1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Driver for Mediatek IR Receiver Controller
4 *
5 * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com>
6 */
7
8 #include <linux/clk.h>
9 #include <linux/interrupt.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/platform_device.h>
13 #include <linux/reset.h>
14 #include <media/rc-core.h>
15
16 #define MTK_IR_DEV KBUILD_MODNAME
17
18 /* Register to enable PWM and IR */
19 #define MTK_CONFIG_HIGH_REG 0x0c
20
21 /* Bit to enable IR pulse width detection */
22 #define MTK_PWM_EN BIT(13)
23
24 /*
25 * Register to setting ok count whose unit based on hardware sampling period
26 * indicating IR receiving completion and then making IRQ fires
27 */
28 #define MTK_OK_COUNT_MASK (GENMASK(22, 16))
29 #define MTK_OK_COUNT(x) ((x) << 16)
30
31 /* Bit to enable IR hardware function */
32 #define MTK_IR_EN BIT(0)
33
34 /* Bit to restart IR receiving */
35 #define MTK_IRCLR BIT(0)
36
37 /* Fields containing pulse width data */
38 #define MTK_WIDTH_MASK (GENMASK(7, 0))
39
40 /* IR threshold */
41 #define MTK_IRTHD 0x14
42 #define MTK_DG_CNT_MASK (GENMASK(12, 8))
43 #define MTK_DG_CNT(x) ((x) << 8)
44
45 /* Bit to enable interrupt */
46 #define MTK_IRINT_EN BIT(0)
47
48 /* Bit to clear interrupt status */
49 #define MTK_IRINT_CLR BIT(0)
50
51 /* Maximum count of samples */
52 #define MTK_MAX_SAMPLES 0xff
53 /* Indicate the end of IR message */
54 #define MTK_IR_END(v, p) ((v) == MTK_MAX_SAMPLES && (p) == 0)
55 /* Number of registers to record the pulse width */
56 #define MTK_CHKDATA_SZ 17
57 /* Sample period in us */
58 #define MTK_IR_SAMPLE 46
59
60 enum mtk_fields {
61 /* Register to setting software sampling period */
62 MTK_CHK_PERIOD,
63 /* Register to setting hardware sampling period */
64 MTK_HW_PERIOD,
65 };
66
67 enum mtk_regs {
68 /* Register to clear state of state machine */
69 MTK_IRCLR_REG,
70 /* Register containing pulse width data */
71 MTK_CHKDATA_REG,
72 /* Register to enable IR interrupt */
73 MTK_IRINT_EN_REG,
74 /* Register to ack IR interrupt */
75 MTK_IRINT_CLR_REG
76 };
77
78 static const u32 mt7623_regs[] = {
79 [MTK_IRCLR_REG] = 0x20,
80 [MTK_CHKDATA_REG] = 0x88,
81 [MTK_IRINT_EN_REG] = 0xcc,
82 [MTK_IRINT_CLR_REG] = 0xd0,
83 };
84
85 static const u32 mt7622_regs[] = {
86 [MTK_IRCLR_REG] = 0x18,
87 [MTK_CHKDATA_REG] = 0x30,
88 [MTK_IRINT_EN_REG] = 0x1c,
89 [MTK_IRINT_CLR_REG] = 0x20,
90 };
91
92 struct mtk_field_type {
93 u32 reg;
94 u8 offset;
95 u32 mask;
96 };
97
98 /*
99 * struct mtk_ir_data - This is the structure holding all differences among
100 various hardwares
101 * @regs: The pointer to the array holding registers offset
102 * @fields: The pointer to the array holding fields location
103 * @div: The internal divisor for the based reference clock
104 * @ok_count: The count indicating the completion of IR data
105 * receiving when count is reached
106 * @hw_period: The value indicating the hardware sampling period
107 */
108 struct mtk_ir_data {
109 const u32 *regs;
110 const struct mtk_field_type *fields;
111 u8 div;
112 u8 ok_count;
113 u32 hw_period;
114 };
115
116 static const struct mtk_field_type mt7623_fields[] = {
117 [MTK_CHK_PERIOD] = {0x10, 8, GENMASK(20, 8)},
118 [MTK_HW_PERIOD] = {0x10, 0, GENMASK(7, 0)},
119 };
120
121 static const struct mtk_field_type mt7622_fields[] = {
