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Linux/drivers/input/touchscreen/stmpe-ts.c

  1 /*
  2  * STMicroelectronics STMPE811 Touchscreen Driver
  3  *
  4  * (C) 2010 Luotao Fu <l.fu@pengutronix.de>
  5  * All rights reserved.
  6  *
  7  *  This program is free software; you can redistribute  it and/or modify it
  8  *  under  the terms of  the GNU General  Public License as published by the
  9  *  Free Software Foundation;  either version 2 of the  License, or (at your
 10  *  option) any later version.
 11  *
 12  */
 13 
 14 #include <linux/kernel.h>
 15 #include <linux/module.h>
 16 #include <linux/sched.h>
 17 #include <linux/interrupt.h>
 18 #include <linux/device.h>
 19 #include <linux/of.h>
 20 #include <linux/platform_device.h>
 21 #include <linux/input.h>
 22 #include <linux/slab.h>
 23 #include <linux/delay.h>
 24 #include <linux/i2c.h>
 25 #include <linux/workqueue.h>
 26 
 27 #include <linux/mfd/stmpe.h>
 28 
 29 /* Register layouts and functionalities are identical on all stmpexxx variants
 30  * with touchscreen controller
 31  */
 32 #define STMPE_REG_INT_STA               0x0B
 33 #define STMPE_REG_ADC_CTRL1             0x20
 34 #define STMPE_REG_ADC_CTRL2             0x21
 35 #define STMPE_REG_TSC_CTRL              0x40
 36 #define STMPE_REG_TSC_CFG               0x41
 37 #define STMPE_REG_FIFO_TH               0x4A
 38 #define STMPE_REG_FIFO_STA              0x4B
 39 #define STMPE_REG_FIFO_SIZE             0x4C
 40 #define STMPE_REG_TSC_DATA_XYZ          0x52
 41 #define STMPE_REG_TSC_FRACTION_Z        0x56
 42 #define STMPE_REG_TSC_I_DRIVE           0x58
 43 
 44 #define OP_MOD_XYZ                      0
 45 
 46 #define STMPE_TSC_CTRL_TSC_EN           (1<<0)
 47 
 48 #define STMPE_FIFO_STA_RESET            (1<<0)
 49 
 50 #define STMPE_IRQ_TOUCH_DET             0
 51 
 52 #define SAMPLE_TIME(x)                  ((x & 0xf) << 4)
 53 #define MOD_12B(x)                      ((x & 0x1) << 3)
 54 #define REF_SEL(x)                      ((x & 0x1) << 1)
 55 #define ADC_FREQ(x)                     (x & 0x3)
 56 #define AVE_CTRL(x)                     ((x & 0x3) << 6)
 57 #define DET_DELAY(x)                    ((x & 0x7) << 3)
 58 #define SETTLING(x)                     (x & 0x7)
 59 #define FRACTION_Z(x)                   (x & 0x7)
 60 #define I_DRIVE(x)                      (x & 0x1)
 61 #define OP_MODE(x)                      ((x & 0x7) << 1)
 62 
 63 #define STMPE_TS_NAME                   "stmpe-ts"
 64 #define XY_MASK                         0xfff
 65 
 66 /**
 67  * struct stmpe_touch - stmpe811 touch screen controller state
 68  * @stmpe: pointer back to STMPE MFD container
 69  * @idev: registered input device
 70  * @work: a work item used to scan the device
 71  * @dev: a pointer back to the MFD cell struct device*
 72  * @sample_time: ADC converstion time in number of clock.
 73  * (0 -> 36 clocks, 1 -> 44 clocks, 2 -> 56 clocks, 3 -> 64 clocks,
 74  * 4 -> 80 clocks, 5 -> 96 clocks, 6 -> 144 clocks),
 75  * recommended is 4.
