xref: /openbmc/linux/drivers/media/rc/meson-ir-tx.c (revision 47010c04) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * meson-ir-tx.c - Amlogic Meson IR TX driver
4  *
5  * Copyright (c) 2021, SberDevices. All Rights Reserved.
6  *
7  * Author: Viktor Prutyanov <viktor.prutyanov@phystech.edu>
8  */
9 
10 #include <linux/device.h>
11 #include <linux/module.h>
12 #include <linux/sched.h>
13 #include <linux/platform_device.h>
14 #include <linux/of.h>
15 #include <linux/interrupt.h>
16 #include <linux/spinlock.h>
17 #include <linux/of_irq.h>
18 #include <linux/clk.h>
19 #include <linux/slab.h>
20 #include <media/rc-core.h>
21 
22 #define DEVICE_NAME	"Meson IR TX"
23 #define DRIVER_NAME	"meson-ir-tx"
24 
25 #define MIRTX_DEFAULT_CARRIER		38000
26 #define MIRTX_DEFAULT_DUTY_CYCLE	50
27 #define MIRTX_FIFO_THD			32
28 
29 #define IRB_MOD_1US_CLK_RATE	1000000
30 
31 #define IRB_FIFO_LEN	128
32 
33 #define IRB_ADDR0	0x0
34 #define IRB_ADDR1	0x4
35 #define IRB_ADDR2	0x8
36 #define IRB_ADDR3	0xc
37 
38 #define IRB_MAX_DELAY	(1 << 10)
39 #define IRB_DELAY_MASK	(IRB_MAX_DELAY - 1)
40 
41 /* IRCTRL_IR_BLASTER_ADDR0 */
42 #define IRB_MOD_CLK(x)		((x) << 12)
43 #define IRB_MOD_SYS_CLK		0
44 #define IRB_MOD_XTAL3_CLK	1
45 #define IRB_MOD_1US_CLK		2
46 #define IRB_MOD_10US_CLK	3
47 #define IRB_INIT_HIGH		BIT(2)
48 #define IRB_ENABLE		BIT(0)
49 
50 /* IRCTRL_IR_BLASTER_ADDR2 */
51 #define IRB_MOD_COUNT(lo, hi)	((((lo) - 1) << 16) | ((hi) - 1))
52 
53 /* IRCTRL_IR_BLASTER_ADDR2 */
54 #define IRB_WRITE_FIFO	BIT(16)
55 #define IRB_MOD_ENABLE	BIT(12)
56 #define IRB_TB_1US	(0x0 << 10)
57 #define IRB_TB_10US	(0x1 << 10)
58 #define IRB_TB_100US	(0x2 << 10)
59 #define IRB_TB_MOD_CLK	(0x3 << 10)
60 
61 /* IRCTRL_IR_BLASTER_ADDR3 */
62 #define IRB_FIFO_THD_PENDING	BIT(16)
63 #define IRB_FIFO_IRQ_ENABLE	BIT(8)
64 
65 struct meson_irtx {
66 	struct device *dev;
67 	void __iomem *reg_base;
68 	u32 *buf;
69 	unsigned int buf_len;
70 	unsigned int buf_head;
71 	unsigned int carrier;
72 	unsigned int duty_cycle;
73 	/* Locks buf */
74 	spinlock_t lock;
75 	struct completion completion;
76 	unsigned long clk_rate;
77 };
78 
79 static void meson_irtx_set_mod(struct meson_irtx *ir)
80 {
81 	unsigned int cnt = DIV_ROUND_CLOSEST(ir->clk_rate, ir->carrier);
82 	unsigned int pulse_cnt = DIV_ROUND_CLOSEST(cnt * ir->duty_cycle, 100);
83 	unsigned int space_cnt = cnt - pulse_cnt;
84 
85 	dev_dbg(ir->dev, "F_mod = %uHz, T_mod = %luns, duty_cycle = %u%%\n",
86 		ir->carrier, NSEC_PER_SEC / ir->clk_rate * cnt,
87 		100 * pulse_cnt / cnt);
88 
89 	writel(IRB_MOD_COUNT(pulse_cnt, space_cnt),
90 	       ir->reg_base + IRB_ADDR1);
91 }
92 
93 static void meson_irtx_setup(struct meson_irtx *ir, unsigned int clk_nr)
94 {
95 	/*
96 	 * Disable the TX, set modulator clock tick and set initialize
97 	 * output to be high. Set up carrier frequency and duty cycle. Then
98 	 * unset initialize output. Enable FIFO interrupt, set FIFO interrupt
99 	 * threshold. Finally, enable the transmitter back.
