1 /*
2  * Touchkey driver for Freescale MPR121 Controllor
3  *
4  * Copyright (C) 2011 Freescale Semiconductor, Inc.
5  * Author: Zhang Jiejing <jiejing.zhang@freescale.com>
6  *
7  * Based on mcs_touchkey.c
8  *
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.
12  *
13  */
14 
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/input.h>
18 #include <linux/i2c.h>
19 #include <linux/slab.h>
20 #include <linux/delay.h>
21 #include <linux/bitops.h>
22 #include <linux/interrupt.h>
23 #include <linux/i2c/mpr121_touchkey.h>
24 
25 /* Register definitions */
26 #define ELE_TOUCH_STATUS_0_ADDR	0x0
27 #define ELE_TOUCH_STATUS_1_ADDR	0X1
28 #define MHD_RISING_ADDR		0x2b
29 #define NHD_RISING_ADDR		0x2c
30 #define NCL_RISING_ADDR		0x2d
31 #define FDL_RISING_ADDR		0x2e
32 #define MHD_FALLING_ADDR	0x2f
33 #define NHD_FALLING_ADDR	0x30
34 #define NCL_FALLING_ADDR	0x31
35 #define FDL_FALLING_ADDR	0x32
36 #define ELE0_TOUCH_THRESHOLD_ADDR	0x41
37 #define ELE0_RELEASE_THRESHOLD_ADDR	0x42
38 #define AFE_CONF_ADDR			0x5c
39 #define FILTER_CONF_ADDR		0x5d
40 
41 /*
42  * ELECTRODE_CONF_ADDR: This register configures the number of
43  * enabled capacitance sensing inputs and its run/suspend mode.
44  */
45 #define ELECTRODE_CONF_ADDR		0x5e
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
50 
51 /* Threshold of touch/release trigger */
52 #define TOUCH_THRESHOLD			0x0f
53 #define RELEASE_THRESHOLD		0x0a
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
58 
59 struct mpr121_touchkey {
60 	struct i2c_client	*client;
61 	struct input_dev	*input_dev;
62 	unsigned int		key_val;
63 	unsigned int		statusbits;
64 	unsigned int		keycount;
65 	u16			keycodes[MPR121_MAX_KEY_COUNT];
66 };
67 
68 struct mpr121_init_register {
69 	int addr;
70 	u8 val;
71 };
72 
73 static const struct mpr121_init_register init_reg_table[] __devinitconst = {
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 },
83 };
84 
85 static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
86 {
87 	struct mpr121_touchkey *mpr121 = dev_id;
88 	struct i2c_client *client = mpr121->client;
89 	struct input_dev *input = mpr121->input_dev;
90 	unsigned int key_num, key_val, pressed;
91 	int reg;
92 
93 	reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
94 	if (reg < 0) {
95 		dev_err(&client->dev, "i2c read error [%d]\n", reg);
96 		goto out;
97 	}
98 
99 	reg <<= 8;
100 	reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
101 	if (reg < 0) {
102 		dev_err(&client->dev, "i2c read error [%d]\n", reg);
103 		goto out;
104 	}
105 
106 	reg &= TOUCH_STATUS_MASK;
107 	/* use old press bit to figure out which bit changed */
108 	key_num = ffs(reg ^ mpr121->statusbits) - 1;
109 	pressed = reg & (1 << key_num);
110 	mpr121->statusbits = reg;
111 
112 	key_val = mpr121->keycodes[key_num];
113 
114 	input_event(input, EV_MSC, MSC_SCAN, key_num);
115 	input_report_key(input, key_val, pressed);
116 	input_sync(input);
117 
118 	dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
119 		pressed ? "pressed" : "released");
120 
121 out:
122 	return IRQ_HANDLED;
123 }
124 
125 static int __devinit mpr121_phys_init(const struct mpr121_platform_data *pdata,
126 				      struct mpr121_touchkey *mpr121,
127 				      struct i2c_client *client)
128 {
129 	const struct mpr121_init_register *reg;
130 	unsigned char usl, lsl, tl;
131 	int i, t, vdd, ret;
132 
133 	/* Set up touch/release threshold for ele0-ele11 */
134 	for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
135 		t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
136 		ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
137 		if (ret < 0)
138 			goto err_i2c_write;
139 		ret = i2c_smbus_write_byte_data(client, t + 1,
140 						RELEASE_THRESHOLD);
141 		if (ret < 0)
142 			goto err_i2c_write;
143 	}
144 
145 	/* Set up init register */
146 	for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
147 		reg = &init_reg_table[i];
148 		ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
149 		if (ret < 0)
150 			goto err_i2c_write;
151 	}
152 
153 
154 	/*
155 	 * Capacitance on sensing input varies and needs to be compensated.
156 	 * The internal MPR121-auto-configuration can do this if it's
157 	 * registers are set properly (based on pdata->vdd_uv).
