| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Rohm BU21029 touchscreen controller driver |
| * |
| * Copyright (C) 2015-2018 Bosch Sicherheitssysteme GmbH |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/delay.h> |
| #include <linux/gpio/consumer.h> |
| #include <linux/i2c.h> |
| #include <linux/input.h> |
| #include <linux/input/touchscreen.h> |
| #include <linux/interrupt.h> |
| #include <linux/irq.h> |
| #include <linux/module.h> |
| #include <linux/regulator/consumer.h> |
| #include <linux/timer.h> |
| |
| /* |
| * HW_ID1 Register (PAGE=0, ADDR=0x0E, Reset value=0x02, Read only) |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | HW_IDH | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * HW_ID2 Register (PAGE=0, ADDR=0x0F, Reset value=0x29, Read only) |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | HW_IDL | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * HW_IDH: high 8bits of IC's ID |
| * HW_IDL: low 8bits of IC's ID |
| */ |
| #define BU21029_HWID_REG (0x0E << 3) |
| #define SUPPORTED_HWID 0x0229 |
| |
| /* |
| * CFR0 Register (PAGE=0, ADDR=0x00, Reset value=0x20) |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | 0 | 0 | CALIB | INTRM | 0 | 0 | 0 | 0 | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * CALIB: 0 = not to use calibration result (*) |
| * 1 = use calibration result |
| * INTRM: 0 = INT output depend on "pen down" (*) |
| * 1 = INT output always "0" |
| */ |
| #define BU21029_CFR0_REG (0x00 << 3) |
| #define CFR0_VALUE 0x00 |
| |
| /* |
| * CFR1 Register (PAGE=0, ADDR=0x01, Reset value=0xA6) |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | MAV | AVE[2:0] | 0 | SMPL[2:0] | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * MAV: 0 = median average filter off |
| * 1 = median average filter on (*) |
| * AVE: AVE+1 = number of average samples for MAV, |
| * if AVE>SMPL, then AVE=SMPL (=3) |
| * SMPL: SMPL+1 = number of conversion samples for MAV (=7) |
| */ |
| #define BU21029_CFR1_REG (0x01 << 3) |
| #define CFR1_VALUE 0xA6 |
| |
| /* |
| * CFR2 Register (PAGE=0, ADDR=0x02, Reset value=0x04) |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | INTVL_TIME[3:0] | TIME_ST_ADC[3:0] | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * INTVL_TIME: waiting time between completion of conversion |
| * and start of next conversion, only usable in |
| * autoscan mode (=20.480ms) |
| * TIME_ST_ADC: waiting time between application of voltage |
| * to panel and start of A/D conversion (=100us) |
| */ |
| #define BU21029_CFR2_REG (0x02 << 3) |
| #define CFR2_VALUE 0xC9 |
| |
| /* |
| * CFR3 Register (PAGE=0, ADDR=0x0B, Reset value=0x72) |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | RM8 | STRETCH| PU90K | DUAL | PIDAC_OFS[3:0] | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * RM8: 0 = coordinate resolution is 12bit (*) |
| * 1 = coordinate resolution is 8bit |
| * STRETCH: 0 = SCL_STRETCH function off |
| * 1 = SCL_STRETCH function on (*) |
| * PU90K: 0 = internal pull-up resistance for touch detection is ~50kohms (*) |
| * 1 = internal pull-up resistance for touch detection is ~90kohms |
| * DUAL: 0 = dual touch detection off (*) |
| * 1 = dual touch detection on |
| * PIDAC_OFS: dual touch detection circuit adjustment, it is not necessary |
| * to change this from initial value |
| */ |
| #define BU21029_CFR3_REG (0x0B << 3) |
| #define CFR3_VALUE 0x42 |
| |
| /* |
| * LDO Register (PAGE=0, ADDR=0x0C, Reset value=0x00) |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | 0 | PVDD[2:0] | 0 | AVDD[2:0] | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * PVDD: output voltage of panel output regulator (=2.000V) |
