1 /*
2  * Allwinner sunxi resistive touchscreen controller driver
3  *
4  * Copyright (C) 2013 - 2014 Hans de Goede <hdegoede@redhat.com>
5  *
6  * The hwmon parts are based on work by Corentin LABBE which is:
7  * Copyright (C) 2013 Corentin LABBE <clabbe.montjoie@gmail.com>
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 as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  */
19 
20 /*
21  * The sun4i-ts controller is capable of detecting a second touch, but when a
22  * second touch is present then the accuracy becomes so bad the reported touch
23  * location is not useable.
24  *
25  * The original android driver contains some complicated heuristics using the
26  * aprox. distance between the 2 touches to see if the user is making a pinch
27  * open / close movement, and then reports emulated multi-touch events around
28  * the last touch coordinate (as the dual-touch coordinates are worthless).
29  *
30  * These kinds of heuristics are just asking for trouble (and don't belong
31  * in the kernel). So this driver offers straight forward, reliable single
32  * touch functionality only.
33  */
34 
35 #include <linux/err.h>
36 #include <linux/hwmon.h>
37 #include <linux/init.h>
38 #include <linux/input.h>
39 #include <linux/interrupt.h>
40 #include <linux/io.h>
41 #include <linux/module.h>
42 #include <linux/of_platform.h>
43 #include <linux/platform_device.h>
44 #include <linux/slab.h>
45 
46 #define TP_CTRL0		0x00
47 #define TP_CTRL1		0x04
48 #define TP_CTRL2		0x08
49 #define TP_CTRL3		0x0c
50 #define TP_INT_FIFOC		0x10
51 #define TP_INT_FIFOS		0x14
52 #define TP_TPR			0x18
53 #define TP_CDAT			0x1c
54 #define TEMP_DATA		0x20
55 #define TP_DATA			0x24
56 
57 /* TP_CTRL0 bits */
58 #define ADC_FIRST_DLY(x)	((x) << 24) /* 8 bits */
59 #define ADC_FIRST_DLY_MODE(x)	((x) << 23)
60 #define ADC_CLK_SEL(x)		((x) << 22)
61 #define ADC_CLK_DIV(x)		((x) << 20) /* 3 bits */
62 #define FS_DIV(x)		((x) << 16) /* 4 bits */
63 #define T_ACQ(x)		((x) << 0) /* 16 bits */
64 
65 /* TP_CTRL1 bits */
66 #define STYLUS_UP_DEBOUN(x)	((x) << 12) /* 8 bits */
67 #define STYLUS_UP_DEBOUN_EN(x)	((x) << 9)
68 #define TOUCH_PAN_CALI_EN(x)	((x) << 6)
69 #define TP_DUAL_EN(x)		((x) << 5)
70 #define TP_MODE_EN(x)		((x) << 4)
71 #define TP_ADC_SELECT(x)	((x) << 3)
72 #define ADC_CHAN_SELECT(x)	((x) << 0)  /* 3 bits */
73 
74 /* TP_CTRL2 bits */
75 #define TP_SENSITIVE_ADJUST(x)	((x) << 28) /* 4 bits */
76 #define TP_MODE_SELECT(x)	((x) << 26) /* 2 bits */
77 #define PRE_MEA_EN(x)		((x) << 24)
78 #define PRE_MEA_THRE_CNT(x)	((x) << 0) /* 24 bits */
79 
80 /* TP_CTRL3 bits */
81 #define FILTER_EN(x)		((x) << 2)
82 #define FILTER_TYPE(x)		((x) << 0)  /* 2 bits */
83 
84 /* TP_INT_FIFOC irq and fifo mask / control bits */
85 #define TEMP_IRQ_EN(x)		((x) << 18)
86 #define OVERRUN_IRQ_EN(x)	((x) << 17)
87 #define DATA_IRQ_EN(x)		((x) << 16)
88 #define TP_DATA_XY_CHANGE(x)	((x) << 13)
89 #define FIFO_TRIG(x)		((x) << 8)  /* 5 bits */
90 #define DATA_DRQ_EN(x)		((x) << 7)
91 #define FIFO_FLUSH(x)		((x) << 4)
92 #define TP_UP_IRQ_EN(x)		((x) << 1)
93 #define TP_DOWN_IRQ_EN(x)	((x) << 0)
94 
95 /* TP_INT_FIFOS irq and fifo status bits */
96 #define TEMP_DATA_PENDING	BIT(18)
97 #define FIFO_OVERRUN_PENDING	BIT(17)
98 #define FIFO_DATA_PENDING	BIT(16)
99 #define TP_IDLE_FLG		BIT(2)
100 #define TP_UP_PENDING		BIT(1)
101 #define TP_DOWN_PENDING		BIT(0)
102 
103 /* TP_TPR bits */
104 #define TEMP_ENABLE(x)		((x) << 16)
105 #define TEMP_PERIOD(x)		((x) << 0)  /* t = x * 256 * 16 / clkin */
106 
107 struct sun4i_ts_data {
108 	struct device *dev;
109 	struct input_dev *input;
110 	void __iomem *base;
111 	unsigned int irq;
112 	bool ignore_fifo_data;
113 	int temp_data;
114 };
115 
116 static void sun4i_ts_irq_handle_input(struct sun4i_ts_data *ts, u32 reg_val)
117 {
118 	u32 x, y;
119 
120 	if (reg_val & FIFO_DATA_PENDING) {
121 		x = readl(ts->base + TP_DATA);
122 		y = readl(ts->base + TP_DATA);
123 		/* The 1st location reported after an up event is unreliable */
124 		if (!ts->ignore_fifo_data) {
125 			input_report_abs(ts->input, ABS_X, x);
126 			input_report_abs(ts->input, ABS_Y, y);
127 			/*
128 			 * The hardware has a separate down status bit, but
129 			 * that gets set before we get the first location,
130 			 * resulting in reporting a click on the old location.
