1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Allwinner sunxi resistive touchscreen controller driver
4  *
5  * Copyright (C) 2013 - 2014 Hans de Goede <hdegoede@redhat.com>
6  *
7  * The hwmon parts are based on work by Corentin LABBE which is:
8  * Copyright (C) 2013 Corentin LABBE <clabbe.montjoie@gmail.com>
9  */
10 
11 /*
12  * The sun4i-ts controller is capable of detecting a second touch, but when a
13  * second touch is present then the accuracy becomes so bad the reported touch
14  * location is not useable.
15  *
16  * The original android driver contains some complicated heuristics using the
17  * aprox. distance between the 2 touches to see if the user is making a pinch
18  * open / close movement, and then reports emulated multi-touch events around
19  * the last touch coordinate (as the dual-touch coordinates are worthless).
20  *
21  * These kinds of heuristics are just asking for trouble (and don't belong
22  * in the kernel). So this driver offers straight forward, reliable single
23  * touch functionality only.
24  *
25  * s.a. A20 User Manual "1.15 TP" (Documentation/arm/sunxi.rst)
26  * (looks like the description in the A20 User Manual v1.3 is better
27  * than the one in the A10 User Manual v.1.5)
28  */
29 
30 #include <linux/err.h>
31 #include <linux/hwmon.h>
32 #include <linux/thermal.h>
33 #include <linux/init.h>
34 #include <linux/input.h>
35 #include <linux/interrupt.h>
36 #include <linux/io.h>
37 #include <linux/module.h>
38 #include <linux/of_platform.h>
39 #include <linux/platform_device.h>
40 #include <linux/slab.h>
41 
42 #define TP_CTRL0		0x00
43 #define TP_CTRL1		0x04
44 #define TP_CTRL2		0x08
45 #define TP_CTRL3		0x0c
46 #define TP_INT_FIFOC		0x10
47 #define TP_INT_FIFOS		0x14
48 #define TP_TPR			0x18
49 #define TP_CDAT			0x1c
50 #define TEMP_DATA		0x20
51 #define TP_DATA			0x24
52 
53 /* TP_CTRL0 bits */
54 #define ADC_FIRST_DLY(x)	((x) << 24) /* 8 bits */
55 #define ADC_FIRST_DLY_MODE(x)	((x) << 23)
56 #define ADC_CLK_SEL(x)		((x) << 22)
57 #define ADC_CLK_DIV(x)		((x) << 20) /* 3 bits */
58 #define FS_DIV(x)		((x) << 16) /* 4 bits */
59 #define T_ACQ(x)		((x) << 0) /* 16 bits */
60 
61 /* TP_CTRL1 bits */
62 #define STYLUS_UP_DEBOUN(x)	((x) << 12) /* 8 bits */
63 #define STYLUS_UP_DEBOUN_EN(x)	((x) << 9)
64 #define TOUCH_PAN_CALI_EN(x)	((x) << 6)
65 #define TP_DUAL_EN(x)		((x) << 5)
66 #define TP_MODE_EN(x)		((x) << 4)
67 #define TP_ADC_SELECT(x)	((x) << 3)
68 #define ADC_CHAN_SELECT(x)	((x) << 0)  /* 3 bits */
69 
70 /* on sun6i, bits 3~6 are left shifted by 1 to 4~7 */
71 #define SUN6I_TP_MODE_EN(x)	((x) << 5)
72 
73 /* TP_CTRL2 bits */
74 #define TP_SENSITIVE_ADJUST(x)	((x) << 28) /* 4 bits */
75 #define TP_MODE_SELECT(x)	((x) << 26) /* 2 bits */
76 #define PRE_MEA_EN(x)		((x) << 24)
77 #define PRE_MEA_THRE_CNT(x)	((x) << 0) /* 24 bits */
78 
79 /* TP_CTRL3 bits */
80 #define FILTER_EN(x)		((x) << 2)
81 #define FILTER_TYPE(x)		((x) << 0)  /* 2 bits */
82 
83 /* TP_INT_FIFOC irq and fifo mask / control bits */
84 #define TEMP_IRQ_EN(x)		((x) << 18)
85 #define OVERRUN_IRQ_EN(x)	((x) << 17)
86 #define DATA_IRQ_EN(x)		((x) << 16)
87 #define TP_DATA_XY_CHANGE(x)	((x) << 13)
88 #define FIFO_TRIG(x)		((x) << 8)  /* 5 bits */
89 #define DATA_DRQ_EN(x)		((x) << 7)
90 #define FIFO_FLUSH(x)		((x) << 4)
91 #define TP_UP_IRQ_EN(x)		((x) << 1)
92 #define TP_DOWN_IRQ_EN(x)	((x) << 0)
93 
94 /* TP_INT_FIFOS irq and fifo status bits */
95 #define TEMP_DATA_PENDING	BIT(18)
96 #define FIFO_OVERRUN_PENDING	BIT(17)
97 #define FIFO_DATA_PENDING	BIT(16)
98 #define TP_IDLE_FLG		BIT(2)
99 #define TP_UP_PENDING		BIT(1)
