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-rw-r--r--firmware/target/arm/s5l8702/i2c-s5l8702.c244
1 files changed, 120 insertions, 124 deletions
diff --git a/firmware/target/arm/s5l8702/i2c-s5l8702.c b/firmware/target/arm/s5l8702/i2c-s5l8702.c
index a795c9f18c..4f3b012410 100644
--- a/firmware/target/arm/s5l8702/i2c-s5l8702.c
+++ b/firmware/target/arm/s5l8702/i2c-s5l8702.c
@@ -25,165 +25,167 @@
#include "i2c-s5l8702.h"
#include "clocking-s5l8702.h"
-/* Driver for the s5l8700 built-in I2C controller in master mode
+/* Driver for the s5l8702 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.
+ 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".
+ * blocks the calling thread for the entire duraton of the i2c transfer.
*/
static struct mutex i2c_mtx[2];
+void i2c_init()
+{
+ mutex_init(&i2c_mtx[0]);
+ mutex_init(&i2c_mtx[1]);
+}
+
+static void wait_rdy(int bus)
+{
+ while (IICUNK10(bus));
+}
+
static void i2c_on(int bus)
{
/* enable I2C clock */
clockgate_enable(I2CCLKGATE(bus), true);
-
- IICCON(bus) = (0 << 8) | /* INT_EN = disabled */
- (1 << 7) | /* ACK_GEN */
- (0 << 6) | /* CLKSEL = PCLK/16 */
- (7 << 0); /* CK_REG */
-
- /* serial output on */
- IICSTAT(bus) = (1 << 4);
}
static void i2c_off(int bus)
{
/* serial output off */
+ wait_rdy(bus);
IICSTAT(bus) = 0;
-
/* disable I2C clock */
+ wait_rdy(bus);
clockgate_enable(I2CCLKGATE(bus), false);
}
-void i2c_init()
+/* wait for bus not busy, or tx/rx byte (should return once
+ 8 data + 1 ack clocks are generated), or STOP. */
+static void i2c_wait_io(int bus)
{
- mutex_init(&i2c_mtx[0]);
- mutex_init(&i2c_mtx[1]);
+ while (((IICSTAT(bus) & (1 << 5)) != 0) &&
+ ((IICSTA2(bus) & ((1 << 8)|(1 << 13))) == 0)) {
+ wait_rdy(bus);
+ }
+ IICSTA2(bus) |= (1 << 8)|(1 << 13);
}
-int i2c_wr(int bus, unsigned char slave, int address, int len, const unsigned char *data)
+static int i2c_start(int bus, unsigned char slave, bool rd)
{
- i2c_on(bus);
- long timeout = USEC_TIMER + 20000;
+ /* configure port */
+ wait_rdy(bus);
+ IICCON(bus) = (0 << 8) | /* INT_EN = disabled */
+ (1 << 7) | /* ACK_GEN */
+ (0 << 6) | /* CLKSEL = PCLK/32 (TBC) */
+ (4 << 0); /* CK_REG */
/* START */
- IICDS(bus) = slave & ~1;
- IICSTAT(bus) = 0xF0;
- while ((IICCON(bus) & 0x10) == 0)
- if (TIME_AFTER(USEC_TIMER, timeout))
- return 1;
-
- if (address >= 0) {
- /* write address */
- IICDS(bus) = address;
- IICCON(bus) = IICCON(bus);
- while ((IICCON(bus) & 0x10) == 0)
- if (TIME_AFTER(USEC_TIMER, timeout))
- return 2;
- }
+ wait_rdy(bus);
+ IICDS(bus) = slave | rd;
+ wait_rdy(bus);
+ IICSTAT(bus) = rd ? 0xB0 : 0xF0;
- /* write data */
- while (len--) {
- IICDS(bus) = *data++;
- IICCON(bus) = IICCON(bus);
- while ((IICCON(bus) & 0x10) == 0)
- if (TIME_AFTER(USEC_TIMER, timeout))
- return 4;
- }
+ i2c_wait_io(bus);
- /* STOP */
- IICSTAT(bus) = 0xD0;
- IICCON(bus) = IICCON(bus);
- while ((IICSTAT(bus) & (1 << 5)) != 0)
- if (TIME_AFTER(USEC_TIMER, timeout))
- return 5;
+ /* check ACK */
+ if (IICSTAT(bus) & 1)
+ return 1;
- i2c_off(bus);
return 0;
}
-int i2c_rd(int bus, unsigned char slave, int address, int len, unsigned char *data)
+static void i2c_stop(int bus)
{
- i2c_on(bus);
- long timeout = USEC_TIMER + 20000;
-
- if (address >= 0) {
- /* START */
- IICDS(bus) = slave & ~1;
- IICSTAT(bus) = 0xF0;
- while ((IICCON(bus) & 0x10) == 0)
- if (TIME_AFTER(USEC_TIMER, timeout))
- return 1;
-
