zephyr/drivers/adc/adc_sam0.c

616 lines
15 KiB
C

/*
* Copyright (c) 2019 Derek Hageman <hageman@inthat.cloud>
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <soc.h>
#include <drivers/adc.h>
#include <logging/log.h>
LOG_MODULE_REGISTER(adc_sam0, CONFIG_ADC_LOG_LEVEL);
#define ADC_CONTEXT_USES_KERNEL_TIMER
#include "adc_context.h"
#if defined(CONFIG_SOC_SERIES_SAMD21) || defined(CONFIG_SOC_SERIES_SAMR21) || \
defined(CONFIG_SOC_SERIES_SAMD20)
/*
* SAMD21 Manual 33.6.2.1: The first conversion after changing the reference
* is invalid, so we have to discard it.
*/
#define ADC_SAM0_REFERENCE_GLITCH 1
#endif
struct adc_sam0_data {
struct adc_context ctx;
struct device *dev;
u16_t *buffer;
/*
* Saved initial start, so we can reset the advances we've done
* if required
*/
u16_t *repeat_buffer;
#ifdef ADC_SAM0_REFERENCE_GLITCH
u8_t reference_changed;
#endif
};
struct adc_sam0_cfg {
Adc *regs;
#ifdef MCLK
u32_t mclk_mask;
u32_t gclk_mask;
u16_t gclk_id;
#else
u32_t gclk;
#endif
u32_t freq;
u16_t prescaler;
void (*config_func)(struct device *dev);
};
#define DEV_CFG(dev) \
((const struct adc_sam0_cfg *const)(dev)->config->config_info)
#define DEV_DATA(dev) \
((struct adc_sam0_data *)(dev)->driver_data)
static void wait_synchronization(Adc *const adc)
{
#if defined(ADC_SYNCBUSY_MASK)
while ((adc->SYNCBUSY.reg & ADC_SYNCBUSY_MASK) != 0) {
}
#else
while ((adc->STATUS.reg & ADC_STATUS_SYNCBUSY) != 0) {
}
#endif
}
static int adc_sam0_acquisition_to_clocks(struct device *dev,
u16_t acquisition_time)
{
const struct adc_sam0_cfg *const cfg = DEV_CFG(dev);
u64_t scaled_acq;
switch (ADC_ACQ_TIME_UNIT(acquisition_time)) {
case ADC_ACQ_TIME_TICKS:
if (ADC_ACQ_TIME_VALUE(acquisition_time) > 64U) {
return -EINVAL;
}
return (int)ADC_ACQ_TIME_VALUE(acquisition_time) - 1;
case ADC_ACQ_TIME_MICROSECONDS:
scaled_acq = (u64_t)ADC_ACQ_TIME_VALUE(acquisition_time) *
1000000U;
break;
case ADC_ACQ_TIME_NANOSECONDS:
scaled_acq = (u64_t)ADC_ACQ_TIME_VALUE(acquisition_time) *
1000U;
break;
default:
return -EINVAL;
}
/*
* sample_time = (sample_length+1) * (clk_adc / 2)
* sample_length = sample_time * (2/clk_adc) - 1,
*/
scaled_acq *= 2U;
scaled_acq += cfg->freq / 2U;
scaled_acq /= cfg->freq;
if (scaled_acq <= 1U) {
return 0;
}
scaled_acq -= 1U;
if (scaled_acq >= 64U) {
return -EINVAL;
}
return (int)scaled_acq;
}
static int adc_sam0_channel_setup(struct device *dev,
const struct adc_channel_cfg *channel_cfg)
{
const struct adc_sam0_cfg *const cfg = DEV_CFG(dev);
Adc *const adc = cfg->regs;
int retval;
u8_t SAMPCTRL = 0;
if (channel_cfg->acquisition_time != ADC_ACQ_TIME_DEFAULT) {
retval = adc_sam0_acquisition_to_clocks(dev,
channel_cfg->acquisition_time);
if (retval < 0) {
LOG_ERR("Selected ADC acquisition time is not valid");
return retval;
}
SAMPCTRL |= ADC_SAMPCTRL_SAMPLEN(retval);
}
adc->SAMPCTRL.reg = SAMPCTRL;
wait_synchronization(adc);
u8_t REFCTRL;
switch (channel_cfg->reference) {
case ADC_REF_INTERNAL:
