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    Subject[PATCH] Input: add bu21029 touch driver
    Date
    From: Zhu Yi <yi.zhu5@cn.bosch.com>

    Add the ROHM BU21029 resistive touch panel controller
    support with i2c interface.

    Signed-off-by: Zhu Yi <yi.zhu5@cn.bosch.com>
    Signed-off-by: Mark Jonas <mark.jonas@de.bosch.com>
    Reviewed-by: Heiko Schocher <hs@denx.de>
    ---
    .../bindings/input/touchscreen/bu21029.txt | 30 ++
    drivers/input/touchscreen/Kconfig | 12 +
    drivers/input/touchscreen/Makefile | 1 +
    drivers/input/touchscreen/bu21029_ts.c | 456 +++++++++++++++++++++
    4 files changed, 499 insertions(+)
    create mode 100644 Documentation/devicetree/bindings/input/touchscreen/bu21029.txt
    create mode 100644 drivers/input/touchscreen/bu21029_ts.c

    diff --git a/Documentation/devicetree/bindings/input/touchscreen/bu21029.txt b/Documentation/devicetree/bindings/input/touchscreen/bu21029.txt
    new file mode 100644
    index 0000000..7b61602
    --- /dev/null
    +++ b/Documentation/devicetree/bindings/input/touchscreen/bu21029.txt
    @@ -0,0 +1,30 @@
    +* Rohm BU21029 Touch Screen Controller
    +
    +Required properties:
    + - compatible : must be "rohm,bu21029"
    + - reg : i2c device address of the chip
    + - interrupt-parent : the phandle for the gpio controller
    + - interrupts : (gpio) interrupt to which the chip is connected
    + - reset-gpios : gpio pin to reset the chip
    + - rohm,x-plate-ohms : x-plate resistance in ohms
    +
    +Optional properties:
    + - touchscreen-max-pressure: maximum pressure value
    +
    +Example:
    +
    + &i2c1 {
    + /* ... */
    +
    + bu21029: bu21029@40 {
    + compatible = "rohm,bu21029";
    + reg = <0x40>;
    + interrupt-parent = <&gpio1>;
    + interrupts = <4 IRQ_TYPE_EDGE_FALLING>;
    + reset-gpios = <&gpio6 16 GPIO_ACTIVE_LOW>;
    + rohm,x-plate-ohms = <600>;
    + touchscreen-max-pressure = <4095>;
    + };
    +
    + /* ... */
    + };
    diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
    index 4f15496..e09fe8f 100644
    --- a/drivers/input/touchscreen/Kconfig
    +++ b/drivers/input/touchscreen/Kconfig
    @@ -151,6 +151,18 @@ config TOUCHSCREEN_BU21013
    To compile this driver as a module, choose M here: the
    module will be called bu21013_ts.

