cpu/native: add pwm implementation

Simulate PWM signals with a 2 dimensions array.

Signed-off-by: Gilles DOFFE <g.doffe@gmail.com>

cpu/native/Makefile.features

@@ -2,3 +2,4 @@ FEATURES_PROVIDED += cpp
 FEATURES_PROVIDED += periph_cpuid
 FEATURES_PROVIDED += periph_hwrng
 FEATURES_PROVIDED += periph_pm
+FEATURES_PROVIDED += periph_pwm

cpu/native/include/periph_conf.h

@@ -72,6 +72,13 @@
 #endif
 /** @} */
 
+/**
+ * @brief PWM configuration
+ */
+#ifndef PWM_NUMOF
+#define PWM_NUMOF (8U)
+#endif
+
 /**
  * @brief QDEC configuration
  */

cpu/native/periph/pwm.c

@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2018 Gilles DOFFE <g.doffe@gmail.com>
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     cpu_native
+ * @ingroup     drivers_periph_pwm
+ * @{
+ *
+ * @file
+ * @brief       Low-level PWM driver implementation
+ *
+ * @author      Gilles DOFFE <g.doffe@gmail.com>
+ * @}
+ */
+
+#include <errno.h>
+
+#include "periph/pwm.h"
+
+#define ENABLE_DEBUG (0)
+#include "debug.h"
+
+#ifdef PWM_NUMOF
+
+#define NATIVE_PWM_SPEED    1000000
+#define NATIVE_PWM_NB_CHAN  2
+#define NATIVE_PWM_MAX      65535
+
+typedef struct {
+    uint16_t duty_cycle;
+    uint8_t on;
+} native_pwm_t;
+
+native_pwm_t pwms[PWM_NUMOF][NATIVE_PWM_NB_CHAN];
+
+uint32_t pwm_init(pwm_t pwm, pwm_mode_t mode, uint32_t freq, uint16_t res)
+{
+    uint8_t i = 0;
+
+    (void) mode;
+    (void) freq;
+    (void) res;
+
+    if (pwm >= PWM_NUMOF)
+    {
+        errno = ENODEV;
+        goto pwm_init_err;
+    }
+
+    /* reset pwm channels */
+    for (i = 0; i < NATIVE_PWM_NB_CHAN; i++)
+    {
+        pwms[pwm][i].duty_cycle = 0;
+        pwms[pwm][i].on = 0;
+    }
+
+    return freq;
+
+pwm_init_err:
+    return 0;
+}
+
+uint8_t pwm_channels(pwm_t pwm)
+{
+    (void) pwm;
+    return NATIVE_PWM_NB_CHAN;
+}
+
+void pwm_set(pwm_t pwm, uint8_t channel, uint16_t value)
+{
+    assert(pwm < PWM_NUMOF);
+
+    /* set new value */
+    pwms[pwm][channel].duty_cycle = value;
+    DEBUG("%s pwms[%u][%u] = %u\n", __func__, pwm, channel, value);
+}
+
+void pwm_poweron(pwm_t pwm)
+{
+    uint8_t i = 0;
+
+    assert(pwm < PWM_NUMOF);
+    /* reset pwm channels */
+    for (i = 0; i < NATIVE_PWM_NB_CHAN; i++)
+        pwms[pwm][i].on = 1;
+}
+
+void pwm_poweroff(pwm_t pwm)
+{
+    uint8_t i = 0;
+
+    assert(pwm < PWM_NUMOF);
+    /* reset pwm channels */
+    for (i = 0; i < NATIVE_PWM_NB_CHAN; i++)
+        pwms[pwm][i].on = 0;
+}
+
+#endif /* PWM_NUMOF */