| * AVDD: output voltage of analog circuit regulator (=2.000V) |
| */ |
| #define BU21029_LDO_REG (0x0C << 3) |
| #define LDO_VALUE 0x77 |
| |
| /* |
| * Serial Interface Command Byte 1 (CID=1) |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * | 1 | CF | CMSK | PDM | STP | |
| * +--------+--------+--------+--------+--------+--------+--------+--------+ |
| * CF: conversion function, see table 3 in datasheet p6 (=0000, automatic scan) |
| * CMSK: 0 = executes convert function (*) |
| * 1 = reads the convert result |
| * PDM: 0 = power down after convert function stops (*) |
| * 1 = keep power on after convert function stops |
| * STP: 1 = abort current conversion and power down, set to "0" automatically |
| */ |
| #define BU21029_AUTOSCAN 0x80 |
| |
| /* |
| * The timeout value needs to be larger than INTVL_TIME + tConv4 (sample and |
| * conversion time), where tConv4 is calculated by formula: |
| * tPON + tDLY1 + (tTIME_ST_ADC + (tADC * tSMPL) * 2 + tDLY2) * 3 |
| * see figure 8 in datasheet p15 for details of each field. |
| */ |
| #define PEN_UP_TIMEOUT_MS 50 |
| |
| #define STOP_DELAY_MIN_US 50 |
| #define STOP_DELAY_MAX_US 1000 |
| #define START_DELAY_MS 2 |
| #define BUF_LEN 8 |
| #define SCALE_12BIT (1 << 12) |
| #define MAX_12BIT ((1 << 12) - 1) |
| #define DRIVER_NAME "bu21029" |
| |
| struct bu21029_ts_data { |
| struct i2c_client *client; |
| struct input_dev *in_dev; |
| struct timer_list timer; |
| struct regulator *vdd; |
| struct gpio_desc *reset_gpios; |
| u32 x_plate_ohms; |
| struct touchscreen_properties prop; |
| }; |
| |
| static void bu21029_touch_report(struct bu21029_ts_data *bu21029, const u8 *buf) |
| { |
| u16 x, y, z1, z2; |
| u32 rz; |
| s32 max_pressure = input_abs_get_max(bu21029->in_dev, ABS_PRESSURE); |
| |
| /* |
| * compose upper 8 and lower 4 bits into a 12bit value: |
| * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ |
| * | ByteH | ByteL | |
| * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ |
| * |b07|b06|b05|b04|b03|b02|b01|b00|b07|b06|b05|b04|b03|b02|b01|b00| |
| * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ |
| * |v11|v10|v09|v08|v07|v06|v05|v04|v03|v02|v01|v00| 0 | 0 | 0 | 0 | |
| * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ |
| */ |
| x = (buf[0] << 4) | (buf[1] >> 4); |
| y = (buf[2] << 4) | (buf[3] >> 4); |
| z1 = (buf[4] << 4) | (buf[5] >> 4); |
| z2 = (buf[6] << 4) | (buf[7] >> 4); |
| |
| if (z1 && z2) { |
| /* |
| * calculate Rz (pressure resistance value) by equation: |
| * Rz = Rx * (x/Q) * ((z2/z1) - 1), where |
| * Rx is x-plate resistance, |
| * Q is the touch screen resolution (8bit = 256, 12bit = 4096) |
| * x, z1, z2 are the measured positions. |
| */ |
| rz = z2 - z1; |
| rz *= x; |
| rz *= bu21029->x_plate_ohms; |
| rz /= z1; |
| rz = DIV_ROUND_CLOSEST(rz, SCALE_12BIT); |
| if (rz <= max_pressure) { |
| touchscreen_report_pos(bu21029->in_dev, &bu21029->prop, |
| x, y, false); |
| input_report_abs(bu21029->in_dev, ABS_PRESSURE, |
| max_pressure - rz); |
| input_report_key(bu21029->in_dev, BTN_TOUCH, 1); |
| input_sync(bu21029->in_dev); |
| } |
| } |
| } |
| |
| static void bu21029_touch_release(struct timer_list *t) |
| { |
| struct bu21029_ts_data *bu21029 = from_timer(bu21029, t, timer); |
| |
| input_report_abs(bu21029->in_dev, ABS_PRESSURE, 0); |
| input_report_key(bu21029->in_dev, BTN_TOUCH, 0); |
| input_sync(bu21029->in_dev); |
| } |
| |
| static irqreturn_t bu21029_touch_soft_irq(int irq, void *data) |
