1 // SPDX-License-Identifier: GPL-2.0
11  * The DAC is used to find the peak level of an alternating voltage input
16  *     input +------>-------|+ \
18  *            .-------.     |    }---.
20  *            |    dac|-->--|- /     |
24  *            |    irq|------<-------'
26  *            '-------'
62 	int high;  member
63 	int level;  member
72  * (one-bit memory) for if the interrupt has triggered since last calling
75  * need to service a possible interrupt flood from the comparator when no-one
83 	spin_lock_irq(&env->comp_lock);  in envelope_detector_comp_latch()
84 	comp = env->comp;  in envelope_detector_comp_latch()
85 	env->comp = 0;  in envelope_detector_comp_latch()
86 	spin_unlock_irq(&env->comp_lock);  in envelope_detector_comp_latch()
98 	enable_irq(env->comp_irq);  in envelope_detector_comp_latch()
101 	synchronize_irq(env->comp_irq);  in envelope_detector_comp_latch()
104 	spin_lock_irq(&env->comp_lock);  in envelope_detector_comp_latch()
105 	comp = env->comp;  in envelope_detector_comp_latch()
106 	env->comp = 0;  in envelope_detector_comp_latch()
107 	spin_unlock_irq(&env->comp_lock);  in envelope_detector_comp_latch()
110 		enable_irq(env->comp_irq);  in envelope_detector_comp_latch()
119 	spin_lock(&env->comp_lock);  in envelope_detector_comp_isr()
120 	env->comp = 1;  in envelope_detector_comp_isr()
121 	disable_irq_nosync(env->comp_irq);  in envelope_detector_comp_isr()
122 	spin_unlock(&env->comp_lock);  in envelope_detector_comp_isr()
132 	 * Do a binary search for the peak input level, and stop  in envelope_detector_setup_compare()
133 	 * when that level is "trapped" between two adjacent DAC  in envelope_detector_setup_compare()
136 	 * env->level ends up as env->low when the termination  in envelope_detector_setup_compare()
138 	 * ceiling when invert is not active so that env->level  in envelope_detector_setup_compare()
139 	 * ends up as env->high in that case.  in envelope_detector_setup_compare()
141 	env->level = (env->high + env->low + !env->invert) / 2;  in envelope_detector_setup_compare()
143 	if (env->high == env->low + 1) {  in envelope_detector_setup_compare()
144 		complete(&env->done);  in envelope_detector_setup_compare()
148 	/* Set a "safe" DAC level (if there is such a thing)... */  in envelope_detector_setup_compare()
149 	ret = iio_write_channel_raw(env->dac, env->invert ? 0 : env->dac_max);  in envelope_detector_setup_compare()
156 	/* ...set the real DAC level... */  in envelope_detector_setup_compare()
157 	ret = iio_write_channel_raw(env->dac, env->level);  in envelope_detector_setup_compare()
162 	schedule_delayed_work(&env->comp_timeout,  in envelope_detector_setup_compare()
163 			      msecs_to_jiffies(env->comp_interval));  in envelope_detector_setup_compare()
167 	env->level = ret;  in envelope_detector_setup_compare()
168 	complete(&env->done);  in envelope_detector_setup_compare()
176 	/* Adjust low/high depending on the latch content... */  in envelope_detector_timeout()
177 	if (!envelope_detector_comp_latch(env) ^ !env->invert)  in envelope_detector_timeout()
178 		env->low = env->level;  in envelope_detector_timeout()
180 		env->high = env->level;  in envelope_detector_timeout()
196 		 * When invert is active, start with high=max+1 and low=0  in envelope_detector_read_raw()
199 		 * start with high=max and low=-1 when invert is not active  in envelope_detector_read_raw()
200 		 * since we will end up with the high value in that case.  in envelope_detector_read_raw()
205 		mutex_lock(&env->read_lock);  in envelope_detector_read_raw()
206 		env->high = env->dac_max + env->invert;  in envelope_detector_read_raw()
207 		env->low = -1 + env->invert;  in envelope_detector_read_raw()
209 		wait_for_completion(&env->done);  in envelope_detector_read_raw()
210 		if (env->level < 0) {  in envelope_detector_read_raw()
