1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2013 STMicroelectronics Limited
4 * Author: Srinivas Kandagatla <srinivas.kandagatla@st.com>
5 */
6 #include <linux/kernel.h>
7 #include <linux/clk.h>
8 #include <linux/interrupt.h>
9 #include <linux/module.h>
10 #include <linux/of.h>
11 #include <linux/platform_device.h>
12 #include <linux/reset.h>
13 #include <media/rc-core.h>
14 #include <linux/pinctrl/consumer.h>
15 #include <linux/pm_wakeirq.h>
16
17 struct st_rc_device {
18 struct device *dev;
19 int irq;
20 int irq_wake;
21 struct clk *sys_clock;
22 void __iomem *base; /* Register base address */
23 void __iomem *rx_base;/* RX Register base address */
24 struct rc_dev *rdev;
25 bool overclocking;
26 int sample_mult;
27 int sample_div;
28 bool rxuhfmode;
29 struct reset_control *rstc;
30 };
31
32 /* Registers */
33 #define IRB_SAMPLE_RATE_COMM 0x64 /* sample freq divisor*/
34 #define IRB_CLOCK_SEL 0x70 /* clock select */
35 #define IRB_CLOCK_SEL_STATUS 0x74 /* clock status */
36 /* IRB IR/UHF receiver registers */
37 #define IRB_RX_ON 0x40 /* pulse time capture */
38 #define IRB_RX_SYS 0X44 /* sym period capture */
39 #define IRB_RX_INT_EN 0x48 /* IRQ enable (R/W) */
40 #define IRB_RX_INT_STATUS 0x4c /* IRQ status (R/W) */
41 #define IRB_RX_EN 0x50 /* Receive enable */
42 #define IRB_MAX_SYM_PERIOD 0x54 /* max sym value */
43 #define IRB_RX_INT_CLEAR 0x58 /* overrun status */
44 #define IRB_RX_STATUS 0x6c /* receive status */
45 #define IRB_RX_NOISE_SUPPR 0x5c /* noise suppression */
46 #define IRB_RX_POLARITY_INV 0x68 /* polarity inverter */
47
48 /*
49 * IRQ set: Enable full FIFO 1 -> bit 3;
50 * Enable overrun IRQ 1 -> bit 2;
51 * Enable last symbol IRQ 1 -> bit 1:
52 * Enable RX interrupt 1 -> bit 0;
53 */
54 #define IRB_RX_INTS 0x0f
55 #define IRB_RX_OVERRUN_INT 0x04
56 /* maximum symbol period (microsecs),timeout to detect end of symbol train */
57 #define MAX_SYMB_TIME 0x5000
58 #define IRB_SAMPLE_FREQ 10000000
59 #define IRB_FIFO_NOT_EMPTY 0xff00
60 #define IRB_OVERFLOW 0x4
61 #define IRB_TIMEOUT 0xffff
62 #define IR_ST_NAME "st-rc"
63
st_rc_send_lirc_timeout(struct rc_dev * rdev)64 static void st_rc_send_lirc_timeout(struct rc_dev *rdev)
65 {
66 struct ir_raw_event ev = { .timeout = true, .duration = rdev->timeout };
67 ir_raw_event_store(rdev, &ev);
68 }
69
70 /*
71 * RX graphical example to better understand the difference between ST IR block
72 * output and standard definition used by LIRC (and most of the world!)
73 *
74 * mark mark
75 * |-IRB_RX_ON-| |-IRB_RX_ON-|
76 * ___ ___ ___ ___ ___ ___ _
77 * | | | | | | | | | | | | |
78 * | | | | | | space 0 | | | | | | space 1 |
79 * _____| |__| |__| |____________________________| |__| |__| |_____________|
80 *
81 * |--------------- IRB_RX_SYS -------------|------ IRB_RX_SYS -------|
82 *
83 * |------------- encoding bit 0 -----------|---- encoding bit 1 -----|
84 *
85 * ST hardware returns mark (IRB_RX_ON) and total symbol time (IRB_RX_SYS), so
86 * convert to standard mark/space we have to calculate space=(IRB_RX_SYS-mark)
87 * The mark time represents the amount of time the carrier (usually 36-40kHz)
88 * is detected.The above examples shows Pulse Width Modulation encoding where
89 * bit 0 is represented by space>mark.
