Aaron Cook
8f0f0a0535
Planning on abstracting this behind hardware setup APIs, but this works for a simple demo until then
75 lines
1.6 KiB
C
75 lines
1.6 KiB
C
#include <inttypes.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <zephyr/device.h>
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#include <zephyr/devicetree.h>
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#include <zephyr/drivers/adc.h>
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#include <zephyr/kernel.h>
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/** Setup code referenced from Zephyr ADC example **/
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#if !DT_NODE_EXISTS(DT_PATH(zephyr_user)) || \
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!DT_NODE_HAS_PROP(DT_PATH(zephyr_user), io_channels)
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#error "No suitable devicetree overlay specified"
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#endif
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#define DT_SPEC_AND_COMMA(node_id, prop, idx) \
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ADC_DT_SPEC_GET_BY_IDX(node_id, idx),
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static const struct adc_dt_spec adc_channels[] = {
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DT_FOREACH_PROP_ELEM(DT_PATH(zephyr_user), io_channels, DT_SPEC_AND_COMMA)
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};
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static int setup = 0;
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int
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adc_init()
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{
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for (int i = 0; i < ARRAY_SIZE(adc_channels); i++) {
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int err;
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const struct adc_dt_spec *chan = &adc_channels[i];
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if (!adc_is_ready_dt(chan)) {
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return (-1);
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}
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err = adc_channel_setup_dt(chan);
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if (err) {
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return (err);
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}
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}
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setup = 1;
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return (0);
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}
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int
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adc_get_mv(int channel)
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{
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uint16_t val_raw;
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int32_t val_mv;
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struct adc_sequence seq = {
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.buffer = &val_raw,
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.buffer_size = sizeof(val_raw)
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};
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const struct adc_dt_spec *chan;
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if ((channel >= ARRAY_SIZE(adc_channels)) ||
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(!setup)) {
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return (INT32_MIN);
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}
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chan = &adc_channels[channel];
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adc_sequence_init_dt(chan, &seq);
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if (adc_read_dt(chan, &seq) < 0) {
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return (INT32_MIN);
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}
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val_mv = (int32_t)val_raw;
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if (adc_raw_to_millivolts_dt(chan, &val_mv)) {
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return (INT32_MIN);
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}
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return (val_mv);
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}
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