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  * s.a. A20 User Manual "1.15 TP" (Documentation/arm/sunxi/README)
35  * (looks like the description in the A20 User Manual v1.3 is better
36  * than the one in the A10 User Manual v.1.5)
37  */
38 
39 #include <linux/err.h>
40 #include <linux/hwmon.h>
41 #include <linux/thermal.h>
42 #include <linux/init.h>
43 #include <linux/input.h>
44 #include <linux/interrupt.h>
45 #include <linux/io.h>
46 #include <linux/module.h>
47 #include <linux/of_platform.h>
48 #include <linux/platform_device.h>
49 #include <linux/slab.h>
50 
51 #define TP_CTRL0		0x00
52 #define TP_CTRL1		0x04
53 #define TP_CTRL2		0x08
54 #define TP_CTRL3		0x0c
55 #define TP_INT_FIFOC		0x10
56 #define TP_INT_FIFOS		0x14
57 #define TP_TPR			0x18
58 #define TP_CDAT			0x1c
59 #define TEMP_DATA		0x20
60 #define TP_DATA			0x24
61 
62 /* TP_CTRL0 bits */
63 #define ADC_FIRST_DLY(x)	((x) << 24) /* 8 bits */
64 #define ADC_FIRST_DLY_MODE(x)	((x) << 23)
65 #define ADC_CLK_SEL(x)		((x) << 22)
66 #define ADC_CLK_DIV(x)		((x) << 20) /* 3 bits */
67 #define FS_DIV(x)		((x) << 16) /* 4 bits */
68 #define T_ACQ(x)		((x) << 0) /* 16 bits */
69 
70 /* TP_CTRL1 bits */
71 #define STYLUS_UP_DEBOUN(x)	((x) << 12) /* 8 bits */
72 #define STYLUS_UP_DEBOUN_EN(x)	((x) << 9)
73 #define TOUCH_PAN_CALI_EN(x)	((x) << 6)
74 #define TP_DUAL_EN(x)		((x) << 5)
75 #define TP_MODE_EN(x)		((x) << 4)
76 #define TP_ADC_SELECT(x)	((x) << 3)
77 #define ADC_CHAN_SELECT(x)	((x) << 0)  /* 3 bits */
78 
79 /* on sun6i, bits 3~6 are left shifted by 1 to 4~7 */
80 #define SUN6I_TP_MODE_EN(x)	((x) << 5)
81 
82 /* TP_CTRL2 bits */
83 #define TP_SENSITIVE_ADJUST(x)	((x) << 28) /* 4 bits */
84 #define TP_MODE_SELECT(x)	((x) << 26) /* 2 bits */
85 #define PRE_MEA_EN(x)		((x) << 24)
86 #define PRE_MEA_THRE_CNT(x)	((x) << 0) /* 24 bits */
87 
88 /* TP_CTRL3 bits */
89 #define FILTER_EN(x)		((x) << 2)
90 #define FILTER_TYPE(x)		((x) << 0)  /* 2 bits */
91 
92 /* TP_INT_FIFOC irq and fifo mask / control bits */
93 #define TEMP_IRQ_EN(x)		((x) << 18)
94 #define OVERRUN_IRQ_EN(x)	((x) << 17)
95 #define DATA_IRQ_EN(x)		((x) << 16)
96 #define TP_DATA_XY_CHANGE(x)	((x) << 13)
97 #define FIFO_TRIG(x)		((x) << 8)  /* 5 bits */
98 #define DATA_DRQ_EN(x)		((x) << 7)
99 #define FIFO_FLUSH(x)		((x) << 4)
100 #define TP_UP_IRQ_EN(x)		((x) << 1)
101 #define TP_DOWN_IRQ_EN(x)	((x) << 0)
102 
103 /* TP_INT_FIFOS irq and fifo status bits */
104 #define TEMP_DATA_PENDING	BIT(18)
105 #define FIFO_OVERRUN_PENDING	BIT(17)
106 #define FIFO_DATA_PENDING	BIT(16)
107 #define TP_IDLE_FLG		BIT(2)
108 #define TP_UP_PENDING		BIT(1)
109 #define TP_DOWN_PENDING		BIT(0)
110 
111 /* TP_TPR bits */
112 #define TEMP_ENABLE(x)		((x) << 16)
113 #define TEMP_PERIOD(x)		((x) << 0)  /* t = x * 256 * 16 / clkin */
114 
115 struct sun4i_ts_data {
116 	struct device *dev;
117 	struct input_dev *input;
118 	void __iomem *base;
119 	unsigned int irq;
120 	bool ignore_fifo_data;
121 	int temp_data;
122 	int temp_offset;
123 	int temp_step;
124 };
125 
126 static void sun4i_ts_irq_handle_input(struct sun4i_ts_data *ts, u32 reg_val)
127 {
128 	u32 x, y;
129 
130 	if (reg_val & FIFO_DATA_PENDING) {
131 		x = readl(ts->base + TP_DATA);
132 		y = readl(ts->base + TP_DATA);
133 		/* The 1st location reported after an up event is unreliable */
134 		if (!ts->ignore_fifo_data) {
135 			input_report_abs(ts->input, ABS_X, x);
136 			input_report_abs(ts->input, ABS_Y, y);
137 			/*
138 			 * The hardware has a separate down status bit, but
139 			 * that gets set before we get the first location,
140 			 * resulting in reporting a click on the old location.
