2 * Touchkey driver for Freescale MPR121 Controllor
4 * Copyright (C) 2011 Freescale Semiconductor, Inc.
5 * Author: Zhang Jiejing <jiejing.zhang@freescale.com>
7 * Based on mcs_touchkey.c
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
15 #include <linux/module.h>
16 #include <linux/input.h>
17 #include <linux/i2c.h>
18 #include <linux/slab.h>
19 #include <linux/delay.h>
20 #include <linux/bitops.h>
21 #include <linux/interrupt.h>
22 #include <linux/i2c/mpr121_touchkey.h>
24 /* Register definitions */
25 #define ELE_TOUCH_STATUS_0_ADDR 0x0
26 #define ELE_TOUCH_STATUS_1_ADDR 0X1
27 #define MHD_RISING_ADDR 0x2b
28 #define NHD_RISING_ADDR 0x2c
29 #define NCL_RISING_ADDR 0x2d
30 #define FDL_RISING_ADDR 0x2e
31 #define MHD_FALLING_ADDR 0x2f
32 #define NHD_FALLING_ADDR 0x30
33 #define NCL_FALLING_ADDR 0x31
34 #define FDL_FALLING_ADDR 0x32
35 #define ELE0_TOUCH_THRESHOLD_ADDR 0x41
36 #define ELE0_RELEASE_THRESHOLD_ADDR 0x42
37 #define AFE_CONF_ADDR 0x5c
38 #define FILTER_CONF_ADDR 0x5d
41 * ELECTRODE_CONF_ADDR: This register configures the number of
42 * enabled capacitance sensing inputs and its run/suspend mode.
44 #define ELECTRODE_CONF_ADDR 0x5e
45 #define ELECTRODE_CONF_QUICK_CHARGE 0x80
46 #define AUTO_CONFIG_CTRL_ADDR 0x7b
47 #define AUTO_CONFIG_USL_ADDR 0x7d
48 #define AUTO_CONFIG_LSL_ADDR 0x7e
49 #define AUTO_CONFIG_TL_ADDR 0x7f
51 /* Threshold of touch/release trigger */
52 #define TOUCH_THRESHOLD 0x08
53 #define RELEASE_THRESHOLD 0x05
54 /* Masks for touch and release triggers */
55 #define TOUCH_STATUS_MASK 0xfff
56 /* MPR121 has 12 keys */
57 #define MPR121_MAX_KEY_COUNT 12
59 struct mpr121_touchkey {
60 struct i2c_client *client;
61 struct input_dev *input_dev;
63 unsigned int statusbits;
64 unsigned int keycount;
65 u16 keycodes[MPR121_MAX_KEY_COUNT];
68 struct mpr121_init_register {
73 static const struct mpr121_init_register init_reg_table[] = {
74 { MHD_RISING_ADDR, 0x1 },
75 { NHD_RISING_ADDR, 0x1 },
76 { MHD_FALLING_ADDR, 0x1 },
77 { NHD_FALLING_ADDR, 0x1 },
78 { NCL_FALLING_ADDR, 0xff },
79 { FDL_FALLING_ADDR, 0x02 },
80 { FILTER_CONF_ADDR, 0x04 },
81 { AFE_CONF_ADDR, 0x0b },
82 { AUTO_CONFIG_CTRL_ADDR, 0x0b },
85 static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
87 struct mpr121_touchkey *mpr121 = dev_id;
88 struct i2c_client *client = mpr121->client;
89 struct input_dev *input = mpr121->input_dev;
90 unsigned long bit_changed;
94 reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
96 dev_err(&client->dev, "i2c read error [%d]\n", reg);
101 reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
103 dev_err(&client->dev, "i2c read error [%d]\n", reg);
107 reg &= TOUCH_STATUS_MASK;
108 /* use old press bit to figure out which bit changed */
109 bit_changed = reg ^ mpr121->statusbits;
110 mpr121->statusbits = reg;
111 for_each_set_bit(key_num, &bit_changed, mpr121->keycount) {
112 unsigned int key_val, pressed;
114 pressed = reg & BIT(key_num);
115 key_val = mpr121->keycodes[key_num];
117 input_event(input, EV_MSC, MSC_SCAN, key_num);
118 input_report_key(input, key_val, pressed);
120 dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
121 pressed ? "pressed" : "released");
130 static int mpr121_phys_init(const struct mpr121_platform_data *pdata,
131 struct mpr121_touchkey *mpr121,
132 struct i2c_client *client)
134 const struct mpr121_init_register *reg;
135 unsigned char usl, lsl, tl, eleconf;
138 /* Set up touch/release threshold for ele0-ele11 */
139 for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
140 t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
141 ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
144 ret = i2c_smbus_write_byte_data(client, t + 1,
150 /* Set up init register */
151 for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
152 reg = &init_reg_table[i];
153 ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
160 * Capacitance on sensing input varies and needs to be compensated.
