1 // SPDX-License-Identifier: GPL-2.0
3 // Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <mpa@pengutronix.de>
4 // Based on driver from 2011:
5 // Juergen Beisert, Pengutronix <kernel@pengutronix.de>
7 // This is the driver for the imx25 TCQ (Touchscreen Conversion Queue)
8 // connected to the imx25 ADC.
10 #include <linux/clk.h>
11 #include <linux/device.h>
12 #include <linux/input.h>
13 #include <linux/interrupt.h>
14 #include <linux/mfd/imx25-tsadc.h>
15 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/regmap.h>
20 static const char mx25_tcq_name
[] = "mx25-tcq";
26 struct mx25_tcq_priv
{
28 struct regmap
*core_regs
;
29 struct input_dev
*idev
;
30 enum mx25_tcq_mode mode
;
31 unsigned int pen_threshold
;
32 unsigned int sample_count
;
33 unsigned int expected_samples
;
34 unsigned int pen_debounce
;
35 unsigned int settling_time
;
41 static struct regmap_config mx25_tcq_regconfig
= {
49 static const struct of_device_id mx25_tcq_ids
[] = {
50 { .compatible
= "fsl,imx25-tcq", },
53 MODULE_DEVICE_TABLE(of
, mx25_tcq_ids
);
55 #define TSC_4WIRE_PRE_INDEX 0
56 #define TSC_4WIRE_X_INDEX 1
57 #define TSC_4WIRE_Y_INDEX 2
58 #define TSC_4WIRE_POST_INDEX 3
59 #define TSC_4WIRE_LEAVE 4
61 #define MX25_TSC_DEF_THRESHOLD 80
62 #define TSC_MAX_SAMPLES 16
64 #define MX25_TSC_REPEAT_WAIT 14
66 enum mx25_adc_configurations
{
67 MX25_CFG_PRECHARGE
= 0,
68 MX25_CFG_TOUCH_DETECT
,
69 MX25_CFG_X_MEASUREMENT
,
70 MX25_CFG_Y_MEASUREMENT
,
73 #define MX25_PRECHARGE_VALUE (\
74 MX25_ADCQ_CFG_YPLL_OFF | \
75 MX25_ADCQ_CFG_XNUR_OFF | \
76 MX25_ADCQ_CFG_XPUL_HIGH | \
77 MX25_ADCQ_CFG_REFP_INT | \
78 MX25_ADCQ_CFG_IN_XP | \
79 MX25_ADCQ_CFG_REFN_NGND2 | \
82 #define MX25_TOUCH_DETECT_VALUE (\
83 MX25_ADCQ_CFG_YNLR | \
84 MX25_ADCQ_CFG_YPLL_OFF | \
85 MX25_ADCQ_CFG_XNUR_OFF | \
86 MX25_ADCQ_CFG_XPUL_OFF | \
87 MX25_ADCQ_CFG_REFP_INT | \
88 MX25_ADCQ_CFG_IN_XP | \
89 MX25_ADCQ_CFG_REFN_NGND2 | \
90 MX25_ADCQ_CFG_PENIACK)
92 static void imx25_setup_queue_cfgs(struct mx25_tcq_priv
*priv
,
93 unsigned int settling_cnt
)
96 MX25_PRECHARGE_VALUE
|
97 MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt
);
98 u32 touch_detect_cfg
=
99 MX25_TOUCH_DETECT_VALUE
|
100 MX25_ADCQ_CFG_NOS(1) |
101 MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt
);
103 regmap_write(priv
->core_regs
, MX25_TSC_TICR
, precharge_cfg
);
106 regmap_write(priv
->regs
, MX25_ADCQ_CFG(MX25_CFG_PRECHARGE
),
110 regmap_write(priv
->regs
, MX25_ADCQ_CFG(MX25_CFG_TOUCH_DETECT
),
114 regmap_write(priv
->regs
, MX25_ADCQ_CFG(MX25_CFG_X_MEASUREMENT
),
115 MX25_ADCQ_CFG_YPLL_OFF
|
116 MX25_ADCQ_CFG_XNUR_LOW
|
117 MX25_ADCQ_CFG_XPUL_HIGH
|
