1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * STMicroelectronics STMPE811 Touchscreen Driver
4 *
5 * (C) 2010 Luotao Fu <l.fu@pengutronix.de>
6 * All rights reserved.
7 */
8
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/sched.h>
12 #include <linux/interrupt.h>
13 #include <linux/device.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/input.h>
17 #include <linux/input/touchscreen.h>
18 #include <linux/slab.h>
19 #include <linux/delay.h>
20 #include <linux/i2c.h>
21 #include <linux/workqueue.h>
22
23 #include <linux/mfd/stmpe.h>
24
25 /* Register layouts and functionalities are identical on all stmpexxx variants
26 * with touchscreen controller
27 */
28 #define STMPE_REG_INT_STA 0x0B
29 #define STMPE_REG_TSC_CTRL 0x40
30 #define STMPE_REG_TSC_CFG 0x41
31 #define STMPE_REG_FIFO_TH 0x4A
32 #define STMPE_REG_FIFO_STA 0x4B
33 #define STMPE_REG_FIFO_SIZE 0x4C
34 #define STMPE_REG_TSC_DATA_XYZ 0x52
35 #define STMPE_REG_TSC_FRACTION_Z 0x56
36 #define STMPE_REG_TSC_I_DRIVE 0x58
37
38 #define OP_MOD_XYZ 0
39
40 #define STMPE_TSC_CTRL_TSC_EN (1<<0)
41
42 #define STMPE_FIFO_STA_RESET (1<<0)
43
44 #define STMPE_IRQ_TOUCH_DET 0
45
46 #define STMPE_TS_NAME "stmpe-ts"
47 #define XY_MASK 0xfff
48
49 /**
50 * struct stmpe_touch - stmpe811 touch screen controller state
51 * @stmpe: pointer back to STMPE MFD container
52 * @idev: registered input device
53 * @work: a work item used to scan the device
54 * @dev: a pointer back to the MFD cell struct device*
55 * @prop: Touchscreen properties
56 * @ave_ctrl: Sample average control
57 * (0 -> 1 sample, 1 -> 2 samples, 2 -> 4 samples, 3 -> 8 samples)
58 * @touch_det_delay: Touch detect interrupt delay
59 * (0 -> 10 us, 1 -> 50 us, 2 -> 100 us, 3 -> 500 us,
60 * 4-> 1 ms, 5 -> 5 ms, 6 -> 10 ms, 7 -> 50 ms)
61 * recommended is 3
62 * @settling: Panel driver settling time
63 * (0 -> 10 us, 1 -> 100 us, 2 -> 500 us, 3 -> 1 ms,
64 * 4 -> 5 ms, 5 -> 10 ms, 6 for 50 ms, 7 -> 100 ms)
65 * recommended is 2
66 * @fraction_z: Length of the fractional part in z
67 * (fraction_z ([0..7]) = Count of the fractional part)
68 * recommended is 7
69 * @i_drive: current limit value of the touchscreen drivers
70 * (0 -> 20 mA typical 35 mA max, 1 -> 50 mA typical 80 mA max)
71 */
72 struct stmpe_touch {
73 struct stmpe *stmpe;
74 struct input_dev *idev;
75 struct delayed_work work;
76 struct device *dev;
77 struct touchscreen_properties prop;
78 u8 ave_ctrl;
79 u8 touch_det_delay;
80 u8 settling;
81 u8 fraction_z;
82 u8 i_drive;
83 };
84
__stmpe_reset_fifo(struct stmpe * stmpe)85 static int __stmpe_reset_fifo(struct stmpe *stmpe)
86 {
87 int ret;
88
89 ret = stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
90 STMPE_FIFO_STA_RESET, STMPE_FIFO_STA_RESET);
91 if (ret)
92 return ret;
93
94 return stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
95 STMPE_FIFO_STA_RESET, 0);
96 }
97
stmpe_work(struct work_struct * work)98 static void stmpe_work(struct work_struct *work)
99 {
100 int int_sta;
101 u32 timeout = 40;
102
103 struct stmpe_touch *ts =
104 container_of(work, struct stmpe_touch, work.work);
105
106 int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
107
108 /*
109 * touch_det sometimes get desasserted or just get stuck. This appears
110 * to be a silicon bug, We still have to clearify this with the
111 * manufacture. As a workaround We release the key anyway if the
112 * touch_det keeps coming in after 4ms, while the FIFO contains no value
113 * during the whole time.