#ifdef ADC_REFCTRL_REFSEL_INTREF
REFCTRL = ADC_REFCTRL_REFSEL_INTREF | ADC_REFCTRL_REFCOMP;
/* Enable the internal reference, defaulting to 1V */
SUPC->VREF.bit.VREFOE = 1;
#else
REFCTRL = ADC_REFCTRL_REFSEL_INT1V | ADC_REFCTRL_REFCOMP;
/* Enable the internal bandgap reference */
SYSCTRL->VREF.bit.BGOUTEN = 1;
#endif
break;
case ADC_REF_VDD_1_2:
#ifdef ADC_REFCTRL_REFSEL_INTVCC0
REFCTRL = ADC_REFCTRL_REFSEL_INTVCC0 | ADC_REFCTRL_REFCOMP;
#else
REFCTRL = ADC_REFCTRL_REFSEL_INTVCC1 | ADC_REFCTRL_REFCOMP;
#endif
break;
#ifdef ADC_REFCTRL_REFSEL_INTVCC1
case ADC_REF_VDD_1:
REFCTRL = ADC_REFCTRL_REFSEL_INTVCC1 | ADC_REFCTRL_REFCOMP;
break;
#endif
case ADC_REF_EXTERNAL0:
REFCTRL = ADC_REFCTRL_REFSEL_AREFA;
break;
case ADC_REF_EXTERNAL1:
REFCTRL = ADC_REFCTRL_REFSEL_AREFB;
break;
default:
LOG_ERR("Selected reference is not valid");
return -EINVAL;
}
if (adc->REFCTRL.reg != REFCTRL) {
adc->REFCTRL.reg = REFCTRL;
wait_synchronization(adc);
#ifdef ADC_SAM0_REFERENCE_GLITCH
struct adc_sam0_data *data = DEV_DATA(dev);
data->reference_changed = 1;
#endif
}
u32_t INPUTCTRL = 0;
switch (channel_cfg->gain) {
case ADC_GAIN_1:
#ifdef ADC_INPUTCTRL_GAIN_1X
INPUTCTRL = ADC_INPUTCTRL_GAIN_1X;
#endif
break;
#ifdef ADC_INPUTCTRL_GAIN_DIV2
case ADC_GAIN_1_2:
INPUTCTRL = ADC_INPUTCTRL_GAIN_DIV2;
break;
#endif
#ifdef ADC_INPUTCTRL_GAIN_2X
case ADC_GAIN_2:
INPUTCTRL = ADC_INPUTCTRL_GAIN_2X;
break;
#endif
#ifdef ADC_INPUTCTRL_GAIN_4X
case ADC_GAIN_4:
INPUTCTRL = ADC_INPUTCTRL_GAIN_4X;
break;
#endif
#ifdef ADC_INPUTCTRL_GAIN_8X
case ADC_GAIN_8:
INPUTCTRL = ADC_INPUTCTRL_GAIN_8X;
break;
#endif
#ifdef ADC_INPUTCTRL_GAIN_16X
case ADC_GAIN_16:
INPUTCTRL = ADC_INPUTCTRL_GAIN_16X;
break;
#endif
default:
LOG_ERR("Selected ADC gain is not valid");
return -EINVAL;
}
INPUTCTRL |= ADC_INPUTCTRL_MUXPOS(channel_cfg->input_positive);
if (channel_cfg->differential) {
INPUTCTRL |= ADC_INPUTCTRL_MUXNEG(channel_cfg->input_negative);
#ifdef ADC_INPUTCTRL_DIFFMODE
INPUTCTRL |= ADC_INPUTCTRL_DIFFMODE;
#else
adc->CTRLB.bit.DIFFMODE = 1;
wait_synchronization(adc);
#endif
} else {
INPUTCTRL |= ADC_INPUTCTRL_MUXNEG_GND;
#ifndef ADC_INPUTCTRL_DIFFMODE
adc->CTRLB.bit.DIFFMODE = 0;
wait_synchronization(adc);
#endif
}
adc->INPUTCTRL.reg = INPUTCTRL;
wait_synchronization(adc);
/* Enable references if they're selected */
switch (channel_cfg->input_positive) {
#ifdef ADC_INPUTCTRL_MUXPOS_TEMP_Val
case ADC_INPUTCTRL_MUXPOS_TEMP_Val:
SYSCTRL->VREF.bit.TSEN = 1;
break;
#endif
#ifdef ADC_INPUTCTRL_MUXPOS_PTAT_Val
case ADC_INPUTCTRL_MUXPOS_PTAT_Val:
SUPC->VREF.bit.TSEN = 1;
break;
#endif
#ifdef ADC_INPUTCTRL_MUXPOS_CTAT_Val
case ADC_INPUTCTRL_MUXPOS_CTAT_Val:
SUPC->VREF.bit.TSEN = 1;
break;
#endif
case ADC_INPUTCTRL_MUXPOS_BANDGAP_Val:
#ifdef ADC_REFCTRL_REFSEL_INTREF
SUPC->VREF.bit.VREFOE = 1;
#else
SYSCTRL->VREF.bit.BGOUTEN = 1;
#endif
break;
default:
break;
}
return 0;
}
static void adc_sam0_start_conversion(struct device *dev)
{