| { |
| struct bu21029_ts_data *bu21029 = data; |
| u8 buf[BUF_LEN]; |
| int error; |
| |
| /* |
| * Read touch data and deassert interrupt (will assert again after |
| * INTVL_TIME + tConv4 for continuous touch) |
| */ |
| error = i2c_smbus_read_i2c_block_data(bu21029->client, BU21029_AUTOSCAN, |
| sizeof(buf), buf); |
| if (error < 0) |
| goto out; |
| |
| bu21029_touch_report(bu21029, buf); |
| |
| /* reset timer for pen up detection */ |
| mod_timer(&bu21029->timer, |
| jiffies + msecs_to_jiffies(PEN_UP_TIMEOUT_MS)); |
| |
| out: |
| return IRQ_HANDLED; |
| } |
| |
| static void bu21029_put_chip_in_reset(struct bu21029_ts_data *bu21029) |
| { |
| if (bu21029->reset_gpios) { |
| gpiod_set_value_cansleep(bu21029->reset_gpios, 1); |
| usleep_range(STOP_DELAY_MIN_US, STOP_DELAY_MAX_US); |
| } |
| } |
| |
| static int bu21029_start_chip(struct input_dev *dev) |
| { |
| struct bu21029_ts_data *bu21029 = input_get_drvdata(dev); |
| struct i2c_client *i2c = bu21029->client; |
| struct { |
| u8 reg; |
| u8 value; |
| } init_table[] = { |
| {BU21029_CFR0_REG, CFR0_VALUE}, |
| {BU21029_CFR1_REG, CFR1_VALUE}, |
| {BU21029_CFR2_REG, CFR2_VALUE}, |
| {BU21029_CFR3_REG, CFR3_VALUE}, |
| {BU21029_LDO_REG, LDO_VALUE} |
| }; |
| int error, i; |
| __be16 hwid; |
| |
| error = regulator_enable(bu21029->vdd); |
| if (error) { |
| dev_err(&i2c->dev, "failed to power up chip: %d", error); |
| return error; |
| } |
| |
| /* take chip out of reset */ |
| if (bu21029->reset_gpios) { |
| gpiod_set_value_cansleep(bu21029->reset_gpios, 0); |
| msleep(START_DELAY_MS); |
| } |
| |
| error = i2c_smbus_read_i2c_block_data(i2c, BU21029_HWID_REG, |
| sizeof(hwid), (u8 *)&hwid); |
| if (error < 0) { |
| dev_err(&i2c->dev, "failed to read HW ID\n"); |
| goto err_out; |
| } |
| |
| if (be16_to_cpu(hwid) != SUPPORTED_HWID) { |
| dev_err(&i2c->dev, |
| "unsupported HW ID 0x%x\n", be16_to_cpu(hwid)); |
| error = -ENODEV; |
| goto err_out; |
| } |
| |
| for (i = 0; i < ARRAY_SIZE(init_table); ++i) { |
| error = i2c_smbus_write_byte_data(i2c, |
| init_table[i].reg, |
| init_table[i].value); |
| if (error < 0) { |
| dev_err(&i2c->dev, |
| "failed to write %#02x to register %#02x: %d\n", |
| init_table[i].value, init_table[i].reg, |
| error); |
| goto err_out; |
| } |
| } |
| |
| error = i2c_smbus_write_byte(i2c, BU21029_AUTOSCAN); |
| if (error < 0) { |
| dev_err(&i2c->dev, "failed to start autoscan\n"); |
| goto err_out; |
| } |
| |
| enable_irq(bu21029->client->irq); |
| return 0; |
| |
| err_out: |
| bu21029_put_chip_in_reset(bu21029); |
| regulator_disable(bu21029->vdd); |
| return error; |
| } |
| |
| static void bu21029_stop_chip(struct input_dev *dev) |
| { |
| struct bu21029_ts_data *bu21029 = input_get_drvdata(dev); |
| |
| disable_irq(bu21029->client->irq); |
| del_timer_sync(&bu21029->timer); |
| |
| bu21029_put_chip_in_reset(bu21029); |
| regulator_disable(bu21029->vdd); |
| } |
| |
| static int bu21029_probe(struct i2c_client *client) |
| { |
| struct device *dev = &client->dev; |
| struct bu21029_ts_data *bu21029; |
| struct input_dev *in_dev; |
| int error; |
| |
| if (!i2c_check_functionality(client->adapter, |
| I2C_FUNC_SMBUS_WRITE_BYTE | |
| I2C_FUNC_SMBUS_WRITE_BYTE_DATA | |
| I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { |
| dev_err(dev, "i2c functionality support is not sufficient\n"); |
| return -EIO; |
| } |
| |
| bu21029 = devm_kzalloc(dev, sizeof(*bu21029), GFP_KERNEL); |
| if (!bu21029) |
| return -ENOMEM; |
| |
| error = device_property_read_u32(dev, "rohm,x-plate-ohms", &bu21029->x_plate_ohms); |
