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// SPDX-License-Identifier: GPL-2.0-only
/*
* Touchkey driver for Freescale MPR121 Controllor
*
* Copyright (C) 2011 Freescale Semiconductor, Inc.
* Author: Zhang Jiejing <jiejing.zhang@freescale.com>
*
* Based on mcs_touchkey.c
*/
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
/* Register definitions */
#define ELE_TOUCH_STATUS_0_ADDR 0x0
#define ELE_TOUCH_STATUS_1_ADDR 0X1
#define MHD_RISING_ADDR 0x2b
#define NHD_RISING_ADDR 0x2c
#define NCL_RISING_ADDR 0x2d
#define FDL_RISING_ADDR 0x2e
#define MHD_FALLING_ADDR 0x2f
#define NHD_FALLING_ADDR 0x30
#define NCL_FALLING_ADDR 0x31
#define FDL_FALLING_ADDR 0x32
#define ELE0_TOUCH_THRESHOLD_ADDR 0x41
#define ELE0_RELEASE_THRESHOLD_ADDR 0x42
#define AFE_CONF_ADDR 0x5c
#define FILTER_CONF_ADDR 0x5d
/*
* ELECTRODE_CONF_ADDR: This register configures the number of
* enabled capacitance sensing inputs and its run/suspend mode.
*/
#define ELECTRODE_CONF_ADDR 0x5e
#define ELECTRODE_CONF_QUICK_CHARGE 0x80
#define AUTO_CONFIG_CTRL_ADDR 0x7b
#define AUTO_CONFIG_USL_ADDR 0x7d
#define AUTO_CONFIG_LSL_ADDR 0x7e
#define AUTO_CONFIG_TL_ADDR 0x7f
/* Threshold of touch/release trigger */
#define TOUCH_THRESHOLD 0x08
#define RELEASE_THRESHOLD 0x05
/* Masks for touch and release triggers */
#define TOUCH_STATUS_MASK 0xfff
/* MPR121 has 12 keys */
#define MPR121_MAX_KEY_COUNT 12
struct mpr121_touchkey {
struct i2c_client *client;
struct input_dev *input_dev;
unsigned int statusbits;
unsigned int keycount;
u32 keycodes[MPR121_MAX_KEY_COUNT];
};
struct mpr121_init_register {
int addr;
u8 val;
};
static const struct mpr121_init_register init_reg_table[] = {
{ MHD_RISING_ADDR, 0x1 },
{ NHD_RISING_ADDR, 0x1 },
{ MHD_FALLING_ADDR, 0x1 },
{ NHD_FALLING_ADDR, 0x1 },
{ NCL_FALLING_ADDR, 0xff },
{ FDL_FALLING_ADDR, 0x02 },
{ FILTER_CONF_ADDR, 0x04 },
{ AFE_CONF_ADDR, 0x0b },
{ AUTO_CONFIG_CTRL_ADDR, 0x0b },
};
static void mpr121_vdd_supply_disable(void *data)
{
struct regulator *vdd_supply = data;
regulator_disable(vdd_supply);
}
static struct regulator *mpr121_vdd_supply_init(struct device *dev)
{
struct regulator *vdd_supply;
int err;
vdd_supply = devm_regulator_get(dev, "vdd");
if (IS_ERR(vdd_supply)) {
dev_err(dev, "failed to get vdd regulator: %ld\n",
PTR_ERR(vdd_supply));
return vdd_supply;
}
err = regulator_enable(vdd_supply);
if (err) {
dev_err(dev, "failed to enable vdd regulator: %d\n", err);
return ERR_PTR(err);
}
err = devm_add_action(dev, mpr121_vdd_supply_disable, vdd_supply);
if (err) {
regulator_disable(vdd_supply);
dev_err(dev, "failed to add disable regulator action: %d\n",
err);
return ERR_PTR(err);
}
return vdd_supply;
}
static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
{
struct mpr121_touchkey *mpr121 = dev_id;
struct i2c_client *client = mpr121->client;
struct input_dev *input = mpr121->input_dev;
unsigned long bit_changed;
unsigned int key_num;
int reg;
reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
if (reg < 0) {
dev_err(&client->dev, "i2c read error [%d]\n", reg);
goto out;
}
reg <<= 8;
reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
if (reg < 0) {
dev_err(&client->dev, "i2c read error [%d]\n", reg);
goto out;