131 			 */
132 			input_report_key(ts->input, BTN_TOUCH, 1);
133 			input_sync(ts->input);
134 		} else {
135 			ts->ignore_fifo_data = false;
136 		}
137 	}
138 
139 	if (reg_val & TP_UP_PENDING) {
140 		ts->ignore_fifo_data = true;
141 		input_report_key(ts->input, BTN_TOUCH, 0);
142 		input_sync(ts->input);
143 	}
144 }
145 
146 static irqreturn_t sun4i_ts_irq(int irq, void *dev_id)
147 {
148 	struct sun4i_ts_data *ts = dev_id;
149 	u32 reg_val;
150 
151 	reg_val  = readl(ts->base + TP_INT_FIFOS);
152 
153 	if (reg_val & TEMP_DATA_PENDING)
154 		ts->temp_data = readl(ts->base + TEMP_DATA);
155 
156 	if (ts->input)
157 		sun4i_ts_irq_handle_input(ts, reg_val);
158 
159 	writel(reg_val, ts->base + TP_INT_FIFOS);
160 
161 	return IRQ_HANDLED;
162 }
163 
164 static int sun4i_ts_open(struct input_dev *dev)
165 {
166 	struct sun4i_ts_data *ts = input_get_drvdata(dev);
167 
168 	/* Flush, set trig level to 1, enable temp, data and up irqs */
169 	writel(TEMP_IRQ_EN(1) | DATA_IRQ_EN(1) | FIFO_TRIG(1) | FIFO_FLUSH(1) |
170 		TP_UP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
171 
172 	return 0;
173 }
174 
175 static void sun4i_ts_close(struct input_dev *dev)
176 {
177 	struct sun4i_ts_data *ts = input_get_drvdata(dev);
178 
179 	/* Deactivate all input IRQs */
180 	writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
181 }
182 
183 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
184 			 char *buf)
185 {
186 	struct sun4i_ts_data *ts = dev_get_drvdata(dev);
187 
188 	/* No temp_data until the first irq */
189 	if (ts->temp_data == -1)
190 		return -EAGAIN;
191 
192 	return sprintf(buf, "%d\n", (ts->temp_data - 1447) * 100);
193 }
194 
195 static ssize_t show_temp_label(struct device *dev,
196 			      struct device_attribute *devattr, char *buf)
197 {
198 	return sprintf(buf, "SoC temperature\n");
199 }
200 
201 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
202 static DEVICE_ATTR(temp1_label, S_IRUGO, show_temp_label, NULL);
203 
204 static struct attribute *sun4i_ts_attrs[] = {
205 	&dev_attr_temp1_input.attr,
206 	&dev_attr_temp1_label.attr,
207 	NULL
208 };
209 ATTRIBUTE_GROUPS(sun4i_ts);
210 
211 static int sun4i_ts_probe(struct platform_device *pdev)
212 {
213 	struct sun4i_ts_data *ts;
214 	struct device *dev = &pdev->dev;
215 	struct device_node *np = dev->of_node;
216 	struct device *hwmon;
217 	int error;
218 	bool ts_attached;
219 
220 	ts = devm_kzalloc(dev, sizeof(struct sun4i_ts_data), GFP_KERNEL);
221 	if (!ts)
222 		return -ENOMEM;
223 
224 	ts->dev = dev;
225 	ts->ignore_fifo_data = true;
226 	ts->temp_data = -1;
227 
228 	ts_attached = of_property_read_bool(np, "allwinner,ts-attached");
229 	if (ts_attached) {
230 		ts->input = devm_input_allocate_device(dev);
231 		if (!ts->input)
232 			return -ENOMEM;
233 
234 		ts->input->name = pdev->name;
235 		ts->input->phys = "sun4i_ts/input0";
236 		ts->input->open = sun4i_ts_open;
237 		ts->input->close = sun4i_ts_close;
238 		ts->input->id.bustype = BUS_HOST;
239 		ts->input->id.vendor = 0x0001;
240 		ts->input->id.product = 0x0001;
241 		ts->input->id.version = 0x0100;
