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1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Samsung S3C24XX touchscreen driver
4  *
5  * Copyright 2004 Arnaud Patard <arnaud.patard@rtp-net.org>
6  * Copyright 2008 Ben Dooks <ben-linux@fluff.org>
7  * Copyright 2009 Simtec Electronics <linux@simtec.co.uk>
8  *
9  * Additional work by Herbert Pötzl <herbert@13thfloor.at> and
10  * Harald Welte <laforge@openmoko.org>
11  */
12 
13 #include <linux/errno.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/gpio.h>
17 #include <linux/input.h>
18 #include <linux/delay.h>
19 #include <linux/interrupt.h>
20 #include <linux/platform_device.h>
21 #include <linux/clk.h>
22 #include <linux/io.h>
23 
24 #include <plat/adc.h>
25 #include <plat/regs-adc.h>
26 #include <linux/platform_data/touchscreen-s3c2410.h>
27 
28 #define TSC_SLEEP  (S3C2410_ADCTSC_PULL_UP_DISABLE | S3C2410_ADCTSC_XY_PST(0))
29 
30 #define INT_DOWN	(0)
31 #define INT_UP		(1 << 8)
32 
33 #define WAIT4INT	(S3C2410_ADCTSC_YM_SEN | \
34 			 S3C2410_ADCTSC_YP_SEN | \
35 			 S3C2410_ADCTSC_XP_SEN | \
36 			 S3C2410_ADCTSC_XY_PST(3))
37 
38 #define AUTOPST		(S3C2410_ADCTSC_YM_SEN | \
39 			 S3C2410_ADCTSC_YP_SEN | \
40 			 S3C2410_ADCTSC_XP_SEN | \
41 			 S3C2410_ADCTSC_AUTO_PST | \
42 			 S3C2410_ADCTSC_XY_PST(0))
43 
44 #define FEAT_PEN_IRQ	(1 << 0)	/* HAS ADCCLRINTPNDNUP */
45 
46 /* Per-touchscreen data. */
47 
48 /**
49  * struct s3c2410ts - driver touchscreen state.
50  * @client: The ADC client we registered with the core driver.
51  * @dev: The device we are bound to.
52  * @input: The input device we registered with the input subsystem.
53  * @clock: The clock for the adc.
54  * @io: Pointer to the IO base.
55  * @xp: The accumulated X position data.
56  * @yp: The accumulated Y position data.
57  * @irq_tc: The interrupt number for pen up/down interrupt
58  * @count: The number of samples collected.
59  * @shift: The log2 of the maximum count to read in one go.
60  * @features: The features supported by the TSADC MOdule.
61  */
62 struct s3c2410ts {
63 	struct s3c_adc_client *client;
64 	struct device *dev;
65 	struct input_dev *input;
66 	struct clk *clock;
67 	void __iomem *io;
68 	unsigned long xp;
69 	unsigned long yp;
70 	int irq_tc;
71 	int count;
72 	int shift;
73 	int features;
74 };
75 
76 static struct s3c2410ts ts;
77 
78 /**
79  * get_down - return the down state of the pen
80  * @data0: The data read from ADCDAT0 register.
81  * @data1: The data read from ADCDAT1 register.
82  *
83  * Return non-zero if both readings show that the pen is down.
