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9374e8f5 OR |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Texas Instruments TSC2046 SPI ADC driver | |
4 | * | |
5 | * Copyright (c) 2021 Oleksij Rempel <kernel@pengutronix.de>, Pengutronix | |
6 | */ | |
7 | ||
8 | #include <linux/bitfield.h> | |
9 | #include <linux/delay.h> | |
10 | #include <linux/module.h> | |
a616a6a1 | 11 | #include <linux/regulator/consumer.h> |
9374e8f5 | 12 | #include <linux/spi/spi.h> |
a616a6a1 | 13 | #include <linux/units.h> |
9374e8f5 OR |
14 | |
15 | #include <asm/unaligned.h> | |
16 | ||
17 | #include <linux/iio/buffer.h> | |
18 | #include <linux/iio/trigger_consumer.h> | |
19 | #include <linux/iio/triggered_buffer.h> | |
20 | #include <linux/iio/trigger.h> | |
21 | ||
22 | /* | |
23 | * The PENIRQ of TSC2046 controller is implemented as level shifter attached to | |
24 | * the X+ line. If voltage of the X+ line reaches a specific level the IRQ will | |
25 | * be activated or deactivated. | |
26 | * To make this kind of IRQ reusable as trigger following additions were | |
27 | * implemented: | |
28 | * - rate limiting: | |
29 | * For typical touchscreen use case, we need to trigger about each 10ms. | |
30 | * - hrtimer: | |
31 | * Continue triggering at least once after the IRQ was deactivated. Then | |
32 | * deactivate this trigger to stop sampling in order to reduce power | |
33 | * consumption. | |
34 | */ | |
35 | ||
36 | #define TI_TSC2046_NAME "tsc2046" | |
37 | ||
38 | /* This driver doesn't aim at the peak continuous sample rate */ | |
39 | #define TI_TSC2046_MAX_SAMPLE_RATE 125000 | |
40 | #define TI_TSC2046_SAMPLE_BITS \ | |
41 | BITS_PER_TYPE(struct tsc2046_adc_atom) | |
42 | #define TI_TSC2046_MAX_CLK_FREQ \ | |
43 | (TI_TSC2046_MAX_SAMPLE_RATE * TI_TSC2046_SAMPLE_BITS) | |
44 | ||
45 | #define TI_TSC2046_SAMPLE_INTERVAL_US 10000 | |
46 | ||
47 | #define TI_TSC2046_START BIT(7) | |
48 | #define TI_TSC2046_ADDR GENMASK(6, 4) | |
49 | #define TI_TSC2046_ADDR_TEMP1 7 | |
50 | #define TI_TSC2046_ADDR_AUX 6 | |
51 | #define TI_TSC2046_ADDR_X 5 | |
52 | #define TI_TSC2046_ADDR_Z2 4 | |
53 | #define TI_TSC2046_ADDR_Z1 3 | |
54 | #define TI_TSC2046_ADDR_VBAT 2 | |
55 | #define TI_TSC2046_ADDR_Y 1 | |
56 | #define TI_TSC2046_ADDR_TEMP0 0 | |
57 | ||
58 | /* | |
59 | * The mode bit sets the resolution of the ADC. With this bit low, the next | |
60 | * conversion has 12-bit resolution, whereas with this bit high, the next | |
61 | * conversion has 8-bit resolution. This driver is optimized for 12-bit mode. | |
62 | * So, for this driver, this bit should stay zero. | |
63 | */ | |
64 | #define TI_TSC2046_8BIT_MODE BIT(3) | |
65 | ||
66 | /* | |
67 | * SER/DFR - The SER/DFR bit controls the reference mode, either single-ended | |
68 | * (high) or differential (low). | |
69 | */ | |
70 | #define TI_TSC2046_SER BIT(2) | |
71 | ||
72 | /* | |
73 | * If VREF_ON and ADC_ON are both zero, then the chip operates in | |
74 | * auto-wake/suspend mode. In most case this bits should stay zero. | |
75 | */ | |
76 | #define TI_TSC2046_PD1_VREF_ON BIT(1) | |
77 | #define TI_TSC2046_PD0_ADC_ON BIT(0) | |
78 | ||
79 | /* | |
80 | * All supported devices can do 8 or 12bit resolution. This driver | |
81 | * supports only 12bit mode, here we have a 16bit data transfer, where | |
82 | * the MSB and the 3 LSB are 0. | |
83 | */ | |
84 | #define TI_TSC2046_DATA_12BIT GENMASK(14, 3) | |
85 | ||
86 | #define TI_TSC2046_MAX_CHAN 8 | |
84e5d889 OR |
87 | #define TI_TSC2046_MIN_POLL_CNT 3 |
88 | #define TI_TSC2046_EXT_POLL_CNT 3 | |
89 | #define TI_TSC2046_POLL_CNT \ | |
90 | (TI_TSC2046_MIN_POLL_CNT + TI_TSC2046_EXT_POLL_CNT) | |
b617693a | 91 | #define TI_TSC2046_INT_VREF 2500 |
9374e8f5 OR |
92 | |
93 | /* Represents a HW sample */ | |
94 | struct tsc2046_adc_atom { | |
95 | /* | |
96 | * Command transmitted to the controller. This field is empty on the RX | |
97 | * buffer. | |
98 | */ | |
99 | u8 cmd; | |
100 | /* | |
101 | * Data received from the controller. This field is empty for the TX | |
102 | * buffer | |
