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 ELECTRODE_CONF_QUICK_CHARGE	0x80
47 #define AUTO_CONFIG_CTRL_ADDR		0x7b
48 #define AUTO_CONFIG_USL_ADDR		0x7d
49 #define AUTO_CONFIG_LSL_ADDR		0x7e
50 #define AUTO_CONFIG_TL_ADDR		0x7f
51 
52 /* Threshold of touch/release trigger */
53 #define TOUCH_THRESHOLD			0x08
54 #define RELEASE_THRESHOLD		0x05
55 /* Masks for touch and release triggers */
56 #define TOUCH_STATUS_MASK		0xfff
57 /* MPR121 has 12 keys */
58 #define MPR121_MAX_KEY_COUNT		12
59 
60 struct mpr121_touchkey {
61 	struct i2c_client	*client;
62 	struct input_dev	*input_dev;
63 	unsigned int		key_val;
64 	unsigned int		statusbits;
65 	unsigned int		keycount;
66 	u16			keycodes[MPR121_MAX_KEY_COUNT];
67 };
68 
69 struct mpr121_init_register {
70 	int addr;
71 	u8 val;
72 };
73 
74 static const struct mpr121_init_register init_reg_table[] = {
75 	{ MHD_RISING_ADDR,	0x1 },
76 	{ NHD_RISING_ADDR,	0x1 },
77 	{ MHD_FALLING_ADDR,	0x1 },
78 	{ NHD_FALLING_ADDR,	0x1 },
79 	{ NCL_FALLING_ADDR,	0xff },
80 	{ FDL_FALLING_ADDR,	0x02 },
81 	{ FILTER_CONF_ADDR,	0x04 },
82 	{ AFE_CONF_ADDR,	0x0b },
83 	{ AUTO_CONFIG_CTRL_ADDR, 0x0b },
84 };
85 
86 static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
87 {
88 	struct mpr121_touchkey *mpr121 = dev_id;
89 	struct i2c_client *client = mpr121->client;
90 	struct input_dev *input = mpr121->input_dev;
91 	unsigned int key_num, key_val, pressed;
92 	int reg;
93 
94 	reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
95 	if (reg < 0) {
96 		dev_err(&client->dev, "i2c read error [%d]\n", reg);
97 		goto out;
98 	}
99 
100 	reg <<= 8;
101 	reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
102 	if (reg < 0) {
103 		dev_err(&client->dev, "i2c read error [%d]\n", reg);
104 		goto out;
105 	}
106 
107 	reg &= TOUCH_STATUS_MASK;
108 	/* use old press bit to figure out which bit changed */
109 	key_num = ffs(reg ^ mpr121->statusbits) - 1;
110 	pressed = reg & (1 << key_num);
111 	mpr121->statusbits = reg;
112 
113 	key_val = mpr121->keycodes[key_num];
114 
115 	input_event(input, EV_MSC, MSC_SCAN, key_num);
116 	input_report_key(input, key_val, pressed);
117 	input_sync(input);
118 
119 	dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
120 		pressed ? "pressed" : "released");
121 
122 out:
123 	return IRQ_HANDLED;
124 }
125 
126 static int mpr121_phys_init(const struct mpr121_platform_data *pdata,
127 				      struct mpr121_touchkey *mpr121,
128 				      struct i2c_client *client)
129 {
130 	const struct mpr121_init_register *reg;
131 	unsigned char usl, lsl, tl, eleconf;
132 	int i, t, vdd, ret;
133 
134 	/* Set up touch/release threshold for ele0-ele11 */
135 	for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
136 		t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
137 		ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
138 		if (ret < 0)
139 			goto err_i2c_write;
140 		ret = i2c_smbus_write_byte_data(client, t + 1,
141 						RELEASE_THRESHOLD);
142 		if (ret < 0)
143 			goto err_i2c_write;
144 	}
145 
146 	/* Set up init register */
147 	for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
148 		reg = &init_reg_table[i];
149 		ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
150 		if (ret < 0)
151 			goto err_i2c_write;
152 	}
153 
154 
155 	/*
156 	 * Capacitance on sensing input varies and needs to be compensated.
157 	 * The internal MPR121-auto-configuration can do this if it's
158 	 * registers are set properly (based on pdata->vdd_uv).
159 	 */
160 	vdd = pdata->vdd_uv / 1000;
161 	usl = ((vdd - 700) * 256) / vdd;
162 	lsl = (usl * 65) / 100;
163 	tl = (usl * 90) / 100;
164 	ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
165 	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
166 	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
167 
168 	/*
169 	 * Quick charge bit will let the capacitive charge to ready
170 	 * state quickly, or the buttons may not function after system
171 	 * boot.
