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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2019 David Lechner <david@lechnology.com>
4 *
5 * Counter driver for Texas Instruments Enhanced Quadrature Encoder Pulse (eQEP)
6 */
7
8#include <linux/bitops.h>
9#include <linux/counter.h>
10#include <linux/kernel.h>
11#include <linux/mod_devicetable.h>
12#include <linux/module.h>
13#include <linux/platform_device.h>
14#include <linux/pm_runtime.h>
15#include <linux/regmap.h>
16
17/* 32-bit registers */
18#define QPOSCNT 0x0
19#define QPOSINIT 0x4
20#define QPOSMAX 0x8
21#define QPOSCMP 0xc
22#define QPOSILAT 0x10
23#define QPOSSLAT 0x14
24#define QPOSLAT 0x18
25#define QUTMR 0x1c
26#define QUPRD 0x20
27
28/* 16-bit registers */
29#define QWDTMR 0x0 /* 0x24 */
30#define QWDPRD 0x2 /* 0x26 */
31#define QDECCTL 0x4 /* 0x28 */
32#define QEPCTL 0x6 /* 0x2a */
33#define QCAPCTL 0x8 /* 0x2c */
34#define QPOSCTL 0xa /* 0x2e */
35#define QEINT 0xc /* 0x30 */
36#define QFLG 0xe /* 0x32 */
37#define QCLR 0x10 /* 0x34 */
38#define QFRC 0x12 /* 0x36 */
39#define QEPSTS 0x14 /* 0x38 */
40#define QCTMR 0x16 /* 0x3a */
41#define QCPRD 0x18 /* 0x3c */
42#define QCTMRLAT 0x1a /* 0x3e */
43#define QCPRDLAT 0x1c /* 0x40 */
44
45#define QDECCTL_QSRC_SHIFT 14
46#define QDECCTL_QSRC GENMASK(15, 14)
47#define QDECCTL_SOEN BIT(13)
48#define QDECCTL_SPSEL BIT(12)
49#define QDECCTL_XCR BIT(11)
50#define QDECCTL_SWAP BIT(10)
51#define QDECCTL_IGATE BIT(9)
52#define QDECCTL_QAP BIT(8)
53#define QDECCTL_QBP BIT(7)
54#define QDECCTL_QIP BIT(6)
55#define QDECCTL_QSP BIT(5)
56
57#define QEPCTL_FREE_SOFT GENMASK(15, 14)
58#define QEPCTL_PCRM GENMASK(13, 12)
59#define QEPCTL_SEI GENMASK(11, 10)
60#define QEPCTL_IEI GENMASK(9, 8)
61#define QEPCTL_SWI BIT(7)
62#define QEPCTL_SEL BIT(6)
63#define QEPCTL_IEL GENMASK(5, 4)
64#define QEPCTL_PHEN BIT(3)
65#define QEPCTL_QCLM BIT(2)
66#define QEPCTL_UTE BIT(1)
67#define QEPCTL_WDE BIT(0)
68
69/* EQEP Inputs */
70enum {
71 TI_EQEP_SIGNAL_QEPA, /* QEPA/XCLK */
72 TI_EQEP_SIGNAL_QEPB, /* QEPB/XDIR */
73};
74
75/* Position Counter Input Modes */
76enum {
77 TI_EQEP_COUNT_FUNC_QUAD_COUNT,
78 TI_EQEP_COUNT_FUNC_DIR_COUNT,
79 TI_EQEP_COUNT_FUNC_UP_COUNT,
80 TI_EQEP_COUNT_FUNC_DOWN_COUNT,
81};
82
83enum {
84 TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES,
85 TI_EQEP_SYNAPSE_ACTION_RISING_EDGE,
86 TI_EQEP_SYNAPSE_ACTION_NONE,
87};
88
89struct ti_eqep_cnt {
90 struct counter_device counter;
91 struct regmap *regmap32;
92 struct regmap *regmap16;
93};
94
95static int ti_eqep_count_read(struct counter_device *counter,
96 struct counter_count *count, unsigned long *val)
97{
98 struct ti_eqep_cnt *priv = counter->priv;
99 u32 cnt;
100
101 regmap_read(priv->regmap32, QPOSCNT, &cnt);
102 *val = cnt;
103
104 return 0;
105}
106
107static int ti_eqep_count_write(struct counter_device *counter,
108 struct counter_count *count, unsigned long val)
109{
110 struct ti_eqep_cnt *priv = counter->priv;
111 u32 max;
112
113 regmap_read(priv->regmap32, QPOSMAX, &max);
114 if (val > max)
115 return -EINVAL;
116
117 return regmap_write(priv->regmap32, QPOSCNT, val);
118}
119
120static int ti_eqep_function_get(struct counter_device *counter,