- /* write address */
- IICDS(bus) = address;
- IICCON(bus) = IICCON(bus);
- while ((IICCON(bus) & 0x10) == 0)
- if (TIME_AFTER(USEC_TIMER, timeout))
- return 2;
+ /* STOP */
+ wait_rdy(bus);
+ IICSTAT(bus) &= ~0x20;
+ wait_rdy(bus);
+ IICCON(bus) = 0x10;
+ i2c_wait_io(bus);
+}
+
+static int i2c_wr_internal(int bus, unsigned char slave,
+ int address, int len, const unsigned char *data)
+{
+ int rc = 0;
+
+ if (i2c_start(bus, slave, false) == 0)
+ {
+ /* write address + data */
+ const unsigned char *ptr = data;
+ const unsigned char addr = address;
+ if (address >= 0) {
+ ptr = &addr;
+ len++;
+ }
+ while (len--) {
+ wait_rdy(bus);
+ IICDS(bus) = *ptr;
+ udelay(5);
+ wait_rdy(bus);
+ IICCON(bus) = IICCON(bus);
+ i2c_wait_io(bus);
+ /* check ACK */
+ if (IICSTAT(bus) & 1) {
+ rc = 2;
+ break;
+ }
+ if (ptr == &addr) ptr = data;
+ else ptr++;
+ }
}
+ else
+ rc = 1;
- /* (repeated) START */
- IICDS(bus) = slave | 1;
- IICSTAT(bus) = 0xB0;
- IICCON(bus) = IICCON(bus);
- while ((IICCON(bus) & 0x10) == 0)
- if (TIME_AFTER(USEC_TIMER, timeout))
- return 3;
-
- while (len--) {
- IICCON(bus) &= ~(len ? 0 : 0x80); /* ACK or NAK */
- while ((IICCON(bus) & 0x10) == 0)
- if (TIME_AFTER(USEC_TIMER, timeout))
- return 4;
- *data++ = IICDS(bus);
+ i2c_stop(bus);
+ return rc;
+}
+
+static int i2c_rd_internal(int bus, unsigned char slave, int len, unsigned char *data)
+{
+ int rc = 0;
+
+ if (i2c_start(bus, slave, true) == 0)
+ {
+ while (len--) {
+ wait_rdy(bus);
+ IICCON(bus) &= ~(len ? 0 : 0x80); /* ACK or NAK */
+ i2c_wait_io(bus);
+ *data++ = IICDS(bus);
+ }
}
+ else
+ rc = 3;
- /* STOP */
- IICSTAT(bus) = 0x90;
- IICCON(bus) = IICCON(bus);
- while ((IICSTAT(bus) & (1 << 5)) != 0)
- if (TIME_AFTER(USEC_TIMER, timeout))
- return 5;
+ i2c_stop(bus);
+ return rc;
+}
+int i2c_wr(int bus, unsigned char slave, int address, int len, const unsigned char *data)
+{
+ i2c_on(bus);
+ int rc = i2c_wr_internal(bus, slave, address, len, data);
i2c_off(bus);
- return 0;
+ return rc;
}
-unsigned long i2c_rd_err, i2c_wr_err;
+int i2c_rd(int bus, unsigned char slave, int address, int len, unsigned char *data)
+{
+ i2c_on(bus);
+ int rc = i2c_wr_internal(bus, slave, address, 0, NULL);
+ if (rc == 0)
+ rc = i2c_rd_internal(bus, slave, len, data);
+ i2c_off(bus);
+ return rc;
+}
int i2c_write(int bus, unsigned char slave, int address, int len, const unsigned char *data)
{
@@ -191,7 +193,6 @@ int i2c_write(int bus, unsigned char slave, int address, int len, const unsigned
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;
}
@@ -201,18 +202,14 @@ 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;
}
-static void wait_rdy(int bus)
-{
- while (IICUNK10(bus));
-}
-
void i2c_preinit(int bus)
{
- clockgate_enable(I2CCLKGATE(bus), true);
+ if (bus == 0) PCON3 = (PCON3 & ~0x00000ff0) | 0x00000220;
+ /* TBC: else if(bus == 1) PCON6 = (PCON6 & ~0x0ff00000) | 0x02200000; */
+ i2c_on(bus);
wait_rdy(bus);
IICADD(bus) = 0x40; /* own slave address */
wait_rdy(bus);
@@ -220,11 +217,10 @@ void i2c_preinit(int bus)
wait_rdy(bus);
IICUNK18(bus) = 0;
wait_rdy(bus);
- IICSTAT(bus) = 0x80; /* master Rx mode, Tx/Rx off */
+ IICSTAT(bus) = 0x80; /* master Rx mode, serial output off */
wait_rdy(bus);
IICCON(bus) = 0;
wait_rdy(bus);
- IICSTAT(bus) = 0; /* slave Rx mode, Tx/Rx off */
- wait_rdy(bus);
- clockgate_enable(I2CCLKGATE(bus), false);
+ IICSTA2(bus) = 0x3f00;
+ i2c_off(bus);
}