const struct adc_sam0_cfg *const cfg = DEV_CFG(dev);
Adc *const adc = cfg->regs;
LOG_DBG("Starting conversion");
adc->SWTRIG.reg = ADC_SWTRIG_START;
/*
* Should be safe to not synchronize here because the only things
* that might access the ADC after this will wait for it to complete
* (synchronize finished implicitly)
*/
}
static void adc_context_start_sampling(struct adc_context *ctx)
{
struct adc_sam0_data *data =
CONTAINER_OF(ctx, struct adc_sam0_data, ctx);
adc_sam0_start_conversion(data->dev);
}
static void adc_context_update_buffer_pointer(struct adc_context *ctx,
bool repeat_sampling)
{
struct adc_sam0_data *data =
CONTAINER_OF(ctx, struct adc_sam0_data, ctx);
if (repeat_sampling) {
data->buffer = data->repeat_buffer;
}
}
static int check_buffer_size(const struct adc_sequence *sequence,
u8_t active_channels)
{
size_t needed_buffer_size;
needed_buffer_size = active_channels * sizeof(u16_t);
if (sequence->options) {
needed_buffer_size *= (1U + sequence->options->extra_samplings);
}
if (sequence->buffer_size < needed_buffer_size) {
LOG_ERR("Provided buffer is too small (%u/%u)",
sequence->buffer_size, needed_buffer_size);
return -ENOMEM;
}
return 0;
}
static int start_read(struct device *dev, const struct adc_sequence *sequence)
{
const struct adc_sam0_cfg *const cfg = DEV_CFG(dev);
struct adc_sam0_data *data = DEV_DATA(dev);
Adc *const adc = cfg->regs;
int error;
if (sequence->oversampling > 10U) {
LOG_ERR("Invalid oversampling");
return -EINVAL;
}
adc->AVGCTRL.reg = ADC_AVGCTRL_SAMPLENUM(sequence->oversampling);
/* AVGCTRL is not synchronized */
#ifdef CONFIG_SOC_SERIES_SAMD20
/*
* Errata: silicon revisions B and C do not perform the automatic right
* shifts in accumulation
*/
if (sequence->oversampling > 4U && DSU->DID.bit.REVISION < 3) {
adc->AVGCTRL.bit.ADJRES = sequence->oversampling - 4U;
}
#endif
switch (sequence->resolution) {
case 8:
if (sequence->oversampling) {
LOG_ERR("Oversampling requires 12 bit resolution");
return -EINVAL;
}
adc->CTRLB.bit.RESSEL = ADC_CTRLB_RESSEL_8BIT_Val;
break;
case 10:
if (sequence->oversampling) {
LOG_ERR("Oversampling requires 12 bit resolution");
return -EINVAL;
}
adc->CTRLB.bit.RESSEL = ADC_CTRLB_RESSEL_10BIT_Val;
break;
case 12:
if (sequence->oversampling) {
adc->CTRLB.bit.RESSEL = ADC_CTRLB_RESSEL_16BIT_Val;
} else {
adc->CTRLB.bit.RESSEL = ADC_CTRLB_RESSEL_12BIT_Val;
}
break;
default:
LOG_ERR("ADC resolution value %d is not valid",
sequence->resolution);
return -EINVAL;
}
wait_synchronization(adc);
if (sequence->channels != 1U) {
LOG_ERR("Channel scanning is not supported");
return -ENOTSUP;
}
error = check_buffer_size(sequence, 1);
if (error) {
return error;
}
data->buffer = sequence->buffer;
data->repeat_buffer = sequence->buffer;
/* At this point we allow the scheduler to do other things while
* we wait for the conversions to complete. This is provided by the
* adc_context functions. However, the caller of this function is
* blocked until the results are in.
