+static int zet_cmd_writepage(struct zet_ts_data *ts,
+ int page_id,
+ const u8 *buf)
+{
+ u8 tx_buf[ZET_PAGE_HEADER_COMMAND_LEN + ZET_FLASH_PAGE_LEN];
+ int error;
+
+ switch (ts->model_type) {
+ case ZET_MODEL_6273:
+ case ZET_MODEL_9172:
+ tx_buf[0] = ZET_CMD_WRITE_PROGRAM;
+ tx_buf[1] = (page_id & 0xff);
+ tx_buf[2] = (u8)(page_id >> 8);
+ break;
+ default:
+ kfree(tx_buf);
+ return -EINVAL;
+ }
+
+ memmove(tx_buf + ZET_PAGE_HEADER_COMMAND_LEN, buf, ZET_FLASH_PAGE_LEN);
+
+ /*
+ * i2c_smbus functions only allow us to write 32 bytes at a time
+ * We need to write 131 at a time for each page. i2c_master_send
+ * is needed here
+ */
+ error = i2c_master_send(ts->client, tx_buf,
+ ZET_PAGE_HEADER_COMMAND_LEN +
+ ZET_FLASH_PAGE_LEN);
+ if (error < 0) {
+ dev_err(&ts->client->dev,
+ "Failed to write firmware page: %d\n", page_id);
+ }
+
+ return 0;
+}
+
+static int zet_download_firmware(struct zet_ts_data *ts)
+{
+ const struct firmware *fw;
+ int flash_rest_len = 0;
+ int flash_page_id = 0;
+ int error = 0;
+ int offset;
+
+ error = request_firmware(&fw, ts->fw_name, &ts->client->dev);
+ if (error != 0) {
+ dev_err(&ts->client->dev,
+ "Unable to open firmware %s\n",
+ ts->fw_name);
+ return error;
+ }
+
+ flash_rest_len = fw->size;
+
+ while (flash_rest_len > 0) {
+ offset = flash_page_id * ZET_FLASH_PAGE_LEN;
+ if (zet_ts_check_skip_page(fw->data + offset)) {
+ flash_rest_len -= ZET_FLASH_PAGE_LEN;
+ flash_page_id += 1;
+ continue;
+ }
+
+ error = zet_cmd_writepage(ts, flash_page_id,
+ fw->data + offset);
+ if (error < 0) {
+ dev_err(&ts->client->dev,
+ "Could not write firmware page %d\n", error);
+ goto cleanup;
+ }
+
+
+ flash_rest_len -= ZET_FLASH_PAGE_LEN;
+ flash_page_id++;
+ }
+
+ error = i2c_smbus_write_byte(ts->client, ZET_CMD_RESET_MCU);
+ if (error < 0) {
+ dev_err(&ts->client->dev,
+ "Unable to reset device %d\n", error);
+ goto cleanup;
+ }
+
+ msleep(10);
+ zet_ts_reset(ts);
+
+cleanup:
+ release_firmware(fw);
+
+ return error > 0 ? 0 : error;
+}
+
+static int zet_ts_open(struct input_dev *dev)
+{
+ struct zet_ts_data *ts;
+ int error;
+
+ ts = input_get_drvdata(dev);
+ error = zet_download_firmware(ts);
+ if (error < 0)
+ return error;
+
+ error = zet_ts_get_information(ts);
+ if (error < 0)
+ return error;
+
+ return 0;
+}
+
+static int zet_request_input_dev(struct zet_ts_data *ts)
+{
+ int error;
+
+ ts->input_dev = devm_input_allocate_device(&ts->client->dev);
+ if (!ts->input_dev) {
+ dev_err(&ts->client->dev, "Failed to allocate input device.\n");
+ return -ENOMEM;
+ }
+
+ input_set_capability(ts->input_dev, EV_ABS, ABS_X);
+ input_set_capability(ts->input_dev, EV_ABS, ABS_Y);
+
+ input_set_abs_params(ts->input_dev, ABS_MT_POSITION_X, 0,
+ ts->resolution_x, 0, 0);
+ input_set_abs_params(ts->input_dev, ABS_MT_POSITION_Y, 0,
+ ts->resolution_y, 0, 0);
+
+ input_mt_init_slots(ts->input_dev, ts->finger_num,
+ INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+
+ ts->input_dev->name = "Zeitec touchscreen";
+ ts->input_dev->phys = "input/ts";
+ ts->input_dev->id.bustype = BUS_HOST;
+ ts->input_dev->open = zet_ts_open;
+ input_set_drvdata(ts->input_dev, ts);
+
+ error = input_register_device(ts->input_dev);
+ if (error) {
+ dev_err(&ts->client->dev,
+ "Failed to register input device: %d\n", error);
+ return error;
+ }
+
+ __set_bit(INPUT_PROP_DIRECT, ts->input_dev->propbit);
+
+ return 0;
+}
+
+static void zet_process_events(struct zet_ts_data *ts)
+{
+ char ts_data[ZET_TOTAL_PKT_SIZE];
+ int error;
+ int i;
+ u16 valid;
+ u8 offset;
+ struct zet_finger_coordinate finger_report;
+
+ /*
+ * We do not read from a specific register as i2c_smbus function
+ * require. We know exactly how many bytes are available on the
+ * first read after an IRQ and use i2c_master_recv for it
+ */