84  */
get_down(unsigned long data0,unsigned long data1)85 static inline bool get_down(unsigned long data0, unsigned long data1)
86 {
87 	/* returns true if both data values show stylus down */
88 	return (!(data0 & S3C2410_ADCDAT0_UPDOWN) &&
89 		!(data1 & S3C2410_ADCDAT0_UPDOWN));
90 }
91 
touch_timer_fire(struct timer_list * unused)92 static void touch_timer_fire(struct timer_list *unused)
93 {
94 	unsigned long data0;
95 	unsigned long data1;
96 	bool down;
97 
98 	data0 = readl(ts.io + S3C2410_ADCDAT0);
99 	data1 = readl(ts.io + S3C2410_ADCDAT1);
100 
101 	down = get_down(data0, data1);
102 
103 	if (down) {
104 		if (ts.count == (1 << ts.shift)) {
105 			ts.xp >>= ts.shift;
106 			ts.yp >>= ts.shift;
107 
108 			dev_dbg(ts.dev, "%s: X=%lu, Y=%lu, count=%d\n",
109 				__func__, ts.xp, ts.yp, ts.count);
110 
111 			input_report_abs(ts.input, ABS_X, ts.xp);
112 			input_report_abs(ts.input, ABS_Y, ts.yp);
113 
114 			input_report_key(ts.input, BTN_TOUCH, 1);
115 			input_sync(ts.input);
116 
117 			ts.xp = 0;
118 			ts.yp = 0;
119 			ts.count = 0;
120 		}
121 
122 		s3c_adc_start(ts.client, 0, 1 << ts.shift);
123 	} else {
124 		ts.xp = 0;
125 		ts.yp = 0;
126 		ts.count = 0;
127 
128 		input_report_key(ts.input, BTN_TOUCH, 0);
129 		input_sync(ts.input);
130 
131 		writel(WAIT4INT | INT_DOWN, ts.io + S3C2410_ADCTSC);
132 	}
133 }
134 
135 static DEFINE_TIMER(touch_timer, touch_timer_fire);
136 
137 /**
138  * stylus_irq - touchscreen stylus event interrupt
139  * @irq: The interrupt number
140  * @dev_id: The device ID.
141  *
142  * Called when the IRQ_TC is fired for a pen up or down event.
143  */
stylus_irq(int irq,void * dev_id)144 static irqreturn_t stylus_irq(int irq, void *dev_id)
145 {
146 	unsigned long data0;
147 	unsigned long data1;
148 	bool down;
149 
150 	data0 = readl(ts.io + S3C2410_ADCDAT0);
151 	data1 = readl(ts.io + S3C2410_ADCDAT1);
152 
153 	down = get_down(data0, data1);
154 
155 	/* TODO we should never get an interrupt with down set while
156 	 * the timer is running, but maybe we ought to verify that the
157 	 * timer isn't running anyways. */
158 
159 	if (down)
160 		s3c_adc_start(ts.client, 0, 1 << ts.shift);
161 	else
162 		dev_dbg(ts.dev, "%s: count=%d\n", __func__, ts.count);
163 
164 	if (ts.features & FEAT_PEN_IRQ) {
165 		/* Clear pen down/up interrupt */
166 		writel(0x0, ts.io + S3C64XX_ADCCLRINTPNDNUP);
167 	}
168 
169 	return IRQ_HANDLED;
170 }
171 
172 /**
173  * s3c24xx_ts_conversion - ADC conversion callback
174  * @client: The client that was registered with the ADC core.
175  * @data0: The reading from ADCDAT0.
176  * @data1: The reading from ADCDAT1.
177  * @left: The number of samples left.
178  *
179  * Called when a conversion has finished.
180  */
s3c24xx_ts_conversion(struct s3c_adc_client * client,unsigned data0,unsigned data1,unsigned * left)181 static void s3c24xx_ts_conversion(struct s3c_adc_client *client,
182 				  unsigned data0, unsigned data1,
183 				  unsigned *left)
184 {
185 	dev_dbg(ts.dev, "%s: %d,%d\n", __func__, data0, data1);
186 
187 	ts.xp += data0;
188 	ts.yp += data1;
189 
190 	ts.count++;
191 
192 	/* From tests, it seems that it is unlikely to get a pen-up
193 	 * event during the conversion process which means we can
194 	 * ignore any pen-up events with less than the requisite
195 	 * count done.
196 	 *
197 	 * In several thousand conversions, no pen-ups where detected
198 	 * before count completed.
199 	 */
200 }
201 
202 /**
203  * s3c24xx_ts_select - ADC selection callback.
204  * @client: The client that was registered with the ADC core.
205  * @select: The reason for select.
206  *
207  * Called when the ADC core selects (or deslects) us as a client.