118 MX25_ADCQ_CFG_REFP_XP
|
119 MX25_ADCQ_CFG_IN_YP
|
120 MX25_ADCQ_CFG_REFN_XN
|
121 MX25_ADCQ_CFG_NOS(priv
->sample_count
) |
122 MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt
));
125 regmap_write(priv
->regs
, MX25_ADCQ_CFG(MX25_CFG_Y_MEASUREMENT
),
127 MX25_ADCQ_CFG_YPLL_HIGH
|
128 MX25_ADCQ_CFG_XNUR_OFF
|
129 MX25_ADCQ_CFG_XPUL_OFF
|
130 MX25_ADCQ_CFG_REFP_YP
|
131 MX25_ADCQ_CFG_IN_XP
|
132 MX25_ADCQ_CFG_REFN_YN
|
133 MX25_ADCQ_CFG_NOS(priv
->sample_count
) |
134 MX25_ADCQ_CFG_SETTLING_TIME(settling_cnt
));
136 /* Enable the touch detection right now */
137 regmap_write(priv
->core_regs
, MX25_TSC_TICR
, touch_detect_cfg
|
141 static int imx25_setup_queue_4wire(struct mx25_tcq_priv
*priv
,
142 unsigned settling_cnt
, int *items
)
144 imx25_setup_queue_cfgs(priv
, settling_cnt
);
146 /* Setup the conversion queue */
147 regmap_write(priv
->regs
, MX25_ADCQ_ITEM_7_0
,
148 MX25_ADCQ_ITEM(0, MX25_CFG_PRECHARGE
) |
149 MX25_ADCQ_ITEM(1, MX25_CFG_TOUCH_DETECT
) |
150 MX25_ADCQ_ITEM(2, MX25_CFG_X_MEASUREMENT
) |
151 MX25_ADCQ_ITEM(3, MX25_CFG_Y_MEASUREMENT
) |
152 MX25_ADCQ_ITEM(4, MX25_CFG_PRECHARGE
) |
153 MX25_ADCQ_ITEM(5, MX25_CFG_TOUCH_DETECT
));
156 * We measure X/Y with 'sample_count' number of samples and execute a
157 * touch detection twice, with 1 sample each
159 priv
->expected_samples
= priv
->sample_count
* 2 + 2;
165 static void mx25_tcq_disable_touch_irq(struct mx25_tcq_priv
*priv
)
167 regmap_update_bits(priv
->regs
, MX25_ADCQ_CR
, MX25_ADCQ_CR_PDMSK
,
171 static void mx25_tcq_enable_touch_irq(struct mx25_tcq_priv
*priv
)
173 regmap_update_bits(priv
->regs
, MX25_ADCQ_CR
, MX25_ADCQ_CR_PDMSK
, 0);
176 static void mx25_tcq_disable_fifo_irq(struct mx25_tcq_priv
*priv
)
178 regmap_update_bits(priv
->regs
, MX25_ADCQ_MR
, MX25_ADCQ_MR_FDRY_IRQ
,
179 MX25_ADCQ_MR_FDRY_IRQ
);
182 static void mx25_tcq_enable_fifo_irq(struct mx25_tcq_priv
*priv
)
184 regmap_update_bits(priv
->regs
, MX25_ADCQ_MR
, MX25_ADCQ_MR_FDRY_IRQ
, 0);
187 static void mx25_tcq_force_queue_start(struct mx25_tcq_priv
*priv
)
189 regmap_update_bits(priv
->regs
, MX25_ADCQ_CR
,
194 static void mx25_tcq_force_queue_stop(struct mx25_tcq_priv
*priv
)
196 regmap_update_bits(priv
->regs
, MX25_ADCQ_CR
,
197 MX25_ADCQ_CR_FQS
, 0);
200 static void mx25_tcq_fifo_reset(struct mx25_tcq_priv
*priv
)
204 regmap_read(priv
->regs
, MX25_ADCQ_CR
, &tcqcr
);
205 regmap_update_bits(priv
->regs
, MX25_ADCQ_CR
, MX25_ADCQ_CR_FRST
,
207 regmap_update_bits(priv
->regs
, MX25_ADCQ_CR
, MX25_ADCQ_CR_FRST
, 0);
208 regmap_write(priv
->regs
, MX25_ADCQ_CR
, tcqcr
);
211 static void mx25_tcq_re_enable_touch_detection(struct mx25_tcq_priv
