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* Copyright (c) 2018 SiFive Inc.
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <logging/log.h>
LOG_MODULE_REGISTER(pwm_sifive, CONFIG_PWM_LOG_LEVEL);
#include <sys_io.h>
#include <device.h>
#include <pwm.h>
/* Macros */
#define PWM_REG(z_config, _offset) ((mem_addr_t) ((z_config)->base + _offset))
/* Register Offsets */
#define REG_PWMCFG 0x00
#define REG_PWMCOUNT 0x08
#define REG_PWMS 0x10
#define REG_PWMCMP0 0x20
#define REG_PWMCMP(_channel) (REG_PWMCMP0 + ((_channel) * 0x4))
/* Number of PWM Channels */
#define SF_NUMCHANNELS 4
/* pwmcfg Bit Offsets */
#define SF_PWMSTICKY 8
#define SF_PWMZEROCMP 9
#define SF_PWMDEGLITCH 10
#define SF_PWMENALWAYS 12
#define SF_PWMENONESHOT 13
#define SF_PWMCMPCENTER(_channel) (16 + (_channel))
#define SF_PWMCMPGANG(_channel) (24 + (_channel))
#define SF_PWMCMPIP(_channel) (28 + (_channel))
/* pwmcount scale factor */
#define SF_PWMSCALEMASK 0xF
#define SF_PWMSCALE(_val) (SF_PWMSCALEMASK & (_val))
#define SF_PWMCOUNT_MIN_WIDTH 15
/* Structure Declarations */
struct pwm_sifive_data {};
struct pwm_sifive_cfg {
u32_t base;
u32_t f_sys;
u32_t cmpwidth;
};
/* Helper Functions */
static inline void sys_set_mask(mem_addr_t addr, u32_t mask, u32_t value)
{
u32_t temp = sys_read32(addr);
temp &= ~(mask);
temp |= value;
sys_write32(temp, addr);
}
/* API Functions */
static int pwm_sifive_init(struct device *dev)
{
const struct pwm_sifive_cfg *config = dev->config->config_info;
/* When pwms == pwmcmp0, reset the counter */
sys_set_bit(PWM_REG(config, REG_PWMCFG), SF_PWMZEROCMP);
/* Enable continuous operation */
sys_set_bit(PWM_REG(config, REG_PWMCFG), SF_PWMENALWAYS);
/* Clear IP config bits */
sys_clear_bit(PWM_REG(config, REG_PWMCFG), SF_PWMSTICKY);
sys_clear_bit(PWM_REG(config, REG_PWMCFG), SF_PWMDEGLITCH);
/* Clear all channels */
for (int i = 0; i < SF_NUMCHANNELS; i++) {
/* Clear the channel comparator */
sys_write32(0, PWM_REG(config, REG_PWMCMP(i)));
/* Clear the compare center and compare gang bits */
sys_clear_bit(PWM_REG(config, REG_PWMCFG), SF_PWMCMPCENTER(i));
sys_clear_bit(PWM_REG(config, REG_PWMCFG), SF_PWMCMPGANG(i));
}
return 0;
}
static int pwm_sifive_pin_set(struct device *dev,
u32_t pwm,
u32_t period_cycles,
u32_t pulse_cycles)
{
const struct pwm_sifive_cfg *config = NULL;
u32_t count_max = 0U;
u32_t max_cmp_val = 0U;
u32_t pwmscale = 0U;
if (dev == NULL) {
LOG_ERR("The device instance pointer was NULL\n");
return -EFAULT;
}
if (dev->config == NULL) {
LOG_ERR("The device config pointer was NULL\n");
return -EFAULT;
}
config = dev->config->config_info;
if (config == NULL) {
LOG_ERR("The device configuration is NULL\n");
return -EFAULT;
}
if (pwm >= SF_NUMCHANNELS) {
LOG_ERR("The requested PWM channel %d is invalid\n", pwm);
return -EINVAL;
}
/* Channel 0 sets the period, we can't output PWM with it */
if ((pwm == 0U)) {
LOG_ERR("PWM channel 0 cannot be configured\n");
