kinetis: Add support for LPUART module in parallel with UART module

A dispatcher function is implemented for directing writes to the correct
function. The dispatcher is bypassed completely if the CPU only contain
one kind of UART module.

There are at least two different UART hardware modules deployed in
different Kinetis CPU families (or possibly three or more when counting
variations of the UART module). The UART module is an older 8 bit module
with advanced functionality, while the LPUART is a 32 bit module with
focus on low power consumption.

 - The older families in the K series all have UART modules.
 - The K22F family have both UART and LPUART modules in the same CPU.
 - Older L series (e.g. KL25Z) have two variations of the UART module
 - Newer L series (e.g. KL43Z) have LPUART modules, and sometimes
   UART as well.
 - Newer W series (KW41Z) have only LPUART

boards/frdm-k22f/include/periph_conf.h

@@ -93,6 +93,7 @@ static const uart_conf_t uart_config[] = {
         .scgc_addr = &SIM_SCGC4,
         .scgc_bit = SIM_SCGC4_UART1_SHIFT,
         .mode   = UART_MODE_8N1,
+        .type   = KINETIS_UART,
     },
 };
 

boards/frdm-k64f/include/periph_conf.h

@@ -89,7 +89,8 @@ static const uart_conf_t uart_config[] = {
         .irqn   = UART0_RX_TX_IRQn,
         .scgc_addr = &SIM->SCGC4,
         .scgc_bit = SIM_SCGC4_UART0_SHIFT,
-        .mode   = UART_MODE_8N1
+        .mode   = UART_MODE_8N1,
+        .type   = KINETIS_UART,
     },
 };
 

boards/mulle/include/periph_conf.h

@@ -105,7 +105,8 @@ static const uart_conf_t uart_config[] = {
         .irqn   = UART0_RX_TX_IRQn,
         .scgc_addr = &SIM->SCGC4,
         .scgc_bit = SIM_SCGC4_UART0_SHIFT,
-        .mode   = UART_MODE_8N1
+        .mode   = UART_MODE_8N1,
+        .type   = KINETIS_UART,
     },
     {
         .dev    = UART1,
@@ -117,7 +118,8 @@ static const uart_conf_t uart_config[] = {
         .irqn   = UART1_RX_TX_IRQn,
         .scgc_addr = &SIM->SCGC4,
         .scgc_bit = SIM_SCGC4_UART1_SHIFT,
-        .mode   = UART_MODE_8N1
+        .mode   = UART_MODE_8N1,
+        .type   = KINETIS_UART,
     },
 };
 

boards/pba-d-01-kw2x/include/periph_conf.h

@@ -91,7 +91,8 @@ static const uart_conf_t uart_config[] = {
         .irqn   = UART2_RX_TX_IRQn,
         .scgc_addr = &SIM->SCGC4,
         .scgc_bit = SIM_SCGC4_UART2_SHIFT,
-        .mode   = UART_MODE_8N1
+        .mode   = UART_MODE_8N1,
+        .type   = KINETIS_UART,
     },
     {
         .dev    = UART0,
@@ -103,7 +104,8 @@ static const uart_conf_t uart_config[] = {
         .irqn   = UART0_RX_TX_IRQn,
         .scgc_addr = &SIM->SCGC4,
         .scgc_bit = SIM_SCGC4_UART0_SHIFT,
-        .mode   = UART_MODE_8N1
+        .mode   = UART_MODE_8N1,
+        .type   = KINETIS_UART,
     }
 };
 

cpu/kinetis_common/include/periph_cpu.h

@@ -307,11 +307,19 @@ enum {
 #define TIMER_LPTMR_DEV(x) (TIMER_DEV(PIT_NUMOF + (x)))
 /** @} */
 
+/**
+ * @brief UART hardware module types
+ */
+enum {
+    KINETIS_UART,   /**< Kinetis UART module type */
+    KINETIS_LPUART, /**< Kinetis Low-power UART (LPUART) module type */
+};
+
 /**
  * @brief UART module configuration options
  */
 typedef struct {
-    UART_Type *dev;               /**< Pointer to module hardware registers */
+    void *dev;                    /**< Pointer to module hardware registers */
     uint32_t freq;                /**< Module clock frequency, usually CLOCK_CORECLOCK or CLOCK_BUSCLOCK */
     gpio_t pin_rx;                /**< RX pin, GPIO_UNDEF disables RX */
     gpio_t pin_tx;                /**< TX pin */
@@ -321,6 +329,7 @@ typedef struct {
     volatile uint32_t *scgc_addr; /**< Clock enable register, in SIM module */
     uint8_t scgc_bit;             /**< Clock enable bit, within the register */
     uint8_t mode;                 /**< UART mode: data bits, parity, stop bits */
+    uint8_t type;                 /**< Hardware module type (KINETIS_UART or KINETIS_LPUART)*/
 } uart_conf_t;
 
 /**