*priv
)
213 /* stop the queue from looping */
214 mx25_tcq_force_queue_stop(priv
);
216 /* for a clean touch detection, preload the X plane */
217 regmap_write(priv
->core_regs
, MX25_TSC_TICR
, MX25_PRECHARGE_VALUE
);
219 /* waste some time now to pre-load the X plate to high voltage */
220 mx25_tcq_fifo_reset(priv
);
222 /* re-enable the detection right now */
223 regmap_write(priv
->core_regs
, MX25_TSC_TICR
,
224 MX25_TOUCH_DETECT_VALUE
| MX25_ADCQ_CFG_IGS
);
226 regmap_update_bits(priv
->regs
, MX25_ADCQ_SR
, MX25_ADCQ_SR_PD
,
229 /* enable the pen down event to be a source for the interrupt */
230 regmap_update_bits(priv
->regs
, MX25_ADCQ_MR
, MX25_ADCQ_MR_PD_IRQ
, 0);
232 /* lets fire the next IRQ if someone touches the touchscreen */
233 mx25_tcq_enable_touch_irq(priv
);
236 static void mx25_tcq_create_event_for_4wire(struct mx25_tcq_priv
*priv
,
238 unsigned int samples
)
240 unsigned int x_pos
= 0;
241 unsigned int y_pos
= 0;
242 unsigned int touch_pre
= 0;
243 unsigned int touch_post
= 0;
246 for (i
= 0; i
< samples
; i
++) {
247 unsigned int index
= MX25_ADCQ_FIFO_ID(sample_buf
[i
]);
248 unsigned int val
= MX25_ADCQ_FIFO_DATA(sample_buf
[i
]);
264 dev_dbg(priv
->dev
, "Dropped samples because of invalid index %d\n",
272 * only if both touch measures are below a threshold,
273 * the position is valid
275 if (touch_pre
< priv
->pen_threshold
&&
276 touch_post
< priv
->pen_threshold
) {
277 /* valid samples, generate a report */
278 x_pos
/= priv
->sample_count
;
279 y_pos
/= priv
->sample_count
;
280 input_report_abs(priv
->idev
, ABS_X
, x_pos
);
281 input_report_abs(priv
->idev
, ABS_Y
, y_pos
);
282 input_report_key(priv
->idev
, BTN_TOUCH
, 1);
283 input_sync(priv
->idev
);
285 /* get next sample */
286 mx25_tcq_enable_fifo_irq(priv
);
287 } else if (touch_pre
>= priv
->pen_threshold
&&
288 touch_post
>= priv
->pen_threshold
) {
290 * if both samples are invalid,
291 * generate a release report
293 input_report_key(priv
->idev
, BTN_TOUCH
, 0);
294 input_sync(priv
->idev
);
295 mx25_tcq_re_enable_touch_detection(priv
);
298 * if only one of both touch measurements are
299 * below the threshold, still some bouncing
300 * happens. Take additional samples in this
303 mx25_tcq_enable_fifo_irq(priv
);
308 static irqreturn_t
mx25_tcq_irq_thread(int irq
, void *dev_id
)
310 struct mx25_tcq_priv
*priv
= dev_id
;
311 u32 sample_buf
[TSC_MAX_SAMPLES
];
312 unsigned int samples
;
317 * Check how many samples are available. We always have to read exactly
318 * sample_count samples from the fifo, or a multiple of sample_count.
319 * Otherwise we mixup samples into different touch events.
