Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * Driver for an envelope detector using a DAC and a comparator
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Copyright (C) 2016 Axentia Technologies AB
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  * Author: Peter Rosin <peda@axentia.se>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11)  * The DAC is used to find the peak level of an alternating voltage input
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  * signal by a binary search using the output of a comparator wired to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  * an interrupt pin. Like so:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  *                           _
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  *                          | \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16)  *     input +------>-------|+ \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17)  *                          |   \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18)  *            .-------.     |    }---.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19)  *            |       |     |   /    |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20)  *            |    dac|-->--|- /     |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  *            |       |     |_/      |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  *            |       |              |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23)  *            |       |              |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24)  *            |    irq|------<-------'
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25)  *            |       |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26)  *            '-------'
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) #include <linux/completion.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) #include <linux/device.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) #include <linux/err.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) #include <linux/mutex.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) #include <linux/iio/consumer.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) #include <linux/iio/iio.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) #include <linux/iio/sysfs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) #include <linux/interrupt.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) #include <linux/irq.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) #include <linux/of.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) #include <linux/of_device.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) #include <linux/platform_device.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) #include <linux/spinlock.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) #include <linux/workqueue.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) struct envelope {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	spinlock_t comp_lock; /* protects comp */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	int comp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	struct mutex read_lock; /* protects everything else */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 	int comp_irq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	u32 comp_irq_trigger;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 	u32 comp_irq_trigger_inv;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	struct iio_channel *dac;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	struct delayed_work comp_timeout;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	unsigned int comp_interval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	bool invert;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 	u32 dac_max;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	int high;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	int level;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	int low;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	struct completion done;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71)  * The envelope_detector_comp_latch function works together with the compare
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72)  * interrupt service routine below (envelope_detector_comp_isr) as a latch
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73)  * (one-bit memory) for if the interrupt has triggered since last calling
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74)  * this function.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75)  * The ..._comp_isr function disables the interrupt so that the cpu does not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76)  * need to service a possible interrupt flood from the comparator when no-one
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77)  * cares anyway, and this ..._comp_latch function reenables them again if
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78)  * needed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) static int envelope_detector_comp_latch(struct envelope *env)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	int comp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	spin_lock_irq(&env->comp_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 	comp = env->comp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 	env->comp = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	spin_unlock_irq(&env->comp_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	if (!comp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	 * The irq was disabled, and is reenabled just now.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	 * But there might have been a pending irq that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	 * happened while the irq was disabled that fires
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	 * just as the irq is reenabled. That is not what
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	 * is desired.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	enable_irq(env->comp_irq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	/* So, synchronize this possibly pending irq... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	synchronize_irq(env->comp_irq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	/* ...and redo the whole dance. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	spin_lock_irq(&env->comp_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 	comp = env->comp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	env->comp = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	spin_unlock_irq(&env->comp_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	if (comp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 		enable_irq(env->comp_irq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) static irqreturn_t envelope_detector_comp_isr(int irq, void *ctx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	struct envelope *env = ctx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	spin_lock(&env->comp_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	env->comp = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	disable_irq_nosync(env->comp_irq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	spin_unlock(&env->comp_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	return IRQ_HANDLED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) static void envelope_detector_setup_compare(struct envelope *env)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	 * Do a binary search for the peak input level, and stop
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	 * when that level is "trapped" between two adjacent DAC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	 * values.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	 * When invert is active, use the midpoint floor so that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	 * env->level ends up as env->low when the termination
