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 	struct thermal_zone_device *tz;
119 	void __iomem *base;
120 	unsigned int irq;
121 	bool ignore_fifo_data;
122 	int temp_data;
123 	int temp_offset;
124 	int temp_step;
125 };
126 
127 static void sun4i_ts_irq_handle_input(struct sun4i_ts_data *ts, u32 reg_val)
128 {
129 	u32 x, y;
130 
131 	if (reg_val & FIFO_DATA_PENDING) {
132 		x = readl(ts->base + TP_DATA);
133 		y = readl(ts->base + TP_DATA);
134 		/* The 1st location reported after an up event is unreliable */
135 		if (!ts->ignore_fifo_data) {
136 			input_report_abs(ts->input, ABS_X, x);
137 			input_report_abs(ts->input, ABS_Y, y);
138 			/*
139 			 * The hardware has a separate down status bit, but
140 			 * that gets set before we get the first location,
141 			 * resulting in reporting a click on the old location.
142 			 */
143 			input_report_key(ts->input, BTN_TOUCH, 1);
144 			input_sync(ts->input);
145 		} else {
146 			ts->ignore_fifo_data = false;
147 		}
148 	}
149 
150 	if (reg_val & TP_UP_PENDING) {
151 		ts->ignore_fifo_data = true;
152 		input_report_key(ts->input, BTN_TOUCH, 0);
153 		input_sync(ts->input);
154 	}
155 }
156 
157 static irqreturn_t sun4i_ts_irq(int irq, void *dev_id)
158 {
159 	struct sun4i_ts_data *ts = dev_id;
160 	u32 reg_val;
161 
162 	reg_val  = readl(ts->base + TP_INT_FIFOS);
163 
164 	if (reg_val & TEMP_DATA_PENDING)
165 		ts->temp_data = readl(ts->base + TEMP_DATA);
166 
167 	if (ts->input)
168 		sun4i_ts_irq_handle_input(ts, reg_val);
169 
170 	writel(reg_val, ts->base + TP_INT_FIFOS);
171 
172 	return IRQ_HANDLED;
173 }
174 
175 static int sun4i_ts_open(struct input_dev *dev)
176 {
177 	struct sun4i_ts_data *ts = input_get_drvdata(dev);
178 
179 	/* Flush, set trig level to 1, enable temp, data and up irqs */
180 	writel(TEMP_IRQ_EN(1) | DATA_IRQ_EN(1) | FIFO_TRIG(1) | FIFO_FLUSH(1) |
181 		TP_UP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
182 
183 	return 0;
184 }
185 
186 static void sun4i_ts_close(struct input_dev *dev)
187 {
188 	struct sun4i_ts_data *ts = input_get_drvdata(dev);
189 
190 	/* Deactivate all input IRQs */
191 	writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
192 }
193 
194 static int sun4i_get_temp(const struct sun4i_ts_data *ts, long *temp)
195 {
196 	/* No temp_data until the first irq */
197 	if (ts->temp_data == -1)
198 		return -EAGAIN;
199 
200 	*temp = ts->temp_data * ts->temp_step - ts->temp_offset;
201 
202 	return 0;
203 }
204 
205 static int sun4i_get_tz_temp(void *data, long *temp)
206 {
207 	return sun4i_get_temp(data, temp);
208 }
209 
210 static struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
211 	.get_temp = sun4i_get_tz_temp,
212 };
213 
214 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
215 			 char *buf)
216 {
217 	struct sun4i_ts_data *ts = dev_get_drvdata(dev);
218 	long temp;
219 	int error;
220 
221 	error = sun4i_get_temp(ts, &temp);
222 	if (error)
223 		return error;
224 
225 	return sprintf(buf, "%ld\n", temp);
226 }
227 
228 static ssize_t show_temp_label(struct device *dev,
229 			      struct device_attribute *devattr, char *buf)
230 {
231 	return sprintf(buf, "SoC temperature\n");
232 }
233 
234 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
235 static DEVICE_ATTR(temp1_label, S_IRUGO, show_temp_label, NULL);
236 
237 static struct attribute *sun4i_ts_attrs[] = {
238 	&dev_attr_temp1_input.attr,
239 	&dev_attr_temp1_label.attr,
240 	NULL
241 };
242 ATTRIBUTE_GROUPS(sun4i_ts);
243 