*/
adc_context_start_read(&data->ctx, sequence);
error = adc_context_wait_for_completion(&data->ctx);
return error;
}
static int adc_sam0_read(struct device *dev,
const struct adc_sequence *sequence)
{
struct adc_sam0_data *data = DEV_DATA(dev);
int error;
adc_context_lock(&data->ctx, false, NULL);
error = start_read(dev, sequence);
adc_context_release(&data->ctx, error);
return error;
}
static void adc_sam0_isr(void *arg)
{
struct device *dev = (struct device *)arg;
struct adc_sam0_data *data = DEV_DATA(dev);
const struct adc_sam0_cfg *const cfg = DEV_CFG(dev);
Adc *const adc = cfg->regs;
u16_t result;
adc->INTFLAG.reg = ADC_INTFLAG_MASK;
result = (u16_t)(adc->RESULT.reg);
#ifdef ADC_SAM0_REFERENCE_GLITCH
if (data->reference_changed) {
data->reference_changed = 0;
LOG_DBG("Discarded initial conversion due to reference change");
adc_sam0_start_conversion(dev);
return;
}
#endif
*data->buffer++ = result;
adc_context_on_sampling_done(&data->ctx, dev);
}
static int adc_sam0_init(struct device *dev)
{
const struct adc_sam0_cfg *const cfg = DEV_CFG(dev);
struct adc_sam0_data *data = DEV_DATA(dev);
Adc *const adc = cfg->regs;
#ifdef MCLK
GCLK->PCHCTRL[cfg->gclk_id].reg = cfg->gclk_mask | GCLK_PCHCTRL_CHEN;
MCLK->APBDMASK.reg |= cfg->mclk_mask;
#else
PM->APBCMASK.bit.ADC_ = 1;
GCLK->CLKCTRL.reg = cfg->gclk | GCLK_CLKCTRL_CLKEN;
#endif
#ifdef ADC_CTRLA_PRESCALER_Pos
adc->CTRLA.reg = cfg->prescaler;
#else
adc->CTRLB.reg = cfg->prescaler;
#endif
wait_synchronization(adc);
adc->INTENCLR.reg = ADC_INTENCLR_MASK;
adc->INTFLAG.reg = ADC_INTFLAG_MASK;
cfg->config_func(dev);
adc->INTENSET.reg = ADC_INTENSET_RESRDY;
data->dev = dev;
#ifdef ADC_SAM0_REFERENCE_GLITCH
data->reference_changed = 1;
#endif
adc->CTRLA.bit.ENABLE = 1;
wait_synchronization(adc);
adc_context_unlock_unconditionally(&data->ctx);
return 0;
}
#ifdef CONFIG_ADC_ASYNC
static int adc_sam0_read_async(struct device *dev,
const struct adc_sequence *sequence,
struct k_poll_signal *async)
{
struct adc_sam0_data *data = DEV_DATA(dev);
int error;
adc_context_lock(&data->ctx, true, async);
error = start_read(dev, sequence);
adc_context_release(&data->ctx, error);
return error;
}
#endif
static const struct adc_driver_api adc_sam0_api = {
.channel_setup = adc_sam0_channel_setup,
.read = adc_sam0_read,
#ifdef CONFIG_ADC_ASYNC
.read_async = adc_sam0_read_async,
#endif
};
#ifdef MCLK
#define ADC_SAM0_CLOCK_CONTROL(n) \
.mclk_mask = MCLK_APBDMASK_ADC##n, \
.gclk_mask = UTIL_CAT(GCLK_PCHCTRL_GEN_GCLK, \
DT_ATMEL_SAM0_ADC_ADC_##n##_GCLK), \
.gclk_id = ADC##n##_GCLK_ID, \
.prescaler = UTIL_CAT(ADC_CTRLA_PRESCALER_DIV, \
DT_ATMEL_SAM0_ADC_ADC_##n##_PRESCALER),
#define ADC_SAM0_CONFIGURE(n) do { \