121 struct counter_count *count, size_t *function)
122{
123 struct ti_eqep_cnt *priv = counter->priv;
124 u32 qdecctl;
125
126 regmap_read(priv->regmap16, QDECCTL, &qdecctl);
127 *function = (qdecctl & QDECCTL_QSRC) >> QDECCTL_QSRC_SHIFT;
128
129 return 0;
130}
131
132static int ti_eqep_function_set(struct counter_device *counter,
133 struct counter_count *count, size_t function)
134{
135 struct ti_eqep_cnt *priv = counter->priv;
136
137 return regmap_write_bits(priv->regmap16, QDECCTL, QDECCTL_QSRC,
138 function << QDECCTL_QSRC_SHIFT);
139}
140
141static int ti_eqep_action_get(struct counter_device *counter,
142 struct counter_count *count,
143 struct counter_synapse *synapse, size_t *action)
144{
145 struct ti_eqep_cnt *priv = counter->priv;
146 size_t function;
147 u32 qdecctl;
148 int err;
149
150 err = ti_eqep_function_get(counter, count, &function);
151 if (err)
152 return err;
153
154 switch (function) {
155 case TI_EQEP_COUNT_FUNC_QUAD_COUNT:
156 /* In quadrature mode, the rising and falling edge of both
157 * QEPA and QEPB trigger QCLK.
158 */
159 *action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
160 break;
161 case TI_EQEP_COUNT_FUNC_DIR_COUNT:
162 /* In direction-count mode only rising edge of QEPA is counted
163 * and QEPB gives direction.
164 */
165 switch (synapse->signal->id) {
166 case TI_EQEP_SIGNAL_QEPA:
167 *action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
168 break;
169 default:
170 *action = TI_EQEP_SYNAPSE_ACTION_NONE;
171 break;
172 }
173 break;
174 case TI_EQEP_COUNT_FUNC_UP_COUNT:
175 case TI_EQEP_COUNT_FUNC_DOWN_COUNT:
176 /* In up/down-count modes only QEPA is counted and QEPB is not
177 * used.
178 */
179 switch (synapse->signal->id) {
180 case TI_EQEP_SIGNAL_QEPA:
181 err = regmap_read(priv->regmap16, QDECCTL, &qdecctl);
182 if (err)
183 return err;
184
185 if (qdecctl & QDECCTL_XCR)
186 *action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
187 else
188 *action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
189 break;
190 default:
191 *action = TI_EQEP_SYNAPSE_ACTION_NONE;
192 break;
193 }
194 break;
195 }
196
197 return 0;
198}
199
200static const struct counter_ops ti_eqep_counter_ops = {
201 .count_read = ti_eqep_count_read,
202 .count_write = ti_eqep_count_write,
203 .function_get = ti_eqep_function_get,
204 .function_set = ti_eqep_function_set,
205 .action_get = ti_eqep_action_get,
206};
207
208static ssize_t ti_eqep_position_ceiling_read(struct counter_device *counter,
209 struct counter_count *count,
210 void *ext_priv, char *buf)
211{
212 struct ti_eqep_cnt *priv = counter->priv;
213 u32 qposmax;
214
215 regmap_read(priv->regmap32, QPOSMAX, &qposmax);
216
217 return sprintf(buf, "%u\n", qposmax);
218}
219
220static ssize_t ti_eqep_position_ceiling_write(struct counter_device *counter,
221 struct counter_count *count,
222 void *ext_priv, const char *buf,
223 size_t len)
224{
225 struct ti_eqep_cnt *priv = counter->priv;
226 int err;
227 u32 res;
228
229 err = kstrtouint(buf, 0, &res);
230 if (err < 0)
231 return err;
232
233 regmap_write(priv->regmap32, QPOSMAX, res);
234
235 return len;
236}
237
238static ssize_t ti_eqep_position_floor_read(struct counter_device *counter,