122 [MTK_CHK_PERIOD] = {0x24, 0, GENMASK(24, 0)},
123 [MTK_HW_PERIOD] = {0x10, 0, GENMASK(24, 0)},
124 };
125
126 /*
127 * struct mtk_ir - This is the main datasructure for holding the state
128 * of the driver
129 * @dev: The device pointer
130 * @rc: The rc instrance
131 * @base: The mapped register i/o base
132 * @irq: The IRQ that we are using
133 * @clk: The clock that IR internal is using
134 * @bus: The clock that software decoder is using
135 * @data: Holding specific data for vaious platform
136 */
137 struct mtk_ir {
138 struct device *dev;
139 struct rc_dev *rc;
140 void __iomem *base;
141 int irq;
142 struct clk *clk;
143 struct clk *bus;
144 const struct mtk_ir_data *data;
145 };
146
mtk_chkdata_reg(struct mtk_ir * ir,u32 i)147 static inline u32 mtk_chkdata_reg(struct mtk_ir *ir, u32 i)
148 {
149 return ir->data->regs[MTK_CHKDATA_REG] + 4 * i;
150 }
151
mtk_chk_period(struct mtk_ir * ir)152 static inline u32 mtk_chk_period(struct mtk_ir *ir)
153 {
154 u32 val;
155
156 /*
157 * Period for software decoder used in the
158 * unit of raw software sampling
159 */
160 val = DIV_ROUND_CLOSEST(clk_get_rate(ir->bus),
161 USEC_PER_SEC * ir->data->div / MTK_IR_SAMPLE);
162
163 dev_dbg(ir->dev, "@pwm clk = \t%lu\n",
164 clk_get_rate(ir->bus) / ir->data->div);
165 dev_dbg(ir->dev, "@chkperiod = %08x\n", val);
166
167 return val;
168 }
169
mtk_w32_mask(struct mtk_ir * ir,u32 val,u32 mask,unsigned int reg)170 static void mtk_w32_mask(struct mtk_ir *ir, u32 val, u32 mask, unsigned int reg)
171 {
172 u32 tmp;
173
174 tmp = __raw_readl(ir->base + reg);
175 tmp = (tmp & ~mask) | val;
176 __raw_writel(tmp, ir->base + reg);
177 }
178
mtk_w32(struct mtk_ir * ir,u32 val,unsigned int reg)179 static void mtk_w32(struct mtk_ir *ir, u32 val, unsigned int reg)
180 {
181 __raw_writel(val, ir->base + reg);
182 }
183
mtk_r32(struct mtk_ir * ir,unsigned int reg)184 static u32 mtk_r32(struct mtk_ir *ir, unsigned int reg)
185 {
186 return __raw_readl(ir->base + reg);
187 }
188
mtk_irq_disable(struct mtk_ir * ir,u32 mask)189 static inline void mtk_irq_disable(struct mtk_ir *ir, u32 mask)
190 {
191 u32 val;
192
193 val = mtk_r32(ir, ir->data->regs[MTK_IRINT_EN_REG]);
194 mtk_w32(ir, val & ~mask, ir->data->regs[MTK_IRINT_EN_REG]);
195 }
196
mtk_irq_enable(struct mtk_ir * ir,u32 mask)197 static inline void mtk_irq_enable(struct mtk_ir *ir, u32 mask)
198 {
199 u32 val;
200
201 val = mtk_r32(ir, ir->data->regs[MTK_IRINT_EN_REG]);
202 mtk_w32(ir, val | mask, ir->data->regs[MTK_IRINT_EN_REG]);
203 }
204
mtk_ir_irq(int irqno,void * dev_id)205 static irqreturn_t mtk_ir_irq(int irqno, void *dev_id)
206 {
207 struct ir_raw_event rawir = {};
208 struct mtk_ir *ir = dev_id;
209 u32 i, j, val;
210 u8 wid;
211
212 /*
213 * Each pulse and space is encoded as a single byte, each byte
214 * alternating between pulse and space. If a pulse or space is longer
215 * than can be encoded in a single byte, it is encoded as the maximum
216 * value 0xff.
217 *
218 * If a space is longer than ok_count (about 23ms), the value is
219 * encoded as zero, and all following bytes are zero. Any IR that
220 * follows will be presented in the next interrupt.
221 *
222 * If there are more than 68 (=MTK_CHKDATA_SZ * 4) pulses and spaces,
223 * then the only the first 68 will be presented; the rest is lost.
