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pwm_sam0_tcc.c
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pwm_sam0_tcc.c
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/*
* Copyright (c) 2020 Google LLC.
*
* SPDX-License-Identifier: Apache-2.0
*/
/*
* PWM driver using the SAM0 Timer/Counter (TCC) in Normal PWM (NPWM) mode.
* Supports the SAMD21 and SAMD5x series.
*/
#define DT_DRV_COMPAT atmel_sam0_tcc_pwm
#include <zephyr/device.h>
#include <errno.h>
#include <zephyr/drivers/pwm.h>
#include <zephyr/drivers/pinctrl.h>
#include <soc.h>
/* Static configuration */
struct pwm_sam0_config {
Tcc *regs;
const struct pinctrl_dev_config *pcfg;
uint8_t channels;
uint8_t counter_size;
uint16_t prescaler;
uint32_t freq;
#ifdef MCLK
volatile uint32_t *mclk;
uint32_t mclk_mask;
uint16_t gclk_id;
#else
uint32_t pm_apbcmask;
uint16_t gclk_clkctrl_id;
#endif
};
/* Wait for the peripheral to finish all commands */
static void wait_synchronization(Tcc *regs)
{
while (regs->SYNCBUSY.reg != 0) {
}
}
static int pwm_sam0_get_cycles_per_sec(const struct device *dev,
uint32_t channel, uint64_t *cycles)
{
const struct pwm_sam0_config *const cfg = dev->config;
if (channel >= cfg->channels) {
return -EINVAL;
}
*cycles = cfg->freq;
return 0;
}
static int pwm_sam0_set_cycles(const struct device *dev, uint32_t channel,
uint32_t period_cycles, uint32_t pulse_cycles,
pwm_flags_t flags)
{
const struct pwm_sam0_config *const cfg = dev->config;
Tcc *regs = cfg->regs;
uint32_t top = 1 << cfg->counter_size;
uint32_t invert_mask = 1 << channel;
bool invert = ((flags & PWM_POLARITY_INVERTED) != 0);
bool inverted = ((regs->DRVCTRL.vec.INVEN & invert_mask) != 0);
if (channel >= cfg->channels) {
return -EINVAL;
}
if (period_cycles >= top || pulse_cycles >= top) {
return -EINVAL;
}
/*
* Update the buffered width and period. These will be automatically
* loaded on the next cycle.
*/
#ifdef TCC_PERBUF_PERBUF
/* SAME51 naming */
regs->CCBUF[channel].reg = TCC_CCBUF_CCBUF(pulse_cycles);
regs->PERBUF.reg = TCC_PERBUF_PERBUF(period_cycles);
#else
/* SAMD21 naming */
regs->CCB[channel].reg = TCC_CCB_CCB(pulse_cycles);
regs->PERB.reg = TCC_PERB_PERB(period_cycles);
#endif
if (invert != inverted) {
regs->CTRLA.bit.ENABLE = 0;
wait_synchronization(regs);
regs->DRVCTRL.vec.INVEN ^= invert_mask;
regs->CTRLA.bit.ENABLE = 1;
wait_synchronization(regs);
}
return 0;
}
static int pwm_sam0_init(const struct device *dev)
{
const struct pwm_sam0_config *const cfg = dev->config;
Tcc *regs = cfg->regs;
int retval;
/* Enable the clocks */
#ifdef MCLK
GCLK->PCHCTRL[cfg->gclk_id].reg =
GCLK_PCHCTRL_GEN_GCLK0 | GCLK_PCHCTRL_CHEN;
*cfg->mclk |= cfg->mclk_mask;
#else
GCLK->CLKCTRL.reg = cfg->gclk_clkctrl_id | GCLK_CLKCTRL_GEN_GCLK0 |
GCLK_CLKCTRL_CLKEN;
PM->APBCMASK.reg |= cfg->pm_apbcmask;
#endif
retval = pinctrl_apply_state(cfg->pcfg, PINCTRL_STATE_DEFAULT);
if (retval < 0) {
return retval;
}
regs->CTRLA.bit.SWRST = 1;
wait_synchronization(regs);
regs->CTRLA.reg = cfg->prescaler;
regs->WAVE.reg = TCC_WAVE_WAVEGEN_NPWM;
regs->PER.reg = TCC_PER_PER(1);
regs->CTRLA.bit.ENABLE = 1;
wait_synchronization(regs);
return 0;
}
static const struct pwm_driver_api pwm_sam0_driver_api = {
.set_cycles = pwm_sam0_set_cycles,
.get_cycles_per_sec = pwm_sam0_get_cycles_per_sec,
};
#ifdef MCLK
#define PWM_SAM0_INIT_CLOCKS(inst) \
.mclk = (volatile uint32_t *)MCLK_MASK_DT_INT_REG_ADDR(inst), \
.mclk_mask = BIT(DT_INST_CLOCKS_CELL_BY_NAME(inst, mclk, bit)), \
.gclk_id = DT_INST_CLOCKS_CELL_BY_NAME(inst, gclk, periph_ch)
#else
#define PWM_SAM0_INIT_CLOCKS(inst) \
.pm_apbcmask = BIT(DT_INST_CLOCKS_CELL_BY_NAME(inst, pm, bit)), \
.gclk_clkctrl_id = DT_INST_CLOCKS_CELL_BY_NAME(inst, gclk, clkctrl_id)
#endif
#define PWM_SAM0_INIT(inst) \
PINCTRL_DT_INST_DEFINE(inst); \
static const struct pwm_sam0_config pwm_sam0_config_##inst = { \
.regs = (Tcc *)DT_INST_REG_ADDR(inst), \
.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(inst), \
.channels = DT_INST_PROP(inst, channels), \
.counter_size = DT_INST_PROP(inst, counter_size), \
.prescaler = UTIL_CAT(TCC_CTRLA_PRESCALER_DIV, \
DT_INST_PROP(inst, prescaler)), \
.freq = SOC_ATMEL_SAM0_GCLK0_FREQ_HZ / \
DT_INST_PROP(inst, prescaler), \
PWM_SAM0_INIT_CLOCKS(inst), \
}; \
\
DEVICE_DT_INST_DEFINE(inst, &pwm_sam0_init, NULL, \
NULL, &pwm_sam0_config_##inst, \
POST_KERNEL, CONFIG_PWM_INIT_PRIORITY, \
&pwm_sam0_driver_api);
DT_INST_FOREACH_STATUS_OKAY(PWM_SAM0_INIT)