114 */
115 while ((int_sta & (1 << STMPE_IRQ_TOUCH_DET)) && (timeout > 0)) {
116 timeout--;
117 int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
118 udelay(100);
119 }
120
121 /* reset the FIFO before we report release event */
122 __stmpe_reset_fifo(ts->stmpe);
123
124 input_report_abs(ts->idev, ABS_PRESSURE, 0);
125 input_report_key(ts->idev, BTN_TOUCH, 0);
126 input_sync(ts->idev);
127 }
128
stmpe_ts_handler(int irq,void * data)129 static irqreturn_t stmpe_ts_handler(int irq, void *data)
130 {
131 u8 data_set[4];
132 int x, y, z;
133 struct stmpe_touch *ts = data;
134
135 /*
136 * Cancel scheduled polling for release if we have new value
137 * available. Wait if the polling is already running.
138 */
139 cancel_delayed_work_sync(&ts->work);
140
141 /*
142 * The FIFO sometimes just crashes and stops generating interrupts. This
143 * appears to be a silicon bug. We still have to clearify this with
144 * the manufacture. As a workaround we disable the TSC while we are
145 * collecting data and flush the FIFO after reading
146 */
147 stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
148 STMPE_TSC_CTRL_TSC_EN, 0);
149
150 stmpe_block_read(ts->stmpe, STMPE_REG_TSC_DATA_XYZ, 4, data_set);
151
152 x = (data_set[0] << 4) | (data_set[1] >> 4);
153 y = ((data_set[1] & 0xf) << 8) | data_set[2];
154 z = data_set[3];
155
156 touchscreen_report_pos(ts->idev, &ts->prop, x, y, false);
157 input_report_abs(ts->idev, ABS_PRESSURE, z);
158 input_report_key(ts->idev, BTN_TOUCH, 1);
159 input_sync(ts->idev);
160
161 /* flush the FIFO after we have read out our values. */
162 __stmpe_reset_fifo(ts->stmpe);
163
164 /* reenable the tsc */
165 stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
166 STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
167
168 /* start polling for touch_det to detect release */
169 schedule_delayed_work(&ts->work, msecs_to_jiffies(50));
170
171 return IRQ_HANDLED;
172 }
173
stmpe_init_hw(struct stmpe_touch * ts)174 static int stmpe_init_hw(struct stmpe_touch *ts)
175 {
176 int ret;
177 u8 tsc_cfg, tsc_cfg_mask;
178 struct stmpe *stmpe = ts->stmpe;
179 struct device *dev = ts->dev;
180
181 ret = stmpe_enable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
182 if (ret) {
183 dev_err(dev, "Could not enable clock for ADC and TS\n");
184 return ret;
185 }
186
187 ret = stmpe811_adc_common_init(stmpe);
188 if (ret) {
189 stmpe_disable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
190 return ret;
191 }
192
193 tsc_cfg = STMPE_AVE_CTRL(ts->ave_ctrl) |
194 STMPE_DET_DELAY(ts->touch_det_delay) |
195 STMPE_SETTLING(ts->settling);
196 tsc_cfg_mask = STMPE_AVE_CTRL(0xff) | STMPE_DET_DELAY(0xff) |
197 STMPE_SETTLING(0xff);
198
199 ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CFG, tsc_cfg_mask, tsc_cfg);
200 if (ret) {
201 dev_err(dev, "Could not config touch\n");
202 return ret;
203 }
204
205 ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_FRACTION_Z,
206 STMPE_FRACTION_Z(0xff), STMPE_FRACTION_Z(ts->fraction_z));
207 if (ret) {
208 dev_err(dev, "Could not config touch\n");
209 return ret;
210 }
211
212 ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_I_DRIVE,
213 STMPE_I_DRIVE(0xff), STMPE_I_DRIVE(ts->i_drive));
214 if (ret) {
215 dev_err(dev, "Could not config touch\n");
216 return ret;
217 }
218
219 /* set FIFO to 1 for single point reading */
220 ret = stmpe_reg_write(stmpe, STMPE_REG_FIFO_TH, 1);
221 if (ret) {
222 dev_err(dev, "Could not set FIFO\n");
223 return ret;
224 }
225
226 ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CTRL,
227 STMPE_OP_MODE(0xff), STMPE_OP_MODE(OP_MOD_XYZ));
228 if (ret) {
229 dev_err(dev, "Could not set mode\n");
230 return ret;
231 }
232
233 return 0;
234 }
235
stmpe_ts_open(struct input_dev * dev)236 static int stmpe_ts_open(struct input_dev *dev)
237 {
238 struct stmpe_touch *ts = input_get_drvdata(dev);
239 int ret = 0;
240
241 ret = __stmpe_reset_fifo(ts->stmpe);
242 if (ret)
243 return ret;
244
