1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * LPC32xx built-in touchscreen driver
4 *
5 * Copyright (C) 2010 NXP Semiconductors
6 */
7
8 #include <linux/platform_device.h>
9 #include <linux/input.h>
10 #include <linux/interrupt.h>
11 #include <linux/module.h>
12 #include <linux/clk.h>
13 #include <linux/io.h>
14 #include <linux/slab.h>
15 #include <linux/of.h>
16
17 /*
18 * Touchscreen controller register offsets
19 */
20 #define LPC32XX_TSC_STAT 0x00
21 #define LPC32XX_TSC_SEL 0x04
22 #define LPC32XX_TSC_CON 0x08
23 #define LPC32XX_TSC_FIFO 0x0C
24 #define LPC32XX_TSC_DTR 0x10
25 #define LPC32XX_TSC_RTR 0x14
26 #define LPC32XX_TSC_UTR 0x18
27 #define LPC32XX_TSC_TTR 0x1C
28 #define LPC32XX_TSC_DXP 0x20
29 #define LPC32XX_TSC_MIN_X 0x24
30 #define LPC32XX_TSC_MAX_X 0x28
31 #define LPC32XX_TSC_MIN_Y 0x2C
32 #define LPC32XX_TSC_MAX_Y 0x30
33 #define LPC32XX_TSC_AUX_UTR 0x34
34 #define LPC32XX_TSC_AUX_MIN 0x38
35 #define LPC32XX_TSC_AUX_MAX 0x3C
36
37 #define LPC32XX_TSC_STAT_FIFO_OVRRN (1 << 8)
38 #define LPC32XX_TSC_STAT_FIFO_EMPTY (1 << 7)
39
40 #define LPC32XX_TSC_SEL_DEFVAL 0x0284
41
42 #define LPC32XX_TSC_ADCCON_IRQ_TO_FIFO_4 (0x1 << 11)
43 #define LPC32XX_TSC_ADCCON_X_SAMPLE_SIZE(s) ((10 - (s)) << 7)
44 #define LPC32XX_TSC_ADCCON_Y_SAMPLE_SIZE(s) ((10 - (s)) << 4)
45 #define LPC32XX_TSC_ADCCON_POWER_UP (1 << 2)
46 #define LPC32XX_TSC_ADCCON_AUTO_EN (1 << 0)
47
48 #define LPC32XX_TSC_FIFO_TS_P_LEVEL (1 << 31)
49 #define LPC32XX_TSC_FIFO_NORMALIZE_X_VAL(x) (((x) & 0x03FF0000) >> 16)
50 #define LPC32XX_TSC_FIFO_NORMALIZE_Y_VAL(y) ((y) & 0x000003FF)
51
52 #define LPC32XX_TSC_ADCDAT_VALUE_MASK 0x000003FF
53
54 #define LPC32XX_TSC_MIN_XY_VAL 0x0
55 #define LPC32XX_TSC_MAX_XY_VAL 0x3FF
56
57 #define MOD_NAME "ts-lpc32xx"
58
59 #define tsc_readl(dev, reg) \
60 __raw_readl((dev)->tsc_base + (reg))
61 #define tsc_writel(dev, reg, val) \
62 __raw_writel((val), (dev)->tsc_base + (reg))
63
64 struct lpc32xx_tsc {
65 struct input_dev *dev;
66 void __iomem *tsc_base;
67 int irq;
68 struct clk *clk;
69 };
70
lpc32xx_fifo_clear(struct lpc32xx_tsc * tsc)71 static void lpc32xx_fifo_clear(struct lpc32xx_tsc *tsc)
72 {
73 while (!(tsc_readl(tsc, LPC32XX_TSC_STAT) &
74 LPC32XX_TSC_STAT_FIFO_EMPTY))
75 tsc_readl(tsc, LPC32XX_TSC_FIFO);
76 }
77
lpc32xx_ts_interrupt(int irq,void * dev_id)78 static irqreturn_t lpc32xx_ts_interrupt(int irq, void *dev_id)
79 {
80 u32 tmp, rv[4], xs[4], ys[4];
81 int idx;
82 struct lpc32xx_tsc *tsc = dev_id;
83 struct input_dev *input = tsc->dev;
84
85 tmp = tsc_readl(tsc, LPC32XX_TSC_STAT);
86
87 if (tmp & LPC32XX_TSC_STAT_FIFO_OVRRN) {
88 /* FIFO overflow - throw away samples */
89 lpc32xx_fifo_clear(tsc);
90 return IRQ_HANDLED;
91 }
92
93 /*
94 * Gather and normalize 4 samples. Pen-up events may have less
95 * than 4 samples, but its ok to pop 4 and let the last sample
96 * pen status check drop the samples.