321 regmap_read(priv
->regs
, MX25_ADCQ_SR
, &stats
);
322 samples
= MX25_ADCQ_SR_FDN(stats
);
323 samples
-= samples
% priv
->sample_count
;
328 for (i
= 0; i
!= samples
; ++i
)
329 regmap_read(priv
->regs
, MX25_ADCQ_FIFO
, &sample_buf
[i
]);
331 mx25_tcq_create_event_for_4wire(priv
, sample_buf
, samples
);
336 static irqreturn_t
mx25_tcq_irq(int irq
, void *dev_id
)
338 struct mx25_tcq_priv
*priv
= dev_id
;
340 int ret
= IRQ_HANDLED
;
342 regmap_read(priv
->regs
, MX25_ADCQ_SR
, &stat
);
344 if (stat
& (MX25_ADCQ_SR_FRR
| MX25_ADCQ_SR_FUR
| MX25_ADCQ_SR_FOR
))
345 mx25_tcq_re_enable_touch_detection(priv
);
347 if (stat
& MX25_ADCQ_SR_PD
) {
348 mx25_tcq_disable_touch_irq(priv
);
349 mx25_tcq_force_queue_start(priv
);
350 mx25_tcq_enable_fifo_irq(priv
);
353 if (stat
& MX25_ADCQ_SR_FDRY
) {
354 mx25_tcq_disable_fifo_irq(priv
);
355 ret
= IRQ_WAKE_THREAD
;
358 regmap_update_bits(priv
->regs
, MX25_ADCQ_SR
, MX25_ADCQ_SR_FRR
|
359 MX25_ADCQ_SR_FUR
| MX25_ADCQ_SR_FOR
|
361 MX25_ADCQ_SR_FRR
| MX25_ADCQ_SR_FUR
|
362 MX25_ADCQ_SR_FOR
| MX25_ADCQ_SR_PD
);
367 /* configure the state machine for a 4-wire touchscreen */
368 static int mx25_tcq_init(struct mx25_tcq_priv
*priv
)
371 unsigned int ipg_div
;
372 unsigned int adc_period
;
373 unsigned int debounce_cnt
;
374 unsigned int settling_cnt
;
378 regmap_read(priv
->core_regs
, MX25_TSC_TGCR
, &tgcr
);
379 ipg_div
= max_t(unsigned int, 4, MX25_TGCR_GET_ADCCLK(tgcr
));
380 adc_period
= USEC_PER_SEC
* ipg_div
* 2 + 2;
381 adc_period
/= clk_get_rate(priv
->clk
) / 1000 + 1;
382 debounce_cnt
= DIV_ROUND_UP(priv
->pen_debounce
, adc_period
* 8) - 1;
383 settling_cnt
= DIV_ROUND_UP(priv
->settling_time
, adc_period
* 8) - 1;
386 regmap_write(priv
->regs
, MX25_ADCQ_CR
,
387 MX25_ADCQ_CR_QRST
| MX25_ADCQ_CR_FRST
);
388 regmap_update_bits(priv
->regs
, MX25_ADCQ_CR
,
389 MX25_ADCQ_CR_QRST
| MX25_ADCQ_CR_FRST
, 0);
391 /* up to 128 * 8 ADC clocks are possible */
392 if (debounce_cnt
> 127)
395 /* up to 255 * 8 ADC clocks are possible */
396 if (settling_cnt
> 255)
399 error
= imx25_setup_queue_4wire(priv
, settling_cnt
, &itemct
);
403 regmap_update_bits(priv
->regs
, MX25_ADCQ_CR
,
404 MX25_ADCQ_CR_LITEMID_MASK
| MX25_ADCQ_CR_WMRK_MASK
,
405 MX25_ADCQ_CR_LITEMID(itemct
- 1) |
406 MX25_ADCQ_CR_WMRK(priv
->expected_samples
- 1));
408 /* setup debounce count */
409 regmap_update_bits(priv
->core_regs
, MX25_TSC_TGCR
,
410 MX25_TGCR_PDBTIME_MASK
,
411 MX25_TGCR_PDBTIME(debounce_cnt
));
413 /* enable debounce */
414 regmap_update_bits(priv
->core_regs
, MX25_TSC_TGCR
, MX25_TGCR_PDBEN
,
416 regmap_update_bits(priv
->core_regs
, MX25_TSC_TGCR
, MX25_TGCR_PDEN
,
419 /* enable the engine on demand */
420 regmap_update_bits(priv
->regs
, MX25_ADCQ_CR
, MX25_ADCQ_CR_QSM_MASK
,
421 MX25_ADCQ_CR_QSM_FQS
);
423 /* Enable repeat and repeat wait */
424 regmap_update_bits(priv
->regs
, MX25_ADCQ_CR
,
425 MX25_ADCQ_CR_RPT
| MX25_ADCQ_CR_RWAIT_MASK
,
427 MX25_ADCQ_CR_RWAIT(MX25_TSC_REPEAT_WAIT
));
432 static int mx25_tcq_parse_dt(struct platform_device
*pdev
,
433 struct mx25_tcq_priv
*priv
)
435 struct device_node
*np
= pdev
->dev
.of_node
;