100 #define TP_DOWN_PENDING		BIT(0)
101 
102 /* TP_TPR bits */
103 #define TEMP_ENABLE(x)		((x) << 16)
104 #define TEMP_PERIOD(x)		((x) << 0)  /* t = x * 256 * 16 / clkin */
105 
106 struct sun4i_ts_data {
107 	struct device *dev;
108 	struct input_dev *input;
109 	void __iomem *base;
110 	unsigned int irq;
111 	bool ignore_fifo_data;
112 	int temp_data;
113 	int temp_offset;
114 	int temp_step;
115 };
116 
117 static void sun4i_ts_irq_handle_input(struct sun4i_ts_data *ts, u32 reg_val)
118 {
119 	u32 x, y;
120 
121 	if (reg_val & FIFO_DATA_PENDING) {
122 		x = readl(ts->base + TP_DATA);
123 		y = readl(ts->base + TP_DATA);
124 		/* The 1st location reported after an up event is unreliable */
125 		if (!ts->ignore_fifo_data) {
126 			input_report_abs(ts->input, ABS_X, x);
127 			input_report_abs(ts->input, ABS_Y, y);
128 			/*
129 			 * The hardware has a separate down status bit, but
130 			 * that gets set before we get the first location,
131 			 * resulting in reporting a click on the old location.
132 			 */
133 			input_report_key(ts->input, BTN_TOUCH, 1);
134 			input_sync(ts->input);
135 		} else {
136 			ts->ignore_fifo_data = false;
137 		}
138 	}
139 
140 	if (reg_val & TP_UP_PENDING) {
141 		ts->ignore_fifo_data = true;
142 		input_report_key(ts->input, BTN_TOUCH, 0);
143 		input_sync(ts->input);
144 	}
145 }
146 
147 static irqreturn_t sun4i_ts_irq(int irq, void *dev_id)
148 {
149 	struct sun4i_ts_data *ts = dev_id;
150 	u32 reg_val;
151 
152 	reg_val  = readl(ts->base + TP_INT_FIFOS);
153 
154 	if (reg_val & TEMP_DATA_PENDING)
155 		ts->temp_data = readl(ts->base + TEMP_DATA);
156 
157 	if (ts->input)
158 		sun4i_ts_irq_handle_input(ts, reg_val);
159 
160 	writel(reg_val, ts->base + TP_INT_FIFOS);
161 
162 	return IRQ_HANDLED;
163 }
164 
165 static int sun4i_ts_open(struct input_dev *dev)
166 {
167 	struct sun4i_ts_data *ts = input_get_drvdata(dev);
168 
169 	/* Flush, set trig level to 1, enable temp, data and up irqs */
170 	writel(TEMP_IRQ_EN(1) | DATA_IRQ_EN(1) | FIFO_TRIG(1) | FIFO_FLUSH(1) |
171 		TP_UP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
172 
173 	return 0;
174 }
175 
176 static void sun4i_ts_close(struct input_dev *dev)
177 {
178 	struct sun4i_ts_data *ts = input_get_drvdata(dev);
179 
180 	/* Deactivate all input IRQs */
181 	writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
182 }
183 
184 static int sun4i_get_temp(const struct sun4i_ts_data *ts, int *temp)
185 {
186 	/* No temp_data until the first irq */
187 	if (ts->temp_data == -1)
188 		return -EAGAIN;
189 
190 	*temp = ts->temp_data * ts->temp_step - ts->temp_offset;
191 
192 	return 0;
193 }
194 
195 static int sun4i_get_tz_temp(struct thermal_zone_device *tz, int *temp)
196 {
197 	return sun4i_get_temp(thermal_zone_device_priv(tz), temp);
198 }
199 
200 static const struct thermal_zone_device_ops sun4i_ts_tz_ops = {
201 	.get_temp = sun4i_get_tz_temp,
202 };
203 
204 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
205 			 char *buf)
206 {
207 	struct sun4i_ts_data *ts = dev_get_drvdata(dev);
208 	int temp;
209 	int error;
210 
211 	error = sun4i_get_temp(ts, &temp);
212 	if (error)
213 		return error;
214 
215 	return sprintf(buf, "%d\n", temp);
216 }
217 
218 static ssize_t show_temp_label(struct device *dev,
219 			      struct device_attribute *devattr, char *buf)
220 {
221 	return sprintf(buf, "SoC temperature\n");
222 }
223 
224 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
225 static DEVICE_ATTR(temp1_label, S_IRUGO, show_temp_label, NULL);
226 
227 static struct attribute *sun4i_ts_attrs[] = {
