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