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
115struct 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
127static 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
157static 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
175static 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
186static 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
194static 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
205static int sun4i_get_tz_temp(void *data, long *temp)
206{
207	return sun4i_get_temp(data, temp);
208}
209
210static struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
211	.get_temp = sun4i_get_tz_temp,
212};
213
214static 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
228static 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
234static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
235static DEVICE_ATTR(temp1_label, S_IRUGO, show_temp_label, NULL);
236
237static struct attribute *sun4i_ts_attrs[] = {
238	&dev_attr_temp1_input.attr,
239	&dev_attr_temp1_label.attr,
240	NULL
241};
242ATTRIBUTE_GROUPS(sun4i_ts);
243
244static 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
389static 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
405static 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};
411MODULE_DEVICE_TABLE(of, sun4i_ts_of_match);
412
413static 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
422module_platform_driver(sun4i_ts_driver);
423
424MODULE_DESCRIPTION("Allwinner sun4i resistive touchscreen controller driver");
425MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
426MODULE_LICENSE("GPL");
427