}
reg &= TOUCH_STATUS_MASK;
/* use old press bit to figure out which bit changed */
bit_changed = reg ^ mpr121->statusbits;
mpr121->statusbits = reg;
for_each_set_bit(key_num, &bit_changed, mpr121->keycount) {
unsigned int key_val, pressed;
pressed = reg & BIT(key_num);
key_val = mpr121->keycodes[key_num];
input_event(input, EV_MSC, MSC_SCAN, key_num);
input_report_key(input, key_val, pressed);
dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
pressed ? "pressed" : "released");
}
input_sync(input);
out:
return IRQ_HANDLED;
}
static int mpr121_phys_init(struct mpr121_touchkey *mpr121,
struct i2c_client *client, int vdd_uv)
{
const struct mpr121_init_register *reg;
unsigned char usl, lsl, tl, eleconf;
int i, t, vdd, ret;
/* Set up touch/release threshold for ele0-ele11 */
for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
if (ret < 0)
goto err_i2c_write;
ret = i2c_smbus_write_byte_data(client, t + 1,
RELEASE_THRESHOLD);
if (ret < 0)
goto err_i2c_write;
}
/* Set up init register */
for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
reg = &init_reg_table[i];
ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
if (ret < 0)
goto err_i2c_write;
}
/*
* Capacitance on sensing input varies and needs to be compensated.
* The internal MPR121-auto-configuration can do this if it's
* registers are set properly (based on vdd_uv).
*/
vdd = vdd_uv / 1000;
usl = ((vdd - 700) * 256) / vdd;
lsl = (usl * 65) / 100;
tl = (usl * 90) / 100;
ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
/*
* Quick charge bit will let the capacitive charge to ready
* state quickly, or the buttons may not function after system
* boot.
*/
eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
eleconf);
if (ret != 0)
goto err_i2c_write;
dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
return 0;
err_i2c_write:
dev_err(&client->dev, "i2c write error: %d\n", ret);
return ret;
}
static int mpr_touchkey_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct regulator *vdd_supply;
int vdd_uv;
struct mpr121_touchkey *mpr121;
struct input_dev *input_dev;
int error;
int i;
if (!client->irq) {
dev_err(dev, "irq number should not be zero\n");
return -EINVAL;
}
vdd_supply = mpr121_vdd_supply_init(dev);
if (IS_ERR(vdd_supply))
return PTR_ERR(vdd_supply);
vdd_uv = regulator_get_voltage(vdd_supply);
mpr121 = devm_kzalloc(dev, sizeof(*mpr121), GFP_KERNEL);
if (!mpr121)
return -ENOMEM;
input_dev = devm_input_allocate_device(dev);
if (!input_dev)
return -ENOMEM;
mpr121->client = client;
mpr121->input_dev = input_dev;
mpr121->keycount = device_property_read_u32_array(dev, "linux,keycodes",
NULL, 0);
if (mpr121->keycount > MPR121_MAX_KEY_COUNT) {
dev_err(dev, "too many keys defined (%d)\n", mpr121->keycount);
return -EINVAL;
}
error = device_property_read_u32_array(dev, "linux,keycodes",
mpr121->keycodes,
mpr121->keycount);
if (error) {
dev_err(dev,
"failed to read linux,keycode property: %d\n", error);
return error;
}
input_dev->name = "Freescale MPR121 Touchkey";
input_dev->id.bustype = BUS_I2C;
input_dev->dev.parent = dev;
if (device_property_read_bool(dev, "autorepeat"))
__set_bit(EV_REP, input_dev->evbit);
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