103 | */ | |
104 | __be16 data; | |
105 | } __packed; | |
106 | ||
107 | /* Layout of atomic buffers within big buffer */ | |
108 | struct tsc2046_adc_group_layout { | |
109 | /* Group offset within the SPI RX buffer */ | |
110 | unsigned int offset; | |
111 | /* | |
112 | * Amount of tsc2046_adc_atom structs within the same command gathered | |
113 | * within same group. | |
114 | */ | |
115 | unsigned int count; | |
116 | /* | |
117 | * Settling samples (tsc2046_adc_atom structs) which should be skipped | |
118 | * before good samples will start. | |
119 | */ | |
120 | unsigned int skip; | |
121 | }; | |
122 | ||
123 | struct tsc2046_adc_dcfg { | |
124 | const struct iio_chan_spec *channels; | |
125 | unsigned int num_channels; | |
126 | }; | |
127 | ||
128 | struct tsc2046_adc_ch_cfg { | |
129 | unsigned int settling_time_us; | |
130 | unsigned int oversampling_ratio; | |
131 | }; | |
132 | ||
84e5d889 OR |
133 | enum tsc2046_state { |
134 | TSC2046_STATE_SHUTDOWN, | |
135 | TSC2046_STATE_STANDBY, | |
136 | TSC2046_STATE_POLL, | |
137 | TSC2046_STATE_POLL_IRQ_DISABLE, | |
138 | TSC2046_STATE_ENABLE_IRQ, | |
139 | }; | |
140 | ||
9374e8f5 OR |
141 | struct tsc2046_adc_priv { |
142 | struct spi_device *spi; | |
143 | const struct tsc2046_adc_dcfg *dcfg; | |
a616a6a1 | 144 | struct regulator *vref_reg; |
9374e8f5 OR |
145 | |
146 | struct iio_trigger *trig; | |
147 | struct hrtimer trig_timer; | |
84e5d889 OR |
148 | enum tsc2046_state state; |
149 | int poll_cnt; | |
150 | spinlock_t state_lock; | |
9374e8f5 OR |
151 | |
152 | struct spi_transfer xfer; | |
153 | struct spi_message msg; | |
154 | ||
155 | struct { | |
156 | /* Scan data for each channel */ | |
157 | u16 data[TI_TSC2046_MAX_CHAN]; | |
158 | /* Timestamp */ | |
159 | s64 ts __aligned(8); | |
160 | } scan_buf; | |
161 | ||
162 | /* | |
163 | * Lock to protect the layout and the SPI transfer buffer. | |
164 | * tsc2046_adc_group_layout can be changed within update_scan_mode(), | |
165 | * in this case the l[] and tx/rx buffer will be out of sync to each | |
166 | * other. | |
167 | */ | |
168 | struct mutex slock; | |
169 | struct tsc2046_adc_group_layout l[TI_TSC2046_MAX_CHAN]; | |
170 | struct tsc2046_adc_atom *rx; | |
171 | struct tsc2046_adc_atom *tx; | |
172 | ||
9374e8f5 OR |
173 | unsigned int count; |
174 | unsigned int groups; | |
175 | u32 effective_speed_hz; | |
176 | u32 scan_interval_us; | |
177 | u32 time_per_scan_us; | |
178 | u32 time_per_bit_ns; | |
a616a6a1 | 179 | unsigned int vref_mv; |
9374e8f5 OR |
180 | |
181 | struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN]; | |
182 | }; | |
183 | ||
184 | #define TI_TSC2046_V_CHAN(index, bits, name) \ | |
185 | { \ | |
186 | .type = IIO_VOLTAGE, \ | |
187 | .indexed = 1, \ | |
188 | .channel = index, \ | |
b617693a OR |
189 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
190 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ | |
9374e8f5 OR |
191 | .datasheet_name = "#name", \ |
192 | .scan_index = index, \ | |
193 | .scan_type = { \ | |
194 | .sign = 'u', \ | |
195 | .realbits = bits, \ | |
196 | .storagebits = 16, \ | |
197 | .endianness = IIO_CPU, \ | |
198 | }, \ | |
199 | } | |
200 | ||
201 | #define DECLARE_TI_TSC2046_8_CHANNELS(name, bits) \ | |
202 | const struct iio_chan_spec name ## _channels[] = { \ | |
203 | TI_TSC2046_V_CHAN(0, bits, TEMP0), \ | |
204 | TI_TSC2046_V_CHAN(1, bits, Y), \ | |
205 | TI_TSC2046_V_CHAN(2, bits, VBAT), \ | |
206 | TI_TSC2046_V_CHAN(3, bits, Z1), \ | |
207 | TI_TSC2046_V_CHAN(4, bits, Z2), \ | |
208 | TI_TSC2046_V_CHAN(5, bits, X), \ | |
209 | TI_TSC2046_V_CHAN(6, bits, AUX), \ | |
210 | TI_TSC2046_V_CHAN(7, bits, TEMP1), \ | |
211 | IIO_CHAN_SOFT_TIMESTAMP(8), \ | |
212 | } | |
213 | ||
214 | static DECLARE_TI_TSC2046_8_CHANNELS(tsc2046_adc, 12); | |
215 | ||
216 | static const struct tsc2046_adc_dcfg tsc2046_adc_dcfg_tsc2046e = { | |
217 | .channels = tsc2046_adc_channels, | |
218 | .num_channels = ARRAY_SIZE(tsc2046_adc_channels), | |
219 | }; | |
220 | ||
221 | /* | |