+ error = i2c_master_recv(ts->client, &ts_data[0],
+ ts->finger_packet_size);
+ if (error < 0) {
+ dev_err(&ts->client->dev,
+ "Unable to open read touch info %d\n",
+ error);
+ return;
+ }
+
+ if (ts_data[0] != ZET_FINGER_REPROT_DATA_HEADER)
+ return;
+
+ valid = get_unaligned_be16(&ts_data[1]);
+
+ for (i = 0; i < ts->finger_num; i++) {
+ /*if not pressed, go on */
+ if (!(valid & BIT(15 - i)))
+ continue;
+
+ /* get the finger data */
+ offset = FINGER_HEADER_SHIFT + FINGER_PACK_SIZE * i;
+ finger_report.report_x =
+ (u32)(ts_data[offset] >> 4) * 256 +
+ ts_data[offset + 1];
+
+ finger_report.report_y =
+ (u32)(ts_data[offset] & 0x0f) * 256 +
+ ts_data[offset + 2];
+
+ input_mt_slot(ts->input_dev, i);
+ input_mt_report_slot_state(ts->input_dev,
+ MT_TOOL_FINGER,
+ true);
+ input_report_abs(ts->input_dev, ABS_MT_POSITION_X,
+ finger_report.report_x);
+ input_report_abs(ts->input_dev, ABS_MT_POSITION_Y,
+ finger_report.report_y);
+ }
+
+ input_mt_sync_frame(ts->input_dev);
+ input_sync(ts->input_dev);
+}
+
+static irqreturn_t zet_ts_irq_handler(int irq, void *dev_id)
+{
+ zet_process_events((struct zet_ts_data *)dev_id);
+ return IRQ_HANDLED;
+}
+
+static int zet_ts_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct zet_ts_data *ts;
+ int error;
+ int flags;
+
+ dev_dbg(&client->dev, "I2C Address: 0x%02x\n", client->addr);
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+ dev_err(&client->dev, "I2C check functionality failed.\n");
+ return -ENXIO;
+ }
+
+ ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
+ if (!ts)
+ return -ENOMEM;
+ ts->client = client;
+
+ error = zet_gpio_probe(ts);
+ if (error)
+ return error;
+
+ i2c_set_clientdata(client, ts);
+
+ error = i2c_smbus_write_word_data(ts->client,
+ ZET_CMD_WRITE_PASSWORD,
+ cpu_to_le16(ZET_PASSWORD));
+ if (error < 0) {
+ dev_err(&client->dev,
+ "Could not unlock device. error: %d\n", error);
+ return error;
+ }
+
+ error = zet_get_model_type(ts);
+ if (error < 0)
+ return error;
+
+ error = zet_request_input_dev(ts);
+ if (error)
+ return error;
+
+ flags = IRQF_TRIGGER_FALLING | IRQF_ONESHOT;
+ error = devm_request_threaded_irq(&ts->client->dev, client->irq,
+ NULL, zet_ts_irq_handler,
+ flags, client->name, ts);
+ if (error) {
+ dev_err(&client->dev, "request IRQ failed: %d\n", error);
+ return error;
+ }
+
+ return error;
+}
+
+static int zet_suspend(struct device *dev)
+{
+ int error;
+ struct i2c_client *client;
+
+ client = to_i2c_client(dev);
+ disable_irq(client->irq);
+
+ error = i2c_smbus_write_byte(client, ZET_CMD_ENTER_SLEEP);
+ if (error < 0) {
+ dev_err(dev, "could not enter sleep error= %d\n", error);
+ return error;
+ }
+
+ dev_dbg(dev, "sleeping\n");
+ return 0;
+}
+
+static int zet_wakeup(struct device *dev)
+{
+ struct i2c_client *client;
+ struct zet_ts_data *ts;
+
+ client = to_i2c_client(dev);
+ ts = (struct zet_ts_data *)i2c_get_clientdata(client);
+
+ enable_irq(ts->client->irq);
+
+ zet_ts_reset(ts);
+
+ return 0;
+}
+
+static const struct i2c_device_id zet_ts_idtable[] = {
+ { "zet6273", 0 },
+ { "zet9172", 0 },
+ { }
+};
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id zeitec_acpi_match[] = {
+ { "ZET6273", 0 },
+ { "ZET9172", 0 },
+ { }
+};
+#endif
+
+static SIMPLE_DEV_PM_OPS(zet_pm_ops, zet_suspend, zet_wakeup);
+
+static struct i2c_driver zet_i2c_driver = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "zeitec_ts",
+ .pm = &zet_pm_ops,
+ .acpi_match_table = ACPI_PTR(zeitec_acpi_match),
+ },
+ .probe = zet_ts_probe,
+ .id_table = zet_ts_idtable,
+};
+
+module_i2c_driver(zet_i2c_driver);
+
+MODULE_AUTHOR("Bogdan George Stefan <bogdan.g.stefan@xxxxxxxxx>");
+MODULE_DESCRIPTION("ZEITEC I2C Touch Screen driver");
+MODULE_LICENSE("GPL v2");
--
1.9.1

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