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