172 	 */
173 	eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
174 	ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
175 					 eleconf);
176 	if (ret != 0)
177 		goto err_i2c_write;
178 
179 	dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
180 
181 	return 0;
182 
183 err_i2c_write:
184 	dev_err(&client->dev, "i2c write error: %d\n", ret);
185 	return ret;
186 }
187 
188 static int mpr_touchkey_probe(struct i2c_client *client,
189 			      const struct i2c_device_id *id)
190 {
191 	const struct mpr121_platform_data *pdata = client->dev.platform_data;
192 	struct mpr121_touchkey *mpr121;
193 	struct input_dev *input_dev;
194 	int error;
195 	int i;
196 
197 	if (!pdata) {
198 		dev_err(&client->dev, "no platform data defined\n");
199 		return -EINVAL;
200 	}
201 
202 	if (!pdata->keymap || !pdata->keymap_size) {
203 		dev_err(&client->dev, "missing keymap data\n");
204 		return -EINVAL;
205 	}
206 
207 	if (pdata->keymap_size > MPR121_MAX_KEY_COUNT) {
208 		dev_err(&client->dev, "too many keys defined\n");
209 		return -EINVAL;
210 	}
211 
212 	if (!client->irq) {
213 		dev_err(&client->dev, "irq number should not be zero\n");
214 		return -EINVAL;
215 	}
216 
217 	mpr121 = kzalloc(sizeof(struct mpr121_touchkey), GFP_KERNEL);
218 	input_dev = input_allocate_device();
219 	if (!mpr121 || !input_dev) {
220 		dev_err(&client->dev, "Failed to allocate memory\n");
221 		error = -ENOMEM;
222 		goto err_free_mem;
223 	}
224 
225 	mpr121->client = client;
226 	mpr121->input_dev = input_dev;
227 	mpr121->keycount = pdata->keymap_size;
228 
229 	input_dev->name = "Freescale MPR121 Touchkey";
230 	input_dev->id.bustype = BUS_I2C;
231 	input_dev->dev.parent = &client->dev;
232 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
233 
234 	input_dev->keycode = mpr121->keycodes;
235 	input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
236 	input_dev->keycodemax = mpr121->keycount;
237 
238 	for (i = 0; i < pdata->keymap_size; i++) {
239 		input_set_capability(input_dev, EV_KEY, pdata->keymap[i]);
240 		mpr121->keycodes[i] = pdata->keymap[i];
241 	}
242 
243 	error = mpr121_phys_init(pdata, mpr121, client);
244 	if (error) {
245 		dev_err(&client->dev, "Failed to init register\n");
246 		goto err_free_mem;
247 	}
248 
249 	error = request_threaded_irq(client->irq, NULL,
250 				     mpr_touchkey_interrupt,
251 				     IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
252 				     client->dev.driver->name, mpr121);
253 	if (error) {
254 		dev_err(&client->dev, "Failed to register interrupt\n");
255 		goto err_free_mem;
256 	}
257 
258 	error = input_register_device(input_dev);
259 	if (error)
260 		goto err_free_irq;
261 
262 	i2c_set_clientdata(client, mpr121);
263 	device_init_wakeup(&client->dev, pdata->wakeup);
264 
265 	return 0;
266 
267 err_free_irq:
268 	free_irq(client->irq, mpr121);
269 err_free_mem:
270 	input_free_device(input_dev);
271 	kfree(mpr121);
272 	return error;
273 }
274 
275 static int mpr_touchkey_remove(struct i2c_client *client)
276 {
277 	struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
278 
279 	free_irq(client->irq, mpr121);
280 	input_unregister_device(mpr121->input_dev);
281 	kfree(mpr121);
282 
283 	return 0;
284 }
285 
286 #ifdef CONFIG_PM_SLEEP
287 static int mpr_suspend(struct device *dev)
288 {
289 	struct i2c_client *client = to_i2c_client(dev);
290 
291 	if (device_may_wakeup(&client->dev))
292 		enable_irq_wake(client->irq);
293 
294 	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
295 
296 	return 0;
297 }
298 
299 static int mpr_resume(struct device *dev)
300 {
301 	struct i2c_client *client = to_i2c_client(dev);
302 	struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
303 
304 	if (device_may_wakeup(&client->dev))
305 		disable_irq_wake(client->irq);
306 
307 	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
308 				  mpr121->keycount);
309 
310 	return 0;
311 }
312 #endif
313 
314 static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
315 
316 static const struct i2c_device_id mpr121_id[] = {
317 	{ "mpr121_touchkey", 0 },
318 	{ }
319 };
320 MODULE_DEVICE_TABLE(i2c, mpr121_id);
321 
322 static struct i2c_driver mpr_touchkey_driver = {
323 	.driver = {
324 		.name	= "mpr121",
325 		.owner	= THIS_MODULE,
326 		.pm	= &mpr121_touchkey_pm_ops,
327 	},
328 	.id_table	= mpr121_id,
329 	.probe		= mpr_touchkey_probe,
330 	.remove		= mpr_touchkey_remove,
331 };
332 
333 module_i2c_driver(mpr_touchkey_driver);
334 
335 MODULE_LICENSE("GPL");
336 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
337 MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");
338