141 			 */
142 			input_report_key(ts->input, BTN_TOUCH, 1);
143 			input_sync(ts->input);
144 		} else {
145 			ts->ignore_fifo_data = false;
146 		}
147 	}
148 
149 	if (reg_val & TP_UP_PENDING) {
150 		ts->ignore_fifo_data = true;
151 		input_report_key(ts->input, BTN_TOUCH, 0);
152 		input_sync(ts->input);
153 	}
154 }
155 
156 static irqreturn_t sun4i_ts_irq(int irq, void *dev_id)
157 {
158 	struct sun4i_ts_data *ts = dev_id;
159 	u32 reg_val;
160 
161 	reg_val  = readl(ts->base + TP_INT_FIFOS);
162 
163 	if (reg_val & TEMP_DATA_PENDING)
164 		ts->temp_data = readl(ts->base + TEMP_DATA);
165 
166 	if (ts->input)
167 		sun4i_ts_irq_handle_input(ts, reg_val);
168 
169 	writel(reg_val, ts->base + TP_INT_FIFOS);
170 
171 	return IRQ_HANDLED;
172 }
173 
174 static int sun4i_ts_open(struct input_dev *dev)
175 {
176 	struct sun4i_ts_data *ts = input_get_drvdata(dev);
177 
178 	/* Flush, set trig level to 1, enable temp, data and up irqs */
179 	writel(TEMP_IRQ_EN(1) | DATA_IRQ_EN(1) | FIFO_TRIG(1) | FIFO_FLUSH(1) |
180 		TP_UP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
181 
182 	return 0;
183 }
184 
185 static void sun4i_ts_close(struct input_dev *dev)
186 {
187 	struct sun4i_ts_data *ts = input_get_drvdata(dev);
188 
189 	/* Deactivate all input IRQs */
190 	writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
191 }
192 
193 static int sun4i_get_temp(const struct sun4i_ts_data *ts, int *temp)
194 {
195 	/* No temp_data until the first irq */
196 	if (ts->temp_data == -1)
197 		return -EAGAIN;
198 
199 	*temp = ts->temp_data * ts->temp_step - ts->temp_offset;
200 
201 	return 0;
202 }
203 
204 static int sun4i_get_tz_temp(void *data, int *temp)
205 {
206 	return sun4i_get_temp(data, temp);
207 }
208 
209 static struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
210 	.get_temp = sun4i_get_tz_temp,
211 };
212 
213 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
214 			 char *buf)
215 {
216 	struct sun4i_ts_data *ts = dev_get_drvdata(dev);
217 	int temp;
218 	int error;
219 
220 	error = sun4i_get_temp(ts, &temp);
221 	if (error)
222 		return error;
223 
224 	return sprintf(buf, "%d\n", temp);
225 }
226 
227 static ssize_t show_temp_label(struct device *dev,
228 			      struct device_attribute *devattr, char *buf)
229 {
230 	return sprintf(buf, "SoC temperature\n");
231 }
232 
233 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
234 static DEVICE_ATTR(temp1_label, S_IRUGO, show_temp_label, NULL);
235 
236 static struct attribute *sun4i_ts_attrs[] = {
237 	&dev_attr_temp1_input.attr,
238 	&dev_attr_temp1_label.attr,
239 	NULL
240 };
241 ATTRIBUTE_GROUPS(sun4i_ts);
242 
243 static int sun4i_ts_probe(struct platform_device *pdev)
244 {
245 	struct sun4i_ts_data *ts;
246 	struct device *dev = &pdev->dev;
247 	struct device_node *np = dev->of_node;
248 	struct device *hwmon;
249 	int error;
250 	u32 reg;
251 	bool ts_attached;
252 	u32 tp_sensitive_adjust = 15;
253 	u32 filter_type = 1;
254 
255 	ts = devm_kzalloc(dev, sizeof(struct sun4i_ts_data), GFP_KERNEL);
256 	if (!ts)
257 		return -ENOMEM;