245 return stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
246 STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
247 }
248
stmpe_ts_close(struct input_dev * dev)249 static void stmpe_ts_close(struct input_dev *dev)
250 {
251 struct stmpe_touch *ts = input_get_drvdata(dev);
252
253 cancel_delayed_work_sync(&ts->work);
254
255 stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
256 STMPE_TSC_CTRL_TSC_EN, 0);
257 }
258
stmpe_ts_get_platform_info(struct platform_device * pdev,struct stmpe_touch * ts)259 static void stmpe_ts_get_platform_info(struct platform_device *pdev,
260 struct stmpe_touch *ts)
261 {
262 struct device_node *np = pdev->dev.of_node;
263 u32 val;
264
265 if (np) {
266 if (!of_property_read_u32(np, "st,sample-time", &val))
267 ts->stmpe->sample_time = val;
268 if (!of_property_read_u32(np, "st,mod-12b", &val))
269 ts->stmpe->mod_12b = val;
270 if (!of_property_read_u32(np, "st,ref-sel", &val))
271 ts->stmpe->ref_sel = val;
272 if (!of_property_read_u32(np, "st,adc-freq", &val))
273 ts->stmpe->adc_freq = val;
274 if (!of_property_read_u32(np, "st,ave-ctrl", &val))
275 ts->ave_ctrl = val;
276 if (!of_property_read_u32(np, "st,touch-det-delay", &val))
277 ts->touch_det_delay = val;
278 if (!of_property_read_u32(np, "st,settling", &val))
279 ts->settling = val;
280 if (!of_property_read_u32(np, "st,fraction-z", &val))
281 ts->fraction_z = val;
282 if (!of_property_read_u32(np, "st,i-drive", &val))
283 ts->i_drive = val;
284 }
285 }
286
stmpe_input_probe(struct platform_device * pdev)287 static int stmpe_input_probe(struct platform_device *pdev)
288 {
289 struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
290 struct stmpe_touch *ts;
291 struct input_dev *idev;
292 int error;
293 int ts_irq;
294
295 ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");
296 if (ts_irq < 0)
297 return ts_irq;
298
299 ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
300 if (!ts)
301 return -ENOMEM;
302
303 idev = devm_input_allocate_device(&pdev->dev);
304 if (!idev)
305 return -ENOMEM;
306
307 platform_set_drvdata(pdev, ts);
308 ts->stmpe = stmpe;
309 ts->idev = idev;
310 ts->dev = &pdev->dev;
311
312 stmpe_ts_get_platform_info(pdev, ts);
313
314 INIT_DELAYED_WORK(&ts->work, stmpe_work);
315
316 error = devm_request_threaded_irq(&pdev->dev, ts_irq,
317 NULL, stmpe_ts_handler,
318 IRQF_ONESHOT, STMPE_TS_NAME, ts);
319 if (error) {
320 dev_err(&pdev->dev, "Failed to request IRQ %d\n", ts_irq);
321 return error;
322 }
323
324 error = stmpe_init_hw(ts);
325 if (error)
326 return error;
327
328 idev->name = STMPE_TS_NAME;
329 idev->phys = STMPE_TS_NAME"/input0";
330 idev->id.bustype = BUS_I2C;
331
332 idev->open = stmpe_ts_open;
333 idev->close = stmpe_ts_close;
334
335 input_set_drvdata(idev, ts);
336
337 input_set_capability(idev, EV_KEY, BTN_TOUCH);
338 input_set_abs_params(idev, ABS_X, 0, XY_MASK, 0, 0);
339 input_set_abs_params(idev, ABS_Y, 0, XY_MASK, 0, 0);
340 input_set_abs_params(idev, ABS_PRESSURE, 0x0, 0xff, 0, 0);
341
342 touchscreen_parse_properties(idev, false, &ts->prop);
343
344 error = input_register_device(idev);
345 if (error) {
346 dev_err(&pdev->dev, "Could not register input device\n");
347 return error;
348 }
349
350 return 0;
351 }
352
stmpe_ts_remove(struct platform_device * pdev)353 static int stmpe_ts_remove(struct platform_device *pdev)
354 {
355 struct stmpe_touch *ts = platform_get_drvdata(pdev);
356
357 stmpe_disable(ts->stmpe, STMPE_BLOCK_TOUCHSCREEN);
358
359 return 0;
360 }
361
362 static struct platform_driver stmpe_ts_driver = {
363 .driver = {
364 .name = STMPE_TS_NAME,
365 },
366 .probe = stmpe_input_probe,
367 .remove = stmpe_ts_remove,
368 };
369 module_platform_driver(stmpe_ts_driver);
370
371 static const struct of_device_id stmpe_ts_ids[] = {
372 { .compatible = "st,stmpe-ts", },
373 { },
374 };
375 MODULE_DEVICE_TABLE(of, stmpe_ts_ids);
376
377 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
378 MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
379 MODULE_LICENSE("GPL");
380