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	 * criteria below is fulfilled, and use the midpoint
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	 * ceiling when invert is not active so that env->level
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	 * ends up as env->high in that case.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	env->level = (env->high + env->low + !env->invert) / 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	if (env->high == env->low + 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 		complete(&env->done);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 	/* Set a "safe" DAC level (if there is such a thing)... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	ret = iio_write_channel_raw(env->dac, env->invert ? 0 : env->dac_max);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 		goto err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	/* ...clear the comparison result... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	envelope_detector_comp_latch(env);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	/* ...set the real DAC level... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	ret = iio_write_channel_raw(env->dac, env->level);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 		goto err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	/* ...and wait for a bit to see if the latch catches anything. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	schedule_delayed_work(&env->comp_timeout,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 			      msecs_to_jiffies(env->comp_interval));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) err:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	env->level = ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	complete(&env->done);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) static void envelope_detector_timeout(struct work_struct *work)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	struct envelope *env = container_of(work, struct envelope,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 					    comp_timeout.work);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	/* Adjust low/high depending on the latch content... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	if (!envelope_detector_comp_latch(env) ^ !env->invert)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 		env->low = env->level;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 		env->high = env->level;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 	/* ...and continue the search. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 	envelope_detector_setup_compare(env);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) static int envelope_detector_read_raw(struct iio_dev *indio_dev,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 				      struct iio_chan_spec const *chan,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 				      int *val, int *val2, long mask)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 	struct envelope *env = iio_priv(indio_dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	switch (mask) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	case IIO_CHAN_INFO_RAW:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 		 * When invert is active, start with high=max+1 and low=0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 		 * since we will end up with the low value when the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 		 * termination criteria is fulfilled (rounding down). And
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 		 * start with high=max and low=-1 when invert is not active
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 		 * since we will end up with the high value in that case.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 		 * This ensures that the returned value in both cases are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 		 * in the same range as the DAC and is a value that has not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 		 * triggered the comparator.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 		mutex_lock(&env->read_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 		env->high = env->dac_max + env->invert;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 		env->low = -1 + env->invert;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 		envelope_detector_setup_compare(env);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 		wait_for_completion(&env->done);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 		if (env->level < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 			ret = env->level;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 			goto err_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 		*val = env->invert ? env->dac_max - env->level : env->level;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 		mutex_unlock(&env->read_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 		return IIO_VAL_INT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 	case IIO_CHAN_INFO_SCALE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 		return iio_read_channel_scale(env->dac, val, val2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 	return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) err_unlock:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 	mutex_unlock(&env->read_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) static ssize_t envelope_show_invert(struct iio_dev *indio_dev,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 				    uintptr_t private,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 				    struct iio_chan_spec const *ch, char *buf)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 	struct envelope *env = iio_priv(indio_dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 	return sprintf(buf, "%u\n", env->invert);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) static ssize_t envelope_store_invert(struct iio_dev *indio_dev,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 				     uintptr_t private,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 				     struct iio_chan_spec const *ch,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 				     const char *buf, size_t len)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	struct envelope *env = iio_priv(indio_dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 	unsigned long invert;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	u32 trigger;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	ret = kstrtoul(buf, 0, &invert);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 		return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 	if (invert > 1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	trigger = invert ? env->comp_irq_trigger_inv : env->comp_irq_trigger;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	mutex_lock(&env->read_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	if (invert != env->invert)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 		ret = irq_set_irq_type(env->comp_irq, trigger);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 	if (!ret) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 		env->invert = invert;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 		ret = len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 	mutex_unlock(&env->read_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) static ssize_t envelope_show_comp_interval(struct iio_dev *indio_dev,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 					   uintptr_t private,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 					   struct iio_chan_spec const *ch,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 					   char *buf)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	struct envelope *env = iio_priv(indio_dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 	return sprintf(buf, "%u\n", env->comp_interval);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) static ssize_t envelope_store_comp_interval(struct