100 	 */
101 	writel(~IRB_ENABLE & (IRB_MOD_CLK(clk_nr) | IRB_INIT_HIGH),
102 	       ir->reg_base + IRB_ADDR0);
103 	meson_irtx_set_mod(ir);
104 	writel(readl(ir->reg_base + IRB_ADDR0) & ~IRB_INIT_HIGH,
105 	       ir->reg_base + IRB_ADDR0);
106 	writel(IRB_FIFO_IRQ_ENABLE | MIRTX_FIFO_THD,
107 	       ir->reg_base + IRB_ADDR3);
108 	writel(readl(ir->reg_base + IRB_ADDR0) | IRB_ENABLE,
109 	       ir->reg_base + IRB_ADDR0);
110 }
111 
112 static u32 meson_irtx_prepare_pulse(struct meson_irtx *ir, unsigned int time)
113 {
114 	unsigned int delay;
115 	unsigned int tb = IRB_TB_MOD_CLK;
116 	unsigned int tb_us = DIV_ROUND_CLOSEST(USEC_PER_SEC, ir->carrier);
117 
118 	delay = (DIV_ROUND_CLOSEST(time, tb_us) - 1) & IRB_DELAY_MASK;
119 
120 	return ((IRB_WRITE_FIFO | IRB_MOD_ENABLE) | tb | delay);
121 }
122 
123 static u32 meson_irtx_prepare_space(struct meson_irtx *ir, unsigned int time)
124 {
125 	unsigned int delay;
126 	unsigned int tb = IRB_TB_100US;
127 	unsigned int tb_us = 100;
128 
129 	if (time <= IRB_MAX_DELAY) {
130 		tb = IRB_TB_1US;
131 		tb_us = 1;
132 	} else if (time <= 10 * IRB_MAX_DELAY) {
133 		tb = IRB_TB_10US;
134 		tb_us = 10;
135 	} else if (time <= 100 * IRB_MAX_DELAY) {
136 		tb = IRB_TB_100US;
137 		tb_us = 100;
138 	}
139 
140 	delay = (DIV_ROUND_CLOSEST(time, tb_us) - 1) & IRB_DELAY_MASK;
141 
142 	return ((IRB_WRITE_FIFO & ~IRB_MOD_ENABLE) | tb | delay);
143 }
144 
145 static void meson_irtx_send_buffer(struct meson_irtx *ir)
146 {
147 	unsigned int nr = 0;
148 	unsigned int max_fifo_level = IRB_FIFO_LEN - MIRTX_FIFO_THD;
149 
150 	while (ir->buf_head < ir->buf_len && nr < max_fifo_level) {
151 		writel(ir->buf[ir->buf_head], ir->reg_base + IRB_ADDR2);
152 
153 		ir->buf_head++;
154 		nr++;
155 	}
156 }
157 
158 static bool meson_irtx_check_buf(struct meson_irtx *ir,
159 				 unsigned int *buf, unsigned int len)
160 {
161 	unsigned int i;
162 
163 	for (i = 0; i < len; i++) {
164 		unsigned int max_tb_us;
165 		/*
166 		 * Max space timebase is 100 us.
167 		 * Pulse timebase equals to carrier period.
