// 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 #include #include #include #include #include #include #include #include #include /* * 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, const struct i2c_device_id *id) { 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(&client->dev, "i2c functionality support is not sufficient\n"); return -EIO; } bu21029 = devm_kzalloc(&client->dev, sizeof(*bu21029), GFP_KERNEL); if (!bu21029) return -ENOMEM; error = device_property_read_u32(&client->dev, "rohm,x-plate-ohms", &bu21029->x_plate_ohms); if (error) { dev_err(&client->dev, "invalid 'x-plate-ohms' supplied: %d\n", error); return error; } bu21029->vdd = devm_regulator_get(&client->dev, "vdd"); if (IS_ERR(bu21029->vdd)) { error = PTR_ERR(bu21029->vdd); if (error != -EPROBE_DEFER) dev_err(&client->dev, "failed to acquire 'vdd' supply: %d\n", error); return error; } bu21029->reset_gpios = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH); if (IS_ERR(bu21029->reset_gpios)) { error = PTR_ERR(bu21029->reset_gpios); if (error != -EPROBE_DEFER) dev_err(&client->dev, "failed to acquire 'reset' gpio: %d\n", error); return error; } in_dev = devm_input_allocate_device(&client->dev); if (!in_dev) { dev_err(&client->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(&client->dev, client->irq, NULL, bu21029_touch_soft_irq, IRQF_ONESHOT | IRQF_NO_AUTOEN, DRIVER_NAME, bu21029); if (error) { dev_err(&client->dev, "unable to request touch irq: %d\n", error); return error; } error = input_register_device(in_dev); if (error) { dev_err(&client->dev, "unable to register input device: %d\n", error); return error; } i2c_set_clientdata(client, bu21029); return 0; } static int __maybe_unused 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 __maybe_unused 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 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 = &bu21029_pm_ops, }, .id_table = bu21029_ids, .probe = bu21029_probe, }; module_i2c_driver(bu21029_driver); MODULE_AUTHOR("Zhu Yi "); MODULE_DESCRIPTION("Rohm BU21029 touchscreen controller driver"); MODULE_LICENSE("GPL v2");