222 | * Convert time to a number of samples which can be transferred within this | |
223 | * time. | |
224 | */ | |
225 | static unsigned int tsc2046_adc_time_to_count(struct tsc2046_adc_priv *priv, | |
226 | unsigned long time) | |
227 | { | |
228 | unsigned int bit_count, sample_count; | |
229 | ||
230 | bit_count = DIV_ROUND_UP(time * NSEC_PER_USEC, priv->time_per_bit_ns); | |
231 | sample_count = DIV_ROUND_UP(bit_count, TI_TSC2046_SAMPLE_BITS); | |
232 | ||
233 | dev_dbg(&priv->spi->dev, "Effective speed %u, time per bit: %u, count bits: %u, count samples: %u\n", | |
234 | priv->effective_speed_hz, priv->time_per_bit_ns, | |
235 | bit_count, sample_count); | |
236 | ||
237 | return sample_count; | |
238 | } | |
239 | ||
240 | static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx, | |
241 | bool keep_power) | |
242 | { | |
243 | u32 pd; | |
244 | ||
245 | /* | |
246 | * if PD bits are 0, controller will automatically disable ADC, VREF and | |
247 | * enable IRQ. | |
248 | */ | |
249 | if (keep_power) | |
250 | pd = TI_TSC2046_PD0_ADC_ON; | |
251 | else | |
252 | pd = 0; | |
253 | ||
b617693a OR |
254 | switch (ch_idx) { |
255 | case TI_TSC2046_ADDR_TEMP1: | |
256 | case TI_TSC2046_ADDR_AUX: | |
257 | case TI_TSC2046_ADDR_VBAT: | |
258 | case TI_TSC2046_ADDR_TEMP0: | |
a616a6a1 OR |
259 | pd |= TI_TSC2046_SER; |
260 | if (!priv->vref_reg) | |
261 | pd |= TI_TSC2046_PD1_VREF_ON; | |
b617693a OR |
262 | } |
263 | ||
9374e8f5 OR |
264 | return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd; |
265 | } | |
266 | ||
267 | static u16 tsc2046_adc_get_value(struct tsc2046_adc_atom *buf) | |
268 | { | |
269 | return FIELD_GET(TI_TSC2046_DATA_12BIT, get_unaligned_be16(&buf->data)); | |
270 | } | |
271 | ||
272 | static int tsc2046_adc_read_one(struct tsc2046_adc_priv *priv, int ch_idx, | |
273 | u32 *effective_speed_hz) | |
274 | { | |
b617693a OR |
275 | struct tsc2046_adc_ch_cfg *ch = &priv->ch_cfg[ch_idx]; |
276 | struct tsc2046_adc_atom *rx_buf, *tx_buf; | |
277 | unsigned int val, val_normalized = 0; | |
278 | int ret, i, count_skip = 0, max_count; | |
9374e8f5 OR |
279 | struct spi_transfer xfer; |
280 | struct spi_message msg; | |
b617693a OR |
281 | u8 cmd; |
282 | ||
283 | if (!effective_speed_hz) { | |
284 | count_skip = tsc2046_adc_time_to_count(priv, ch->settling_time_us); | |
285 | max_count = count_skip + ch->oversampling_ratio; | |
286 | } else { | |
287 | max_count = 1; | |
288 | } | |
289 | ||
290 | if (sizeof(*tx_buf) * max_count > PAGE_SIZE) | |
291 | return -ENOSPC; | |
292 | ||
293 | tx_buf = kcalloc(max_count, sizeof(*tx_buf), GFP_KERNEL); | |
294 | if (!tx_buf) | |
295 | return -ENOMEM; | |
296 | ||
297 | rx_buf = kcalloc(max_count, sizeof(*rx_buf), GFP_KERNEL); | |
298 | if (!rx_buf) { | |
299 | ret = -ENOMEM; | |
300 | goto free_tx; | |
301 | } | |
302 | ||
303 | /* | |
304 | * Do not enable automatic power down on working samples. Otherwise the | |
305 | * plates will never be completely charged. | |
306 | */ | |
307 | cmd = tsc2046_adc_get_cmd(priv, ch_idx, true); | |
308 | ||
309 | for (i = 0; i < max_count - 1; i++) | |
310 | tx_buf[i].cmd = cmd; | |
311 | ||
312 | /* automatically power down on last sample */ | |
313 | tx_buf[i].cmd = tsc2046_adc_get_cmd(priv, ch_idx, false); | |
9374e8f5 OR |
314 | |
315 | memset(&xfer, 0, sizeof(xfer)); | |
b617693a OR |
316 | xfer.tx_buf = tx_buf; |
317 | xfer.rx_buf = rx_buf; | |
318 | xfer.len = sizeof(*tx_buf) * max_count; | |
9374e8f5 OR |
319 | spi_message_init_with_transfers(&msg, &xfer, 1); |
320 | ||
321 | /* | |
322 | * We aren't using spi_write_then_read() because we need to be able | |
323 | * to get hold of the effective_speed_hz from the xfer | |
324 | */ | |
325 | ret = spi_sync(priv->spi, &msg); | |
326 | if (ret) { | |
327 | dev_err_ratelimited(&priv->spi->dev, "SPI transfer failed %pe\n", | |
328 | ERR_PTR(ret)); | |
b617693a | 329 | goto free_bufs; |
9374e8f5 OR |
330 | } |
331 | ||
332 | if (effective_speed_hz) | |
333 | *effective_speed_hz = xfer.effective_speed_hz; | |
334 | ||
b617693a OR |