168 		 */
169 		if (i % 2 == 0)
170 			max_tb_us = USEC_PER_SEC / ir->carrier;
171 		else
172 			max_tb_us = 100;
173 
174 		if (buf[i] >= max_tb_us * IRB_MAX_DELAY)
175 			return false;
176 	}
177 
178 	return true;
179 }
180 
181 static void meson_irtx_fill_buf(struct meson_irtx *ir, u32 *dst_buf,
182 				unsigned int *src_buf, unsigned int len)
183 {
184 	unsigned int i;
185 
186 	for (i = 0; i < len; i++) {
187 		if (i % 2 == 0)
188 			dst_buf[i] = meson_irtx_prepare_pulse(ir, src_buf[i]);
189 		else
190 			dst_buf[i] = meson_irtx_prepare_space(ir, src_buf[i]);
191 	}
192 }
193 
194 static irqreturn_t meson_irtx_irqhandler(int irq, void *data)
195 {
196 	unsigned long flags;
197 	struct meson_irtx *ir = data;
198 
199 	writel(readl(ir->reg_base + IRB_ADDR3) & ~IRB_FIFO_THD_PENDING,
200 	       ir->reg_base + IRB_ADDR3);
201 
202 	if (completion_done(&ir->completion))
203 		return IRQ_HANDLED;
204 
205 	spin_lock_irqsave(&ir->lock, flags);
206 	if (ir->buf_head < ir->buf_len)
207 		meson_irtx_send_buffer(ir);
208 	else
209 		complete(&ir->completion);
210 	spin_unlock_irqrestore(&ir->lock, flags);
211 
212 	return IRQ_HANDLED;
213 }
214 
215 static int meson_irtx_set_carrier(struct rc_dev *rc, u32 carrier)
216 {
217 	struct meson_irtx *ir = rc->priv;
218 
219 	if (carrier == 0)
220 		return -EINVAL;
221 
222 	ir->carrier = carrier;
223 	meson_irtx_set_mod(ir);
224 
225 	return 0;
226 }
227 
228 static int meson_irtx_set_duty_cycle(struct rc_dev *rc, u32 duty_cycle)
229 {
230 	struct meson_irtx *ir = rc->priv;
231 
232 	ir->duty_cycle = duty_cycle;
233 	meson_irtx_set_mod(ir);
234 
235 	return 0;
236 }
237 
238 static void meson_irtx_update_buf(struct meson_irtx *ir, u32 *buf,
239 				  unsigned int len, unsigned int head)
240 {
241 	ir->buf = buf;
242 	ir->buf_len = len;
243 	ir->buf_head = head;
244 }
245 
246 static int meson_irtx_transmit(struct rc_dev *rc, unsigned int *buf,
247 			       unsigned int len)
248 {
249 	unsigned long flags;
250 	struct meson_irtx *ir = rc->priv;
251 	u32 *tx_buf;
252 	int ret = len;
253 
254 	if (!meson_irtx_check_buf(ir, buf, len))
255 		return -EINVAL;
256 
257 	tx_buf = kmalloc_array(len, sizeof(u32), GFP_KERNEL);
258 	if (!tx_buf)
259 		return -ENOMEM;
260 
261 	meson_irtx_fill_buf(ir, tx_buf, buf, len);
262 	dev_dbg(ir->dev, "TX buffer filled, length = %u\n", len);
263 
264 	spin_lock_irqsave(&ir->lock, flags);
265 	meson_irtx_update_buf(ir, tx_buf, len, 0);
266 	reinit_completion(&ir->completion);
267 	meson_irtx_send_buffer(ir);
268 	spin_unlock_irqrestore(&ir->lock, flags);
269 
270 	if (!wait_for_completion_timeout(&ir->completion,
271 					 usecs_to_jiffies(IR_MAX_DURATION)))
272 		ret = -ETIMEDOUT;
273 
274 	spin_lock_irqsave(&ir->lock, flags);
275 	kfree(ir->buf);
276 	meson_irtx_update_buf(ir, NULL, 0, 0);
277 	spin_unlock_irqrestore(&ir->lock, flags);
278 
279 	return ret;
280 }
281 
282 static int meson_irtx_mod_clock_probe(struct meson_irtx *ir,
283 				      unsigned int *clk_nr)
284 {
285 	struct device_node *np = ir->dev->of_node;
