zephyr/drivers/pwm/pwm_sam.c

144 lines
3.6 KiB
C

/*
* Copyright (c) 2019 Aurelien Jarno
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT atmel_sam_pwm
#include <zephyr/device.h>
#include <errno.h>
#include <zephyr/drivers/pwm.h>
#include <zephyr/drivers/pinctrl.h>
#include <zephyr/drivers/clock_control/atmel_sam_pmc.h>
#include <soc.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(pwm_sam, CONFIG_PWM_LOG_LEVEL);
/* Some SoCs use a slightly different naming scheme */
#if !defined(PWMCHNUM_NUMBER) && defined(PWMCH_NUM_NUMBER)
#define PWMCHNUM_NUMBER PWMCH_NUM_NUMBER
#endif
struct sam_pwm_config {
Pwm *regs;
const struct atmel_sam_pmc_config clock_cfg;
const struct pinctrl_dev_config *pcfg;
uint8_t prescaler;
uint8_t divider;
};
static int sam_pwm_get_cycles_per_sec(const struct device *dev,
uint32_t channel, uint64_t *cycles)
{
const struct sam_pwm_config *config = dev->config;
uint8_t prescaler = config->prescaler;
uint8_t divider = config->divider;
*cycles = SOC_ATMEL_SAM_MCK_FREQ_HZ /
((1 << prescaler) * divider);
return 0;
}
static int sam_pwm_set_cycles(const struct device *dev, uint32_t channel,
uint32_t period_cycles, uint32_t pulse_cycles,
pwm_flags_t flags)
{
const struct sam_pwm_config *config = dev->config;
Pwm * const pwm = config->regs;
uint32_t cmr;
if (channel >= PWMCHNUM_NUMBER) {
return -EINVAL;
}
if (period_cycles == 0U) {
return -ENOTSUP;
}
if (period_cycles > 0xffff) {
return -ENOTSUP;
}
/* Select clock A */
cmr = PWM_CMR_CPRE_CLKA;
if ((flags & PWM_POLARITY_MASK) == PWM_POLARITY_NORMAL) {
cmr |= PWM_CMR_CPOL;
}
/* Disable the output if changing polarity (or clock) */
if (pwm->PWM_CH_NUM[channel].PWM_CMR != cmr) {
pwm->PWM_DIS = 1 << channel;
pwm->PWM_CH_NUM[channel].PWM_CMR = cmr;
pwm->PWM_CH_NUM[channel].PWM_CPRD = period_cycles;
pwm->PWM_CH_NUM[channel].PWM_CDTY = pulse_cycles;
} else {
/* Update period and pulse using the update registers, so that the
* change is triggered at the next PWM period.
*/
pwm->PWM_CH_NUM[channel].PWM_CPRDUPD = period_cycles;
pwm->PWM_CH_NUM[channel].PWM_CDTYUPD = pulse_cycles;
}
/* Enable the output */
pwm->PWM_ENA = 1 << channel;
return 0;
}
static int sam_pwm_init(const struct device *dev)
{
const struct sam_pwm_config *config = dev->config;
Pwm * const pwm = config->regs;
uint8_t prescaler = config->prescaler;
uint8_t divider = config->divider;
int retval;
/* FIXME: way to validate prescaler & divider */
/* Enable PWM clock in PMC */
(void)clock_control_on(SAM_DT_PMC_CONTROLLER,
(clock_control_subsys_t)&config->clock_cfg);
retval = pinctrl_apply_state(config->pcfg, PINCTRL_STATE_DEFAULT);
if (retval < 0) {
return retval;
}
/* Configure the clock A that will be used by all 4 channels */
pwm->PWM_CLK = PWM_CLK_PREA(prescaler) | PWM_CLK_DIVA(divider);
return 0;
}
static const struct pwm_driver_api sam_pwm_driver_api = {
.set_cycles = sam_pwm_set_cycles,
.get_cycles_per_sec = sam_pwm_get_cycles_per_sec,
};
#define SAM_INST_INIT(inst) \
PINCTRL_DT_INST_DEFINE(inst); \
static const struct sam_pwm_config sam_pwm_config_##inst = { \
.regs = (Pwm *)DT_INST_REG_ADDR(inst), \
.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(inst), \
.clock_cfg = SAM_DT_INST_CLOCK_PMC_CFG(inst), \
.prescaler = DT_INST_PROP(inst, prescaler), \
.divider = DT_INST_PROP(inst, divider), \
}; \
\
DEVICE_DT_INST_DEFINE(inst, \
&sam_pwm_init, NULL, \
NULL, &sam_pwm_config_##inst, \
POST_KERNEL, \
CONFIG_PWM_INIT_PRIORITY, \
&sam_pwm_driver_api);
DT_INST_FOREACH_STATUS_OKAY(SAM_INST_INIT)