228 	&dev_attr_temp1_input.attr,
229 	&dev_attr_temp1_label.attr,
230 	NULL
231 };
232 ATTRIBUTE_GROUPS(sun4i_ts);
233 
234 static int sun4i_ts_probe(struct platform_device *pdev)
235 {
236 	struct sun4i_ts_data *ts;
237 	struct device *dev = &pdev->dev;
238 	struct device_node *np = dev->of_node;
239 	struct device *hwmon;
240 	struct thermal_zone_device *thermal;
241 	int error;
242 	u32 reg;
243 	bool ts_attached;
244 	u32 tp_sensitive_adjust = 15;
245 	u32 filter_type = 1;
246 
247 	ts = devm_kzalloc(dev, sizeof(struct sun4i_ts_data), GFP_KERNEL);
248 	if (!ts)
249 		return -ENOMEM;
250 
251 	ts->dev = dev;
252 	ts->ignore_fifo_data = true;
253 	ts->temp_data = -1;
254 	if (of_device_is_compatible(np, "allwinner,sun6i-a31-ts")) {
255 		/* Allwinner SDK has temperature (C) = (value / 6) - 271 */
256 		ts->temp_offset = 271000;
257 		ts->temp_step = 167;
258 	} else if (of_device_is_compatible(np, "allwinner,sun4i-a10-ts")) {
259 		/*
260 		 * The A10 temperature sensor has quite a wide spread, these
261 		 * parameters are based on the averaging of the calibration
262 		 * results of 4 completely different boards, with a spread of
263 		 * temp_step from 0.096 - 0.170 and temp_offset from 176 - 331.
264 		 */
265 		ts->temp_offset = 257000;
266 		ts->temp_step = 133;
267 	} else {
268 		/*
269 		 * The user manuals do not contain the formula for calculating
270 		 * the temperature. The formula used here is from the AXP209,
271 		 * which is designed by X-Powers, an affiliate of Allwinner:
272 		 *
273 		 *     temperature (C) = (value * 0.1) - 144.7
274 		 *
275 		 * Allwinner does not have any documentation whatsoever for
276 		 * this hardware. Moreover, it is claimed that the sensor
277 		 * is inaccurate and cannot work properly.
278 		 */
279 		ts->temp_offset = 144700;
280 		ts->temp_step = 100;
281 	}
282 
283 	ts_attached = of_property_read_bool(np, "allwinner,ts-attached");
284 	if (ts_attached) {
285 		ts->input = devm_input_allocate_device(dev);
286 		if (!ts->input)
287 			return -ENOMEM;
288 
289 		ts->input->name = pdev->name;
290 		ts->input->phys = "sun4i_ts/input0";
291 		ts->input->open = sun4i_ts_open;
292 		ts->input->close = sun4i_ts_close;
293 		ts->input->id.bustype = BUS_HOST;
294 		ts->input->id.vendor = 0x0001;
295 		ts->input->id.product = 0x0001;
296 		ts->input->id.version = 0x0100;
297 		ts->input->evbit[0] =  BIT(EV_SYN) | BIT(EV_KEY) | BIT(EV_ABS);
298 		__set_bit(BTN_TOUCH, ts->input->keybit);
299 		input_set_abs_params(ts->input, ABS_X, 0, 4095, 0, 0);
300 		input_set_abs_params(ts->input, ABS_Y, 0, 4095, 0, 0);
301 		input_set_drvdata(ts->input, ts);
302 	}
303 
304 	ts->base = devm_platform_ioremap_resource(pdev, 0);
305 	if (IS_ERR(ts->base))
306 		return PTR_ERR(ts->base);
307 
308 	ts->irq = platform_get_irq(pdev, 0);
309 	error = devm_request_irq(dev, ts->irq, sun4i_ts_irq, 0, "sun4i-ts", ts);
310 	if (error)
311 		return error;
312 
313 	/*
314 	 * Select HOSC clk, clkin = clk / 6, adc samplefreq = clkin / 8192,
315 	 * t_acq = clkin / (16 * 64)
316 	 */
317 	writel(ADC_CLK_SEL(0) | ADC_CLK_DIV(2) | FS_DIV(7) | T_ACQ(63),
318 	       ts->base + TP_CTRL0);
319 
320 	/*
321 	 * tp_sensitive_adjust is an optional property
322 	 * tp_mode = 0 : only x and y coordinates, as we don't use dual touch
323 	 */
324 	of_property_read_u32(np, "allwinner,tp-sensitive-adjust",
325 			     &tp_sensitive_adjust);
326 	writel(TP_SENSITIVE_ADJUST(tp_sensitive_adjust) | TP_MODE_SELECT(0),
327 	       ts->base + TP_CTRL2);
328 
329 	/*
330 	 * Enable median and averaging filter, optional property for
331 	 * filter type.
