Add DREQ methods for PWM/SPI/UART/I2C (#603)

src/rp2_common/hardware_i2c/include/hardware/i2c.h

@@ -10,6 +10,7 @@
 #include "pico.h"
 #include "pico/time.h"
 #include "hardware/structs/i2c.h"
+#include "hardware/regs/dreq.h"
 
 // PICO_CONFIG: PARAM_ASSERTIONS_ENABLED_I2C, Enable/disable assertions in the I2C module, type=bool, default=0, group=hardware_i2c
 #ifndef PARAM_ASSERTIONS_ENABLED_I2C
@@ -311,6 +312,19 @@ static inline void i2c_read_raw_blocking(i2c_inst_t *i2c, uint8_t *dst, size_t l
     }
 }
 
+/*! \brief Return the DREQ to use for pacing transfers to/from a particular I2C instance
+ *  \ingroup hardware_i2c
+ *
+ * \param i2c Either \ref i2c0 or \ref i2c1
+ * \param is_tx true for sending data to the I2C instance, false for receiving data from the I2C instance
+ */
+static inline uint i2c_get_dreq(i2c_inst_t *i2c, bool is_tx) {
+    static_assert(DREQ_I2C0_RX == DREQ_I2C0_TX + 1, "");
+    static_assert(DREQ_I2C1_RX == DREQ_I2C1_TX + 1, "");
+    static_assert(DREQ_I2C1_TX == DREQ_I2C0_TX + 2, "");
+    return DREQ_I2C0_TX + i2c_hw_index(i2c) * 2 + !is_tx;
+}
+
 #ifdef __cplusplus
 }
 #endif

src/rp2_common/hardware_pio/include/hardware/pio.h

@@ -436,14 +436,19 @@ static inline void pio_gpio_init(PIO pio, uint pin) {
     gpio_set_function(pin, pio == pio0 ? GPIO_FUNC_PIO0 : GPIO_FUNC_PIO1);
 }
 
-/*! \brief Return the DREQ to use for pacing transfers to a particular state machine
+/*! \brief Return the DREQ to use for pacing transfers to/from a particular state machine FIFO
  *  \ingroup hardware_pio
  *
  * \param pio The PIO instance; either \ref pio0 or \ref pio1
  * \param sm State machine index (0..3)
- * \param is_tx true for sending data to the state machine, false for received data from the state machine
+ * \param is_tx true for sending data to the state machine, false for receiving data from the state machine
  */
 static inline uint pio_get_dreq(PIO pio, uint sm, bool is_tx) {
+    static_assert(DREQ_PIO0_TX1 == DREQ_PIO0_TX0 + 1, "");
+    static_assert(DREQ_PIO0_TX2 == DREQ_PIO0_TX0 + 2, "");
+    static_assert(DREQ_PIO0_TX3 == DREQ_PIO0_TX0 + 3, "");
+    static_assert(DREQ_PIO0_RX0 == DREQ_PIO0_TX0 + NUM_PIO_STATE_MACHINES, "");
+    static_assert(DREQ_PIO1_RX0 == DREQ_PIO1_TX0 + NUM_PIO_STATE_MACHINES, "");
     check_pio_param(pio);
     check_sm_param(sm);
     return sm + (is_tx ? 0 : NUM_PIO_STATE_MACHINES) + (pio == pio0 ? DREQ_PIO0_TX0 : DREQ_PIO1_TX0);

src/rp2_common/hardware_pwm/include/hardware/pwm.h

@@ -9,6 +9,7 @@
 
 #include "pico.h"
 #include "hardware/structs/pwm.h"
+#include "hardware/regs/dreq.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -539,6 +540,18 @@ static inline void pwm_force_irq(uint slice_num) {
     pwm_hw->intf = 1u << slice_num;
 }
 
+/*! \brief Return the DREQ to use for pacing transfers to a particular PWM slice
+ *  \ingroup hardware_pwm
+ *
+ * \param slice_num PWM slice number
+ */
+static inline uint pwm_get_dreq(uint slice_num) {
+    static_assert(DREQ_PWM_WRAP1 == DREQ_PWM_WRAP0 + 1, "");
+    static_assert(DREQ_PWM_WRAP7 == DREQ_PWM_WRAP0 + 7, "");
+    check_slice_num_param(slice_num);
+    return DREQ_PWM_WRAP0 + slice_num;
+}
+
 #ifdef __cplusplus
 }
 #endif

src/rp2_common/hardware_spi/include/hardware/spi.h

@@ -10,6 +10,7 @@
 #include "pico.h"
 #include "pico/time.h"
 #include "hardware/structs/spi.h"
+#include "hardware/regs/dreq.h"
 
 // PICO_CONFIG: PARAM_ASSERTIONS_ENABLED_SPI, Enable/disable assertions in the SPI module, type=bool, default=0, group=hardware_spi
 #ifndef PARAM_ASSERTIONS_ENABLED_SPI
@@ -337,6 +338,19 @@ int spi_write16_blocking(spi_inst_t *spi, const uint16_t *src, size_t len);
  */
 int spi_read16_blocking(spi_inst_t *spi, uint16_t repeated_tx_data, uint16_t *dst, size_t len);
 
+/*! \brief Return the DREQ to use for pacing transfers to/from a particular SPI instance
+ *  \ingroup hardware_spi
+ *
+ * \param spi SPI instance specifier, either \ref spi0 or \ref spi1
+ * \param is_tx true for sending data to the SPI instance, false for receiving data from the SPI instance
+ */
+static inline uint spi_get_dreq(spi_inst_t *spi, bool is_tx) {
+    static_assert(DREQ_SPI0_RX == DREQ_SPI0_TX + 1, "");
+    static_assert(DREQ_SPI1_RX == DREQ_SPI1_TX + 1, "");
+    static_assert(DREQ_SPI1_TX == DREQ_SPI0_TX + 2, "");
+    return DREQ_SPI0_TX + spi_get_index(spi) * 2 + !is_tx;
+}
+
 #ifdef __cplusplus
 }
 #endif

src/rp2_common/hardware_uart/include/hardware/uart.h

@@ -9,6 +9,7 @@
 
 #include "pico.h"
 #include "hardware/structs/uart.h"
+#include "hardware/regs/dreq.h"
 
 // PICO_CONFIG: PARAM_ASSERTIONS_ENABLED_UART, Enable/disable assertions in the UART module, type=bool, default=0, group=hardware_uart
 #ifndef PARAM_ASSERTIONS_ENABLED_UART
@@ -432,6 +433,19 @@ static inline void uart_default_tx_wait_blocking(void) {
  */
 bool uart_is_readable_within_us(uart_inst_t *uart, uint32_t us);
 
+/*! \brief Return the DREQ to use for pacing transfers to/from a particular UART instance
+ *  \ingroup hardware_uart
+ *
+ * \param uart UART instance. \ref uart0 or \ref uart1
+ * \param is_tx true for sending data to the UART instance, false for receiving data from the UART instance
+ */
+static inline uint uart_get_dreq(uart_inst_t *uart, bool is_tx) {
+    static_assert(DREQ_UART0_RX == DREQ_UART0_TX + 1, "");
+    static_assert(DREQ_UART1_RX == DREQ_UART1_TX + 1, "");
+    static_assert(DREQ_UART1_TX == DREQ_UART0_TX + 2, "");
+    return DREQ_UART0_TX + uart_get_index(uart) * 2 + !is_tx;
+}
+
 #ifdef __cplusplus
 }
 #endif