// SPDX-License-Identifier: GPL-2.0-only /* * Driver for Hynitron cstxxx Touchscreen * * Copyright (c) 2022 Chris Morgan <[email protected]> * * This code is based on hynitron_core.c authored by Hynitron. * Note that no datasheet was available, so much of these registers * are undocumented. This is essentially a cleaned-up version of the * vendor driver with support removed for hardware I cannot test and * device-specific functions replated with generic functions wherever * possible. */ #include <linux/delay.h> #include <linux/err.h> #include <linux/gpio/consumer.h> #include <linux/i2c.h> #include <linux/input.h> #include <linux/input/mt.h> #include <linux/input/touchscreen.h> #include <linux/mod_devicetable.h> #include <linux/module.h> #include <linux/property.h> #include <linux/unaligned.h> /* Per chip data */ struct hynitron_ts_chip_data { … }; /* Data generic to all (supported and non-supported) controllers. */ struct hynitron_ts_data { … }; /* * Since I have no datasheet, these values are guessed and/or assumed * based on observation and testing. */ #define CST3XX_FIRMWARE_INFO_START_CMD … #define CST3XX_FIRMWARE_INFO_END_CMD … #define CST3XX_FIRMWARE_CHK_CODE_REG … #define CST3XX_FIRMWARE_VERSION_REG … #define CST3XX_FIRMWARE_VER_INVALID_VAL … #define CST3XX_BOOTLDR_PROG_CMD … #define CST3XX_BOOTLDR_PROG_CHK_REG … #define CST3XX_BOOTLDR_CHK_VAL … #define CST3XX_TOUCH_DATA_PART_REG … #define CST3XX_TOUCH_DATA_FULL_REG … #define CST3XX_TOUCH_DATA_CHK_VAL … #define CST3XX_TOUCH_DATA_TOUCH_VAL … #define CST3XX_TOUCH_DATA_STOP_CMD … #define CST3XX_TOUCH_COUNT_MASK … /* * Hard coded reset delay value of 20ms not IC dependent in * vendor driver. */ static void hyn_reset_proc(struct i2c_client *client, int delay) { … } static irqreturn_t hyn_interrupt_handler(int irq, void *dev_id) { … } /* * The vendor driver would retry twice before failing to read or write * to the i2c device. */ static int cst3xx_i2c_write(struct i2c_client *client, unsigned char *buf, int len) { … } static int cst3xx_i2c_read_register(struct i2c_client *client, u16 reg, u8 *val, u16 len) { … } static int cst3xx_firmware_info(struct i2c_client *client) { … } static int cst3xx_bootloader_enter(struct i2c_client *client) { … } static void cst3xx_report_contact(struct hynitron_ts_data *ts_data, u8 id, unsigned int x, unsigned int y, u8 w) { … } static int cst3xx_finish_touch_read(struct i2c_client *client) { … } /* * Handle events from IRQ. Note that for cst3xx it appears that IRQ * fires continuously while touched, otherwise once every 1500ms * when not touched (assume touchscreen waking up periodically). * Note buffer is sized for 5 fingers, if more needed buffer must * be increased. The buffer contains 5 bytes for each touch point, * a touch count byte, a check byte, and then a second check byte after * all other touch points. * * For example 1 touch would look like this: * touch1[5]:touch_count[1]:chk_byte[1] * * 3 touches would look like this: * touch1[5]:touch_count[1]:chk_byte[1]:touch2[5]:touch3[5]:chk_byte[1] */ static void cst3xx_touch_report(struct i2c_client *client) { … } static int cst3xx_input_dev_int(struct i2c_client *client) { … } static int hyn_probe(struct i2c_client *client) { … } static const struct hynitron_ts_chip_data cst3xx_data = …; static const struct i2c_device_id hyn_tpd_id[] = …; MODULE_DEVICE_TABLE(i2c, hyn_tpd_id); static const struct of_device_id hyn_dt_match[] = …; MODULE_DEVICE_TABLE(of, hyn_dt_match); static struct i2c_driver hynitron_i2c_driver = …; module_i2c_driver(…) …; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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