335 | for (i = 0; i < max_count - count_skip; i++) { |
336 | val = tsc2046_adc_get_value(&rx_buf[count_skip + i]); | |
337 | val_normalized += val; | |
338 | } | |
339 | ||
340 | ret = DIV_ROUND_UP(val_normalized, max_count - count_skip); | |
341 | ||
342 | free_bufs: | |
343 | kfree(rx_buf); | |
344 | free_tx: | |
345 | kfree(tx_buf); | |
346 | ||
347 | return ret; | |
9374e8f5 OR |
348 | } |
349 | ||
350 | static size_t tsc2046_adc_group_set_layout(struct tsc2046_adc_priv *priv, | |
351 | unsigned int group, | |
352 | unsigned int ch_idx) | |
353 | { | |
354 | struct tsc2046_adc_ch_cfg *ch = &priv->ch_cfg[ch_idx]; | |
355 | struct tsc2046_adc_group_layout *cur; | |
356 | unsigned int max_count, count_skip; | |
357 | unsigned int offset = 0; | |
358 | ||
359 | if (group) | |
360 | offset = priv->l[group - 1].offset + priv->l[group - 1].count; | |
361 | ||
362 | count_skip = tsc2046_adc_time_to_count(priv, ch->settling_time_us); | |
363 | max_count = count_skip + ch->oversampling_ratio; | |
364 | ||
365 | cur = &priv->l[group]; | |
366 | cur->offset = offset; | |
367 | cur->count = max_count; | |
368 | cur->skip = count_skip; | |
369 | ||
370 | return sizeof(*priv->tx) * max_count; | |
371 | } | |
372 | ||
373 | static void tsc2046_adc_group_set_cmd(struct tsc2046_adc_priv *priv, | |
374 | unsigned int group, int ch_idx) | |
375 | { | |
376 | struct tsc2046_adc_group_layout *l = &priv->l[group]; | |
377 | unsigned int i; | |
378 | u8 cmd; | |
379 | ||
380 | /* | |
381 | * Do not enable automatic power down on working samples. Otherwise the | |
382 | * plates will never be completely charged. | |
383 | */ | |
384 | cmd = tsc2046_adc_get_cmd(priv, ch_idx, true); | |
385 | ||
386 | for (i = 0; i < l->count - 1; i++) | |
387 | priv->tx[l->offset + i].cmd = cmd; | |
388 | ||
389 | /* automatically power down on last sample */ | |
390 | priv->tx[l->offset + i].cmd = tsc2046_adc_get_cmd(priv, ch_idx, false); | |
391 | } | |
392 | ||
393 | static u16 tsc2046_adc_get_val(struct tsc2046_adc_priv *priv, int group) | |
394 | { | |
395 | struct tsc2046_adc_group_layout *l; | |
396 | unsigned int val, val_normalized = 0; | |
397 | int valid_count, i; | |
398 | ||
399 | l = &priv->l[group]; | |
400 | valid_count = l->count - l->skip; | |
401 | ||
402 | for (i = 0; i < valid_count; i++) { | |
403 | val = tsc2046_adc_get_value(&priv->rx[l->offset + l->skip + i]); | |
404 | val_normalized += val; | |
405 | } | |
406 | ||
407 | return DIV_ROUND_UP(val_normalized, valid_count); | |
408 | } | |
409 | ||
410 | static int tsc2046_adc_scan(struct iio_dev *indio_dev) | |
411 | { | |
412 | struct tsc2046_adc_priv *priv = iio_priv(indio_dev); | |
413 | struct device *dev = &priv->spi->dev; | |
414 | int group; | |
415 | int ret; | |
416 | ||
417 | ret = spi_sync(priv->spi, &priv->msg); | |
418 | if (ret < 0) { | |
419 | dev_err_ratelimited(dev, "SPI transfer failed: %pe\n", ERR_PTR(ret)); | |
420 | return ret; | |
421 | } | |
422 | ||
423 | for (group = 0; group < priv->groups; group++) | |
424 | priv->scan_buf.data[group] = tsc2046_adc_get_val(priv, group); | |
425 | ||
426 | ret = iio_push_to_buffers_with_timestamp(indio_dev, &priv->scan_buf, | |
427 | iio_get_time_ns(indio_dev)); | |
428 | /* If the consumer is kfifo, we may get a EBUSY here - ignore it. */ | |
429 | if (ret < 0 && ret != -EBUSY) { | |
430 | dev_err_ratelimited(dev, "Failed to push scan buffer %pe\n", | |
431 | ERR_PTR(ret)); | |
432 | ||
433 | return ret; | |
434 | } | |
435 | ||
436 | return 0; | |
437 | } | |
438 | ||
439 | static irqreturn_t tsc2046_adc_trigger_handler(int irq, void *p) | |
440 | { | |
441 | struct iio_poll_func *pf = p; | |
442 | struct iio_dev *indio_dev = pf->indio_dev; | |
443 | struct tsc2046_adc_priv *priv = iio_priv(indio_dev); | |
444 | ||
445 | mutex_lock(&priv->slock); | |
446 | tsc2046_adc_scan(indio_dev); | |
447 | mutex_unlock(&priv->slock); | |
448 | ||
449 | iio_trigger_notify_done(indio_dev->trig); | |
450 | ||
451 | return IRQ_HANDLED; | |
452 | } | |
453 | ||
b617693a OR |
454 | static int tsc2046_adc_read_raw(struct iio_dev *indio_dev, |