332 	 */
333 	of_property_read_u32(np, "allwinner,filter-type", &filter_type);
334 	writel(FILTER_EN(1) | FILTER_TYPE(filter_type), ts->base + TP_CTRL3);
335 
336 	/* Enable temperature measurement, period 1953 (2 seconds) */
337 	writel(TEMP_ENABLE(1) | TEMP_PERIOD(1953), ts->base + TP_TPR);
338 
339 	/*
340 	 * Set stylus up debounce to aprox 10 ms, enable debounce, and
341 	 * finally enable tp mode.
342 	 */
343 	reg = STYLUS_UP_DEBOUN(5) | STYLUS_UP_DEBOUN_EN(1);
344 	if (of_device_is_compatible(np, "allwinner,sun6i-a31-ts"))
345 		reg |= SUN6I_TP_MODE_EN(1);
346 	else
347 		reg |= TP_MODE_EN(1);
348 	writel(reg, ts->base + TP_CTRL1);
349 
350 	/*
351 	 * The thermal core does not register hwmon devices for DT-based
352 	 * thermal zone sensors, such as this one.
353 	 */
354 	hwmon = devm_hwmon_device_register_with_groups(ts->dev, "sun4i_ts",
355 						       ts, sun4i_ts_groups);
356 	if (IS_ERR(hwmon))
357 		return PTR_ERR(hwmon);
358 
359 	thermal = devm_thermal_of_zone_register(ts->dev, 0, ts,
360 						&sun4i_ts_tz_ops);
361 	if (IS_ERR(thermal))
362 		return PTR_ERR(thermal);
363 
364 	writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
365 
366 	if (ts_attached) {
367 		error = input_register_device(ts->input);
368 		if (error) {
369 			writel(0, ts->base + TP_INT_FIFOC);
370 			return error;
371 		}
372 	}
373 
374 	platform_set_drvdata(pdev, ts);
375 	return 0;
376 }
377 
378 static int sun4i_ts_remove(struct platform_device *pdev)
379 {
380 	struct sun4i_ts_data *ts = platform_get_drvdata(pdev);
381 
382 	/* Explicit unregister to avoid open/close changing the imask later */
383 	if (ts->input)
384 		input_unregister_device(ts->input);
385 
386 	/* Deactivate all IRQs */
387 	writel(0, ts->base + TP_INT_FIFOC);
388 
389 	return 0;
390 }
391 
392 static const struct of_device_id sun4i_ts_of_match[] = {
393 	{ .compatible = "allwinner,sun4i-a10-ts", },
394 	{ .compatible = "allwinner,sun5i-a13-ts", },
395 	{ .compatible = "allwinner,sun6i-a31-ts", },
396 	{ /* sentinel */ }
397 };
398 MODULE_DEVICE_TABLE(of, sun4i_ts_of_match);
399 
400 static struct platform_driver sun4i_ts_driver = {
401 	.driver = {
402 		.name	= "sun4i-ts",
403 		.of_match_table = sun4i_ts_of_match,
404 	},
405 	.probe	= sun4i_ts_probe,
406 	.remove	= sun4i_ts_remove,
407 };
408 
409 module_platform_driver(sun4i_ts_driver);
410 
411 MODULE_DESCRIPTION("Allwinner sun4i resistive touchscreen controller driver");
412 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
413 MODULE_LICENSE("GPL");
414