| if (error) { |
| dev_err(dev, "invalid 'x-plate-ohms' supplied: %d\n", error); |
| return error; |
| } |
| |
| bu21029->vdd = devm_regulator_get(dev, "vdd"); |
| if (IS_ERR(bu21029->vdd)) |
| return dev_err_probe(dev, PTR_ERR(bu21029->vdd), |
| "failed to acquire 'vdd' supply\n"); |
| |
| bu21029->reset_gpios = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); |
| if (IS_ERR(bu21029->reset_gpios)) |
| return dev_err_probe(dev, PTR_ERR(bu21029->reset_gpios), |
| "failed to acquire 'reset' gpio\n"); |
| |
| in_dev = devm_input_allocate_device(dev); |
| if (!in_dev) { |
| dev_err(dev, "unable to allocate input device\n"); |
| return -ENOMEM; |
| } |
| |
| bu21029->client = client; |
| bu21029->in_dev = in_dev; |
| timer_setup(&bu21029->timer, bu21029_touch_release, 0); |
| |
| in_dev->name = DRIVER_NAME; |
| in_dev->id.bustype = BUS_I2C; |
| in_dev->open = bu21029_start_chip; |
| in_dev->close = bu21029_stop_chip; |
| |
| input_set_capability(in_dev, EV_KEY, BTN_TOUCH); |
| input_set_abs_params(in_dev, ABS_X, 0, MAX_12BIT, 0, 0); |
| input_set_abs_params(in_dev, ABS_Y, 0, MAX_12BIT, 0, 0); |
| input_set_abs_params(in_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0); |
| touchscreen_parse_properties(in_dev, false, &bu21029->prop); |
| |
| input_set_drvdata(in_dev, bu21029); |
| |
| error = devm_request_threaded_irq(dev, client->irq, NULL, |
| bu21029_touch_soft_irq, |
| IRQF_ONESHOT | IRQF_NO_AUTOEN, |
| DRIVER_NAME, bu21029); |
| if (error) { |
| dev_err(dev, "unable to request touch irq: %d\n", error); |
| return error; |
| } |
| |
| error = input_register_device(in_dev); |
| if (error) { |
| dev_err(dev, "unable to register input device: %d\n", error); |
| return error; |
| } |
| |
| i2c_set_clientdata(client, bu21029); |
| |
| return 0; |
| } |
| |
| static int bu21029_suspend(struct device *dev) |
| { |
| struct i2c_client *i2c = to_i2c_client(dev); |
| struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c); |
| |
| if (!device_may_wakeup(dev)) { |
| mutex_lock(&bu21029->in_dev->mutex); |
| if (input_device_enabled(bu21029->in_dev)) |
| bu21029_stop_chip(bu21029->in_dev); |
| mutex_unlock(&bu21029->in_dev->mutex); |
| } |
| |
| return 0; |
| } |
| |
| static int bu21029_resume(struct device *dev) |
| { |
| struct i2c_client *i2c = to_i2c_client(dev); |
| struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c); |
| |
| if (!device_may_wakeup(dev)) { |
| mutex_lock(&bu21029->in_dev->mutex); |
| if (input_device_enabled(bu21029->in_dev)) |
| bu21029_start_chip(bu21029->in_dev); |
| mutex_unlock(&bu21029->in_dev->mutex); |
| } |
| |
| return 0; |
| } |
| static DEFINE_SIMPLE_DEV_PM_OPS(bu21029_pm_ops, bu21029_suspend, bu21029_resume); |
| |
| static const struct i2c_device_id bu21029_ids[] = { |
| { DRIVER_NAME, 0 }, |
| { /* sentinel */ } |
| }; |
| MODULE_DEVICE_TABLE(i2c, bu21029_ids); |
| |
| #ifdef CONFIG_OF |
| static const struct of_device_id bu21029_of_ids[] = { |
| { .compatible = "rohm,bu21029" }, |
| { /* sentinel */ } |
| }; |
| MODULE_DEVICE_TABLE(of, bu21029_of_ids); |
| #endif |
| |
| static struct i2c_driver bu21029_driver = { |
| .driver = { |
| .name = DRIVER_NAME, |
| .of_match_table = of_match_ptr(bu21029_of_ids), |
| .pm = pm_sleep_ptr(&bu21029_pm_ops), |
| }, |
| .id_table = bu21029_ids, |
| .probe = bu21029_probe, |
| }; |
| module_i2c_driver(bu21029_driver); |
| |
| MODULE_AUTHOR("Zhu Yi <yi.zhu5@cn.bosch.com>"); |
| MODULE_DESCRIPTION("Rohm BU21029 touchscreen controller driver"); |
| MODULE_LICENSE("GPL v2"); |