211 			ret = env->level;  in envelope_detector_read_raw()
214 		*val = env->invert ? env->dac_max - env->level : env->level;  in envelope_detector_read_raw()
215 		mutex_unlock(&env->read_lock);  in envelope_detector_read_raw()
220 		return iio_read_channel_scale(env->dac, val, val2);  in envelope_detector_read_raw()
223 	return -EINVAL;  in envelope_detector_read_raw()
226 	mutex_unlock(&env->read_lock);  in envelope_detector_read_raw()
236 	return sprintf(buf, "%u\n", env->invert);  in envelope_show_invert()
253 		return -EINVAL;  in envelope_store_invert()
255 	trigger = invert ? env->comp_irq_trigger_inv : env->comp_irq_trigger;  in envelope_store_invert()
257 	mutex_lock(&env->read_lock);  in envelope_store_invert()
258 	if (invert != env->invert)  in envelope_store_invert()
259 		ret = irq_set_irq_type(env->comp_irq, trigger);  in envelope_store_invert()
261 		env->invert = invert;  in envelope_store_invert()
264 	mutex_unlock(&env->read_lock);  in envelope_store_invert()
276 	return sprintf(buf, "%u\n", env->comp_interval);  in envelope_show_comp_interval()
292 		return -EINVAL;  in envelope_store_comp_interval()
294 	mutex_lock(&env->read_lock);  in envelope_store_comp_interval()
295 	env->comp_interval = interval;  in envelope_store_comp_interval()
296 	mutex_unlock(&env->read_lock);  in envelope_store_comp_interval()
325 	struct device *dev = &pdev->dev;  in envelope_detector_probe()
333 		return -ENOMEM;  in envelope_detector_probe()
337 	env->comp_interval = 50; /* some sensible default? */  in envelope_detector_probe()
339 	spin_lock_init(&env->comp_lock);  in envelope_detector_probe()
340 	mutex_init(&env->read_lock);  in envelope_detector_probe()
341 	init_completion(&env->done);  in envelope_detector_probe()
342 	INIT_DELAYED_WORK(&env->comp_timeout, envelope_detector_timeout);  in envelope_detector_probe()
344 	indio_dev->name = dev_name(dev);  in envelope_detector_probe()
345 	indio_dev->info = &envelope_detector_info;  in envelope_detector_probe()
346 	indio_dev->channels = &envelope_detector_iio_channel;  in envelope_detector_probe()
347 	indio_dev->num_channels = 1;  in envelope_detector_probe()
349 	env->dac = devm_iio_channel_get(dev, "dac");  in envelope_detector_probe()
350 	if (IS_ERR(env->dac))  in envelope_detector_probe()
351 		return dev_err_probe(dev, PTR_ERR(env->dac),  in envelope_detector_probe()
354 	env->comp_irq = platform_get_irq_byname(pdev, "comp");  in envelope_detector_probe()
355 	if (env->comp_irq < 0)  in envelope_detector_probe()
356 		return env->comp_irq;  in envelope_detector_probe()
358 	ret = devm_request_irq(dev, env->comp_irq, envelope_detector_comp_isr,  in envelope_detector_probe()
359 			       0, "envelope-detector", env);  in envelope_detector_probe()
363 	env->comp_irq_trigger = irq_get_trigger_type(env->comp_irq);  in envelope_detector_probe()
364 	if (env->comp_irq_trigger & IRQF_TRIGGER_RISING)  in envelope_detector_probe()
365 		env->comp_irq_trigger_inv |= IRQF_TRIGGER_FALLING;  in envelope_detector_probe()
366 	if (env->comp_irq_trigger & IRQF_TRIGGER_FALLING)  in envelope_detector_probe()
367 		env->comp_irq_trigger_inv |= IRQF_TRIGGER_RISING;  in envelope_detector_probe()
368 	if (env->comp_irq_trigger & IRQF_TRIGGER_HIGH)  in envelope_detector_probe()
369 		env->comp_irq_trigger_inv |= IRQF_TRIGGER_LOW;  in envelope_detector_probe()
370 	if (env->comp_irq_trigger & IRQF_TRIGGER_LOW)  in envelope_detector_probe()
371 		env->comp_irq_trigger_inv |= IRQF_TRIGGER_HIGH;  in envelope_detector_probe()
373 	ret = iio_get_channel_type(env->dac, &type);  in envelope_detector_probe()
379 		return -EINVAL;  in envelope_detector_probe()
382 	ret = iio_read_max_channel_raw(env->dac, &env->dac_max);  in envelope_detector_probe()
392 	{ .compatible = "axentia,tse850-envelope-detector", },
400 		.name = "iio-envelope-detector",