286 	struct clk *clock;
287 
288 	if (!np)
289 		return -ENODEV;
290 
291 	clock = devm_clk_get(ir->dev, "xtal");
292 	if (IS_ERR(clock) || clk_prepare_enable(clock))
293 		return -ENODEV;
294 
295 	*clk_nr = IRB_MOD_XTAL3_CLK;
296 	ir->clk_rate = clk_get_rate(clock) / 3;
297 
298 	if (ir->clk_rate < IRB_MOD_1US_CLK_RATE) {
299 		*clk_nr = IRB_MOD_1US_CLK;
300 		ir->clk_rate = IRB_MOD_1US_CLK_RATE;
301 	}
302 
303 	dev_info(ir->dev, "F_clk = %luHz\n", ir->clk_rate);
304 
305 	return 0;
306 }
307 
308 static int __init meson_irtx_probe(struct platform_device *pdev)
309 {
310 	struct device *dev = &pdev->dev;
311 	struct meson_irtx *ir;
312 	struct rc_dev *rc;
313 	int irq;
314 	unsigned int clk_nr;
315 	int ret;
316 
317 	ir = devm_kzalloc(dev, sizeof(*ir), GFP_KERNEL);
318 	if (!ir)
319 		return -ENOMEM;
320 
321 	ir->reg_base = devm_platform_ioremap_resource(pdev, 0);
322 	if (IS_ERR(ir->reg_base))
323 		return PTR_ERR(ir->reg_base);
324 
325 	irq = platform_get_irq(pdev, 0);
326 	if (irq < 0) {
327 		dev_err(dev, "no irq resource found\n");
328 		return -ENODEV;
329 	}
330 
331 	ir->dev = dev;
332 	ir->carrier = MIRTX_DEFAULT_CARRIER;
333 	ir->duty_cycle = MIRTX_DEFAULT_DUTY_CYCLE;
334 	init_completion(&ir->completion);
335 	spin_lock_init(&ir->lock);
336 
337 	ret = meson_irtx_mod_clock_probe(ir, &clk_nr);
338 	if (ret) {
339 		dev_err(dev, "modulator clock setup failed\n");
340 		return ret;
341 	}
342 	meson_irtx_setup(ir, clk_nr);
343 
344 	ret = devm_request_irq(dev, irq,
345 			       meson_irtx_irqhandler,
346 			       IRQF_TRIGGER_RISING,
347 			       DRIVER_NAME, ir);
348 	if (ret) {
349 		dev_err(dev, "irq request failed\n");
350 		return ret;
351 	}
352 
353 	rc = rc_allocate_device(RC_DRIVER_IR_RAW_TX);
354 	if (!rc)
355 		return -ENOMEM;
356 
357 	rc->driver_name = DRIVER_NAME;
358 	rc->device_name = DEVICE_NAME;
359 	rc->priv = ir;
360 
361 	rc->tx_ir = meson_irtx_transmit;
362 	rc->s_tx_carrier = meson_irtx_set_carrier;
363 	rc->s_tx_duty_cycle = meson_irtx_set_duty_cycle;
364 
365 	ret = rc_register_device(rc);
366 	if (ret < 0) {
367 		dev_err(dev, "rc_dev registration failed\n");
368 		rc_free_device(rc);
369 		return ret;
370 	}
371 
372 	platform_set_drvdata(pdev, rc);
373 
374 	return 0;
375 }
376 
377 static int meson_irtx_remove(struct platform_device *pdev)
378 {
379 	struct rc_dev *rc = platform_get_drvdata(pdev);
380 
381 	rc_unregister_device(rc);
382 
383 	return 0;
384 }
385 
386 static const struct of_device_id meson_irtx_dt_match[] = {
387 	{
388 		.compatible = "amlogic,meson-g12a-ir-tx",
389 	},
390 	{},
391 };
392 MODULE_DEVICE_TABLE(of, meson_irtx_dt_match);
393 
394 static struct platform_driver meson_irtx_pd = {
395 	.remove = meson_irtx_remove,
396 	.driver = {
397 		.name = DRIVER_NAME,
398 		.of_match_table = meson_irtx_dt_match,
399 	},
400 };
401 
402 module_platform_driver_probe(meson_irtx_pd, meson_irtx_probe);
403 
404 MODULE_DESCRIPTION("Meson IR TX driver");
405 MODULE_AUTHOR("Viktor Prutyanov <viktor.prutyanov@phystech.edu>");
406 MODULE_LICENSE("GPL");
407