208  */
s3c24xx_ts_select(struct s3c_adc_client * client,unsigned select)209 static void s3c24xx_ts_select(struct s3c_adc_client *client, unsigned select)
210 {
211 	if (select) {
212 		writel(S3C2410_ADCTSC_PULL_UP_DISABLE | AUTOPST,
213 		       ts.io + S3C2410_ADCTSC);
214 	} else {
215 		mod_timer(&touch_timer, jiffies+1);
216 		writel(WAIT4INT | INT_UP, ts.io + S3C2410_ADCTSC);
217 	}
218 }
219 
220 /**
221  * s3c2410ts_probe - device core probe entry point
222  * @pdev: The device we are being bound to.
223  *
224  * Initialise, find and allocate any resources we need to run and then
225  * register with the ADC and input systems.
226  */
s3c2410ts_probe(struct platform_device * pdev)227 static int s3c2410ts_probe(struct platform_device *pdev)
228 {
229 	struct s3c2410_ts_mach_info *info;
230 	struct device *dev = &pdev->dev;
231 	struct input_dev *input_dev;
232 	struct resource *res;
233 	int ret = -EINVAL;
234 
235 	/* Initialise input stuff */
236 	memset(&ts, 0, sizeof(struct s3c2410ts));
237 
238 	ts.dev = dev;
239 
240 	info = dev_get_platdata(dev);
241 	if (!info) {
242 		dev_err(dev, "no platform data, cannot attach\n");
243 		return -EINVAL;
244 	}
245 
246 	dev_dbg(dev, "initialising touchscreen\n");
247 
248 	ts.clock = clk_get(dev, "adc");
249 	if (IS_ERR(ts.clock)) {
250 		dev_err(dev, "cannot get adc clock source\n");
251 		return -ENOENT;
252 	}
253 
254 	ret = clk_prepare_enable(ts.clock);
255 	if (ret) {
256 		dev_err(dev, "Failed! to enabled clocks\n");
257 		goto err_clk_get;
258 	}
259 	dev_dbg(dev, "got and enabled clocks\n");
260 
261 	ts.irq_tc = ret = platform_get_irq(pdev, 0);
262 	if (ret < 0) {
263 		dev_err(dev, "no resource for interrupt\n");
264 		goto err_clk;
265 	}
266 
267 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
268 	if (!res) {
269 		dev_err(dev, "no resource for registers\n");
270 		ret = -ENOENT;
271 		goto err_clk;
272 	}
273 
274 	ts.io = ioremap(res->start, resource_size(res));
275 	if (ts.io == NULL) {
276 		dev_err(dev, "cannot map registers\n");
277 		ret = -ENOMEM;
278 		goto err_clk;
279 	}
280 
281 	/* inititalise the gpio */
282 	if (info->cfg_gpio)
283 		info->cfg_gpio(to_platform_device(ts.dev));
284 
285 	ts.client = s3c_adc_register(pdev, s3c24xx_ts_select,
286 				     s3c24xx_ts_conversion, 1);
287 	if (IS_ERR(ts.client)) {
288 		dev_err(dev, "failed to register adc client\n");
289 		ret = PTR_ERR(ts.client);
290 		goto err_iomap;
291 	}
292 
293 	/* Initialise registers */
294 	if ((info->delay & 0xffff) > 0)
295 		writel(info->delay & 0xffff, ts.io + S3C2410_ADCDLY);
296 
297 	writel(WAIT4INT | INT_DOWN, ts.io + S3C2410_ADCTSC);
298 
299 	input_dev = input_allocate_device();
300 	if (!input_dev) {
301 		dev_err(dev, "Unable to allocate the input device !!\n");
302 		ret = -ENOMEM;
303 		goto err_iomap;
304 	}
305 
306 	ts.input = input_dev;
307 	ts.input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
308 	ts.input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
309 	input_set_abs_params(ts.input, ABS_X, 0, 0x3FF, 0, 0);
310 	input_set_abs_params(ts.input, ABS_Y, 0, 0x3FF, 0, 0);
311 
312 	ts.input->name = "S3C24XX TouchScreen";
313 	ts.input->id.bustype = BUS_HOST;
314 	ts.input->id.vendor = 0xDEAD;
315 	ts.input->id.product = 0xBEEF;
316 	ts.input->id.version = 0x0102;
317 
318 	ts.shift = info->oversampling_shift;
319 	ts.features = platform_get_device_id(pdev)->driver_data;
320 
321 	ret = request_irq(ts.irq_tc, stylus_irq, 0,
322 			  "s3c2410_ts_pen", ts.input);
323 	if (ret) {
324 		dev_err(dev, "cannot get TC interrupt\n");
325 		goto err_inputdev;
326 	}
327 
328 	dev_info(dev, "driver attached, registering input device\n");
329 
330 	/* All went ok, so register to the input system */
331 	ret = input_register_device(ts.input);
332 	if (ret < 0) {
333 		dev_err(dev, "failed to register input device\n");
334 		ret = -EIO;
335 		goto err_tcirq;
336 	}
337 
338 	return 0;
339 
340  err_tcirq:
341 	free_irq(ts.irq_tc, ts.input);
342  err_inputdev:
343 	input_free_device(ts.input);
344  err_iomap:
345 	iounmap(ts.io);
346  err_clk:
347 	clk_disable_unprepare(ts.clock);
348 	del_timer_sync(&touch_timer);
349  err_clk_get:
350 	clk_put(ts.clock);
351 	return ret;
352 }
353 
354 /**
355  * s3c2410ts_remove - device core removal entry point
356  * @pdev: The device we are being removed from.