239 struct counter_count *count,
240 void *ext_priv, char *buf)
241{
242 struct ti_eqep_cnt *priv = counter->priv;
243 u32 qposinit;
244
245 regmap_read(priv->regmap32, QPOSINIT, &qposinit);
246
247 return sprintf(buf, "%u\n", qposinit);
248}
249
250static ssize_t ti_eqep_position_floor_write(struct counter_device *counter,
251 struct counter_count *count,
252 void *ext_priv, const char *buf,
253 size_t len)
254{
255 struct ti_eqep_cnt *priv = counter->priv;
256 int err;
257 u32 res;
258
259 err = kstrtouint(buf, 0, &res);
260 if (err < 0)
261 return err;
262
263 regmap_write(priv->regmap32, QPOSINIT, res);
264
265 return len;
266}
267
268static ssize_t ti_eqep_position_enable_read(struct counter_device *counter,
269 struct counter_count *count,
270 void *ext_priv, char *buf)
271{
272 struct ti_eqep_cnt *priv = counter->priv;
273 u32 qepctl;
274
275 regmap_read(priv->regmap16, QEPCTL, &qepctl);
276
277 return sprintf(buf, "%u\n", !!(qepctl & QEPCTL_PHEN));
278}
279
280static ssize_t ti_eqep_position_enable_write(struct counter_device *counter,
281 struct counter_count *count,
282 void *ext_priv, const char *buf,
283 size_t len)
284{
285 struct ti_eqep_cnt *priv = counter->priv;
286 int err;
287 bool res;
288
289 err = kstrtobool(buf, &res);
290 if (err < 0)
291 return err;
292
293 regmap_write_bits(priv->regmap16, QEPCTL, QEPCTL_PHEN, res ? -1 : 0);
294
295 return len;
296}
297
298static struct counter_count_ext ti_eqep_position_ext[] = {
299 {
300 .name = "ceiling",
301 .read = ti_eqep_position_ceiling_read,
302 .write = ti_eqep_position_ceiling_write,
303 },
304 {
305 .name = "floor",
306 .read = ti_eqep_position_floor_read,
307 .write = ti_eqep_position_floor_write,
308 },
309 {
310 .name = "enable",
311 .read = ti_eqep_position_enable_read,
312 .write = ti_eqep_position_enable_write,
313 },
314};
315
316static struct counter_signal ti_eqep_signals[] = {
317 [TI_EQEP_SIGNAL_QEPA] = {
318 .id = TI_EQEP_SIGNAL_QEPA,
319 .name = "QEPA"
320 },
321 [TI_EQEP_SIGNAL_QEPB] = {
322 .id = TI_EQEP_SIGNAL_QEPB,
323 .name = "QEPB"
324 },
325};
326
327static const enum counter_count_function ti_eqep_position_functions[] = {
328 [TI_EQEP_COUNT_FUNC_QUAD_COUNT] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
329 [TI_EQEP_COUNT_FUNC_DIR_COUNT] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
330 [TI_EQEP_COUNT_FUNC_UP_COUNT] = COUNTER_COUNT_FUNCTION_INCREASE,
331 [TI_EQEP_COUNT_FUNC_DOWN_COUNT] = COUNTER_COUNT_FUNCTION_DECREASE,
332};
333
334static const enum counter_synapse_action ti_eqep_position_synapse_actions[] = {
335 [TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
336 [TI_EQEP_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
337 [TI_EQEP_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
338};
339
340static struct counter_synapse ti_eqep_position_synapses[] = {
341 {
342 .actions_list = ti_eqep_position_synapse_actions,
343 .num_actions = ARRAY_SIZE(ti_eqep_position_synapse_actions),
344 .signal = &ti_eqep_signals[TI_EQEP_SIGNAL_QEPA],
345 },
346 {
347 .actions_list = ti_eqep_position_synapse_actions,
348 .num_actions = ARRAY_SIZE(ti_eqep_position_synapse_actions),