97 */
98 idx = 0;
99 while (idx < 4 &&
100 !(tsc_readl(tsc, LPC32XX_TSC_STAT) &
101 LPC32XX_TSC_STAT_FIFO_EMPTY)) {
102 tmp = tsc_readl(tsc, LPC32XX_TSC_FIFO);
103 xs[idx] = LPC32XX_TSC_ADCDAT_VALUE_MASK -
104 LPC32XX_TSC_FIFO_NORMALIZE_X_VAL(tmp);
105 ys[idx] = LPC32XX_TSC_ADCDAT_VALUE_MASK -
106 LPC32XX_TSC_FIFO_NORMALIZE_Y_VAL(tmp);
107 rv[idx] = tmp;
108 idx++;
109 }
110
111 /* Data is only valid if pen is still down in last sample */
112 if (!(rv[3] & LPC32XX_TSC_FIFO_TS_P_LEVEL) && idx == 4) {
113 /* Use average of 2nd and 3rd sample for position */
114 input_report_abs(input, ABS_X, (xs[1] + xs[2]) / 2);
115 input_report_abs(input, ABS_Y, (ys[1] + ys[2]) / 2);
116 input_report_key(input, BTN_TOUCH, 1);
117 } else {
118 input_report_key(input, BTN_TOUCH, 0);
119 }
120
121 input_sync(input);
122
123 return IRQ_HANDLED;
124 }
125
lpc32xx_stop_tsc(struct lpc32xx_tsc * tsc)126 static void lpc32xx_stop_tsc(struct lpc32xx_tsc *tsc)
127 {
128 /* Disable auto mode */
129 tsc_writel(tsc, LPC32XX_TSC_CON,
130 tsc_readl(tsc, LPC32XX_TSC_CON) &
131 ~LPC32XX_TSC_ADCCON_AUTO_EN);
132
133 clk_disable_unprepare(tsc->clk);
134 }
135
lpc32xx_setup_tsc(struct lpc32xx_tsc * tsc)136 static int lpc32xx_setup_tsc(struct lpc32xx_tsc *tsc)
137 {
138 u32 tmp;
139 int err;
140
141 err = clk_prepare_enable(tsc->clk);
142 if (err)
143 return err;
144
145 tmp = tsc_readl(tsc, LPC32XX_TSC_CON) & ~LPC32XX_TSC_ADCCON_POWER_UP;
146
147 /* Set the TSC FIFO depth to 4 samples @ 10-bits per sample (max) */
148 tmp = LPC32XX_TSC_ADCCON_IRQ_TO_FIFO_4 |
149 LPC32XX_TSC_ADCCON_X_SAMPLE_SIZE(10) |
150 LPC32XX_TSC_ADCCON_Y_SAMPLE_SIZE(10);
151 tsc_writel(tsc, LPC32XX_TSC_CON, tmp);
152
153 /* These values are all preset */
154 tsc_writel(tsc, LPC32XX_TSC_SEL, LPC32XX_TSC_SEL_DEFVAL);
155 tsc_writel(tsc, LPC32XX_TSC_MIN_X, LPC32XX_TSC_MIN_XY_VAL);
156 tsc_writel(tsc, LPC32XX_TSC_MAX_X, LPC32XX_TSC_MAX_XY_VAL);
157 tsc_writel(tsc, LPC32XX_TSC_MIN_Y, LPC32XX_TSC_MIN_XY_VAL);
158 tsc_writel(tsc, LPC32XX_TSC_MAX_Y, LPC32XX_TSC_MAX_XY_VAL);
159
160 /* Aux support is not used */
161 tsc_writel(tsc, LPC32XX_TSC_AUX_UTR, 0);
162 tsc_writel(tsc, LPC32XX_TSC_AUX_MIN, 0);
163 tsc_writel(tsc, LPC32XX_TSC_AUX_MAX, 0);
164
165 /*
166 * Set sample rate to about 240Hz per X/Y pair. A single measurement
167 * consists of 4 pairs which gives about a 60Hz sample rate based on
168 * a stable 32768Hz clock source. Values are in clocks.