 76  * @mod_12b: ADC Bit mode (0 -> 10bit ADC, 1 -> 12bit ADC)
 77  * @ref_sel: ADC reference source
 78  * (0 -> internal reference, 1 -> external reference)
 79  * @adc_freq: ADC Clock speed
 80  * (0 -> 1.625 MHz, 1 -> 3.25 MHz, 2 || 3 -> 6.5 MHz)
 81  * @ave_ctrl: Sample average control
 82  * (0 -> 1 sample, 1 -> 2 samples, 2 -> 4 samples, 3 -> 8 samples)
 83  * @touch_det_delay: Touch detect interrupt delay
 84  * (0 -> 10 us, 1 -> 50 us, 2 -> 100 us, 3 -> 500 us,
 85  * 4-> 1 ms, 5 -> 5 ms, 6 -> 10 ms, 7 -> 50 ms)
 86  * recommended is 3
 87  * @settling: Panel driver settling time
 88  * (0 -> 10 us, 1 -> 100 us, 2 -> 500 us, 3 -> 1 ms,
 89  * 4 -> 5 ms, 5 -> 10 ms, 6 for 50 ms, 7 -> 100 ms)
 90  * recommended is 2
 91  * @fraction_z: Length of the fractional part in z
 92  * (fraction_z ([0..7]) = Count of the fractional part)
 93  * recommended is 7
 94  * @i_drive: current limit value of the touchscreen drivers
 95  * (0 -> 20 mA typical 35 mA max, 1 -> 50 mA typical 80 mA max)
 96  */
 97 struct stmpe_touch {
 98         struct stmpe *stmpe;
 99         struct input_dev *idev;
100         struct delayed_work work;
101         struct device *dev;
102         u8 sample_time;
103         u8 mod_12b;
104         u8 ref_sel;
105         u8 adc_freq;
106         u8 ave_ctrl;
107         u8 touch_det_delay;
108         u8 settling;
109         u8 fraction_z;
110         u8 i_drive;
111 };
112 
113 static int __stmpe_reset_fifo(struct stmpe *stmpe)
114 {
115         int ret;
116 
117         ret = stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
118                         STMPE_FIFO_STA_RESET, STMPE_FIFO_STA_RESET);
119         if (ret)
120                 return ret;
121 
122         return stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
123                         STMPE_FIFO_STA_RESET, 0);
124 }
125 
126 static void stmpe_work(struct work_struct *work)
127 {
128         int int_sta;
129         u32 timeout = 40;
130 
131         struct stmpe_touch *ts =
132             container_of(work, struct stmpe_touch, work.work);
133 
134         int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
135 
136         /*
137          * touch_det sometimes get desasserted or just get stuck. This appears
138          * to be a silicon bug, We still have to clearify this with the
139          * manufacture. As a workaround We release the key anyway if the
140          * touch_det keeps coming in after 4ms, while the FIFO contains no value
141          * during the whole time.
142          */
143         while ((int_sta & (1 << STMPE_IRQ_TOUCH_DET)) && (timeout > 0)) {
144                 timeout--;
145                 int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
146                 udelay(100);
147         }
148 
149         /* reset the FIFO before we report release event */
150         __stmpe_reset_fifo(ts->stmpe);
151 
152         input_report_abs(ts->idev, ABS_PRESSURE, 0);
153         input_report_key(ts->idev, BTN_TOUCH, 0);
154         input_sync(ts->idev);
155 }
156 
157 static irqreturn_t stmpe_ts_handler(int irq, void *data)
158 {
159         u8 data_set[4];
160         int x, y, z;
161         struct stmpe_touch *ts = data;
162 
163         /*
164          * Cancel scheduled polling for release if we have new value
165          * available. Wait if the polling is already running.