90 */
91
st_rc_rx_interrupt(int irq,void * data)92 static irqreturn_t st_rc_rx_interrupt(int irq, void *data)
93 {
94 unsigned long timeout;
95 unsigned int symbol, mark = 0;
96 struct st_rc_device *dev = data;
97 int last_symbol = 0;
98 u32 status, int_status;
99 struct ir_raw_event ev = {};
100
101 if (dev->irq_wake)
102 pm_wakeup_event(dev->dev, 0);
103
104 /* FIXME: is 10ms good enough ? */
105 timeout = jiffies + msecs_to_jiffies(10);
106 do {
107 status = readl(dev->rx_base + IRB_RX_STATUS);
108 if (!(status & (IRB_FIFO_NOT_EMPTY | IRB_OVERFLOW)))
109 break;
110
111 int_status = readl(dev->rx_base + IRB_RX_INT_STATUS);
112 if (unlikely(int_status & IRB_RX_OVERRUN_INT)) {
113 /* discard the entire collection in case of errors! */
114 ir_raw_event_overflow(dev->rdev);
115 dev_info(dev->dev, "IR RX overrun\n");
116 writel(IRB_RX_OVERRUN_INT,
117 dev->rx_base + IRB_RX_INT_CLEAR);
118 continue;
119 }
120
121 symbol = readl(dev->rx_base + IRB_RX_SYS);
122 mark = readl(dev->rx_base + IRB_RX_ON);
123
124 if (symbol == IRB_TIMEOUT)
125 last_symbol = 1;
126
127 /* Ignore any noise */
128 if ((mark > 2) && (symbol > 1)) {
129 symbol -= mark;
130 if (dev->overclocking) { /* adjustments to timings */
131 symbol *= dev->sample_mult;
132 symbol /= dev->sample_div;
133 mark *= dev->sample_mult;
134 mark /= dev->sample_div;
135 }
136
137 ev.duration = mark;
138 ev.pulse = true;
139 ir_raw_event_store(dev->rdev, &ev);
140
141 if (!last_symbol) {
142 ev.duration = symbol;
143 ev.pulse = false;
144 ir_raw_event_store(dev->rdev, &ev);
145 } else {
146 st_rc_send_lirc_timeout(dev->rdev);
147 }
148
149 }
150 last_symbol = 0;
151 } while (time_is_after_jiffies(timeout));
152
153 writel(IRB_RX_INTS, dev->rx_base + IRB_RX_INT_CLEAR);
154
155 /* Empty software fifo */
156 ir_raw_event_handle(dev->rdev);
157 return IRQ_HANDLED;
158 }
159
st_rc_hardware_init(struct st_rc_device * dev)160 static int st_rc_hardware_init(struct st_rc_device *dev)
161 {
162 int ret;
163 int baseclock, freqdiff;
164 unsigned int rx_max_symbol_per = MAX_SYMB_TIME;
165 unsigned int rx_sampling_freq_div;
166
167 /* Enable the IP */
168 reset_control_deassert(dev->rstc);
169
170 ret = clk_prepare_enable(dev->sys_clock);
171 if (ret) {
172 dev_err(dev->dev, "Failed to prepare/enable system clock\n");
173 return ret;
174 }
175
176 baseclock = clk_get_rate(dev->sys_clock);
177
178 /* IRB input pins are inverted internally from high to low. */
179 writel(1, dev->rx_base + IRB_RX_POLARITY_INV);
180
181 rx_sampling_freq_div = baseclock / IRB_SAMPLE_FREQ;
182 writel(rx_sampling_freq_div, dev->base + IRB_SAMPLE_RATE_COMM);
183
184 freqdiff = baseclock - (rx_sampling_freq_div * IRB_SAMPLE_FREQ);
185 if (freqdiff) { /* over clocking, workout the adjustment factors */
186 dev->overclocking = true;
187 dev->sample_mult = 1000;
188 dev->sample_div = baseclock / (10000 * rx_sampling_freq_div);
189 rx_max_symbol_per = (rx_max_symbol_per * 1000)/dev->sample_div;
190 }
191
192 writel(rx_max_symbol_per, dev->rx_base + IRB_MAX_SYM_PERIOD);
193
194 return 0;
195 }
196
st_rc_remove(struct platform_device * pdev)197 static void st_rc_remove(struct platform_device *pdev)
198 {
199 struct st_rc_device *rc_dev = platform_get_drvdata(pdev);
200
201 dev_pm_clear_wake_irq(&pdev->dev);
202 device_init_wakeup(&pdev->dev, false);
203 clk_disable_unprepare(rc_dev->sys_clock);
