[PATCH] Input: add bu21029 touch driver

From: Mark Jonas
Date: Wed Mar 21 2018 - 13:05:37 EST

From: Zhu Yi <yi.zhu5@xxxxxxxxxxxx>

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

Signed-off-by: Zhu Yi <yi.zhu5@xxxxxxxxxxxx>
Signed-off-by: Mark Jonas <mark.jonas@xxxxxxxxxxxx>
Reviewed-by: Heiko Schocher <hs@xxxxxxx>
---
.../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@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Rohm BU21029 touchscreen controller driver");
+MODULE_LICENSE("GPL v2");
--
2.7.4