244 static int sun4i_ts_probe(struct platform_device *pdev)
245 {
246 	struct sun4i_ts_data *ts;
247 	struct device *dev = &pdev->dev;
248 	struct device_node *np = dev->of_node;
249 	struct device *hwmon;
250 	int error;
251 	u32 reg;
252 	bool ts_attached;
253 	u32 tp_sensitive_adjust = 15;
254 	u32 filter_type = 1;
255 
256 	ts = devm_kzalloc(dev, sizeof(struct sun4i_ts_data), GFP_KERNEL);
257 	if (!ts)
258 		return -ENOMEM;
259 
260 	ts->dev = dev;
261 	ts->ignore_fifo_data = true;
262 	ts->temp_data = -1;
263 	if (of_device_is_compatible(np, "allwinner,sun6i-a31-ts")) {
264 		/* Allwinner SDK has temperature (C) = (value / 6) - 271 */
265 		ts->temp_offset = 271000;
266 		ts->temp_step = 167;
267 	} else if (of_device_is_compatible(np, "allwinner,sun4i-a10-ts")) {
268 		/*
269 		 * The A10 temperature sensor has quite a wide spread, these
270 		 * parameters are based on the averaging of the calibration
271 		 * results of 4 completely different boards, with a spread of
272 		 * temp_step from 0.096 - 0.170 and temp_offset from 176 - 331.
273 		 */
274 		ts->temp_offset = 257000;
275 		ts->temp_step = 133;
276 	} else {
277 		/*
278 		 * The user manuals do not contain the formula for calculating
279 		 * the temperature. The formula used here is from the AXP209,
280 		 * which is designed by X-Powers, an affiliate of Allwinner:
281 		 *
282 		 *     temperature (C) = (value * 0.1) - 144.7
283 		 *
284 		 * Allwinner does not have any documentation whatsoever for
285 		 * this hardware. Moreover, it is claimed that the sensor
286 		 * is inaccurate and cannot work properly.
287 		 */
288 		ts->temp_offset = 144700;
289 		ts->temp_step = 100;
290 	}
291 
292 	ts_attached = of_property_read_bool(np, "allwinner,ts-attached");
293 	if (ts_attached) {
294 		ts->input = devm_input_allocate_device(dev);
295 		if (!ts->input)
296 			return -ENOMEM;
297 
298 		ts->input->name = pdev->name;
299 		ts->input->phys = "sun4i_ts/input0";
300 		ts->input->open = sun4i_ts_open;
301 		ts->input->close = sun4i_ts_close;
302 		ts->input->id.bustype = BUS_HOST;
303 		ts->input->id.vendor = 0x0001;
304 		ts->input->id.product = 0x0001;
305 		ts->input->id.version = 0x0100;
306 		ts->input->evbit[0] =  BIT(EV_SYN) | BIT(EV_KEY) | BIT(EV_ABS);
307 		__set_bit(BTN_TOUCH, ts->input->keybit);
308 		input_set_abs_params(ts->input, ABS_X, 0, 4095, 0, 0);
309 		input_set_abs_params(ts->input, ABS_Y, 0, 4095, 0, 0);
310 		input_set_drvdata(ts->input, ts);
311 	}
312 
313 	ts->base = devm_ioremap_resource(dev,
314 			      platform_get_resource(pdev, IORESOURCE_MEM, 0));
315 	if (IS_ERR(ts->base))
316 		return PTR_ERR(ts->base);
317 
318 	ts->irq = platform_get_irq(pdev, 0);
319 	error = devm_request_irq(dev, ts->irq, sun4i_ts_irq, 0, "sun4i-ts", ts);
320 	if (error)
321 		return error;
322 
323 	/*
324 	 * Select HOSC clk, clkin = clk / 6, adc samplefreq = clkin / 8192,
325 	 * t_acq = clkin / (16 * 64)
326 	 */
327 	writel(ADC_CLK_SEL(0) | ADC_CLK_DIV(2) | FS_DIV(7) | T_ACQ(63),
328 	       ts->base + TP_CTRL0);
329 
330 	/*
331 	 * tp_sensitive_adjust is an optional property
332 	 * tp_mode = 0 : only x and y coordinates, as we don't use dual touch
333 	 */
334 	of_property_read_u32(np, "allwinner,tp-sensitive-adjust",
335 			     &tp_sensitive_adjust);
336 	writel(TP_SENSITIVE_ADJUST(tp_sensitive_adjust) | TP_MODE_SELECT(0),
337 	       ts->base + TP_CTRL2);
338 
339 	/*
340 	 * Enable median and averaging filter, optional property for
341 	 * filter type.