258 
259 	ts->dev = dev;
260 	ts->ignore_fifo_data = true;
261 	ts->temp_data = -1;
262 	if (of_device_is_compatible(np, "allwinner,sun6i-a31-ts")) {
263 		/* Allwinner SDK has temperature (C) = (value / 6) - 271 */
264 		ts->temp_offset = 271000;
265 		ts->temp_step = 167;
266 	} else if (of_device_is_compatible(np, "allwinner,sun4i-a10-ts")) {
267 		/*
268 		 * The A10 temperature sensor has quite a wide spread, these
269 		 * parameters are based on the averaging of the calibration
270 		 * results of 4 completely different boards, with a spread of
271 		 * temp_step from 0.096 - 0.170 and temp_offset from 176 - 331.
272 		 */
273 		ts->temp_offset = 257000;
274 		ts->temp_step = 133;
275 	} else {
276 		/*
277 		 * The user manuals do not contain the formula for calculating
278 		 * the temperature. The formula used here is from the AXP209,
279 		 * which is designed by X-Powers, an affiliate of Allwinner:
280 		 *
281 		 *     temperature (C) = (value * 0.1) - 144.7
282 		 *
283 		 * Allwinner does not have any documentation whatsoever for
284 		 * this hardware. Moreover, it is claimed that the sensor
285 		 * is inaccurate and cannot work properly.
286 		 */
287 		ts->temp_offset = 144700;
288 		ts->temp_step = 100;
289 	}
290 
291 	ts_attached = of_property_read_bool(np, "allwinner,ts-attached");
292 	if (ts_attached) {
293 		ts->input = devm_input_allocate_device(dev);
294 		if (!ts->input)
295 			return -ENOMEM;
296 
297 		ts->input->name = pdev->name;
298 		ts->input->phys = "sun4i_ts/input0";
299 		ts->input->open = sun4i_ts_open;
300 		ts->input->close = sun4i_ts_close;
301 		ts->input->id.bustype = BUS_HOST;
302 		ts->input->id.vendor = 0x0001;
303 		ts->input->id.product = 0x0001;
304 		ts->input->id.version = 0x0100;
305 		ts->input->evbit[0] =  BIT(EV_SYN) | BIT(EV_KEY) | BIT(EV_ABS);
306 		__set_bit(BTN_TOUCH, ts->input->keybit);
307 		input_set_abs_params(ts->input, ABS_X, 0, 4095, 0, 0);
308 		input_set_abs_params(ts->input, ABS_Y, 0, 4095, 0, 0);
309 		input_set_drvdata(ts->input, ts);
310 	}
311 
312 	ts->base = devm_ioremap_resource(dev,
313 			      platform_get_resource(pdev, IORESOURCE_MEM, 0));
314 	if (IS_ERR(ts->base))
315 		return PTR_ERR(ts->base);
316 
317 	ts->irq = platform_get_irq(pdev, 0);
318 	error = devm_request_irq(dev, ts->irq, sun4i_ts_irq, 0, "sun4i-ts", ts);
319 	if (error)
320 		return error;
321 
322 	/*
323 	 * Select HOSC clk, clkin = clk / 6, adc samplefreq = clkin / 8192,
324 	 * t_acq = clkin / (16 * 64)
325 	 */
326 	writel(ADC_CLK_SEL(0) | ADC_CLK_DIV(2) | FS_DIV(7) | T_ACQ(63),
327 	       ts->base + TP_CTRL0);
328 
329 	/*
330 	 * tp_sensitive_adjust is an optional property
331 	 * tp_mode = 0 : only x and y coordinates, as we don't use dual touch
332 	 */
333 	of_property_read_u32(np, "allwinner,tp-sensitive-adjust",
334 			     &tp_sensitive_adjust);
335 	writel(TP_SENSITIVE_ADJUST(tp_sensitive_adjust) | TP_MODE_SELECT(0),
336 	       ts->base + TP_CTRL2);
337 
338 	/*
339 	 * Enable median and averaging filter, optional property for
340 	 * filter type.