169 * Rate is (32768 / (RTR + XCONV + RTR + YCONV + DXP + TTR + UTR) / 4
170 */
171 tsc_writel(tsc, LPC32XX_TSC_RTR, 0x2);
172 tsc_writel(tsc, LPC32XX_TSC_DTR, 0x2);
173 tsc_writel(tsc, LPC32XX_TSC_TTR, 0x10);
174 tsc_writel(tsc, LPC32XX_TSC_DXP, 0x4);
175 tsc_writel(tsc, LPC32XX_TSC_UTR, 88);
176
177 lpc32xx_fifo_clear(tsc);
178
179 /* Enable automatic ts event capture */
180 tsc_writel(tsc, LPC32XX_TSC_CON, tmp | LPC32XX_TSC_ADCCON_AUTO_EN);
181
182 return 0;
183 }
184
lpc32xx_ts_open(struct input_dev * dev)185 static int lpc32xx_ts_open(struct input_dev *dev)
186 {
187 struct lpc32xx_tsc *tsc = input_get_drvdata(dev);
188
189 return lpc32xx_setup_tsc(tsc);
190 }
191
lpc32xx_ts_close(struct input_dev * dev)192 static void lpc32xx_ts_close(struct input_dev *dev)
193 {
194 struct lpc32xx_tsc *tsc = input_get_drvdata(dev);
195
196 lpc32xx_stop_tsc(tsc);
197 }
198
lpc32xx_ts_probe(struct platform_device * pdev)199 static int lpc32xx_ts_probe(struct platform_device *pdev)
200 {
201 struct lpc32xx_tsc *tsc;
202 struct input_dev *input;
203 struct resource *res;
204 resource_size_t size;
205 int irq;
206 int error;
207
208 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
209 if (!res) {
210 dev_err(&pdev->dev, "Can't get memory resource\n");
211 return -ENOENT;
212 }
213
214 irq = platform_get_irq(pdev, 0);
215 if (irq < 0)
216 return irq;
217
218 tsc = kzalloc(sizeof(*tsc), GFP_KERNEL);
219 input = input_allocate_device();
220 if (!tsc || !input) {
221 dev_err(&pdev->dev, "failed allocating memory\n");
222 error = -ENOMEM;
223 goto err_free_mem;
224 }
225
226 tsc->dev = input;
227 tsc->irq = irq;
228
229 size = resource_size(res);
230
231 if (!request_mem_region(res->start, size, pdev->name)) {
232 dev_err(&pdev->dev, "TSC registers are not free\n");
233 error = -EBUSY;
234 goto err_free_mem;
235 }
236
237 tsc->tsc_base = ioremap(res->start, size);
238 if (!tsc->tsc_base) {
239 dev_err(&pdev->dev, "Can't map memory\n");
240 error = -ENOMEM;
241 goto err_release_mem;
242 }
243
244 tsc->clk = clk_get(&pdev->dev, NULL);
245 if (IS_ERR(tsc->clk)) {
246 dev_err(&pdev->dev, "failed getting clock\n");
247 error = PTR_ERR(tsc->clk);
248 goto err_unmap;
249 }
250
251 input->name = MOD_NAME;
252 input->phys = "lpc32xx/input0";
253 input->id.bustype = BUS_HOST;
254 input->id.vendor = 0x0001;
255 input->id.product = 0x0002;
256 input->id.version = 0x0100;
257 input->dev.parent = &pdev->dev;
258 input->open = lpc32xx_ts_open;
259 input->close = lpc32xx_ts_close;
260
261 input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
262 input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
263 input_set_abs_params(input, ABS_X, LPC32XX_TSC_MIN_XY_VAL,
264 LPC32XX_TSC_MAX_XY_VAL, 0, 0);
265 input_set_abs_params(input, ABS_Y, LPC32XX_TSC_MIN_XY_VAL,
266 LPC32XX_TSC_MAX_XY_VAL, 0, 0);
267
268 input_set_drvdata(input, tsc);
269
270 error = request_irq(tsc->irq, lpc32xx_ts_interrupt,
271 0, pdev->name, tsc);
272 if (error) {
273 dev_err(&pdev->dev, "failed requesting interrupt\n");
274 goto err_put_clock;
275 }
276
