485 lines
15 KiB
C
485 lines
15 KiB
C
// 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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* 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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* 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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* 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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irq_set_status_flags(client->irq, IRQ_NOAUTOEN);
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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, 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 (bu21029->in_dev->users)
|
|
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 (bu21029->in_dev->users)
|
|
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 <yi.zhu5@cn.bosch.com>");
|
|
MODULE_DESCRIPTION("Rohm BU21029 touchscreen controller driver");
|
|
MODULE_LICENSE("GPL v2");
|