204 rc_unregister_device(rc_dev->rdev);
205 }
206
st_rc_open(struct rc_dev * rdev)207 static int st_rc_open(struct rc_dev *rdev)
208 {
209 struct st_rc_device *dev = rdev->priv;
210 unsigned long flags;
211 local_irq_save(flags);
212 /* enable interrupts and receiver */
213 writel(IRB_RX_INTS, dev->rx_base + IRB_RX_INT_EN);
214 writel(0x01, dev->rx_base + IRB_RX_EN);
215 local_irq_restore(flags);
216
217 return 0;
218 }
219
st_rc_close(struct rc_dev * rdev)220 static void st_rc_close(struct rc_dev *rdev)
221 {
222 struct st_rc_device *dev = rdev->priv;
223 /* disable interrupts and receiver */
224 writel(0x00, dev->rx_base + IRB_RX_EN);
225 writel(0x00, dev->rx_base + IRB_RX_INT_EN);
226 }
227
st_rc_probe(struct platform_device * pdev)228 static int st_rc_probe(struct platform_device *pdev)
229 {
230 int ret = -EINVAL;
231 struct rc_dev *rdev;
232 struct device *dev = &pdev->dev;
233 struct st_rc_device *rc_dev;
234 struct device_node *np = pdev->dev.of_node;
235 const char *rx_mode;
236
237 rc_dev = devm_kzalloc(dev, sizeof(struct st_rc_device), GFP_KERNEL);
238
239 if (!rc_dev)
240 return -ENOMEM;
241
242 rdev = rc_allocate_device(RC_DRIVER_IR_RAW);
243
244 if (!rdev)
245 return -ENOMEM;
246
247 if (np && !of_property_read_string(np, "rx-mode", &rx_mode)) {
248
249 if (!strcmp(rx_mode, "uhf")) {
250 rc_dev->rxuhfmode = true;
251 } else if (!strcmp(rx_mode, "infrared")) {
252 rc_dev->rxuhfmode = false;
253 } else {
254 dev_err(dev, "Unsupported rx mode [%s]\n", rx_mode);
255 goto err;
256 }
257
258 } else {
259 goto err;
260 }
261
262 rc_dev->sys_clock = devm_clk_get(dev, NULL);
263 if (IS_ERR(rc_dev->sys_clock)) {
264 dev_err(dev, "System clock not found\n");
265 ret = PTR_ERR(rc_dev->sys_clock);
266 goto err;
267 }
268
269 rc_dev->irq = platform_get_irq(pdev, 0);
270 if (rc_dev->irq < 0) {
271 ret = rc_dev->irq;
272 goto err;
273 }
274
275 rc_dev->base = devm_platform_ioremap_resource(pdev, 0);
276 if (IS_ERR(rc_dev->base)) {
277 ret = PTR_ERR(rc_dev->base);
278 goto err;
279 }
280
281 if (rc_dev->rxuhfmode)
282 rc_dev->rx_base = rc_dev->base + 0x40;
283 else
284 rc_dev->rx_base = rc_dev->base;
285
286 rc_dev->rstc = reset_control_get_optional_exclusive(dev, NULL);
287 if (IS_ERR(rc_dev->rstc)) {
288 ret = PTR_ERR(rc_dev->rstc);
289 goto err;
290 }
291
292 rc_dev->dev = dev;
293 platform_set_drvdata(pdev, rc_dev);
294 ret = st_rc_hardware_init(rc_dev);
295 if (ret)
296 goto err;
297
298 rdev->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
299 /* rx sampling rate is 10Mhz */
300 rdev->rx_resolution = 100;
301 rdev->timeout = MAX_SYMB_TIME;
302 rdev->priv = rc_dev;
303 rdev->open = st_rc_open;
304 rdev->close = st_rc_close;
305 rdev->driver_name = IR_ST_NAME;
306 rdev->map_name = RC_MAP_EMPTY;
307 rdev->device_name = "ST Remote Control Receiver";
308
309 ret = rc_register_device(rdev);
310 if (ret < 0)
311 goto clkerr;
312
313 rc_dev->rdev = rdev;
314 if (devm_request_irq(dev, rc_dev->irq, st_rc_rx_interrupt,
315 0, IR_ST_NAME, rc_dev) < 0) {
316 dev_err(dev, "IRQ %d register failed\n", rc_dev->irq);
317 ret = -EINVAL;
318 goto rcerr;
319 }
320
321 /* enable wake via this device */
322 device_init_wakeup(dev, true);
323 dev_pm_set_wake_irq(dev, rc_dev->irq);
324
325 /*
326 * for LIRC_MODE_MODE2 or LIRC_MODE_PULSE or LIRC_MODE_RAW
327 * lircd expects a long space first before a signal train to sync.