166          */
167         cancel_delayed_work_sync(&ts->work);
168 
169         /*
170          * The FIFO sometimes just crashes and stops generating interrupts. This
171          * appears to be a silicon bug. We still have to clearify this with
172          * the manufacture. As a workaround we disable the TSC while we are
173          * collecting data and flush the FIFO after reading
174          */
175         stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
176                                 STMPE_TSC_CTRL_TSC_EN, 0);
177 
178         stmpe_block_read(ts->stmpe, STMPE_REG_TSC_DATA_XYZ, 4, data_set);
179 
180         x = (data_set[0] << 4) | (data_set[1] >> 4);
181         y = ((data_set[1] & 0xf) << 8) | data_set[2];
182         z = data_set[3];
183 
184         input_report_abs(ts->idev, ABS_X, x);
185         input_report_abs(ts->idev, ABS_Y, y);
186         input_report_abs(ts->idev, ABS_PRESSURE, z);
187         input_report_key(ts->idev, BTN_TOUCH, 1);
188         input_sync(ts->idev);
189 
190        /* flush the FIFO after we have read out our values. */
191         __stmpe_reset_fifo(ts->stmpe);
192 
193         /* reenable the tsc */
194         stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
195                         STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
196 
197         /* start polling for touch_det to detect release */
198         schedule_delayed_work(&ts->work, msecs_to_jiffies(50));
199 
200         return IRQ_HANDLED;
201 }
202 
203 static int stmpe_init_hw(struct stmpe_touch *ts)
204 {
205         int ret;
206         u8 adc_ctrl1, adc_ctrl1_mask, tsc_cfg, tsc_cfg_mask;
207         struct stmpe *stmpe = ts->stmpe;
208         struct device *dev = ts->dev;
209 
210         ret = stmpe_enable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
211         if (ret) {
212                 dev_err(dev, "Could not enable clock for ADC and TS\n");
213                 return ret;
214         }
215 
216         adc_ctrl1 = SAMPLE_TIME(ts->sample_time) | MOD_12B(ts->mod_12b) |
217                 REF_SEL(ts->ref_sel);
218         adc_ctrl1_mask = SAMPLE_TIME(0xff) | MOD_12B(0xff) | REF_SEL(0xff);
219 
220         ret = stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL1,
221                         adc_ctrl1_mask, adc_ctrl1);
222         if (ret) {
223                 dev_err(dev, "Could not setup ADC\n");
224                 return ret;
225         }
226 
227         ret = stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL2,
228                         ADC_FREQ(0xff), ADC_FREQ(ts->adc_freq));
229         if (ret) {
230                 dev_err(dev, "Could not setup ADC\n");
231                 return ret;
232         }
233 
234         tsc_cfg = AVE_CTRL(ts->ave_ctrl) | DET_DELAY(ts->touch_det_delay) |
235                         SETTLING(ts->settling);
236         tsc_cfg_mask = AVE_CTRL(0xff) | DET_DELAY(0xff) | SETTLING(0xff);
237 
238         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CFG, tsc_cfg_mask, tsc_cfg);
239         if (ret) {
240                 dev_err(dev, "Could not config touch\n");
241                 return ret;
242         }
243 
244         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_FRACTION_Z,
245                         FRACTION_Z(0xff), FRACTION_Z(ts->fraction_z));
246         if (ret) {
247                 dev_err(dev, "Could not config touch\n");
248                 return ret;
249         }
250 
251         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_I_DRIVE,
252                         I_DRIVE(0xff), I_DRIVE(ts->i_drive));
253         if (ret) {
254                 dev_err(dev, "Could not config touch\n");
255                 return ret;
256         }
257 
258         /* set FIFO to 1 for single point reading */
259         ret = stmpe_reg_write(stmpe, STMPE_REG_FIFO_TH, 1);
260         if (ret) {
261                 dev_err(dev, "Could not set FIFO\n");
262                 return ret;
263         }
264 
265         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CTRL,
266                         OP_MODE(0xff), OP_MODE(OP_MOD_XYZ));
267         if (ret) {
268                 dev_err(dev, "Could not set mode\n");
269                 return ret;
270         }
271 
272         return 0;
273 }
274 
275 static int stmpe_ts_open(struct input_dev *dev)
276 {
277         struct stmpe_touch *ts = input_get_drvdata(dev);
278         int ret = 0;
279 
280         ret = __stmpe_reset_fifo(ts->stmpe);
281         if (ret)
282                 return ret;
283 
284         return stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
285                         STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
286 }
287 