455 | struct iio_chan_spec const *chan, | |
456 | int *val, int *val2, long m) | |
457 | { | |
458 | struct tsc2046_adc_priv *priv = iio_priv(indio_dev); | |
459 | int ret; | |
460 | ||
461 | switch (m) { | |
462 | case IIO_CHAN_INFO_RAW: | |
463 | ret = tsc2046_adc_read_one(priv, chan->channel, NULL); | |
464 | if (ret < 0) | |
465 | return ret; | |
466 | ||
467 | *val = ret; | |
468 | ||
469 | return IIO_VAL_INT; | |
470 | case IIO_CHAN_INFO_SCALE: | |
471 | /* | |
472 | * Note: the TSC2046 has internal voltage divider on the VBAT | |
473 | * line. This divider can be influenced by external divider. | |
474 | * So, it is better to use external voltage-divider driver | |
475 | * instead, which is calculating complete chain. | |
476 | */ | |
a616a6a1 | 477 | *val = priv->vref_mv; |
b617693a OR |
478 | *val2 = chan->scan_type.realbits; |
479 | return IIO_VAL_FRACTIONAL_LOG2; | |
480 | } | |
481 | ||
482 | return -EINVAL; | |
483 | } | |
484 | ||
9374e8f5 OR |
485 | static int tsc2046_adc_update_scan_mode(struct iio_dev *indio_dev, |
486 | const unsigned long *active_scan_mask) | |
487 | { | |
488 | struct tsc2046_adc_priv *priv = iio_priv(indio_dev); | |
489 | unsigned int ch_idx, group = 0; | |
490 | size_t size; | |
491 | ||
492 | mutex_lock(&priv->slock); | |
493 | ||
494 | size = 0; | |
b7a78a8a | 495 | for_each_set_bit(ch_idx, active_scan_mask, ARRAY_SIZE(priv->l)) { |
9374e8f5 OR |
496 | size += tsc2046_adc_group_set_layout(priv, group, ch_idx); |
497 | tsc2046_adc_group_set_cmd(priv, group, ch_idx); | |
498 | group++; | |
499 | } | |
500 | ||
501 | priv->groups = group; | |
502 | priv->xfer.len = size; | |
503 | priv->time_per_scan_us = size * 8 * priv->time_per_bit_ns / NSEC_PER_USEC; | |
504 | ||
69b31fd7 | 505 | if (priv->scan_interval_us < priv->time_per_scan_us) |
9374e8f5 OR |
506 | dev_warn(&priv->spi->dev, "The scan interval (%d) is less then calculated scan time (%d)\n", |
507 | priv->scan_interval_us, priv->time_per_scan_us); | |
508 | ||
509 | mutex_unlock(&priv->slock); | |
510 | ||
511 | return 0; | |
512 | } | |
513 | ||
514 | static const struct iio_info tsc2046_adc_info = { | |
b617693a | 515 | .read_raw = tsc2046_adc_read_raw, |
9374e8f5 OR |
516 | .update_scan_mode = tsc2046_adc_update_scan_mode, |
517 | }; | |
518 | ||
84e5d889 | 519 | static enum hrtimer_restart tsc2046_adc_timer(struct hrtimer *hrtimer) |
9374e8f5 OR |
520 | { |
521 | struct tsc2046_adc_priv *priv = container_of(hrtimer, | |
522 | struct tsc2046_adc_priv, | |
523 | trig_timer); | |
524 | unsigned long flags; | |
525 | ||
84e5d889 OR |
526 | /* |
527 | * This state machine should address following challenges : | |
528 | * - the interrupt source is based on level shifter attached to the X | |
529 | * channel of ADC. It will change the state every time we switch | |
530 | * between channels. So, we need to disable IRQ if we do | |
531 | * iio_trigger_poll(). | |
532 | * - we should do iio_trigger_poll() at some reduced sample rate | |
533 | * - we should still trigger for some amount of time after last | |
534 | * interrupt with enabled IRQ was processed. | |
535 | */ | |
9374e8f5 | 536 | |
84e5d889 OR |
537 | spin_lock_irqsave(&priv->state_lock, flags); |
538 | switch (priv->state) { | |
539 | case TSC2046_STATE_ENABLE_IRQ: | |
540 | if (priv->poll_cnt < TI_TSC2046_POLL_CNT) { | |
541 | priv->poll_cnt++; | |
542 | hrtimer_start(&priv->trig_timer, | |
543 | ns_to_ktime(priv->scan_interval_us * | |
544 | NSEC_PER_USEC), | |
545 | HRTIMER_MODE_REL_SOFT); | |
546 | ||
547 | if (priv->poll_cnt >= TI_TSC2046_MIN_POLL_CNT) { | |
548 | priv->state = TSC2046_STATE_POLL_IRQ_DISABLE; | |
549 | enable_irq(priv->spi->irq); | |
550 | } else { | |
551 | priv->state = TSC2046_STATE_POLL; | |
552 | } | |
553 | } else { | |
554 | priv->state = TSC2046_STATE_STANDBY; | |
555 | enable_irq(priv->spi->irq); | |
556 | } | |
557 | break; | |
558 | case TSC2046_STATE_POLL_IRQ_DISABLE: | |
559 | disable_irq_nosync(priv->spi->irq); | |
560 | fallthrough; | |
561 | case TSC2046_STATE_POLL: | |
