From 4e8b171fc4cc3b62a1656ae67e92944ff855dcd3 Mon Sep 17 00:00:00 2001
From: Jens Arnold <amiconn@rockbox.org>
Date: Mon, 30 Jul 2007 23:48:03 +0000
Subject: Interrupt driven ADC reading on the 2nd gen.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@14086 a1c6a512-1295-4272-9138-f99709370657
---
 firmware/target/arm/ipod/1g2g/adc-ipod-1g2g.c | 55 ++++++++++++++++++---------
 firmware/target/arm/system-pp5002.c           | 14 ++++++-
 2 files changed, 50 insertions(+), 19 deletions(-)

diff --git a/firmware/target/arm/ipod/1g2g/adc-ipod-1g2g.c b/firmware/target/arm/ipod/1g2g/adc-ipod-1g2g.c
index 759b6fb592..8866c3dcde 100644
--- a/firmware/target/arm/ipod/1g2g/adc-ipod-1g2g.c
+++ b/firmware/target/arm/ipod/1g2g/adc-ipod-1g2g.c
@@ -24,18 +24,22 @@
 
 static struct mutex adc_mutex NOCACHEBSS_ATTR;
 
+/* used in the 2nd gen ADC interrupt */
+static unsigned int_data;
+static int int_status = -1;
+
 unsigned short adc_scan(int channel)
 {
-    int i, j;
     unsigned short data = 0;
-    unsigned pval;
 
     (void)channel; /* there is only one */
     spinlock_lock(&adc_mutex);
 
     if ((IPOD_HW_REVISION >> 16) == 1)
     {
-        pval = GPIOB_OUTPUT_VAL;
+        int i, j;
+        unsigned pval = GPIOB_OUTPUT_VAL;
+
         GPIOB_OUTPUT_VAL = pval | 0x04;  /* B2 -> high */
         for (i = 32; i > 0; --i);
 
@@ -55,26 +59,43 @@ unsigned short adc_scan(int channel)
     }
     else if ((IPOD_HW_REVISION >> 16) == 2)
     {
-        pval = GPIOB_OUTPUT_VAL;
-        GPIOB_OUTPUT_VAL = pval | 0x0a;  /* B1, B3 -> high */
-        while (!(GPIOB_INPUT_VAL & 0x04)); /* wait for B2 == 1 */
+        int_status = 0;
+        GPIOB_INT_LEV    |= 0x04; /* high active */
+        GPIOB_INT_EN     |= 0x04; /* enable interrupt */
+        GPIOB_OUTPUT_VAL |= 0x0a; /* B1, B3 -> high: start conversion */
 
-        GPIOB_OUTPUT_VAL = pval;         /* B1, B3 -> low */
-        while (GPIOB_INPUT_VAL & 0x04);  /* wait for B2 == 0 */
+        while (int_status >= 0)
+            yield();
 
-        for (j = 0; j < 8; j++)
-        {
-            GPIOB_OUTPUT_VAL = pval | 0x02; /* B1 -> high */
-            while (!(GPIOB_INPUT_VAL & 0x04)); /* wait for B2 == 1 */
+        data = int_data & 0xff;
+    }
+    spinlock_unlock(&adc_mutex);
+    return data;
+}
 
-            data = (data << 1) | ((GPIOB_INPUT_VAL & 0x10) >> 4);
+/* Used for 2nd gen only. Conversion can take several milliseconds there. */
+void ipod_2g_adc_int(void)
+{
+    if (GPIOB_INPUT_VAL & 0x04)
+    {
+        int_data = (int_data << 1) | ((GPIOB_INPUT_VAL & 0x10) >> 4);
 
-            GPIOB_OUTPUT_VAL = pval;     /* B1 -> low */
-            while (GPIOB_INPUT_VAL & 0x04); /* wait for B2 == 0 */
+        GPIOB_OUTPUT_VAL &= ~0x0a; /* B1, B3 -> low */
+        /* B3 needs to be set low in the first call only, but then stays low
+         * anyway so no need for special handling */
+    }
+    else
+    {
+        if (++int_status > 8)
+        {
+            GPIOB_INT_EN &= ~0x04;
+            int_status = -1;
         }
+        else
+            GPIOB_OUTPUT_VAL |= 0x02;  /* B1 -> high */
     }
-    spinlock_unlock(&adc_mutex);
-    return data;
+    GPIOB_INT_LEV ^= 0x04; /* toggle interrupt level */
+    GPIOB_INT_CLR  = 0x04; /* acknowledge interrupt */
 }
 
 void adc_init(void)
diff --git a/firmware/target/arm/system-pp5002.c b/firmware/target/arm/system-pp5002.c
index 6d32d258cc..38dfe5b49c 100644
--- a/firmware/target/arm/system-pp5002.c
+++ b/firmware/target/arm/system-pp5002.c
@@ -22,6 +22,7 @@
 extern void TIMER1(void);
 extern void TIMER2(void);
 extern void ipod_3g_button_int(void);
+extern void ipod_2g_adc_int(void);
 
 void irq(void)
 {
@@ -32,8 +33,17 @@ void irq(void)
         else if (CPU_INT_STAT & TIMER2_MASK)
             TIMER2();
         else if (CPU_INT_STAT & GPIO_MASK)
-            ipod_3g_button_int();
-    } else {
+        {
+            if (GPIOA_INT_STAT)
+                ipod_3g_button_int();
+#ifdef IPOD_1G2G
+            if (GPIOB_INT_STAT & 0x04)
+                ipod_2g_adc_int();
+#endif
+        }
+    } 
+    else
+    {
         if (COP_INT_STAT & TIMER1_MASK)
             TIMER1();
         else if (COP_INT_STAT & TIMER2_MASK)
-- 
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