return -ENOTSUP;
}
/* We can't support periods greater than we can store in pwmcount */
count_max = (1 << (config->cmpwidth + SF_PWMCOUNT_MIN_WIDTH)) - 1;
if (period_cycles > count_max) {
LOG_ERR("Requested period is %d but maximum is %d\n",
period_cycles, count_max);
return -EIO;
}
/* Calculate the maximum value that pwmcmpX can be set to */
max_cmp_val = ((1 << config->cmpwidth) - 1);
/*
* Find the minimum value of pwmscale that will allow us to set the
* requested period
*/
while ((period_cycles >> pwmscale) > max_cmp_val) {
pwmscale++;
}
/* Make sure that we can scale that much */
if (pwmscale > SF_PWMSCALEMASK) {
LOG_ERR("Requested period is %d but maximum is %d\n",
period_cycles, max_cmp_val << pwmscale);
return -EIO;
}
if (pulse_cycles > period_cycles) {
LOG_ERR("Requested pulse %d is longer than period %d\n",
pulse_cycles, period_cycles);
return -EIO;
}
/* Set the pwmscale field */
sys_set_mask(PWM_REG(config, REG_PWMCFG),
SF_PWMSCALEMASK,
SF_PWMSCALE(pwmscale));
/* Set the period by setting pwmcmp0 */
sys_write32((period_cycles >> pwmscale), PWM_REG(config, REG_PWMCMP0));
/* Set the duty cycle by setting pwmcmpX */
sys_write32((pulse_cycles >> pwmscale),
PWM_REG(config, REG_PWMCMP(pwm)));
LOG_DBG("channel: %d, pwmscale: %d, pwmcmp0: %d, pwmcmp%d: %d",
pwm,
pwmscale,
(period_cycles >> pwmscale),
pwm,
(pulse_cycles >> pwmscale));
return 0;
}
static int pwm_sifive_get_cycles_per_sec(struct device *dev,
u32_t pwm,
u64_t *cycles)
{
const struct pwm_sifive_cfg *config;
if (dev == NULL) {
LOG_ERR("The device instance pointer was NULL\n");
return -EFAULT;
}
if (dev->config == NULL) {
LOG_ERR("The device config pointer was NULL\n");
return -EFAULT;
}
config = dev->config->config_info;
if (config == NULL) {
LOG_ERR("The device configuration is NULL\n");
return -EFAULT;
}
/* Fail if we don't have that channel */
if (pwm >= SF_NUMCHANNELS) {
return -EINVAL;
}
*cycles = config->f_sys;
return 0;
}
/* Device Instantiation */
static const struct pwm_driver_api pwm_sifive_api = {
.pin_set = pwm_sifive_pin_set,
.get_cycles_per_sec = pwm_sifive_get_cycles_per_sec,
};
#define PWM_SIFIVE_INIT(n) \
static struct pwm_sifive_data pwm_sifive_data_##n; \
static const struct pwm_sifive_cfg pwm_sifive_cfg_##n = { \
.base = DT_SIFIVE_PWM0_##n##_BASE_ADDRESS, \
.f_sys = DT_SIFIVE_PWM0_##n##_CLOCK_FREQUENCY, \
.cmpwidth = DT_SIFIVE_PWM0_##n##_SIFIVE_COMPARE_WIDTH, \
}; \
DEVICE_AND_API_INIT(pwm_##n, \
DT_SIFIVE_PWM0_##n##_LABEL, \
pwm_sifive_init, \
&pwm_sifive_data_##n, \
&pwm_sifive_cfg_##n, \
POST_KERNEL, \
CONFIG_PWM_SIFIVE_INIT_PRIORITY, \
&pwm_sifive_api)
#ifdef DT_SIFIVE_PWM0_0_LABEL
PWM_SIFIVE_INIT(0);
#endif /* DT_SIFIVE_PWM0_0_LABEL */
#ifdef DT_SIFIVE_PWM0_1_LABEL
PWM_SIFIVE_INIT(1);
#endif /* DT_SIFIVE_PWM0_1_LABEL */
#ifdef DT_SIFIVE_PWM0_2_LABEL
PWM_SIFIVE_INIT(2);
#endif /* DT_SIFIVE_PWM0_2_LABEL */
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