242 		ts->input->evbit[0] =  BIT(EV_SYN) | BIT(EV_KEY) | BIT(EV_ABS);
243 		__set_bit(BTN_TOUCH, ts->input->keybit);
244 		input_set_abs_params(ts->input, ABS_X, 0, 4095, 0, 0);
245 		input_set_abs_params(ts->input, ABS_Y, 0, 4095, 0, 0);
246 		input_set_drvdata(ts->input, ts);
247 	}
248 
249 	ts->base = devm_ioremap_resource(dev,
250 			      platform_get_resource(pdev, IORESOURCE_MEM, 0));
251 	if (IS_ERR(ts->base))
252 		return PTR_ERR(ts->base);
253 
254 	ts->irq = platform_get_irq(pdev, 0);
255 	error = devm_request_irq(dev, ts->irq, sun4i_ts_irq, 0, "sun4i-ts", ts);
256 	if (error)
257 		return error;
258 
259 	/*
260 	 * Select HOSC clk, clkin = clk / 6, adc samplefreq = clkin / 8192,
261 	 * t_acq = clkin / (16 * 64)
262 	 */
263 	writel(ADC_CLK_SEL(0) | ADC_CLK_DIV(2) | FS_DIV(7) | T_ACQ(63),
264 	       ts->base + TP_CTRL0);
265 
266 	/*
267 	 * sensitive_adjust = 15 : max, which is not all that sensitive,
268 	 * tp_mode = 0 : only x and y coordinates, as we don't use dual touch
269 	 */
270 	writel(TP_SENSITIVE_ADJUST(15) | TP_MODE_SELECT(0),
271 	       ts->base + TP_CTRL2);
272 
273 	/* Enable median filter, type 1 : 5/3 */
274 	writel(FILTER_EN(1) | FILTER_TYPE(1), ts->base + TP_CTRL3);
275 
276 	/* Enable temperature measurement, period 1953 (2 seconds) */
277 	writel(TEMP_ENABLE(1) | TEMP_PERIOD(1953), ts->base + TP_TPR);
278 
279 	/*
280 	 * Set stylus up debounce to aprox 10 ms, enable debounce, and
281 	 * finally enable tp mode.
282 	 */
283 	writel(STYLUS_UP_DEBOUN(5) | STYLUS_UP_DEBOUN_EN(1) | TP_MODE_EN(1),
284 	       ts->base + TP_CTRL1);
285 
286 	hwmon = devm_hwmon_device_register_with_groups(ts->dev, "sun4i_ts",
287 						       ts, sun4i_ts_groups);
288 	if (IS_ERR(hwmon))
289 		return PTR_ERR(hwmon);
290 
291 	writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
292 
293 	if (ts_attached) {
294 		error = input_register_device(ts->input);
295 		if (error) {
296 			writel(0, ts->base + TP_INT_FIFOC);
297 			return error;
298 		}
299 	}
300 
301 	platform_set_drvdata(pdev, ts);
302 	return 0;
303 }
304 
305 static int sun4i_ts_remove(struct platform_device *pdev)
306 {
307 	struct sun4i_ts_data *ts = platform_get_drvdata(pdev);
308 
309 	/* Explicit unregister to avoid open/close changing the imask later */
310 	if (ts->input)
311 		input_unregister_device(ts->input);
312 
313 	/* Deactivate all IRQs */
314 	writel(0, ts->base + TP_INT_FIFOC);
315 
316 	return 0;
317 }
318 
319 static const struct of_device_id sun4i_ts_of_match[] = {
320 	{ .compatible = "allwinner,sun4i-a10-ts", },
321 	{ /* sentinel */ }
322 };
323 MODULE_DEVICE_TABLE(of, sun4i_ts_of_match);
324 
325 static struct platform_driver sun4i_ts_driver = {
326 	.driver = {
327 		.owner	= THIS_MODULE,
328 		.name	= "sun4i-ts",
329 		.of_match_table = of_match_ptr(sun4i_ts_of_match),
330 	},
331 	.probe	= sun4i_ts_probe,
332 	.remove	= sun4i_ts_remove,
333 };
334 
335 module_platform_driver(sun4i_ts_driver);
336 
337 MODULE_DESCRIPTION("Allwinner sun4i resistive touchscreen controller driver");
338 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
339 MODULE_LICENSE("GPL");
340