349 .signal = &ti_eqep_signals[TI_EQEP_SIGNAL_QEPB],
350 },
351};
352
353static struct counter_count ti_eqep_counts[] = {
354 {
355 .id = 0,
356 .name = "QPOSCNT",
357 .functions_list = ti_eqep_position_functions,
358 .num_functions = ARRAY_SIZE(ti_eqep_position_functions),
359 .synapses = ti_eqep_position_synapses,
360 .num_synapses = ARRAY_SIZE(ti_eqep_position_synapses),
361 .ext = ti_eqep_position_ext,
362 .num_ext = ARRAY_SIZE(ti_eqep_position_ext),
363 },
364};
365
366static const struct regmap_config ti_eqep_regmap32_config = {
367 .name = "32-bit",
368 .reg_bits = 32,
369 .val_bits = 32,
370 .reg_stride = 4,
371 .max_register = 0x24,
372};
373
374static const struct regmap_config ti_eqep_regmap16_config = {
375 .name = "16-bit",
376 .reg_bits = 16,
377 .val_bits = 16,
378 .reg_stride = 2,
379 .max_register = 0x1e,
380};
381
382static int ti_eqep_probe(struct platform_device *pdev)
383{
384 struct device *dev = &pdev->dev;
385 struct ti_eqep_cnt *priv;
386 void __iomem *base;
387 int err;
388
389 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
390 if (!priv)
391 return -ENOMEM;
392
393 base = devm_platform_ioremap_resource(pdev, 0);
394 if (IS_ERR(base))
395 return PTR_ERR(base);
396
397 priv->regmap32 = devm_regmap_init_mmio(dev, base,
398 &ti_eqep_regmap32_config);
399 if (IS_ERR(priv->regmap32))
400 return PTR_ERR(priv->regmap32);
401
402 priv->regmap16 = devm_regmap_init_mmio(dev, base + 0x24,
403 &ti_eqep_regmap16_config);
404 if (IS_ERR(priv->regmap16))
405 return PTR_ERR(priv->regmap16);
406
407 priv->counter.name = dev_name(dev);
408 priv->counter.parent = dev;
409 priv->counter.ops = &ti_eqep_counter_ops;
410 priv->counter.counts = ti_eqep_counts;
411 priv->counter.num_counts = ARRAY_SIZE(ti_eqep_counts);
412 priv->counter.signals = ti_eqep_signals;
413 priv->counter.num_signals = ARRAY_SIZE(ti_eqep_signals);
414 priv->counter.priv = priv;
415
416 platform_set_drvdata(pdev, priv);
417
418 /*
419 * Need to make sure power is turned on. On AM33xx, this comes from the
420 * parent PWMSS bus driver. On AM17xx, this comes from the PSC power
421 * domain.
422 */
423 pm_runtime_enable(dev);
424 pm_runtime_get_sync(dev);
425
426 err = counter_register(&priv->counter);
427 if (err < 0) {
428 pm_runtime_put_sync(dev);
429 pm_runtime_disable(dev);
430 return err;
431 }
432
433 return 0;
434}
435
436static int ti_eqep_remove(struct platform_device *pdev)
437{
438 struct ti_eqep_cnt *priv = platform_get_drvdata(pdev);
439 struct device *dev = &pdev->dev;
440
441 counter_unregister(&priv->counter);
442 pm_runtime_put_sync(dev),
443 pm_runtime_disable(dev);
444
445 return 0;
446}
447
448static const struct of_device_id ti_eqep_of_match[] = {
449 { .compatible = "ti,am3352-eqep", },
450 { },
451};
452MODULE_DEVICE_TABLE(of, ti_eqep_of_match);
453
454static struct platform_driver ti_eqep_driver = {
455 .probe = ti_eqep_probe,
456 .remove = ti_eqep_remove,
457 .driver = {
458 .name = "ti-eqep-cnt",
459 .of_match_table = ti_eqep_of_match,
460 },
461};
462module_platform_driver(ti_eqep_driver);
463
464MODULE_AUTHOR("David Lechner <david@lechnology.com>");
465MODULE_DESCRIPTION("TI eQEP counter driver");
466MODULE_LICENSE("GPL v2");