224 */
225
226 /* Handle all pulse and space IR controller captures */
227 for (i = 0 ; i < MTK_CHKDATA_SZ ; i++) {
228 val = mtk_r32(ir, mtk_chkdata_reg(ir, i));
229 dev_dbg(ir->dev, "@reg%d=0x%08x\n", i, val);
230
231 for (j = 0 ; j < 4 ; j++) {
232 wid = val & MTK_WIDTH_MASK;
233 val >>= 8;
234 rawir.pulse = !rawir.pulse;
235 rawir.duration = wid * (MTK_IR_SAMPLE + 1);
236 ir_raw_event_store_with_filter(ir->rc, &rawir);
237 }
238 }
239
240 /*
241 * The maximum number of edges the IR controller can
242 * hold is MTK_CHKDATA_SZ * 4. So if received IR messages
243 * is over the limit, the last incomplete IR message would
244 * be appended trailing space and still would be sent into
245 * ir-rc-raw to decode. That helps it is possible that it
246 * has enough information to decode a scancode even if the
247 * trailing end of the message is missing.
248 */
249 if (!MTK_IR_END(wid, rawir.pulse)) {
250 rawir.pulse = false;
251 rawir.duration = MTK_MAX_SAMPLES * (MTK_IR_SAMPLE + 1);
252 ir_raw_event_store_with_filter(ir->rc, &rawir);
253 }
254
255 ir_raw_event_handle(ir->rc);
256
257 /*
258 * Restart controller for the next receive that would
259 * clear up all CHKDATA registers
260 */
261 mtk_w32_mask(ir, 0x1, MTK_IRCLR, ir->data->regs[MTK_IRCLR_REG]);
262
263 /* Clear interrupt status */
264 mtk_w32_mask(ir, 0x1, MTK_IRINT_CLR,
265 ir->data->regs[MTK_IRINT_CLR_REG]);
266
267 return IRQ_HANDLED;
268 }
269
270 static const struct mtk_ir_data mt7623_data = {
271 .regs = mt7623_regs,
272 .fields = mt7623_fields,
273 .ok_count = 3,
274 .hw_period = 0xff,
275 .div = 4,
276 };
277
278 static const struct mtk_ir_data mt7622_data = {
279 .regs = mt7622_regs,
280 .fields = mt7622_fields,
281 .ok_count = 3,
282 .hw_period = 0xffff,
283 .div = 32,
284 };
285
286 static const struct of_device_id mtk_ir_match[] = {
287 { .compatible = "mediatek,mt7623-cir", .data = &mt7623_data},
288 { .compatible = "mediatek,mt7622-cir", .data = &mt7622_data},
289 {},
290 };
291 MODULE_DEVICE_TABLE(of, mtk_ir_match);
292
mtk_ir_probe(struct platform_device * pdev)293 static int mtk_ir_probe(struct platform_device *pdev)
294 {
295 struct device *dev = &pdev->dev;
296 struct device_node *dn = dev->of_node;
297 struct mtk_ir *ir;
298 u32 val;
299 int ret = 0;
300 const char *map_name;
301
302 ir = devm_kzalloc(dev, sizeof(struct mtk_ir), GFP_KERNEL);
303 if (!ir)
304 return -ENOMEM;
305
306 ir->dev = dev;
307 ir->data = of_device_get_match_data(dev);
308
309 ir->clk = devm_clk_get(dev, "clk");
310 if (IS_ERR(ir->clk)) {
311 dev_err(dev, "failed to get a ir clock.\n");
312 return PTR_ERR(ir->clk);
313 }
314
315 ir->bus = devm_clk_get(dev, "bus");
316 if (IS_ERR(ir->bus)) {
317 /*
318 * For compatibility with older device trees try unnamed
319 * ir->bus uses the same clock as ir->clock.
