Clean up pin configuration for peripheral code. Here's the best practice

[tinyos-2.x.git] / tos / chips / msp430 / usci / Msp430SpiP.nc

diff --git a/tos/chips/msp430/usci/Msp430SpiP.nc b/tos/chips/msp430/usci/Msp430SpiP.nc
index 5a23279c4689d8a1e76a625d40f9216c4e03b3dd..e35d54fa9ccd7d8847aac6b7accb9c705ad52984 100644 (file)
--- a/tos/chips/msp430/usci/Msp430SpiP.nc
+++ b/tos/chips/msp430/usci/Msp430SpiP.nc
@@ -54,38 +54,16 @@ generic module Msp430SpiP(uint16_t blockSize) {
 }
 implementation {
   enum {
-    BLOCKSIZE_DEFAULT = 64
-  };
-
-  #define saveBits(pin, pos, dir, out, ren) { \
-               if (call pin.isOutput()) \
-                       dir |= (1 << pos); \
-               if (call pin.getOut()) \
-                       out |= (1 << pos); \
-               if (call pin.isRen()) \
-                       ren |= (1 << pos); \
-       }
+    BLOCKSIZE_DEFAULT = 64,
 
-  #define restoreBits(pin, pos, dir, out, ren) { \
-               if (ren & (1 << pos)) \
-                       call pin.enableRen(); \
-               else \
-                       call pin.disableRen(); \
-               if (out & (1 << pos)) \
-                       call pin.set(); \
-               else \
-                       call pin.clr(); \
-               if (dir & (1 << pos)) \
-                       call pin.makeOutput(); \
-               else \
-                       call pin.makeInput(); \
-       }
-
-  /* Pin IO configuration storage for later restoration */
-  uint8_t m_dir;
-  uint8_t m_out;
-  uint8_t m_ren;
+    /* Bit positions in m_pins */
+    PINS_STE = 1,
+    PINS_SOMI,
+    PINS_SIMO,
+    PINS_CLK,
+  };
 
+  uint8_t m_pins;
   uint8_t* m_txBuf;
   uint8_t* m_rxBuf;
   uint16_t m_len;
@@ -127,59 +105,24 @@ implementation {
       else
        call Registers.clrStat(UCLISTEN);
 
-      /* Save pin IO configuration */
-      m_dir = m_out = m_ren = 0;
-      if (is4pin())
-       saveBits(STE, 0, m_dir, m_out, m_ren);
-      saveBits(SIMO, 1, m_dir, m_out, m_ren);
-      saveBits(SOMI, 2, m_dir, m_out, m_ren);
-      saveBits(CLK, 3, m_dir, m_out, m_ren);
-
-      /* Configure pins for SPI use */
-      if (is4pin()) {
-#if 0 /* Unsure if REN on STE is a valid configuration */
-       /* Configure STE pin for SPI use */
-       if (config->ren & USCI_REN_STE) {
-         if (config->ren & USCI_REN_STE_PULLUP)
-           call STE.set();
-         else
-           call STE.clr();
-         call STE.enableRen();
-       }
-#endif
+      /* Configure pins for SPI, saving prior pin states */
+      m_pins = 0;
+      if (is4pin() && call STE.isIOFunc()) {
+       m_pins |= (1 << PINS_STE);
        call STE.selectModuleFunc();
       }
-      call SOMI.makeInput();
-      if (config->ren & USCI_REN_SOMI) {
-       if (config->ren & USCI_REN_SOMI_PULLUP)
-         call SOMI.set();
-       else
-         call SOMI.clr();
-       call SOMI.enableRen();
+      if (call SOMI.isIOFunc()) {
+       m_pins |= (1 << PINS_SOMI);
+       call SOMI.selectModuleFunc();
       }
-      call SOMI.selectModuleFunc();
-#if 0 /* Unsure if REN on SIMO is a valid configuration */
-      /* Configure SIMO pin for SPI use */
-      if (config->ren & USCI_REN_SIMO) {
-       if (config->ren & USCI_REN_SIMO_PULLUP)
-         call SIMO.set();
-       else
-         call SIMO.clr();
-       call SIMO.enableRen();
+      if (call SIMO.isIOFunc()) {
+       m_pins |= (1 << PINS_SIMO);
+       call SIMO.selectModuleFunc();
       }
-#endif
-      call SIMO.selectModuleFunc();
-#if 0 /* Unsure if REN on CLK is a valid configuration */
-      /* Configure CLK pin for SPI use */
-      if (config->ren & USCI_REN_CLK) {
-       if (config->ren & USCI_REN_CLK_PULLUP)
-         call CLK.set();
-       else
-         call CLK.clr();
-       call CLK.enableRen();
+      if (call CLK.isIOFunc()) {
+       m_pins |= (1 << PINS_CLK);
+       call CLK.selectModuleFunc();
       }
-#endif
-      call CLK.selectModuleFunc();
 
       /* Clear interrupts; we'll add them as needed */
       call Registers.clrIeRx();
@@ -200,19 +143,15 @@ implementation {
       call Registers.clrIeRx();
       call Registers.clrIfgRx();
 
-      /* Restore pins to their preconfigured state */
-#if 0
-      if (is4pin())
-       restoreBits(STE, 0, m_dir, m_out, m_ren);
-      restoreBits(SIMO, 1, m_dir, m_out, m_ren);
-      restoreBits(SOMI, 1, m_dir, m_out, m_ren);
-      restoreBits(CLK, 1, m_dir, m_out, m_ren);
-#endif
-      if (is4pin())
+      /* Restore pins to their pre-configure state */
+      if (is4pin() && (m_pins & PINS_STE))
        call STE.selectIOFunc();
-      call SIMO.selectIOFunc();
-      call SOMI.selectIOFunc();
-      call CLK.selectIOFunc();
+      if (m_pins & PINS_SIMO)
+       call SIMO.selectIOFunc();
+      if (m_pins & PINS_SOMI)
+       call SOMI.selectIOFunc();
+      if (m_pins & PINS_CLK)
+       call CLK.selectIOFunc();
     }
   }