357  *
358  * Free up our state ready to be removed.
359  */
s3c2410ts_remove(struct platform_device * pdev)360 static int s3c2410ts_remove(struct platform_device *pdev)
361 {
362 	free_irq(ts.irq_tc, ts.input);
363 	del_timer_sync(&touch_timer);
364 
365 	clk_disable_unprepare(ts.clock);
366 	clk_put(ts.clock);
367 
368 	input_unregister_device(ts.input);
369 	iounmap(ts.io);
370 
371 	return 0;
372 }
373 
374 #ifdef CONFIG_PM
s3c2410ts_suspend(struct device * dev)375 static int s3c2410ts_suspend(struct device *dev)
376 {
377 	writel(TSC_SLEEP, ts.io + S3C2410_ADCTSC);
378 	disable_irq(ts.irq_tc);
379 	clk_disable(ts.clock);
380 
381 	return 0;
382 }
383 
s3c2410ts_resume(struct device * dev)384 static int s3c2410ts_resume(struct device *dev)
385 {
386 	struct platform_device *pdev = to_platform_device(dev);
387 	struct s3c2410_ts_mach_info *info = dev_get_platdata(&pdev->dev);
388 
389 	clk_enable(ts.clock);
390 	enable_irq(ts.irq_tc);
391 
392 	/* Initialise registers */
393 	if ((info->delay & 0xffff) > 0)
394 		writel(info->delay & 0xffff, ts.io + S3C2410_ADCDLY);
395 
396 	writel(WAIT4INT | INT_DOWN, ts.io + S3C2410_ADCTSC);
397 
398 	return 0;
399 }
400 
401 static const struct dev_pm_ops s3c_ts_pmops = {
402 	.suspend	= s3c2410ts_suspend,
403 	.resume		= s3c2410ts_resume,
404 };
405 #endif
406 
407 static const struct platform_device_id s3cts_driver_ids[] = {
408 	{ "s3c2410-ts", 0 },
409 	{ "s3c2440-ts", 0 },
410 	{ "s3c64xx-ts", FEAT_PEN_IRQ },
411 	{ }
412 };
413 MODULE_DEVICE_TABLE(platform, s3cts_driver_ids);
414 
415 static struct platform_driver s3c_ts_driver = {
416 	.driver         = {
417 		.name   = "samsung-ts",
418 #ifdef CONFIG_PM
419 		.pm	= &s3c_ts_pmops,
420 #endif
421 	},
422 	.id_table	= s3cts_driver_ids,
423 	.probe		= s3c2410ts_probe,
424 	.remove		= s3c2410ts_remove,
425 };
426 module_platform_driver(s3c_ts_driver);
427 
428 MODULE_AUTHOR("Arnaud Patard <arnaud.patard@rtp-net.org>, "
429 	      "Ben Dooks <ben@simtec.co.uk>, "
430 	      "Simtec Electronics <linux@simtec.co.uk>");
431 MODULE_DESCRIPTION("S3C24XX Touchscreen driver");
432 MODULE_LICENSE("GPL v2");
433