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/arch/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
106struct 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
117static 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
147static 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
165static 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
176static 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
184static 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
195static 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
200static const struct thermal_zone_device_ops sun4i_ts_tz_ops = {
201	.get_temp = sun4i_get_tz_temp,
202};
203
204static 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
218static 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
224static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
225static DEVICE_ATTR(temp1_label, S_IRUGO, show_temp_label, NULL);
226
227static struct attribute *sun4i_ts_attrs[] = {
228	&dev_attr_temp1_input.attr,
229	&dev_attr_temp1_label.attr,
230	NULL
231};
232ATTRIBUTE_GROUPS(sun4i_ts);
233
234static 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
378static void 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
390static const struct of_device_id sun4i_ts_of_match[] = {
391	{ .compatible = "allwinner,sun4i-a10-ts", },
392	{ .compatible = "allwinner,sun5i-a13-ts", },
393	{ .compatible = "allwinner,sun6i-a31-ts", },
394	{ /* sentinel */ }
395};
396MODULE_DEVICE_TABLE(of, sun4i_ts_of_match);
397
398static struct platform_driver sun4i_ts_driver = {
399	.driver = {
400		.name	= "sun4i-ts",
401		.of_match_table = sun4i_ts_of_match,
402	},
403	.probe	= sun4i_ts_probe,
404	.remove_new = sun4i_ts_remove,
405};
406
407module_platform_driver(sun4i_ts_driver);
408
409MODULE_DESCRIPTION("Allwinner sun4i resistive touchscreen controller driver");
410MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
411MODULE_LICENSE("GPL");
412