342 	 */
343 	of_property_read_u32(np, "allwinner,filter-type", &filter_type);
344 	writel(FILTER_EN(1) | FILTER_TYPE(filter_type), ts->base + TP_CTRL3);
345 
346 	/* Enable temperature measurement, period 1953 (2 seconds) */
347 	writel(TEMP_ENABLE(1) | TEMP_PERIOD(1953), ts->base + TP_TPR);
348 
349 	/*
350 	 * Set stylus up debounce to aprox 10 ms, enable debounce, and
351 	 * finally enable tp mode.
352 	 */
353 	reg = STYLUS_UP_DEBOUN(5) | STYLUS_UP_DEBOUN_EN(1);
354 	if (of_device_is_compatible(np, "allwinner,sun6i-a31-ts"))
355 		reg |= SUN6I_TP_MODE_EN(1);
356 	else
357 		reg |= TP_MODE_EN(1);
358 	writel(reg, ts->base + TP_CTRL1);
359 
360 	/*
361 	 * The thermal core does not register hwmon devices for DT-based
362 	 * thermal zone sensors, such as this one.
363 	 */
364 	hwmon = devm_hwmon_device_register_with_groups(ts->dev, "sun4i_ts",
365 						       ts, sun4i_ts_groups);
366 	if (IS_ERR(hwmon))
367 		return PTR_ERR(hwmon);
368 
369 	ts->tz = thermal_zone_of_sensor_register(ts->dev, 0, ts,
370 						 &sun4i_ts_tz_ops);
371 	if (IS_ERR(ts->tz))
372 		ts->tz = NULL;
373 
374 	writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
375 
376 	if (ts_attached) {
377 		error = input_register_device(ts->input);
378 		if (error) {
379 			writel(0, ts->base + TP_INT_FIFOC);
380 			thermal_zone_of_sensor_unregister(ts->dev, ts->tz);
381 			return error;
382 		}
383 	}
384 
385 	platform_set_drvdata(pdev, ts);
386 	return 0;
387 }
388 
389 static int sun4i_ts_remove(struct platform_device *pdev)
390 {
391 	struct sun4i_ts_data *ts = platform_get_drvdata(pdev);
392 
393 	/* Explicit unregister to avoid open/close changing the imask later */
394 	if (ts->input)
395 		input_unregister_device(ts->input);
396 
397 	thermal_zone_of_sensor_unregister(ts->dev, ts->tz);
398 
399 	/* Deactivate all IRQs */
400 	writel(0, ts->base + TP_INT_FIFOC);
401 
402 	return 0;
403 }
404 
405 static const struct of_device_id sun4i_ts_of_match[] = {
406 	{ .compatible = "allwinner,sun4i-a10-ts", },
407 	{ .compatible = "allwinner,sun5i-a13-ts", },
408 	{ .compatible = "allwinner,sun6i-a31-ts", },
409 	{ /* sentinel */ }
410 };
411 MODULE_DEVICE_TABLE(of, sun4i_ts_of_match);
412 
413 static struct platform_driver sun4i_ts_driver = {
414 	.driver = {
415 		.name	= "sun4i-ts",
416 		.of_match_table = of_match_ptr(sun4i_ts_of_match),
417 	},
418 	.probe	= sun4i_ts_probe,
419 	.remove	= sun4i_ts_remove,
420 };
421 
422 module_platform_driver(sun4i_ts_driver);
423 
424 MODULE_DESCRIPTION("Allwinner sun4i resistive touchscreen controller driver");
425 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
426 MODULE_LICENSE("GPL");
427