158 	 */
159 	vdd = pdata->vdd_uv / 1000;
160 	usl = ((vdd - 700) * 256) / vdd;
161 	lsl = (usl * 65) / 100;
162 	tl = (usl * 90) / 100;
163 	ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
164 	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
165 	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
166 	ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
167 					 mpr121->keycount);
168 	if (ret != 0)
169 		goto err_i2c_write;
170 
171 	dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
172 
173 	return 0;
174 
175 err_i2c_write:
176 	dev_err(&client->dev, "i2c write error: %d\n", ret);
177 	return ret;
178 }
179 
180 static int __devinit mpr_touchkey_probe(struct i2c_client *client,
181 					const struct i2c_device_id *id)
182 {
183 	const struct mpr121_platform_data *pdata = client->dev.platform_data;
184 	struct mpr121_touchkey *mpr121;
185 	struct input_dev *input_dev;
186 	int error;
187 	int i;
188 
189 	if (!pdata) {
190 		dev_err(&client->dev, "no platform data defined\n");
191 		return -EINVAL;
192 	}
193 
194 	if (!pdata->keymap || !pdata->keymap_size) {
195 		dev_err(&client->dev, "missing keymap data\n");
196 		return -EINVAL;
197 	}
198 
199 	if (pdata->keymap_size > MPR121_MAX_KEY_COUNT) {
200 		dev_err(&client->dev, "too many keys defined\n");
201 		return -EINVAL;
202 	}
203 
204 	if (!client->irq) {
205 		dev_err(&client->dev, "irq number should not be zero\n");
206 		return -EINVAL;
207 	}
208 
209 	mpr121 = kzalloc(sizeof(struct mpr121_touchkey), GFP_KERNEL);
210 	input_dev = input_allocate_device();
211 	if (!mpr121 || !input_dev) {
212 		dev_err(&client->dev, "Failed to allocate memory\n");
213 		error = -ENOMEM;
214 		goto err_free_mem;
215 	}
216 
217 	mpr121->client = client;
218 	mpr121->input_dev = input_dev;
219 	mpr121->keycount = pdata->keymap_size;
220 
221 	input_dev->name = "Freescale MPR121 Touchkey";
222 	input_dev->id.bustype = BUS_I2C;
223 	input_dev->dev.parent = &client->dev;
224 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
225 
226 	input_dev->keycode = mpr121->keycodes;
227 	input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
228 	input_dev->keycodemax = mpr121->keycount;
229 
230 	for (i = 0; i < pdata->keymap_size; i++) {
231 		input_set_capability(input_dev, EV_KEY, pdata->keymap[i]);
232 		mpr121->keycodes[i] = pdata->keymap[i];
233 	}
234 
235 	error = mpr121_phys_init(pdata, mpr121, client);
236 	if (error) {
237 		dev_err(&client->dev, "Failed to init register\n");
238 		goto err_free_mem;
239 	}
240 
241 	error = request_threaded_irq(client->irq, NULL,
242 				     mpr_touchkey_interrupt,
243 				     IRQF_TRIGGER_FALLING,
244 				     client->dev.driver->name, mpr121);
245 	if (error) {
246 		dev_err(&client->dev, "Failed to register interrupt\n");
247 		goto err_free_mem;
248 	}
249 
250 	error = input_register_device(input_dev);
251 	if (error)
252 		goto err_free_irq;
253 
254 	i2c_set_clientdata(client, mpr121);
255 	device_init_wakeup(&client->dev, pdata->wakeup);
256 
257 	return 0;
258 
259 err_free_irq:
260 	free_irq(client->irq, mpr121);
261 err_free_mem:
262 	input_free_device(input_dev);
263 	kfree(mpr121);
264 	return error;
265 }
266 
267 static int __devexit mpr_touchkey_remove(struct i2c_client *client)
268 {
269 	struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
270 
271 	free_irq(client->irq, mpr121);
272 	input_unregister_device(mpr121->input_dev);
273 	kfree(mpr121);
274 
275 	return 0;
276 }
277 
278 #ifdef CONFIG_PM_SLEEP
279 static int mpr_suspend(struct device *dev)
280 {
281 	struct i2c_client *client = to_i2c_client(dev);
282 
283 	if (device_may_wakeup(&client->dev))
284 		enable_irq_wake(client->irq);
285 
286 	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
287 
288 	return 0;
289 }
290 
291 static int mpr_resume(struct device *dev)
292 {
293 	struct i2c_client *client = to_i2c_client(dev);
294 	struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
295 
296 	if (device_may_wakeup(&client->dev))
297 		disable_irq_wake(client->irq);
298 
299 	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
300 				  mpr121->keycount);
301 
302 	return 0;
303 }
304 #endif
305 
306 static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
307 
308 static const struct i2c_device_id mpr121_id[] = {
309 	{ "mpr121_touchkey", 0 },
310 	{ }
311 };
312 MODULE_DEVICE_TABLE(i2c, mpr121_id);
313 
314 static struct i2c_driver mpr_touchkey_driver = {
315 	.driver = {
316 		.name	= "mpr121",
317 		.owner	= THIS_MODULE,
318 		.pm	= &mpr121_touchkey_pm_ops,
319 	},
320 	.id_table	= mpr121_id,
321 	.probe		= mpr_touchkey_probe,
322 	.remove		= __devexit_p(mpr_touchkey_remove),
323 };
324 
325 static int __init mpr_touchkey_init(void)
326 {
327 	return i2c_add_driver(&mpr_touchkey_driver);
328 }
329 module_init(mpr_touchkey_init);
330 
331 static void __exit mpr_touchkey_exit(void)
332 {
333 	i2c_del_driver(&mpr_touchkey_driver);
334 }
335 module_exit(mpr_touchkey_exit);
336 
337 MODULE_LICENSE("GPL");
338 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
339 MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");
340