iPod Classic: i2c updates

Change-Id: Ib516f3f52cf619fb44dc1bb6982b635c49f53a8f

firmware/export/s5l8702.h

@@ -750,18 +750,20 @@
 /////INTERRUPTS/////
 #define IRQ_TIMER32     7
 #define IRQ_TIMER       8
-#define IRQ_SPI(i)      (9+i) /* TBC */
+#define IRQ_SPI(i)      (9+(i)) /* TBC */
 #define IRQ_SPI0        9
 #define IRQ_SPI1        10
 #define IRQ_SPI2        11
 #define IRQ_LCD         14
-#define IRQ_DMAC(d)     (16+d)
+#define IRQ_DMAC(d)     (16+(d))
 #define IRQ_DMAC0       16
 #define IRQ_DMAC1       17
 #define IRQ_USB_FUNC    19
-#define IRQ_I2C         21    /* TBC */
+#define IRQ_I2C(i)      (21+(i))
+#define IRQ_I2C0        21
+#define IRQ_I2C1        22
 #define IRQ_WHEEL       23
-#define IRQ_UART(i)     (24+i)
+#define IRQ_UART(i)     (24+(i))
 #define IRQ_UART0       24
 #define IRQ_UART1       25
 #define IRQ_UART2       26

firmware/target/arm/s5l8702/debug-s5l8702.c

@@ -133,6 +133,9 @@ bool dbg_hw_info(void)
             _DEBUG_PRINTF("accessory present: %s",
                             pmu_accessory_present() ? "true" : "false");
 #endif
+            extern unsigned long i2c_rd_err, i2c_wr_err;
+            line++;
+            _DEBUG_PRINTF("i2c rd/wr errors:: %lu/%lu", i2c_rd_err, i2c_wr_err);
         }
 #ifdef UC870X_DEBUG
         else if(state==2)

firmware/target/arm/s5l8702/i2c-s5l8702.c

@@ -26,18 +26,41 @@
 #include "clocking-s5l8702.h"
 
 /*  Driver for the s5l8700 built-in I2C controller in master mode
-    
+
     Both the i2c_read and i2c_write function take the following arguments:
     * slave, the address of the i2c slave device to read from / write to
     * address, optional sub-address in the i2c slave (unused if -1)
     * len, number of bytes to be transfered
     * data, pointer to data to be transfered
     A return value < 0 indicates an error.
-    
+
     Note:
     * blocks the calling thread for the entire duraton of the i2c transfer but
       uses wakeup_wait/wakeup_signal to allow other threads to run.
     * ACK from slave is not checked, so functions never return an error
+
+    Fixme:
+    * actually there is no STOP + i2c_off() on error
+    * very rare random errors when reading and/or(?) writing registers on some
+      builds/devices, hard to trace, not a 'delay' issue, it seems related
+      with alignment of STRs and/or(?) LDRs, code cache lines, pipelines...
+      The new code tries to mix STRs and LDRs at some points but ATM it is
+      unknown if it might solve or mitigate the problem. Probably it could be
+      really fixed using wait_rdy() before accessing any register, as OF does.
+*/
+
+/*  s5l8702 I2C controller is similar to s5l8700, known differences are:
+
+    * IICCON[5] is not used in s5l8702.
+    * IICCON[13:8] are used to enable interrupts.
+      IICUNK20[13:8] are used to read the status and write-clear interrupts.
+      Known interrupts:
+       [13] STOP on bus (TBC)
+       [12] START on bus (TBC)
+       [8] byte transmited or received in Master mode (not tested in Slave)
+    * IICCON[4] does not clear interrupts, it is enabled when a byte is
+      transmited or received, in Master mode the tx/rx of the next byte
+      starts when it is written as "1".
 */
 
 static struct mutex i2c_mtx[2];
@@ -45,12 +68,11 @@ static struct mutex i2c_mtx[2];
 static void i2c_on(int bus)
 {
     /* enable I2C clock */
-    PWRCON(1) &= ~(1 << 4);
+    clockgate_enable(I2CCLKGATE(bus), true);
 
-    IICCON(bus) = (1 << 7) | /* ACK_GEN */
+    IICCON(bus) = (0 << 8) | /* INT_EN = disabled */
+                  (1 << 7) | /* ACK_GEN */
                   (0 << 6) | /* CLKSEL = PCLK/16 */
-                  (1 << 5) | /* INT_EN */
-                  (1 << 4) | /* IRQ clear */
                   (7 << 0);  /* CK_REG */
 
     /* serial output on */
@@ -63,7 +85,7 @@ static void i2c_off(int bus)
     IICSTAT(bus) = 0;
 