iio_dev *indio_dev,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 					    uintptr_t private,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 					    struct iio_chan_spec const *ch,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 					    const char *buf, size_t len)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 	struct envelope *env = iio_priv(indio_dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 	unsigned long interval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 	ret = kstrtoul(buf, 0, &interval);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 	if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 		return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 	if (interval > 1000)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	mutex_lock(&env->read_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 	env->comp_interval = interval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 	mutex_unlock(&env->read_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 	return len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) static const struct iio_chan_spec_ext_info envelope_detector_ext_info[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 	{ .name = "invert",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 	  .read = envelope_show_invert,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 	  .write = envelope_store_invert, },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 	{ .name = "compare_interval",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 	  .read = envelope_show_comp_interval,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	  .write = envelope_store_comp_interval, },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 	{ /* sentinel */ }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) static const struct iio_chan_spec envelope_detector_iio_channel = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 	.type = IIO_ALTVOLTAGE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 			    | BIT(IIO_CHAN_INFO_SCALE),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 	.ext_info = envelope_detector_ext_info,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 	.indexed = 1,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) static const struct iio_info envelope_detector_info = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 	.read_raw = &envelope_detector_read_raw,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) static int envelope_detector_probe(struct platform_device *pdev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 	struct device *dev = &pdev->dev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 	struct iio_dev *indio_dev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 	struct envelope *env;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 	enum iio_chan_type type;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 	indio_dev = devm_iio_device_alloc(dev, sizeof(*env));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 	if (!indio_dev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) 	platform_set_drvdata(pdev, indio_dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 	env = iio_priv(indio_dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 	env->comp_interval = 50; /* some sensible default? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) 	spin_lock_init(&env->comp_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) 	mutex_init(&env->read_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) 	init_completion(&env->done);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) 	INIT_DELAYED_WORK(&env->comp_timeout, envelope_detector_timeout);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) 	indio_dev->name = dev_name(dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) 	indio_dev->info = &envelope_detector_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) 	indio_dev->channels = &envelope_detector_iio_channel;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) 	indio_dev->num_channels = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) 	env->dac = devm_iio_channel_get(dev, "dac");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 	if (IS_ERR(env->dac))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) 		return dev_err_probe(dev, PTR_ERR(env->dac),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) 				     "failed to get dac input channel\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) 	env->comp_irq = platform_get_irq_byname(pdev, "comp");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) 	if (env->comp_irq < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) 		return env->comp_irq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) 	ret = devm_request_irq(dev, env->comp_irq, envelope_detector_comp_isr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) 			       0, "envelope-detector", env);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) 	if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) 		return dev_err_probe(dev, ret, "failed to request interrupt\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) 	env->comp_irq_trigger = irq_get_trigger_type(env->comp_irq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) 	if (env->comp_irq_trigger & IRQF_TRIGGER_RISING)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) 		env->comp_irq_trigger_inv |= IRQF_TRIGGER_FALLING;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) 	if (env->comp_irq_trigger & IRQF_TRIGGER_FALLING)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) 		env->comp_irq_trigger_inv |= IRQF_TRIGGER_RISING;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) 	if (env->comp_irq_trigger & IRQF_TRIGGER_HIGH)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) 		env->comp_irq_trigger_inv |= IRQF_TRIGGER_LOW;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) 	if (env->comp_irq_trigger & IRQF_TRIGGER_LOW)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) 		env->comp_irq_trigger_inv |= IRQF_TRIGGER_HIGH;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) 	ret = iio_get_channel_type(env->dac, &type);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) 	if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) 		return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) 	if (type != IIO_VOLTAGE) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) 		dev_err(dev, "dac is of the wrong type\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) 	ret = iio_read_max_channel_raw(env->dac, &env->dac_max);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) 	if (ret < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) 		dev_err(dev, "dac does not indicate its raw maximum value\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) 		return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) 	return devm_iio_device_register(dev, indio_dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) static const struct of_device_id envelope_detector_match[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) 	{ .compatible = "axentia,tse850-envelope-detector", },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) 	{ /* sentinel */ }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) MODULE_DEVICE_TABLE(of, envelope_detector_match);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) static struct platform_driver envelope_detector_driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) 	.probe = envelope_detector_probe,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) 	.driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) 		.name = "iio-envelope-detector",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) 		.of_match_table = envelope_detector_match,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) 	},
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) module_platform_driver(envelope_detector_driver);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) MODULE_DESCRIPTION("Envelope detector using a DAC and a comparator");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) MODULE_LICENSE("GPL v2");