320 */
321 ir->bus = ir->clk;
322 }
323
324 ir->base = devm_platform_ioremap_resource(pdev, 0);
325 if (IS_ERR(ir->base))
326 return PTR_ERR(ir->base);
327
328 ir->rc = devm_rc_allocate_device(dev, RC_DRIVER_IR_RAW);
329 if (!ir->rc) {
330 dev_err(dev, "failed to allocate device\n");
331 return -ENOMEM;
332 }
333
334 ir->rc->priv = ir;
335 ir->rc->device_name = MTK_IR_DEV;
336 ir->rc->input_phys = MTK_IR_DEV "/input0";
337 ir->rc->input_id.bustype = BUS_HOST;
338 ir->rc->input_id.vendor = 0x0001;
339 ir->rc->input_id.product = 0x0001;
340 ir->rc->input_id.version = 0x0001;
341 map_name = of_get_property(dn, "linux,rc-map-name", NULL);
342 ir->rc->map_name = map_name ?: RC_MAP_EMPTY;
343 ir->rc->dev.parent = dev;
344 ir->rc->driver_name = MTK_IR_DEV;
345 ir->rc->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
346 ir->rc->rx_resolution = MTK_IR_SAMPLE;
347 ir->rc->timeout = MTK_MAX_SAMPLES * (MTK_IR_SAMPLE + 1);
348
349 ret = devm_rc_register_device(dev, ir->rc);
350 if (ret) {
351 dev_err(dev, "failed to register rc device\n");
352 return ret;
353 }
354
355 platform_set_drvdata(pdev, ir);
356
357 ir->irq = platform_get_irq(pdev, 0);
358 if (ir->irq < 0)
359 return -ENODEV;
360
361 if (clk_prepare_enable(ir->clk)) {
362 dev_err(dev, "try to enable ir_clk failed\n");
363 return -EINVAL;
364 }
365
366 if (clk_prepare_enable(ir->bus)) {
367 dev_err(dev, "try to enable ir_clk failed\n");
368 ret = -EINVAL;
369 goto exit_clkdisable_clk;
370 }
371
372 /*
373 * Enable interrupt after proper hardware
374 * setup and IRQ handler registration
375 */
376 mtk_irq_disable(ir, MTK_IRINT_EN);
377
378 ret = devm_request_irq(dev, ir->irq, mtk_ir_irq, 0, MTK_IR_DEV, ir);
379 if (ret) {
380 dev_err(dev, "failed request irq\n");
381 goto exit_clkdisable_bus;
382 }
383
384 /*
385 * Setup software sample period as the reference of software decoder
386 */
387 val = (mtk_chk_period(ir) << ir->data->fields[MTK_CHK_PERIOD].offset) &
388 ir->data->fields[MTK_CHK_PERIOD].mask;
389 mtk_w32_mask(ir, val, ir->data->fields[MTK_CHK_PERIOD].mask,
390 ir->data->fields[MTK_CHK_PERIOD].reg);
391
392 /*
393 * Setup hardware sampling period used to setup the proper timeout for
394 * indicating end of IR receiving completion
395 */
396 val = (ir->data->hw_period << ir->data->fields[MTK_HW_PERIOD].offset) &
397 ir->data->fields[MTK_HW_PERIOD].mask;
398 mtk_w32_mask(ir, val, ir->data->fields[MTK_HW_PERIOD].mask,
399 ir->data->fields[MTK_HW_PERIOD].reg);
400
401 /* Set de-glitch counter */
402 mtk_w32_mask(ir, MTK_DG_CNT(1), MTK_DG_CNT_MASK, MTK_IRTHD);
403
404 /* Enable IR and PWM */
405 val = mtk_r32(ir, MTK_CONFIG_HIGH_REG) & ~MTK_OK_COUNT_MASK;
406 val |= MTK_OK_COUNT(ir->data->ok_count) | MTK_PWM_EN | MTK_IR_EN;
407 mtk_w32(ir, val, MTK_CONFIG_HIGH_REG);
408
409 mtk_irq_enable(ir, MTK_IRINT_EN);
410
411 dev_info(dev, "Initialized MT7623 IR driver, sample period = %dus\n",
412 MTK_IR_SAMPLE);
413
414 return 0;
415
416 exit_clkdisable_bus:
417 clk_disable_unprepare(ir->bus);
418 exit_clkdisable_clk:
419 clk_disable_unprepare(ir->clk);
420
421 return ret;
422 }
423
mtk_ir_remove(struct platform_device * pdev)424 static void mtk_ir_remove(struct platform_device *pdev)
425 {
426 struct mtk_ir *ir = platform_get_drvdata(pdev);
427
428 /*
429 * Avoid contention between remove handler and
430 * IRQ handler so that disabling IR interrupt and
431 * waiting for pending IRQ handler to complete
432 */
433 mtk_irq_disable(ir, MTK_IRINT_EN);
434 synchronize_irq(ir->irq);
435
436 clk_disable_unprepare(ir->bus);
437 clk_disable_unprepare(ir->clk);
438 }
439
440 static struct platform_driver mtk_ir_driver = {
441 .probe = mtk_ir_probe,
442 .remove_new = mtk_ir_remove,
443 .driver = {
444 .name = MTK_IR_DEV,
445 .of_match_table = mtk_ir_match,
446 },
447 };
448
449 module_platform_driver(mtk_ir_driver);
450
451 MODULE_DESCRIPTION("Mediatek IR Receiver Controller Driver");
452 MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
453 MODULE_LICENSE("GPL");
454