161 * The internal MPR121-auto-configuration can do this if it's
162 * registers are set properly (based on pdata->vdd_uv).
164 vdd = pdata->vdd_uv / 1000;
165 usl = ((vdd - 700) * 256) / vdd;
166 lsl = (usl * 65) / 100;
167 tl = (usl * 90) / 100;
168 ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
169 ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
170 ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
173 * Quick charge bit will let the capacitive charge to ready
174 * state quickly, or the buttons may not function after system
177 eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
178 ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
183 dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
188 dev_err(&client->dev, "i2c write error: %d\n", ret);
192 static int mpr_touchkey_probe(struct i2c_client *client,
193 const struct i2c_device_id *id)
195 const struct mpr121_platform_data *pdata =
196 dev_get_platdata(&client->dev);
197 struct mpr121_touchkey *mpr121;
198 struct input_dev *input_dev;
203 dev_err(&client->dev, "no platform data defined\n");
207 if (!pdata->keymap || !pdata->keymap_size) {
208 dev_err(&client->dev, "missing keymap data\n");
212 if (pdata->keymap_size > MPR121_MAX_KEY_COUNT) {
213 dev_err(&client->dev, "too many keys defined\n");
218 dev_err(&client->dev, "irq number should not be zero\n");
222 mpr121 = devm_kzalloc(&client->dev, sizeof(*mpr121),
227 input_dev = devm_input_allocate_device(&client->dev);
231 mpr121->client = client;
232 mpr121->input_dev = input_dev;
233 mpr121->keycount = pdata->keymap_size;
235 input_dev->name = "Freescale MPR121 Touchkey";
236 input_dev->id.bustype = BUS_I2C;
237 input_dev->dev.parent = &client->dev;
238 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
239 input_set_capability(input_dev, EV_MSC, MSC_SCAN);
241 input_dev->keycode = mpr121->keycodes;
242 input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
243 input_dev->keycodemax = mpr121->keycount;
245 for (i = 0; i < pdata->keymap_size; i++) {
246 input_set_capability(input_dev, EV_KEY, pdata->keymap[i]);
247 mpr121->keycodes[i] = pdata->keymap[i];
250 error = mpr121_phys_init(pdata, mpr121, client);
252 dev_err(&client->dev, "Failed to init register\n");
256 error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
257 mpr_touchkey_interrupt,
258 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
259 client->dev.driver->name, mpr121);
261 dev_err(&client->dev, "Failed to register interrupt\n");
265 error = input_register_device(input_dev);
269 i2c_set_clientdata(client, mpr121);
270 device_init_wakeup(&client->dev, pdata->wakeup);
275 #ifdef CONFIG_PM_SLEEP
276 static int mpr_suspend(struct device *dev)
278 struct i2c_client *client = to_i2c_client(dev);
280 if (device_may_wakeup(&client->dev))
281 enable_irq_wake(client->irq);
283 i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
288 static int mpr_resume(struct device *dev)
290 struct i2c_client *client = to_i2c_client(dev);
291 struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
293 if (device_may_wakeup(&client->dev))
294 disable_irq_wake(client->irq);
296 i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
303 static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
305 static const struct i2c_device_id mpr121_id[] = {
306 { "mpr121_touchkey", 0 },
309 MODULE_DEVICE_TABLE(i2c, mpr121_id);
311 static struct i2c_driver mpr_touchkey_driver = {
314 .pm = &mpr121_touchkey_pm_ops,
316 .id_table = mpr121_id,
317 .probe = mpr_touchkey_probe,
320 module_i2c_driver(mpr_touchkey_driver);
322 MODULE_LICENSE("GPL");
323 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
324 MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");