440 priv
->pen_threshold
= 500;
441 priv
->sample_count
= 3;
442 priv
->pen_debounce
= 1000000;
443 priv
->settling_time
= 250000;
445 error
= of_property_read_u32(np
, "fsl,wires", &wires
);
447 dev_err(&pdev
->dev
, "Failed to find fsl,wires properties\n");
452 priv
->mode
= MX25_TS_4WIRE
;
454 dev_err(&pdev
->dev
, "%u-wire mode not supported\n", wires
);
458 /* These are optional, we don't care about the return values */
459 of_property_read_u32(np
, "fsl,pen-threshold", &priv
->pen_threshold
);
460 of_property_read_u32(np
, "fsl,settling-time-ns", &priv
->settling_time
);
461 of_property_read_u32(np
, "fsl,pen-debounce-ns", &priv
->pen_debounce
);
466 static int mx25_tcq_open(struct input_dev
*idev
)
468 struct device
*dev
= &idev
->dev
;
469 struct mx25_tcq_priv
*priv
= dev_get_drvdata(dev
);
472 error
= clk_prepare_enable(priv
->clk
);
474 dev_err(dev
, "Failed to enable ipg clock\n");
478 error
= mx25_tcq_init(priv
);
480 dev_err(dev
, "Failed to init tcq\n");
481 clk_disable_unprepare(priv
->clk
);
485 mx25_tcq_re_enable_touch_detection(priv
);
490 static void mx25_tcq_close(struct input_dev
*idev
)
492 struct mx25_tcq_priv
*priv
= input_get_drvdata(idev
);
494 mx25_tcq_force_queue_stop(priv
);
495 mx25_tcq_disable_touch_irq(priv
);
496 mx25_tcq_disable_fifo_irq(priv
);
497 clk_disable_unprepare(priv
->clk
);
500 static int mx25_tcq_probe(struct platform_device
*pdev
)
502 struct device
*dev
= &pdev
->dev
;
503 struct input_dev
*idev
;
504 struct mx25_tcq_priv
*priv
;
505 struct mx25_tsadc
*tsadc
= dev_get_drvdata(dev
->parent
);
509 priv
= devm_kzalloc(dev
, sizeof(*priv
), GFP_KERNEL
);
514 mem
= devm_platform_ioremap_resource(pdev
, 0);
518 error
= mx25_tcq_parse_dt(pdev
, priv
);
522 priv
->regs
= devm_regmap_init_mmio(dev
, mem
, &mx25_tcq_regconfig
);
523 if (IS_ERR(priv
->regs
)) {
524 dev_err(dev
, "Failed to initialize regmap\n");
525 return PTR_ERR(priv
->regs
);
528 priv
->irq
= platform_get_irq(pdev
, 0);
532 idev
= devm_input_allocate_device(dev
);
534 dev_err(dev
, "Failed to allocate input device\n");
538 idev
->name
= mx25_tcq_name
;
539 input_set_capability(idev
, EV_KEY
, BTN_TOUCH
);
540 input_set_abs_params(idev
, ABS_X
, 0, 0xfff, 0, 0);
541 input_set_abs_params(idev
, ABS_Y
, 0, 0xfff, 0, 0);
543 idev
->id
.bustype
= BUS_HOST
;
544 idev
->open
= mx25_tcq_open
;
545 idev
->close
= mx25_tcq_close
;
548 input_set_drvdata(idev
, priv
);
550 priv
->core_regs
= tsadc
->regs
;
551 if (!priv
->core_regs
)
554 priv
->clk
= tsadc
->clk
;
558 platform_set_drvdata(pdev
, priv
);
560 error
= devm_request_threaded_irq(dev
, priv
->irq
, mx25_tcq_irq
,
561 mx25_tcq_irq_thread
, 0, pdev
->name
,
564 dev_err(dev
, "Failed requesting IRQ\n");
568 error
= input_register_device(idev
);
570 dev_err(dev
, "Failed to register input device\n");
577 static struct platform_driver mx25_tcq_driver
= {
580 .of_match_table
= mx25_tcq_ids
,
582 .probe
= mx25_tcq_probe
,
584 module_platform_driver(mx25_tcq_driver
);
586 MODULE_DESCRIPTION("TS input driver for Freescale mx25");
587 MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>");
588 MODULE_LICENSE("GPL v2");