     /* disable I2C clock */
-    PWRCON(1) |= (1 << 4);
+    clockgate_enable(I2CCLKGATE(bus), false);
 }
 
 void i2c_init()
@@ -80,7 +102,6 @@ int i2c_wr(int bus, unsigned char slave, int address, int len, const unsigned ch
     /* START */
     IICDS(bus) = slave & ~1;
     IICSTAT(bus) = 0xF0;
-    IICCON(bus) = 0xB3;
     while ((IICCON(bus) & 0x10) == 0)
         if (TIME_AFTER(USEC_TIMER, timeout))
             return 1;
@@ -88,7 +109,7 @@ int i2c_wr(int bus, unsigned char slave, int address, int len, const unsigned ch
     if (address >= 0) {
         /* write address */
         IICDS(bus) = address;
-        IICCON(bus) = 0xB3;
+        IICCON(bus) = IICCON(bus);
         while ((IICCON(bus) & 0x10) == 0)
             if (TIME_AFTER(USEC_TIMER, timeout))
                 return 2;
@@ -97,7 +118,7 @@ int i2c_wr(int bus, unsigned char slave, int address, int len, const unsigned ch
     /* write data */
     while (len--) {
         IICDS(bus) = *data++;
-        IICCON(bus) = 0xB3;
+        IICCON(bus) = IICCON(bus);
         while ((IICCON(bus) & 0x10) == 0)
             if (TIME_AFTER(USEC_TIMER, timeout))
                 return 4;
@@ -105,7 +126,7 @@ int i2c_wr(int bus, unsigned char slave, int address, int len, const unsigned ch
 
     /* STOP */
     IICSTAT(bus) = 0xD0;
-    IICCON(bus) = 0xB3;
+    IICCON(bus) = IICCON(bus);
     while ((IICSTAT(bus) & (1 << 5)) != 0)
         if (TIME_AFTER(USEC_TIMER, timeout))
             return 5;
@@ -123,14 +144,13 @@ int i2c_rd(int bus, unsigned char slave, int address, int len, unsigned char *da
         /* START */
         IICDS(bus) = slave & ~1;
         IICSTAT(bus) = 0xF0;
-        IICCON(bus) = 0xB3;
         while ((IICCON(bus) & 0x10) == 0)
             if (TIME_AFTER(USEC_TIMER, timeout))
                 return 1;
 
         /* write address */
         IICDS(bus) = address;
-        IICCON(bus) = 0xB3;
+        IICCON(bus) = IICCON(bus);
         while ((IICCON(bus) & 0x10) == 0)
             if (TIME_AFTER(USEC_TIMER, timeout))
                 return 2;
@@ -139,13 +159,13 @@ int i2c_rd(int bus, unsigned char slave, int address, int len, unsigned char *da
     /* (repeated) START */
     IICDS(bus) = slave | 1;
     IICSTAT(bus) = 0xB0;
-    IICCON(bus) = 0xB3;
+    IICCON(bus) = IICCON(bus);
     while ((IICCON(bus) & 0x10) == 0)
         if (TIME_AFTER(USEC_TIMER, timeout))
             return 3;
 
     while (len--) {
-        IICCON(bus) = (len == 0) ? 0x33 : 0xB3; /* NAK or ACK */
+        IICCON(bus) &= ~(len ? 0 : 0x80); /* ACK or NAK */
         while ((IICCON(bus) & 0x10) == 0)
             if (TIME_AFTER(USEC_TIMER, timeout))
                 return 4;
@@ -154,7 +174,7 @@ int i2c_rd(int bus, unsigned char slave, int address, int len, unsigned char *da
 
     /* STOP */
     IICSTAT(bus) = 0x90;
-    IICCON(bus) = 0xB3;
+    IICCON(bus) = IICCON(bus);
     while ((IICSTAT(bus) & (1 << 5)) != 0)
         if (TIME_AFTER(USEC_TIMER, timeout))
             return 5;
@@ -163,12 +183,15 @@ int i2c_rd(int bus, unsigned char slave, int address, int len, unsigned char *da
     return 0;
 }
 
+unsigned long i2c_rd_err, i2c_wr_err;
+
 int i2c_write(int bus, unsigned char slave, int address, int len, const unsigned char *data)
 {
     int ret;
     mutex_lock(&i2c_mtx[bus]);
     ret = i2c_wr(bus, slave, address, len, data);
     mutex_unlock(&i2c_mtx[bus]);
+    if (ret) i2c_wr_err++;
     return ret;
 }
 
@@ -178,6 +201,7 @@ int i2c_read(int bus, unsigned char slave, int address, int len, unsigned char *
     mutex_lock(&i2c_mtx[bus]);
     ret = i2c_rd(bus, slave, address, len, data);
     mutex_unlock(&i2c_mtx[bus]);
+    if (ret) i2c_rd_err++;
     return ret;
 }