341 	 */
342 	of_property_read_u32(np, "allwinner,filter-type", &filter_type);
343 	writel(FILTER_EN(1) | FILTER_TYPE(filter_type), ts->base + TP_CTRL3);
344 
345 	/* Enable temperature measurement, period 1953 (2 seconds) */
346 	writel(TEMP_ENABLE(1) | TEMP_PERIOD(1953), ts->base + TP_TPR);
347 
348 	/*
349 	 * Set stylus up debounce to aprox 10 ms, enable debounce, and
350 	 * finally enable tp mode.
351 	 */
352 	reg = STYLUS_UP_DEBOUN(5) | STYLUS_UP_DEBOUN_EN(1);
353 	if (of_device_is_compatible(np, "allwinner,sun6i-a31-ts"))
354 		reg |= SUN6I_TP_MODE_EN(1);
355 	else
356 		reg |= TP_MODE_EN(1);
357 	writel(reg, ts->base + TP_CTRL1);
358 
359 	/*
360 	 * The thermal core does not register hwmon devices for DT-based
361 	 * thermal zone sensors, such as this one.
362 	 */
363 	hwmon = devm_hwmon_device_register_with_groups(ts->dev, "sun4i_ts",
364 						       ts, sun4i_ts_groups);
365 	if (IS_ERR(hwmon))
366 		return PTR_ERR(hwmon);
367 
368 	devm_thermal_zone_of_sensor_register(ts->dev, 0, ts, &sun4i_ts_tz_ops);
369 
370 	writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
371 
372 	if (ts_attached) {
373 		error = input_register_device(ts->input);
374 		if (error) {
375 			writel(0, ts->base + TP_INT_FIFOC);
376 			return error;
377 		}
378 	}
379 
380 	platform_set_drvdata(pdev, ts);
381 	return 0;
382 }
383 
384 static int sun4i_ts_remove(struct platform_device *pdev)
385 {
386 	struct sun4i_ts_data *ts = platform_get_drvdata(pdev);
387 
388 	/* Explicit unregister to avoid open/close changing the imask later */
389 	if (ts->input)
390 		input_unregister_device(ts->input);
391 
392 	/* Deactivate all IRQs */
393 	writel(0, ts->base + TP_INT_FIFOC);
394 
395 	return 0;
396 }
397 
398 static const struct of_device_id sun4i_ts_of_match[] = {
399 	{ .compatible = "allwinner,sun4i-a10-ts", },
400 	{ .compatible = "allwinner,sun5i-a13-ts", },
401 	{ .compatible = "allwinner,sun6i-a31-ts", },
402 	{ /* sentinel */ }
403 };
404 MODULE_DEVICE_TABLE(of, sun4i_ts_of_match);
405 
406 static struct platform_driver sun4i_ts_driver = {
407 	.driver = {
408 		.name	= "sun4i-ts",
409 		.of_match_table = of_match_ptr(sun4i_ts_of_match),
410 	},
411 	.probe	= sun4i_ts_probe,
412 	.remove	= sun4i_ts_remove,
413 };
414 
415 module_platform_driver(sun4i_ts_driver);
416 
417 MODULE_DESCRIPTION("Allwinner sun4i resistive touchscreen controller driver");
418 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
419 MODULE_LICENSE("GPL");
420