562 | priv->state = TSC2046_STATE_ENABLE_IRQ; | |
563 | /* iio_trigger_poll() starts hrtimer */ | |
564 | iio_trigger_poll(priv->trig); | |
565 | break; | |
566 | case TSC2046_STATE_SHUTDOWN: | |
567 | break; | |
568 | case TSC2046_STATE_STANDBY: | |
569 | fallthrough; | |
570 | default: | |
571 | dev_warn(&priv->spi->dev, "Got unexpected state: %i\n", | |
572 | priv->state); | |
573 | break; | |
574 | } | |
575 | spin_unlock_irqrestore(&priv->state_lock, flags); | |
9374e8f5 OR |
576 | |
577 | return HRTIMER_NORESTART; | |
578 | } | |
579 | ||
580 | static irqreturn_t tsc2046_adc_irq(int irq, void *dev_id) | |
581 | { | |
582 | struct iio_dev *indio_dev = dev_id; | |
583 | struct tsc2046_adc_priv *priv = iio_priv(indio_dev); | |
84e5d889 | 584 | unsigned long flags; |
9374e8f5 OR |
585 | |
586 | hrtimer_try_to_cancel(&priv->trig_timer); | |
587 | ||
84e5d889 OR |
588 | spin_lock_irqsave(&priv->state_lock, flags); |
589 | if (priv->state != TSC2046_STATE_SHUTDOWN) { | |
590 | priv->state = TSC2046_STATE_ENABLE_IRQ; | |
591 | priv->poll_cnt = 0; | |
9374e8f5 | 592 | |
84e5d889 OR |
593 | /* iio_trigger_poll() starts hrtimer */ |
594 | disable_irq_nosync(priv->spi->irq); | |
595 | iio_trigger_poll(priv->trig); | |
596 | } | |
597 | spin_unlock_irqrestore(&priv->state_lock, flags); | |
9374e8f5 OR |
598 | |
599 | return IRQ_HANDLED; | |
600 | } | |
601 | ||
602 | static void tsc2046_adc_reenable_trigger(struct iio_trigger *trig) | |
603 | { | |
604 | struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig); | |
605 | struct tsc2046_adc_priv *priv = iio_priv(indio_dev); | |
84e5d889 | 606 | ktime_t tim; |
9374e8f5 OR |
607 | |
608 | /* | |
609 | * We can sample it as fast as we can, but usually we do not need so | |
610 | * many samples. Reduce the sample rate for default (touchscreen) use | |
611 | * case. | |
9374e8f5 | 612 | */ |
84e5d889 OR |
613 | tim = ns_to_ktime((priv->scan_interval_us - priv->time_per_scan_us) * |
614 | NSEC_PER_USEC); | |
615 | hrtimer_start(&priv->trig_timer, tim, HRTIMER_MODE_REL_SOFT); | |
9374e8f5 OR |
616 | } |
617 | ||
618 | static int tsc2046_adc_set_trigger_state(struct iio_trigger *trig, bool enable) | |
619 | { | |
620 | struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig); | |
621 | struct tsc2046_adc_priv *priv = iio_priv(indio_dev); | |
84e5d889 | 622 | unsigned long flags; |
9374e8f5 OR |
623 | |
624 | if (enable) { | |
84e5d889 OR |
625 | spin_lock_irqsave(&priv->state_lock, flags); |
626 | if (priv->state == TSC2046_STATE_SHUTDOWN) { | |
627 | priv->state = TSC2046_STATE_STANDBY; | |
628 | enable_irq(priv->spi->irq); | |
629 | } | |
630 | spin_unlock_irqrestore(&priv->state_lock, flags); | |
9374e8f5 | 631 | } else { |
84e5d889 OR |
632 | spin_lock_irqsave(&priv->state_lock, flags); |
633 | ||
634 | if (priv->state == TSC2046_STATE_STANDBY || | |
635 | priv->state == TSC2046_STATE_POLL_IRQ_DISABLE) | |
636 | disable_irq_nosync(priv->spi->irq); | |
637 | ||
638 | priv->state = TSC2046_STATE_SHUTDOWN; | |
639 | spin_unlock_irqrestore(&priv->state_lock, flags); | |
640 | ||
641 | hrtimer_cancel(&priv->trig_timer); | |
9374e8f5 OR |
642 | } |
643 | ||
644 | return 0; | |
645 | } | |
646 | ||
647 | static const struct iio_trigger_ops tsc2046_adc_trigger_ops = { | |
648 | .set_trigger_state = tsc2046_adc_set_trigger_state, | |
649 | .reenable = tsc2046_adc_reenable_trigger, | |
650 | }; | |
651 | ||
652 | static int tsc2046_adc_setup_spi_msg(struct tsc2046_adc_priv *priv) | |
653 | { | |
654 | unsigned int ch_idx; | |
655 | size_t size; | |
656 | int ret; | |
657 | ||
9374e8f5 OR |
658 | /* |
659 | * Make dummy read to set initial power state and get real SPI clock | |
660 | * freq. It seems to be not important which channel is used for this | |
661 | * case. | |
662 | */ | |
663 | ret = tsc2046_adc_read_one(priv, TI_TSC2046_ADDR_TEMP0, | |
664 | &priv->effective_speed_hz); | |
665 | if (ret < 0) | |
666 | return ret; | |
667 | ||
668 | /* | |
669 | * In case SPI controller do not report effective_speed_hz, use | |