328 */
329 st_rc_send_lirc_timeout(rdev);
330
331 dev_info(dev, "setup in %s mode\n", rc_dev->rxuhfmode ? "UHF" : "IR");
332
333 return ret;
334 rcerr:
335 rc_unregister_device(rdev);
336 rdev = NULL;
337 clkerr:
338 clk_disable_unprepare(rc_dev->sys_clock);
339 err:
340 rc_free_device(rdev);
341 dev_err(dev, "Unable to register device (%d)\n", ret);
342 return ret;
343 }
344
345 #ifdef CONFIG_PM_SLEEP
st_rc_suspend(struct device * dev)346 static int st_rc_suspend(struct device *dev)
347 {
348 struct st_rc_device *rc_dev = dev_get_drvdata(dev);
349
350 if (device_may_wakeup(dev)) {
351 if (!enable_irq_wake(rc_dev->irq))
352 rc_dev->irq_wake = 1;
353 else
354 return -EINVAL;
355 } else {
356 pinctrl_pm_select_sleep_state(dev);
357 writel(0x00, rc_dev->rx_base + IRB_RX_EN);
358 writel(0x00, rc_dev->rx_base + IRB_RX_INT_EN);
359 clk_disable_unprepare(rc_dev->sys_clock);
360 reset_control_assert(rc_dev->rstc);
361 }
362
363 return 0;
364 }
365
st_rc_resume(struct device * dev)366 static int st_rc_resume(struct device *dev)
367 {
368 int ret;
369 struct st_rc_device *rc_dev = dev_get_drvdata(dev);
370 struct rc_dev *rdev = rc_dev->rdev;
371
372 if (rc_dev->irq_wake) {
373 disable_irq_wake(rc_dev->irq);
374 rc_dev->irq_wake = 0;
375 } else {
376 pinctrl_pm_select_default_state(dev);
377 ret = st_rc_hardware_init(rc_dev);
378 if (ret)
379 return ret;
380
381 if (rdev->users) {
382 writel(IRB_RX_INTS, rc_dev->rx_base + IRB_RX_INT_EN);
383 writel(0x01, rc_dev->rx_base + IRB_RX_EN);
384 }
385 }
386
387 return 0;
388 }
389
390 #endif
391
392 static SIMPLE_DEV_PM_OPS(st_rc_pm_ops, st_rc_suspend, st_rc_resume);
393
394 #ifdef CONFIG_OF
395 static const struct of_device_id st_rc_match[] = {
396 { .compatible = "st,comms-irb", },
397 {},
398 };
399
400 MODULE_DEVICE_TABLE(of, st_rc_match);
401 #endif
402
403 static struct platform_driver st_rc_driver = {
404 .driver = {
405 .name = IR_ST_NAME,
406 .of_match_table = of_match_ptr(st_rc_match),
407 .pm = &st_rc_pm_ops,
408 },
409 .probe = st_rc_probe,
410 .remove_new = st_rc_remove,
411 };
412
413 module_platform_driver(st_rc_driver);
414
415 MODULE_DESCRIPTION("RC Transceiver driver for STMicroelectronics platforms");
416 MODULE_AUTHOR("STMicroelectronics (R&D) Ltd");
417 MODULE_LICENSE("GPL");
418