Re: [PATCH v2 1/4] Input: Add driver for Cypress Generation 5 touchscreen

+       select REGMAP_I2C
+       select CRC_ITU_T
+       help
+         Driver for Parade TrueTouch Standard Product
+         Generation 5 touchscreen controllers.
+         I2C bus interface support only.
+         Say Y here if you have a Cypress Gen5 touchscreen.
+         If unsure, say N.
+         To compile this driver as a module, choose M here: the
+         module will be called cyttsp5.

+/*
+ * Parade TrueTouch(TM) Standard Product V5 Module.
+ *
+ * Copyright (C) 2015 Parade Technologies
+ * Copyright (C) 2012-2015 Cypress Semiconductor
+ * Copyright (C) 2018 Bootlin
+ *
+ * Authors: Mylène Josserand <mylene.josserand@bootlin.com>
+ *                Alistair Francis <alistair@alistair23.me>

+#include <linux/crc-itu-t.h>
+#include <linux/delay.h>
+#include <linux/device.h>

+#include <linux/input/mt.h>
+#include <linux/input/touchscreen.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>

+#define CY_HID_OUTPUT_TIMEOUT                  200
+#define CY_HID_OUTPUT_GET_SYSINFO_TIMEOUT      3000
+#define CY_HID_GET_HID_DESCRIPTOR_TIMEOUT      4000

+/* helpers */
+#define HI_BYTE(x)                             ((u8)(((x) >> 8) & 0xFF))
+#define LOW_BYTE(x)                            ((u8)((x) & 0xFF))

+enum cyttsp5_tch_abs { /* for ordering within the extracted touch data array */
+       CY_TCH_X,       /* X */
+       CY_TCH_Y,       /* Y */
+       CY_TCH_P,       /* P (Z) */
+       CY_TCH_T,       /* TOUCH ID */
+       CY_TCH_MAJ,     /* TOUCH_MAJOR */
+       CY_TCH_MIN,     /* TOUCH_MINOR */

+ * but it does mean anything to the device. The important data
+ * to send is the I2C address
+ */

+        * add the register adresse in the frame, we use the LOW_BYTE as
+        * first frame byte for the address register and the first
+        * data byte is the high register + left of the cmd to send
+        */

+static int cyttsp5_parse_dt_key_code(struct device *dev)
+{
+       struct cyttsp5 *ts = dev_get_drvdata(dev);
+       struct cyttsp5_sysinfo *si = &ts->sysinfo;
+       struct device_node *np;
+       int i;

+       np = dev->of_node;
+       if (!np)
+               return -EINVAL;

+       if (!si->num_btns)
+               return 0;
+
+       /* Initialize the button to RESERVED */

+       return of_property_read_u32_array(np, "linux,keycodes",
+                                  si->key_code, si->num_btns);
+}
+#else
+static int cyttsp5_parse_dt_key_code(struct device *dev)
+{
+       struct cyttsp5 *ts = dev_get_drvdata(dev);
+       struct cyttsp5_sysinfo *si = &ts->sysinfo;
+       int i;
+
+       if (!si->num_btns)
+               return 0;
+
+       /* Initialize the button to RESERVED */
+       for (i = 0; i < si->num_btns; i++)
+               si->key_code[i] = KEY_RESERVED;
+
+       return 0;
+}

+               crc = cyttsp5_compute_crc(&ts->response_buf[4], size - 7);
+               if (ts->response_buf[size - 3] != LOW_BYTE(crc) ||
+                   ts->response_buf[size - 2] != HI_BYTE(crc)) {

+                       dev_err(ts->dev, "HID output response, wrong CRC 0x%X\n",
+                               crc);
+                       return -EPROTO;
+               }

+       si->num_btns = 0;
+       for (i = 0; i < HID_SYSINFO_MAX_BTN; i++) {
+               if (btns & BIT(i))
+                       si->num_btns++;
+       }

+       rc = wait_event_timeout(ts->wait_q, (ts->hid_cmd_state == HID_CMD_DONE),
+                               msecs_to_jiffies(CY_HID_OUTPUT_GET_SYSINFO_TIMEOUT));
+       if (!rc) {
+               dev_err(ts->dev, "HID output cmd execution timed out\n");

+       crc = cyttsp5_compute_crc(&cmd[4], 4);
+       cmd[8] = LOW_BYTE(crc);
+       cmd[9] = HI_BYTE(crc);

+       rc = wait_event_timeout(ts->wait_q, (ts->hid_cmd_state == HID_CMD_DONE),
+                               msecs_to_jiffies(CY_HID_OUTPUT_TIMEOUT));
+       if (!rc) {
+               dev_err(ts->dev, "HID output cmd execution timed out\n");

+static const struct of_device_id cyttsp5_of_match[] = {
+       { .compatible = "cypress,tt21000", },
+       { }
+};
+MODULE_DEVICE_TABLE(of, cyttsp5_of_match);
+#endif
+
+static const struct i2c_device_id cyttsp5_i2c_id[] = {
+       { CYTTSP5_NAME, 0, },
+       { }
+};
+MODULE_DEVICE_TABLE(i2c, cyttsp5_i2c_id);

+       /* Reset the gpio to be in a reset state */
+       ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+       if (IS_ERR(ts->reset_gpio)) {
+               rc = PTR_ERR(ts->reset_gpio);
+               dev_err(dev, "Failed to request reset gpio, error %d\n", rc);
+               return rc;
+       }

+static struct i2c_driver cyttsp5_i2c_driver = {
+       .driver = {
+               .name = CYTTSP5_NAME,

+       },
+       .probe = cyttsp5_i2c_probe,
+       .remove = cyttsp5_i2c_remove,
+       .id_table = cyttsp5_i2c_id,
+};