670 | * configure value and hope it will match. | |
671 | */ | |
672 | if (!priv->effective_speed_hz) | |
673 | priv->effective_speed_hz = priv->spi->max_speed_hz; | |
674 | ||
675 | ||
676 | priv->scan_interval_us = TI_TSC2046_SAMPLE_INTERVAL_US; | |
677 | priv->time_per_bit_ns = DIV_ROUND_UP(NSEC_PER_SEC, | |
678 | priv->effective_speed_hz); | |
679 | ||
680 | /* | |
681 | * Calculate and allocate maximal size buffer if all channels are | |
682 | * enabled. | |
683 | */ | |
684 | size = 0; | |
b7a78a8a | 685 | for (ch_idx = 0; ch_idx < ARRAY_SIZE(priv->l); ch_idx++) |
9374e8f5 OR |
686 | size += tsc2046_adc_group_set_layout(priv, ch_idx, ch_idx); |
687 | ||
576434fd OR |
688 | if (size > PAGE_SIZE) { |
689 | dev_err(&priv->spi->dev, | |
690 | "Calculated scan buffer is too big. Try to reduce spi-max-frequency, settling-time-us or oversampling-ratio\n"); | |
691 | return -ENOSPC; | |
692 | } | |
693 | ||
9374e8f5 OR |
694 | priv->tx = devm_kzalloc(&priv->spi->dev, size, GFP_KERNEL); |
695 | if (!priv->tx) | |
696 | return -ENOMEM; | |
697 | ||
698 | priv->rx = devm_kzalloc(&priv->spi->dev, size, GFP_KERNEL); | |
699 | if (!priv->rx) | |
700 | return -ENOMEM; | |
701 | ||
702 | priv->xfer.tx_buf = priv->tx; | |
703 | priv->xfer.rx_buf = priv->rx; | |
704 | priv->xfer.len = size; | |
705 | spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1); | |
706 | ||
707 | return 0; | |
708 | } | |
709 | ||
710 | static void tsc2046_adc_parse_fwnode(struct tsc2046_adc_priv *priv) | |
711 | { | |
712 | struct fwnode_handle *child; | |
713 | struct device *dev = &priv->spi->dev; | |
714 | unsigned int i; | |
715 | ||
716 | for (i = 0; i < ARRAY_SIZE(priv->ch_cfg); i++) { | |
717 | priv->ch_cfg[i].settling_time_us = 1; | |
718 | priv->ch_cfg[i].oversampling_ratio = 1; | |
719 | } | |
720 | ||
721 | device_for_each_child_node(dev, child) { | |
722 | u32 stl, overs, reg; | |
723 | int ret; | |
724 | ||
725 | ret = fwnode_property_read_u32(child, "reg", ®); | |
726 | if (ret) { | |
727 | dev_err(dev, "invalid reg on %pfw, err: %pe\n", child, | |
728 | ERR_PTR(ret)); | |
729 | continue; | |
730 | } | |
731 | ||
732 | if (reg >= ARRAY_SIZE(priv->ch_cfg)) { | |
733 | dev_err(dev, "%pfw: Unsupported reg value: %i, max supported is: %zu.\n", | |
734 | child, reg, ARRAY_SIZE(priv->ch_cfg)); | |
735 | continue; | |
736 | } | |
737 | ||
738 | ret = fwnode_property_read_u32(child, "settling-time-us", &stl); | |
739 | if (!ret) | |
740 | priv->ch_cfg[reg].settling_time_us = stl; | |
741 | ||
742 | ret = fwnode_property_read_u32(child, "oversampling-ratio", | |
743 | &overs); | |
744 | if (!ret) | |
745 | priv->ch_cfg[reg].oversampling_ratio = overs; | |
746 | } | |
747 | } | |
748 | ||
a616a6a1 OR |
749 | static void tsc2046_adc_regulator_disable(void *data) |
750 | { | |
751 | struct tsc2046_adc_priv *priv = data; | |
752 | ||
753 | regulator_disable(priv->vref_reg); | |
754 | } | |
755 | ||
756 | static int tsc2046_adc_configure_regulator(struct tsc2046_adc_priv *priv) | |
757 | { | |
758 | struct device *dev = &priv->spi->dev; | |
759 | int ret; | |
760 | ||
761 | priv->vref_reg = devm_regulator_get_optional(dev, "vref"); | |
762 | if (IS_ERR(priv->vref_reg)) { | |
763 | /* If regulator exists but can't be get, return an error */ | |
764 | if (PTR_ERR(priv->vref_reg) != -ENODEV) | |
765 | return PTR_ERR(priv->vref_reg); | |
766 | priv->vref_reg = NULL; | |
767 | } | |
768 | if (!priv->vref_reg) { | |
769 | /* Use internal reference */ | |
770 | priv->vref_mv = TI_TSC2046_INT_VREF; | |
771 | return 0; | |
772 | } | |
773 | ||
774 | ret = regulator_enable(priv->vref_reg); | |
775 | if (ret) | |
776 | return ret; | |
777 | ||
778 | ret = devm_add_action_or_reset(dev, tsc2046_adc_regulator_disable, | |
779 | priv); | |
780 | if (ret) | |
781 | return ret; | |
782 | ||
783 | ret = regulator_get_voltage(priv->vref_reg); | |
784 | if (ret < 0) | |
785 | return ret; | |
786 | ||
787 | priv->vref_mv = ret / MILLI; | |
788 | ||
789 | return 0; | |
790 | } | |
791 | ||
9374e8f5 OR |
792 | static int tsc2046_adc_probe(struct spi_device *spi) |