288 static void stmpe_ts_close(struct input_dev *dev)
289 {
290         struct stmpe_touch *ts = input_get_drvdata(dev);
291 
292         cancel_delayed_work_sync(&ts->work);
293 
294         stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
295                         STMPE_TSC_CTRL_TSC_EN, 0);
296 }
297 
298 static void stmpe_ts_get_platform_info(struct platform_device *pdev,
299                                         struct stmpe_touch *ts)
300 {
301         struct device_node *np = pdev->dev.of_node;
302         u32 val;
303 
304         if (np) {
305                 if (!of_property_read_u32(np, "st,sample-time", &val))
306                         ts->sample_time = val;
307                 if (!of_property_read_u32(np, "st,mod-12b", &val))
308                         ts->mod_12b = val;
309                 if (!of_property_read_u32(np, "st,ref-sel", &val))
310                         ts->ref_sel = val;
311                 if (!of_property_read_u32(np, "st,adc-freq", &val))
312                         ts->adc_freq = val;
313                 if (!of_property_read_u32(np, "st,ave-ctrl", &val))
314                         ts->ave_ctrl = val;
315                 if (!of_property_read_u32(np, "st,touch-det-delay", &val))
316                         ts->touch_det_delay = val;
317                 if (!of_property_read_u32(np, "st,settling", &val))
318                         ts->settling = val;
319                 if (!of_property_read_u32(np, "st,fraction-z", &val))
320                         ts->fraction_z = val;
321                 if (!of_property_read_u32(np, "st,i-drive", &val))
322                         ts->i_drive = val;
323         }
324 }
325 
326 static int stmpe_input_probe(struct platform_device *pdev)
327 {
328         struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
329         struct stmpe_touch *ts;
330         struct input_dev *idev;
331         int error;
332         int ts_irq;
333 
334         ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");
335         if (ts_irq < 0)
336                 return ts_irq;
337 
338         ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
339         if (!ts)
340                 return -ENOMEM;
341 
342         idev = devm_input_allocate_device(&pdev->dev);
343         if (!idev)
344                 return -ENOMEM;
345 
346         platform_set_drvdata(pdev, ts);
347         ts->stmpe = stmpe;
348         ts->idev = idev;
349         ts->dev = &pdev->dev;
350 
351         stmpe_ts_get_platform_info(pdev, ts);
352 
353         INIT_DELAYED_WORK(&ts->work, stmpe_work);
354 
355         error = devm_request_threaded_irq(&pdev->dev, ts_irq,
356                                           NULL, stmpe_ts_handler,
357                                           IRQF_ONESHOT, STMPE_TS_NAME, ts);
358         if (error) {
359                 dev_err(&pdev->dev, "Failed to request IRQ %d\n", ts_irq);
360                 return error;
361         }
362 
363         error = stmpe_init_hw(ts);
364         if (error)
365                 return error;
366 
367         idev->name = STMPE_TS_NAME;
368         idev->phys = STMPE_TS_NAME"/input0";
369         idev->id.bustype = BUS_I2C;
370 
371         idev->open = stmpe_ts_open;
372         idev->close = stmpe_ts_close;
373 
374         input_set_drvdata(idev, ts);
375 
376         input_set_capability(idev, EV_KEY, BTN_TOUCH);
377         input_set_abs_params(idev, ABS_X, 0, XY_MASK, 0, 0);
378         input_set_abs_params(idev, ABS_Y, 0, XY_MASK, 0, 0);
379         input_set_abs_params(idev, ABS_PRESSURE, 0x0, 0xff, 0, 0);
380 
381         error = input_register_device(idev);
382         if (error) {
383                 dev_err(&pdev->dev, "Could not register input device\n");
384                 return error;
385         }
386 
387         return 0;
388 }
389 
390 static int stmpe_ts_remove(struct platform_device *pdev)
391 {
392         struct stmpe_touch *ts = platform_get_drvdata(pdev);
393 
394         stmpe_disable(ts->stmpe, STMPE_BLOCK_TOUCHSCREEN);
395 
396         return 0;
397 }
398 
399 static struct platform_driver stmpe_ts_driver = {
400         .driver = {
401                 .name = STMPE_TS_NAME,
402         },
403         .probe = stmpe_input_probe,
404         .remove = stmpe_ts_remove,
405 };
406 module_platform_driver(stmpe_ts_driver);
407 
408 static const struct of_device_id stmpe_ts_ids[] = {
409         { .compatible = "st,stmpe-ts", },
410         { },
411 };
412 MODULE_DEVICE_TABLE(of, stmpe_ts_ids);
413 
414 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
415 MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
416 MODULE_LICENSE("GPL");
417 

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