    +config TOUCHSCREEN_BU21029
    + tristate "Rohm BU21029 based touch panel controllers"
    + depends on I2C
    + help
    + Say Y here if you have a Rohm BU21029 touchscreen controller
    + connected to your system.
    +
    + If unsure, say N.
    +
    + To compile this driver as a module, choose M here: the
    + module will be called bu21029_ts.
    +
    config TOUCHSCREEN_CHIPONE_ICN8318
    tristate "chipone icn8318 touchscreen controller"
    depends on GPIOLIB || COMPILE_TEST
    diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
    index dddae79..f50624c 100644
    --- a/drivers/input/touchscreen/Makefile
    +++ b/drivers/input/touchscreen/Makefile
    @@ -18,6 +18,7 @@ obj-$(CONFIG_TOUCHSCREEN_AR1021_I2C) += ar1021_i2c.o
    obj-$(CONFIG_TOUCHSCREEN_ATMEL_MXT) += atmel_mxt_ts.o
    obj-$(CONFIG_TOUCHSCREEN_AUO_PIXCIR) += auo-pixcir-ts.o
    obj-$(CONFIG_TOUCHSCREEN_BU21013) += bu21013_ts.o
    +obj-$(CONFIG_TOUCHSCREEN_BU21029) += bu21029_ts.o
    obj-$(CONFIG_TOUCHSCREEN_CHIPONE_ICN8318) += chipone_icn8318.o
    obj-$(CONFIG_TOUCHSCREEN_CY8CTMG110) += cy8ctmg110_ts.o
    obj-$(CONFIG_TOUCHSCREEN_CYTTSP_CORE) += cyttsp_core.o
    diff --git a/drivers/input/touchscreen/bu21029_ts.c b/drivers/input/touchscreen/bu21029_ts.c
    new file mode 100644
    index 0000000..d5cbf11
    --- /dev/null
    +++ b/drivers/input/touchscreen/bu21029_ts.c
    @@ -0,0 +1,456 @@
    +/*
    + * Rohm BU21029 touchscreen controller driver
    + *
    + * Copyright (C) 2015 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.h>
    +#include <linux/i2c.h>
    +#include <linux/input.h>
    +#include <linux/interrupt.h>
    +#include <linux/kernel.h>
    +#include <linux/module.h>
    +#include <linux/of.h>
    +#include <linux/of_gpio.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 msecs_to_jiffies(50)
    +
    +#define STOP_DELAY_US 50L
    +#define START_DELAY_MS 2L
    +#define BUF_LEN 8L
    +#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;
    + u32 reset_gpios;
    + u32 reset_gpios_assert;
    + u32 x_plate_ohms;
    + u32 max_pressure;
    +};
    +
    +static int bu21029_touch_report(struct bu21029_ts_data *bu21029)
    +{
    + struct i2c_client *i2c = bu21029->client;
    + u8 buf[BUF_LEN];
    + u16 x, y, z1, z2;
    + u32 rz;
    +
    + /* read touch data and deassert INT (by restarting the autoscan mode) */
    + int error = i2c_smbus_read_i2c_block_data(i2c,
    + BU21029_AUTOSCAN,
    + BUF_LEN,
    + buf);
    + if (error < 0)
    + return error;
    +
    + /* 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 == 0 || z2 == 0)
    + return 0;
    +
    + /* 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 <= bu21029->max_pressure) {
    + input_report_abs(bu21029->in_dev, ABS_X, x);
    + input_report_abs(bu21029->in_dev, ABS_Y, y);
    + input_report_abs(bu21029->in_dev, ABS_PRESSURE, rz);
    + input_report_key(bu21029->in_dev, BTN_TOUCH, 1);
    + input_sync(bu21029->in_dev);
    + }
    +
    + return 0;
    +}
    +
    +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;
    + struct i2c_client *i2c = bu21029->client;
    +
    + /* report touch and deassert interrupt (will assert again after
    + * INTVL_TIME + tConv4 for continuous touch)
    + */
    + int error = bu21029_touch_report(bu21029);
    +
    + if (error) {
    + dev_err(&i2c->dev, "failed to report (error: %d)\n", error);
    + return IRQ_NONE;
    + }
    +
    + /* reset timer for pen up detection */
    + mod_timer(&bu21029->timer, jiffies + PEN_UP_TIMEOUT);
    +
    + return IRQ_HANDLED;
    +}
    +
    +static void bu21029_reset_chip(struct bu21029_ts_data *bu21029)
    +{
    + gpio_set_value(bu21029->reset_gpios,
    + bu21029->reset_gpios_assert);
    + udelay(STOP_DELAY_US);
    + gpio_set_value(bu21029->reset_gpios,
    + !bu21029->reset_gpios_assert);
    + mdelay(START_DELAY_MS);
    +}
    +
    +static int bu21029_init_chip(struct bu21029_ts_data *bu21029)
    +{
    + 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;
    + u16 hwid;
    +
    + bu21029_reset_chip(bu21029);
    +
    + error = i2c_smbus_read_i2c_block_data(i2c,
    + BU21029_HWID_REG,
    + 2,