793 | { | |
794 | const struct tsc2046_adc_dcfg *dcfg; | |
795 | struct device *dev = &spi->dev; | |
796 | struct tsc2046_adc_priv *priv; | |
797 | struct iio_dev *indio_dev; | |
798 | struct iio_trigger *trig; | |
799 | int ret; | |
800 | ||
801 | if (spi->max_speed_hz > TI_TSC2046_MAX_CLK_FREQ) { | |
802 | dev_err(dev, "SPI max_speed_hz is too high: %d Hz. Max supported freq is %zu Hz\n", | |
803 | spi->max_speed_hz, TI_TSC2046_MAX_CLK_FREQ); | |
804 | return -EINVAL; | |
805 | } | |
806 | ||
d8f2d8ae | 807 | dcfg = spi_get_device_match_data(spi); |
9374e8f5 OR |
808 | if (!dcfg) |
809 | return -EINVAL; | |
810 | ||
811 | spi->bits_per_word = 8; | |
812 | spi->mode &= ~SPI_MODE_X_MASK; | |
813 | spi->mode |= SPI_MODE_0; | |
814 | ret = spi_setup(spi); | |
815 | if (ret < 0) | |
816 | return dev_err_probe(dev, ret, "Error in SPI setup\n"); | |
817 | ||
818 | indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); | |
819 | if (!indio_dev) | |
820 | return -ENOMEM; | |
821 | ||
822 | priv = iio_priv(indio_dev); | |
823 | priv->dcfg = dcfg; | |
824 | ||
9374e8f5 OR |
825 | priv->spi = spi; |
826 | ||
827 | indio_dev->name = TI_TSC2046_NAME; | |
338222d8 | 828 | indio_dev->modes = INDIO_DIRECT_MODE; |
9374e8f5 OR |
829 | indio_dev->channels = dcfg->channels; |
830 | indio_dev->num_channels = dcfg->num_channels; | |
831 | indio_dev->info = &tsc2046_adc_info; | |
832 | ||
a616a6a1 OR |
833 | ret = tsc2046_adc_configure_regulator(priv); |
834 | if (ret) | |
835 | return ret; | |
836 | ||
9374e8f5 OR |
837 | tsc2046_adc_parse_fwnode(priv); |
838 | ||
839 | ret = tsc2046_adc_setup_spi_msg(priv); | |
840 | if (ret) | |
841 | return ret; | |
842 | ||
843 | mutex_init(&priv->slock); | |
844 | ||
845 | ret = devm_request_irq(dev, spi->irq, &tsc2046_adc_irq, | |
846 | IRQF_NO_AUTOEN, indio_dev->name, indio_dev); | |
847 | if (ret) | |
848 | return ret; | |
849 | ||
850 | trig = devm_iio_trigger_alloc(dev, "touchscreen-%s", indio_dev->name); | |
851 | if (!trig) | |
852 | return -ENOMEM; | |
853 | ||
854 | priv->trig = trig; | |
855 | iio_trigger_set_drvdata(trig, indio_dev); | |
856 | trig->ops = &tsc2046_adc_trigger_ops; | |
857 | ||
84e5d889 OR |
858 | spin_lock_init(&priv->state_lock); |
859 | priv->state = TSC2046_STATE_SHUTDOWN; | |
9374e8f5 OR |
860 | hrtimer_init(&priv->trig_timer, CLOCK_MONOTONIC, |
861 | HRTIMER_MODE_REL_SOFT); | |
84e5d889 | 862 | priv->trig_timer.function = tsc2046_adc_timer; |
9374e8f5 OR |
863 | |
864 | ret = devm_iio_trigger_register(dev, trig); | |
865 | if (ret) { | |
866 | dev_err(dev, "failed to register trigger\n"); | |
867 | return ret; | |
868 | } | |
869 | ||
870 | ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL, | |
871 | &tsc2046_adc_trigger_handler, NULL); | |
872 | if (ret) { | |
873 | dev_err(dev, "Failed to setup triggered buffer\n"); | |
874 | return ret; | |
875 | } | |
876 | ||
877 | /* set default trigger */ | |
878 | indio_dev->trig = iio_trigger_get(priv->trig); | |
879 | ||
880 | return devm_iio_device_register(dev, indio_dev); | |
881 | } | |
882 | ||
883 | static const struct of_device_id ads7950_of_table[] = { | |
884 | { .compatible = "ti,tsc2046e-adc", .data = &tsc2046_adc_dcfg_tsc2046e }, | |
885 | { } | |
886 | }; | |
887 | MODULE_DEVICE_TABLE(of, ads7950_of_table); | |
888 | ||
3f8dd0a7 OR |
889 | static const struct spi_device_id tsc2046_adc_spi_ids[] = { |
890 | { "tsc2046e-adc", (unsigned long)&tsc2046_adc_dcfg_tsc2046e }, | |
891 | { } | |
892 | }; | |
893 | MODULE_DEVICE_TABLE(spi, tsc2046_adc_spi_ids); | |
894 | ||
9374e8f5 OR |
895 | static struct spi_driver tsc2046_adc_driver = { |
896 | .driver = { | |
897 | .name = "tsc2046", | |
898 | .of_match_table = ads7950_of_table, | |
899 | }, | |
3f8dd0a7 | 900 | .id_table = tsc2046_adc_spi_ids, |
9374e8f5 OR |
901 | .probe = tsc2046_adc_probe, |
902 | }; | |
903 | module_spi_driver(tsc2046_adc_driver); | |
904 | ||
905 | MODULE_AUTHOR("Oleksij Rempel <kernel@pengutronix.de>"); | |
906 | MODULE_DESCRIPTION("TI TSC2046 ADC"); | |
907 | MODULE_LICENSE("GPL v2"); |