277 error = input_register_device(input);
278 if (error) {
279 dev_err(&pdev->dev, "failed registering input device\n");
280 goto err_free_irq;
281 }
282
283 platform_set_drvdata(pdev, tsc);
284 device_init_wakeup(&pdev->dev, 1);
285
286 return 0;
287
288 err_free_irq:
289 free_irq(tsc->irq, tsc);
290 err_put_clock:
291 clk_put(tsc->clk);
292 err_unmap:
293 iounmap(tsc->tsc_base);
294 err_release_mem:
295 release_mem_region(res->start, size);
296 err_free_mem:
297 input_free_device(input);
298 kfree(tsc);
299
300 return error;
301 }
302
lpc32xx_ts_remove(struct platform_device * pdev)303 static int lpc32xx_ts_remove(struct platform_device *pdev)
304 {
305 struct lpc32xx_tsc *tsc = platform_get_drvdata(pdev);
306 struct resource *res;
307
308 free_irq(tsc->irq, tsc);
309
310 input_unregister_device(tsc->dev);
311
312 clk_put(tsc->clk);
313
314 iounmap(tsc->tsc_base);
315 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
316 release_mem_region(res->start, resource_size(res));
317
318 kfree(tsc);
319
320 return 0;
321 }
322
323 #ifdef CONFIG_PM
lpc32xx_ts_suspend(struct device * dev)324 static int lpc32xx_ts_suspend(struct device *dev)
325 {
326 struct lpc32xx_tsc *tsc = dev_get_drvdata(dev);
327 struct input_dev *input = tsc->dev;
328
329 /*
330 * Suspend and resume can be called when the device hasn't been
331 * enabled. If there are no users that have the device open, then
332 * avoid calling the TSC stop and start functions as the TSC
333 * isn't yet clocked.
334 */
335 mutex_lock(&input->mutex);
336
337 if (input->users) {
338 if (device_may_wakeup(dev))
339 enable_irq_wake(tsc->irq);
340 else
341 lpc32xx_stop_tsc(tsc);
342 }
343
344 mutex_unlock(&input->mutex);
345
346 return 0;
347 }
348
lpc32xx_ts_resume(struct device * dev)349 static int lpc32xx_ts_resume(struct device *dev)
350 {
351 struct lpc32xx_tsc *tsc = dev_get_drvdata(dev);
352 struct input_dev *input = tsc->dev;
353
354 mutex_lock(&input->mutex);
355
356 if (input->users) {
357 if (device_may_wakeup(dev))
358 disable_irq_wake(tsc->irq);
359 else
360 lpc32xx_setup_tsc(tsc);
361 }
362
363 mutex_unlock(&input->mutex);
364
365 return 0;
366 }
367
368 static const struct dev_pm_ops lpc32xx_ts_pm_ops = {
369 .suspend = lpc32xx_ts_suspend,
370 .resume = lpc32xx_ts_resume,
371 };
372 #define LPC32XX_TS_PM_OPS (&lpc32xx_ts_pm_ops)
373 #else
374 #define LPC32XX_TS_PM_OPS NULL
375 #endif
376
377 #ifdef CONFIG_OF
378 static const struct of_device_id lpc32xx_tsc_of_match[] = {
379 { .compatible = "nxp,lpc3220-tsc", },
380 { },
381 };
382 MODULE_DEVICE_TABLE(of, lpc32xx_tsc_of_match);
383 #endif
384
385 static struct platform_driver lpc32xx_ts_driver = {
386 .probe = lpc32xx_ts_probe,
387 .remove = lpc32xx_ts_remove,
388 .driver = {
389 .name = MOD_NAME,
390 .pm = LPC32XX_TS_PM_OPS,
391 .of_match_table = of_match_ptr(lpc32xx_tsc_of_match),
392 },
393 };
394 module_platform_driver(lpc32xx_ts_driver);
395
396 MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com");
397 MODULE_DESCRIPTION("LPC32XX TSC Driver");
398 MODULE_LICENSE("GPL");
399 MODULE_ALIAS("platform:lpc32xx_ts");
400
