Hello,
On Sun, 11 Jun 2006 15:30:34 +0200
Jean Delvare wrote:
> Fix the scx200_acb state machine:
>
> * Nack was sent one byte too late on reads >= 2 bytes.
> * Stop bit was set one byte too late on reads.
> * Stop bit was set one byte too late on writes.
>
> Credits go to Thomas Andrews for finding and fixing the first
> two items.
>
> Testers wanted! Not suitable for inclusion at this point.
with the patch below i get the correct results.
the patch for testing and some changes for the block reads.
and the ACK seems working - i have some status bits
which get cleared on correct read (i.e. the ACK is sent) and i have them cleared.
> This sounds like your device is expecting an I2C block read rather
> than an SMBus block read. Both transactions look alike, what matters
> is that both sides of the transaction agree on which transaction type
> should be used. I2C block reads are more simple, the data bytes are
> returned directly (no length byte.)
>
> As for ack problem, the patch above should hopefully fix it.
SMBus read it's fixed now on the board. As for the ACK problem i think it is ok.
> The SC1100 WRAP boards are known to use base addresses 0x810 and
> 0x820. If the scx200_acb driver is built into the kernel, add the
> following parameter to your boot command line:
> scx200_acb.base=0x810,0x820
> If the scx200_acb driver is built as a module, add the following line
> to the file /etc/modprobe.conf instead:
> options scx200_acb base=0x810,0x820
>
> There might be a way to have the driver auto-detect the correct
> address but I didn't have the time to look into it lately.
that works. there is a probe function if there is nothing dangerous
known at this address why it can not be auto probed. any pointers where
to check how to autodetect it ?
--
have fun,
alex
--- drivers/i2c/busses/scx200_acb.c.orig 2006-01-04 02:00:00.000000000 +0200
+++ drivers/i2c/busses/scx200_acb.c 2006-06-12 17:02:02.000000000 +0300
@@ -43,10 +43,11 @@
MODULE_LICENSE("GPL");
#define MAX_DEVICES 4
-static int base[MAX_DEVICES] = { 0x820, 0x840 };
+static int base[MAX_DEVICES] = { 0x810, 0x820, 0x840 };
module_param_array(base, int, NULL, 0);
MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
+#define DEBUG
#ifdef DEBUG
#define DBG(x...) printk(KERN_DEBUG NAME ": " x)
#else
@@ -116,6 +117,8 @@
#define ACBCTL2 (iface->base + 5)
#define ACBCTL2_ENABLE 0x01
+#define EXPECT_LEN 42
+
/************************************************************************/
static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
@@ -178,29 +181,50 @@
break;
case state_read:
- /* Set ACK if receiving the last byte */
- if (iface->len == 1)
+ if (iface->len == EXPECT_LEN) {
+ /*
+ * Len = 1 is valid in the spec
+ * and we must set ACK since the next
+ * byte will be the last one
+ * but how we know to send it
+ * if we first read length ?
+ */
+ outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
+
+ iface->len= inb(ACBSDA);
+ if (iface->len > 31) {
+ dev_dbg(&iface->adapter.dev, "Invalid read length %d in state %s\n",
+ iface->len, scx200_acb_state_name[iface->state]);
+ errmsg = "Invalid read length";
+ goto error;
+ }
+ /* the first byte in the buffer is expected to be the length */
+ *iface->ptr++ = iface->len;
+ DBG("Got BLOCK READ len=%d\n", iface->len);
+ break;
+ }
+ /* Set ACK if _next_ byte will be the last one */
+ if (iface->len == 2)
outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
else
outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
- *iface->ptr++ = inb(ACBSDA);
- --iface->len;
-
- if (iface->len == 0) {
+ if (iface->len == 1) {
iface->result = 0;
iface->state = state_idle;
outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
}
+ *iface->ptr++ = inb(ACBSDA);
+ --iface->len;
+
break;
case state_write:
- if (iface->len == 0) {
+ if (iface->len == 1) {
iface->result = 0;
iface->state = state_idle;
outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
- break;
}
outb(*iface->ptr++, ACBSDA);
@@ -317,8 +341,13 @@
buffer = (u8 *)&cur_word;
break;
case I2C_SMBUS_BLOCK_DATA:
- len = data->block[0];
- buffer = &data->block[1];
+ if (rw == I2C_SMBUS_READ) {
+ len = EXPECT_LEN;
+ buffer = &data->block[0];
+ } else {
+ len = data->block[0];;
+ buffer = &data->block[1];
+ }
break;
default:
return -EINVAL;
@@ -373,6 +402,9 @@
data->word = le16_to_cpu(cur_word);
#ifdef DEBUG
+ if (size == I2C_SMBUS_BLOCK_DATA && rw == I2C_SMBUS_READ) {
+ len = buffer[0] + 1;
+ }
DBG(": transfer done, result: %d", rc);
if (buffer) {
int i;
-
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