    + (u8 *)&hwid);
    + if (error < 0) {
    + dev_err(&i2c->dev, "failed to read HW ID\n");
    + return error;
    + }
    +
    + if (cpu_to_be16(hwid) != SUPPORTED_HWID) {
    + dev_err(&i2c->dev, "unsupported HW ID 0x%x\n", hwid);
    + return -ENODEV;
    + }
    +
    + 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 0x%x to register 0x%x\n",
    + init_table[i].value,
    + init_table[i].reg);
    + return error;
    + }
    + }
    +
    + error = i2c_smbus_write_byte(i2c, BU21029_AUTOSCAN);
    + if (error < 0) {
    + dev_err(&i2c->dev, "failed to start autoscan\n");
    + return error;
    + }
    +
    + return 0;
    +}
    +
    +static int bu21029_parse_dt(struct bu21029_ts_data *bu21029)
    +{
    + struct device *dev = &bu21029->client->dev;
    + struct device_node *np = dev->of_node;
    + enum of_gpio_flags flags;
    + u32 val32;
    + int gpio;
    +
    + if (!np) {
    + dev_err(dev, "no device tree data\n");
    + return -EINVAL;
    + }
    +
    + gpio = of_get_named_gpio_flags(np, "reset-gpios", 0, &flags);
    + if (!gpio_is_valid(gpio)) {
    + dev_err(dev, "invalid 'reset-gpios' supplied\n");
    + return -EINVAL;
    + }
    + bu21029->reset_gpios = gpio;
    + bu21029->reset_gpios_assert = (flags & OF_GPIO_ACTIVE_LOW) ? 0 : 1;
    +
    + if (of_property_read_u32(np, "rohm,x-plate-ohms", &val32)) {
    + dev_err(dev, "invalid 'x-plate-ohms' supplied\n");
    + return -EINVAL;
    + }
    + bu21029->x_plate_ohms = val32;
    +
    + if (of_property_read_u32(np, "touchscreen-max-pressure", &val32))
    + bu21029->max_pressure = MAX_12BIT;
    + else
    + bu21029->max_pressure = val32;
    +
    + return 0;
    +}
    +
    +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;
    +
    + 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);
    +
    + error = bu21029_parse_dt(bu21029);
    + if (error)
    + return error;
    +
    + error = devm_gpio_request_one(&client->dev,
    + bu21029->reset_gpios,
    + GPIOF_OUT_INIT_HIGH,
    + DRIVER_NAME);
    + if (error) {
    + dev_err(&client->dev, "unable to request reset-gpios\n");
    + return error;
    + }
    +
    + error = bu21029_init_chip(bu21029);
    + if (error) {
    + dev_err(&client->dev, "unable to config bu21029\n");
    + return error;
    + }
    +
    + in_dev->name = DRIVER_NAME;
    + in_dev->id.bustype = BUS_I2C;
    + in_dev->dev.parent = &client->dev;
    +
    + __set_bit(EV_SYN, in_dev->evbit);
    + __set_bit(EV_KEY, in_dev->evbit);
    + __set_bit(EV_ABS, in_dev->evbit);
    + __set_bit(ABS_X, in_dev->absbit);
    + __set_bit(ABS_Y, in_dev->absbit);
    + __set_bit(ABS_PRESSURE, in_dev->absbit);
    + __set_bit(BTN_TOUCH, in_dev->keybit);
    +
    + 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, bu21029->max_pressure, 0, 0);
    + input_set_drvdata(in_dev, bu21029);
    +
    + error = input_register_device(in_dev);
    + if (error) {
    + dev_err(&client->dev, "unable to register input device\n");
    + return error;
    + }
    +
    + i2c_set_clientdata(client, bu21029);
    +
    + error = devm_request_threaded_irq(&client->dev,
    + client->irq,
    + NULL,
    + bu21029_touch_soft_irq,
    + IRQF_ONESHOT,
    + DRIVER_NAME,
    + bu21029);
    + if (error) {
    + dev_err(&client->dev, "unable to request touch irq\n");
    + return error;
    + }
    +
    + return 0;
    +}
    +
    +static int bu21029_remove(struct i2c_client *client)
    +{
    + struct bu21029_ts_data *bu21029 = i2c_get_clientdata(client);
    +
    + del_timer_sync(&bu21029->timer);
    +
    + return 0;
    +}
    +
    +static const struct i2c_device_id bu21029_ids[] = {
    + {DRIVER_NAME, 0},
    + {}
    +};
    +MODULE_DEVICE_TABLE(i2c, bu21029_ids);
    +
    +static struct i2c_driver bu21029_driver = {
    + .driver = {
    + .name = DRIVER_NAME,
    + .owner = THIS_MODULE,
    + },
    + .id_table = bu21029_ids,
    + .probe = bu21029_probe,
    + .remove = bu21029_remove,
    +};
    +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");
    --
    2.7.4
    \
     
     \ /
      Last update: 2018-03-21 18:06    [W:4.405 / U:0.904 seconds]
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