const struct adc_sam0_cfg *const cfg = DEV_CFG(dev); \
Adc *const adc = cfg->regs; \
u32_t comp = ((*(u32_t *)ADC##n##_FUSES_BIASCOMP_ADDR) & \
ADC##n##_FUSES_BIASCOMP_Msk) >> \
ADC##n##_FUSES_BIASCOMP_Pos; \
u32_t r2r = ((*(u32_t *)ADC##n##_FUSES_BIASR2R_ADDR) & \
ADC##n##_FUSES_BIASR2R_Msk) >> \
ADC##n##_FUSES_BIASR2R_Pos; \
u32_t rbuf = ((*(u32_t *)ADC##n##_FUSES_BIASREFBUF_ADDR) & \
ADC##n##_FUSES_BIASREFBUF_Msk) >> \
ADC##n##_FUSES_BIASREFBUF_Pos; \
adc->CALIB.reg = ADC_CALIB_BIASCOMP(comp) | \
ADC_CALIB_BIASR2R(r2r) | \
ADC_CALIB_BIASREFBUF(rbuf); \
} while (0)
#else
#define ADC_SAM0_CLOCK_CONTROL(n) \
.gclk = UTIL_CAT(GCLK_CLKCTRL_GEN_GCLK, \
DT_ATMEL_SAM0_ADC_ADC_##n##_GCLK) | \
GCLK_CLKCTRL_ID_ADC, \
.prescaler = UTIL_CAT(ADC_CTRLB_PRESCALER_DIV, \
DT_ATMEL_SAM0_ADC_ADC_##n##_PRESCALER),
#define ADC_SAM0_CONFIGURE(n) do { \
const struct adc_sam0_cfg *const cfg = DEV_CFG(dev); \
Adc *const adc = cfg->regs; \
/* Linearity is split across two words */ \
u32_t lin = ((*(u32_t *)ADC_FUSES_LINEARITY_0_ADDR) & \
ADC_FUSES_LINEARITY_0_Msk) >> \
ADC_FUSES_LINEARITY_0_Pos; \
lin |= (((*(u32_t *)ADC_FUSES_LINEARITY_1_ADDR) & \
ADC_FUSES_LINEARITY_1_Msk) >> \
ADC_FUSES_LINEARITY_1_Pos) \
<< 4; \
u32_t bias = ((*(u32_t *)ADC_FUSES_BIASCAL_ADDR) & \
ADC_FUSES_BIASCAL_Msk) >> ADC_FUSES_BIASCAL_Pos;\
adc->CALIB.reg = ADC_CALIB_BIAS_CAL(bias) | \
ADC_CALIB_LINEARITY_CAL(lin); \
} while (0)
#endif
#define ADC_SAM0_DEVICE(n) \
static void adc_sam0_config_##n(struct device *dev); \
static const struct adc_sam0_cfg adc_sam_cfg_##n = { \
.regs = (Adc *)DT_ATMEL_SAM0_ADC_ADC_##n##_BASE_ADDRESS, \
ADC_SAM0_CLOCK_CONTROL(n) \
.freq = UTIL_CAT(UTIL_CAT(SOC_ATMEL_SAM0_GCLK, \
DT_ATMEL_SAM0_ADC_ADC_##n##_GCLK), \
_FREQ_HZ) / \
DT_ATMEL_SAM0_ADC_ADC_##n##_PRESCALER, \
.config_func = &adc_sam0_config_##n, \
}; \
static struct adc_sam0_data adc_sam_data_##n = { \
ADC_CONTEXT_INIT_TIMER(adc_sam_data_##n, ctx), \
ADC_CONTEXT_INIT_LOCK(adc_sam_data_##n, ctx), \
ADC_CONTEXT_INIT_SYNC(adc_sam_data_##n, ctx), \
}; \
DEVICE_AND_API_INIT(adc0_sam_##n, DT_ATMEL_SAM0_ADC_ADC_##n##_LABEL, \
adc_sam0_init, &adc_sam_data_##n, &adc_sam_cfg_##n,\
POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE, \
&adc_sam0_api); \
static void adc_sam0_config_##n(struct device *dev) \
{ \
IRQ_CONNECT(DT_ATMEL_SAM0_ADC_ADC_##n##_IRQ_0, \
DT_ATMEL_SAM0_ADC_ADC_##n##_IRQ_0_PRIORITY, \
adc_sam0_isr, \
DEVICE_GET(adc0_sam_##n), \
0); \
irq_enable(DT_ATMEL_SAM0_ADC_ADC_##n##_IRQ_0); \
ADC_SAM0_CONFIGURE(n); \
}
#if DT_ATMEL_SAM0_ADC_ADC_0_BASE_ADDRESS
ADC_SAM0_DEVICE(0);
#endif
#if DT_ATMEL_SAM0_ADC_ADC_1_BASE_ADDRESS
ADC_SAM0_DEVICE(1);
#endif